2024-03-29T00:08:42Z
http://ir.lib.uwo.ca/do/oai/
oai:ir.lib.uwo.ca:biologypub-1001
2009-05-06T22:31:49Z
publication:biologypub
publication:biology
publication:faculties
Recombination Analysis of Soybean Mosaic Virus Sequences Reveals Evidence of RNA Recombination between Distinct Pathotypes
Gagarinova, Alla G.
Babu, Mohan
Strömvik, Martina V.
Wang, Aiming
RNA recombination is one of the two major factors that create RNA genome variability. Assessing its incidence in plant RNA viruses helps understand the formation of new isolates and evaluate the effectiveness of crop protection strategies. To search for recombination in Soybean mosaic virus (SMV), the causal agent of a worldwide seed-borne, aphid-transmitted viral soybean disease, we obtained all full-length genome sequences of SMV as well as partial sequences encoding the Nterminal most (P1 protease) and the C-terminal most (capsid protein; CP) viral protein. The sequences were analyzed for possible recombination events using a variety of automatic and manual recombination detection and verification approaches. Automatic scanning identified 3, 10, and 17 recombination sites in the P1, CP, and full-length sequences, respectively. Manual analyses confirmed 10 recombination sites in three full-length SMV sequences. To our knowledge, this is the first report of recombination between distinct SMV pathotypes. These data imply that different SMV pathotypes can simultaneously infect a host cell and exchange genetic materials through recombination. The high incidence of SMV recombination suggests that recombination plays an important role in SMV evolution. Obtaining additional full-length sequences will help elucidate this role.
2008-11-26T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/2
http://www.virologyj.com/content/5/1/143
Biology Publications
Scholarship@Western
Soybean mosaic virus
RNA recombination
Plant Sciences
Virus Diseases
oai:ir.lib.uwo.ca:biologypub-1002
2009-05-06T23:08:48Z
publication:biologypub
publication:biology
publication:faculties
Altered Gene Expression Changes in Arabidopsis Leaf Tissues and Protoplasts in Response to Plum Pox Virus Infection
Babu, Mohan
Griffiths, Jonathan S.
Huang, Tyng-Shyan
Wang, Aiming
Background: Virus infection induces the activation and suppression of global gene expression in the host. Profiling gene expression changes in the host may provide insights into the molecular mechanisms that underlie host physiological and phenotypic responses to virus infection. In this study, the Arabidopsis Affymetrix ATH1 array was used to assess global gene expression changes in Arabidopsis thaliana plants infected with Plum pox virus (PPV). To identify early genes in response to PPV infection, an Arabidopsis synchronized single-cell transformation system was developed. Arabidopsis protoplasts were transfected with a PPV infectious clone and global gene expression changes in the transfected protoplasts were profiled.
Results: Microarray analysis of PPV-infected Arabidopsis leaf tissues identified 2013 and 1457 genes that were significantly (Q ≤ 0.05) up- (≥ 2.5 fold) and downregulated (≤ -2.5 fold), respectively. Genes associated with soluble sugar, starch and amino acid, intracellular membrane/membrane-bound organelles, chloroplast, and protein fate were upregulated, while genes related to development/storage proteins, protein synthesis and translation, and cell wall-associated components were downregulated. These gene expression changes were associated with PPV infection and symptom development. Further transcriptional profiling of protoplasts transfected with a PPV infectious clone revealed the upregulation of defence and cellular signalling genes as early as 6 hours post transfection. A cross sequence comparison analysis of genes differentially regulated by PPV-infected Arabidopsis leaves against uniEST sequences derived from PPV-infected leaves of Prunus persica, a natural host of PPV, identified orthologs related to defence, metabolism and protein synthesis. The cross comparison of genes differentially regulated by PPV infection and by the infections of other positive sense RNA viruses revealed a common set of 416 genes. These identified genes, particularly the early responsive genes, may be critical in virus infection.
Conclusion: Gene expression changes in PPV-infected Arabidopsis are the molecular basis of stress and defencelike responses, PPV pathogenesis and symptom development. The differentially regulated genes, particularly the early responsive genes, and a common set of genes regulated by infections of PPV and other positive sense RNA viruses identified in this study are candidates suitable for further functional characterization to shed lights on molecular virus-host interactions.
2008-07-09T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/3
http://www.biomedcentral.com/1471-2164/9/325
Biology Publications
Scholarship@Western
Gene expression
Arabidopsis thaliana
Plum pox virus
Genetics and Genomics
Plant Sciences
Virus Diseases
oai:ir.lib.uwo.ca:biologypub-1000
2009-05-06T22:16:20Z
publication:biologypub
publication:psychiatrypub
publication:biology
publication:pmid
publication:faculties
publication:psychiatry
DNA Methylation and mRNA Expression of SYN III, a Candidate Gene for Schizophrenia
Murphy, Brenda C.
O'Reilly, Richard L.
Singh, Shiva M.
Background: The synapsin III (SYN III) gene on chromosome 22q is a candidate gene for schizophrenia susceptibility due to its chromosome location, neurological function, expression patterns and functional polymorphisms.
Methods: This research has established the mRNA expression of SYN III in 22 adult human brain regions as well as the methylation specificity in the closest CpG island of this gene. The methylation specificity studied in 31 brain regions (from a single individual) was also assessed in 51 human blood samples (representing 20 people affected with schizophrenia and 31 normal controls) including a pair of monozygotic twin discordant for schizophrenia and 2 non-human primates.
Results: The results show that the cytosine methylation in this genomic region is 1) restricted to cytosines in CpG dinucleotides 2) similar in brain regions and blood and 3) appears conserved in primate evolution. Two cytosines (cytosine 8 and 20) localized as the CpG dinucleotide are partially methylated in all brain regions studied. The methylation of these sites in schizophrenia and control blood samples was variable. While cytosine 8 was partially methylated in all samples, the distribution of partial to complete methylation at the cytosine 20 was 22:9 in controls as compared to 18:2 in schizophrenia (p = 0.82). Also, there is no difference in methylation between the affected and unaffected member of a monozygotic twin pair.
Conclusion: The variation in SYN III methylation studied is 1) not related to schizophrenia in the population sample or a monozygotic twin pair discordant for schizophrenia and 2) not related to the mRNA level of SYN IIIa in different human brain regions.
2008-12-22T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/1
http://www.biomedcentral.com/1471-2350/9/115
Biology Publications
Scholarship@Western
Synapsin III gene
Schizophrenia susceptibility
SYN III methylation
mRNA expression
Genetics and Genomics
Medical Genetics
Medical Sciences
Psychiatry
oai:ir.lib.uwo.ca:biologypub-1003
2009-05-12T22:10:29Z
publication:biologypub
publication:med
publication:mnipub
publication:mni
publication:biology
publication:pmid
publication:faculties
publication:medpub
A Novel Expression Platform for the Production of Diabetes-associated Autoantigen Human Glutamic Acid Decarboxylase (hGAD65)
Wang, Xiaofeng
Brandsma, Martin
Tremblay, Reynald
Maxwell, Denis
Jevnikar, Anthony M.
Huner, Norm
Ma, Shengwu
Background: Human glutamic acid decarboxylase 65 (hGAD65) is a key autoantigen in type 1 diabetes, having much potential as an important marker for the prediction and diagnosis of type 1 diabetes, and for the development of novel antigen-specific therapies for the treatment of type 1 diabetes. However, recombinant production of hGAD65 using conventional bacterial or mammalian cell culture-based expression systems or nuclear transformed plants is limited by low yield and low efficiency. Chloroplast transformation of the unicellular eukaryotic alga Chlamydomonas reinhardtii may offer a potential solution.
Results: A DNA cassette encoding full-length hGAD65, under the control of the C. reinhardtii chloroplast rbcL promoter and 5'- and 3'-UTRs, was constructed and introduced into the chloroplast genome of C. reinhardtii by particle bombardment. Integration of hGAD65 DNA into the algal chloroplast genome was confirmed by PCR. Transcriptional expression of hGAD65 was demonstrated by RT-PCR. Immunoblotting verified the expression and accumulation of the recombinant protein. The antigenicity of algal-derived hGAD65 was demonstrated with its immunoreactivity to diabetic sera by ELISA and by its ability to induce proliferation of spleen cells from NOD mice. Recombinant hGAD65 accumulated in transgenic algae, accounts for approximately 0.25–0.3% of its total soluble protein.
Conclusion: Our results demonstrate the potential value of C. reinhardtii chloroplasts as a novel platform for rapid mass production of immunologically active hGAD65. This demonstration opens the future possibility for using algal chloroplasts as novel bioreactors for the production of many other biologically active mammalian therapeutic proteins.
2008-11-17T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/4
http://www.biomedcentral.com/1472-6750/8/87
Biology Publications
Scholarship@Western
Human glutamic acid decarboxylase 65
hGAD65
Type 1 diabetes
Chlamydomonas reinhardtii
Biotechnology
Medical Immunology
Nephrology
oai:ir.lib.uwo.ca:biologypub-1004
2011-09-06T00:51:04Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Membrane Type-1 Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases-2 RNA Levels Mimic Each Other during Xenopus laevis Metamorphosis
Walsh, Logan A.
Carere, Deanna A.
Cooper, Colin A.
Damjanovski, Sashko
Matrix metalloproteinases (MMPs) and their endogenous inhibitors TIMPs (tissue inhibitors of MMPs), are two protein families that work together to remodel the extracellular matrix (ECM). TIMPs serve not only to inhibit MMP activity, but also aid in the activation of MMPs that are secreted as inactive zymogens. Xenopus laevis metamorphosis is an ideal model for studying MMP and TIMP expression levels because all tissues are remodeled under the control of one molecule, thyroid hormone. Here, using RT-PCR analysis, we examine the metamorphic RNA levels of two membrane-type MMPs (MT1-MMP, MT3-MMP), two TIMPs (TIMP-2, TIMP-3) and a potent gelatinase (Gel-A) that can be activated by the combinatory activity of a MT-MMP and a TIMP. In the metamorphic tail and intestine the RNA levels of TIMP-2 and MT1-MMP mirror each other, and closely resemble that of Gel- A as all three are elevated during periods of cell death and proliferation. Conversely, MT3-MMP and TIMP-3 do not have similar RNA level patterns nor do they mimic the RNA levels of the other genes examined. Intriguingly, TIMP-3, which has been shown to have anti-apoptotic activity, is found at low levels in tissues during periods of apoptosis.
2007-10-03T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/5
info:doi/10.1371/journal.pone.0001000
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1991586/
Biology Publications
Scholarship@Western
Matrix metalloproteinases
Tissue inhibitors of matrix metalloproteinases
Extracellular matrix
Xenopus laevis metamorphosis
Cell and Developmental Biology
oai:ir.lib.uwo.ca:biologypub-1005
2009-09-21T00:08:03Z
publication:biologypub
publication:pathol
publication:patholpub
publication:biology
publication:pmid
publication:faculties
Expression of Progesterone Metabolizing Enzyme Genes (AKR1C1, AKR1C2, AKR1C3, SRD5A1, SRD5A2) is Altered in Human Breast Carcinoma
Lewis, Michael J.
Wiebe, John P.
Heathcote, J. Godfrey
Background: Recent evidence suggests that progesterone metabolites play important roles in regulating breast cancer. Previous studies have shown that tumorous tissues have higher 5alpha-reductase (5alphaR) and lower 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO activities. The resulting higher levels of 5alpha-reduced progesterone metabolites such as 5alpha-pregnane-3,20-dione (5alphaP) in tumorous tissue promote cell proliferation and detachment, whereas the 4-pregnene metabolites, 4-pregnen-3alpha-ol-20-one (3alphaHP) and 4-pregnen-20alpha-ol-3-one (20alphaDHP), more prominent in normal tissue, have the opposite (anti-cancer-like) effects. The aim of this study was to determine if the differences in enzyme activities between tumorous and nontumorous breast tissues are associated with differences in progesterone metabolizing enzyme gene expression.
Methods: Semi-quantitative RT-PCR was used to compare relative expression (as a ratio of 18S rRNA) of 5alphaR type 1 (SRD5A1), 5alphaR type 2 (SRD5A2), 3alpha-HSO type 2 (AKR1C3), 3alpha-HSO type 3 (AKR1C2) and 20alpha-HSO (AKR1C1) mRNAs in paired (tumorous and nontumorous) breast tissues from 11 patients, and unpaired tumor tissues from 17 patients and normal tissues from 10 reduction mammoplasty samples.
Results: Expression of 5alphaR1 and 5alphaR2 in 11/11 patients was higher (mean of 4.9- and 3.5-fold, respectively; p < 0.001) in the tumor as compared to the paired normal tissues. Conversely, expression of 3alpha-HSO2, 3alpha-HSO3 and 20alpha-HSO was higher (2.8-, 3.9- and 4.4-fold, respectively; p < 0.001) in normal than in tumor sample. The mean tumor:normal expression ratios for 5alphaR1 and 5alphaR2 were about 35-85-fold higher than the tumor:normal expression ratios for the HSOs. Similarly, in the unmatched samples, the tumor:normal ratios for 5alphaR were significantly higher than the ratios for the HSOs.
Conclusions: The study shows changes in progesterone metabolizing enzyme gene expression in human breast carcinoma. Expression of SRD5A1 (5alphaR1) and SRD5A2 (5alphaR2) is elevated, and expression of AKR1C1 (20alpha-HSO), AKR1C2 (3alpha-HSO3) and AKR1C3 (3alpha-HSO2) is reduced in tumorous as compared to normal breast tissue. The changes in progesterone metabolizing enzyme expression levels help to explain the increases in mitogen/metastasis inducing 5alphaP and decreases in mitogen/metastasis inhibiting 3alphaHP progesterone metabolites found in breast tumor tissues. Understanding what causes these changes in expression could help in designing protocols to prevent or reverse the changes in progesterone metabolism associated with breast cancer.
2004-06-22T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/6
http://www.biomedcentral.com/1471-2407/4/27
Biology Publications
Scholarship@Western
20-Hydroxysteroid Dehydrogenases
3-Hydroxysteroid Dehydrogenases
Adult
Aged
Breast Neoplasms
Carcinoma
Ductal
Breast
Female
Humans
Hydroxyprostaglandin Dehydrogenases
Hydroxysteroid Dehydrogenases
Middle Aged
Progesterone
RNA
Messenger
Testosterone 5-alpha-Reductase
Carcinoma, Ductal, Breast
RNA, Messenger
Biology
oai:ir.lib.uwo.ca:biologypub-1006
2009-10-10T02:57:25Z
publication:biologypub
publication:psychiatrypub
publication:biology
publication:pmid
publication:faculties
publication:psychiatry
Breakpoint Associated with a Novel 2.3 Mb Deletion in the VCFS Region of 22q11 and the Role of Alu (SINE) in Recurring Microdeletions
Uddin, Raihan K.
Zhang, Yang
Siu, Victoria Mok
Fan, Yao-Shan
O'Reilly, Richard L.
Rao, Jay
Singh, Shiva M.
Background: Chromosome 22q11.2 region is highly susceptible to rearrangement, specifically deletions that give rise to a variety of genomic disorders including velocardiofacial or DiGeorge syndrome. Individuals with this 22q11 microdeletion syndrome are at a greatly increased risk to develop schizophrenia.
Methods: Genotype analysis was carried out on the DNA from a patient with the 22q11 microdeletion using genetic markers and custom primer sets to define the deletion. Bioinformatic analysis was performed for molecular characterization of the deletion breakpoint sequences in this patient.
Results: This 22q11 deletion patient was established to have a novel 2.3 Mb deletion with a proximal breakpoint located between genetic markers RH48663 and RH48348 and a distal breakpoint between markers D22S1138 and SHGC-145314. Molecular characterization of the sequences at the breakpoints revealed a 270 bp shared sequence of the breakpoint regions (SSBR) common to both ends that share >90% sequence similarity to each other and also to short interspersed nuclear elements/Alu elements.
Conclusion: This Alu sequence like SSBR is commonly in the proximity of all known deletion breakpoints of 22q11 region and also in the low copy repeat regions (LCRs). This sequence may represent a preferred sequence in the breakpoint regions or LCRs for intra-chromosomal homologous recombination mechanisms resulting in common 22q11 deletion.
2006-03-02T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/7
http://www.biomedcentral.com/1471-2350/7/18
Biology Publications
Scholarship@Western
Adolescent
Alu Elements
Chromosome Breakage
Chromosome Deletion
Chromosomes
Human
Pair 22
DiGeorge Syndrome
Humans
Male
Models
Genetic
Recombination
Genetic
Chromosomes, Human, Pair 22
Models, Genetic
Recombination, Genetic
Biology
Medical Genetics
oai:ir.lib.uwo.ca:biologypub-1007
2011-06-13T00:23:48Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Activity and Expression of Progesterone Metabolizing 5α-reductase, 20α-hydroxysteroid Oxidoreductase and 3α(β)-hydroxysteroid Oxidoreductases in Tumorigenic (MCF-7, MDA-MB-231, T-47D) and Nontumorigenic (MCF-10A) Human Breast Cancer Cells
Wiebe, John P.
Lewis, Michael J.
Background: Recent observations indicate that human tumorous breast tissue metabolizes progesterone differently than nontumorous breast tissue. Specifically, 5alpha-reduced metabolites (5alpha-pregnanes, shown to stimulate cell proliferation and detachment) are produced at a significantly higher rate in tumorous tissue, indicating increased 5alpha-reductase (5alphaR) activity. Conversely, the activities of 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO enzymes appeared to be higher in normal tissues. The elevated conversion to 5alpha-pregnanes occurred regardless of estrogen (ER) or progesterone (PR) receptor levels. To gain insight into these differences, the activities and expression of these progesterone converting enzymes were investigated in a nontumorigenic cell line, MCF-10A (ER- and PR-negative), and the three tumorigenic cell lines, MDA-MB-231 (ER- and PR-negative), MCF-7 and T-47D (ER- and PR-positive).
Methods: For the enzyme activity studies, either whole cells were incubated with [14C]progesterone for 2, 4, 8, and 24 hours, or the microsomal/cytosolic fraction was incubated for 15-60 minutes with [3H]progesterone, and the metabolites were identified and quantified. Semi-quantitative RT-PCR was employed to determine the relative levels of expression of 5alphaR type1 (SRD5A1), 5alphaR type 2 (SRD5A2), 20alpha-HSO (AKR1C1), 3alpha-HSO type 2 (AKR1C3), 3alpha-HSO type 3 (AKR1C2) and 3beta-HSO (HSD3B1/HSD3B2) in the four cell lines using 18S rRNA as an internal control.
Results: The relative 5alpha-reductase activity, when considered as a ratio of 5alpha-pregnanes/4-pregnenes, was 4.21 (+/- 0.49) for MCF-7 cells, 6.24 (+/- 1.14) for MDA-MB-231 cells, 4.62 (+/- 0.43) for T-47D cells and 0.65 (+/- 0.07) for MCF-10A cells, constituting approximately 6.5-fold, 9.6-fold and 7.1 fold higher conversion to 5alpha-pregnanes in the tumorigenic cells, respectively, than in the nontumorigenic MCF-10A cells. Conversely, the 20alpha-HSO and 3alpha-HSO activities were significantly higher (p < 0.001) in MCF-10A cells than in the other three cell types. In the MCF-10A cells, 20alpha-HSO activity was 8-14-fold higher and the 3alpha-HSO activity was 2.5-5.4-fold higher than in the other three cell types. The values of 5alphaR:20alpha-HSO ratios were 16.9-32.6-fold greater and the 5alphaR:3alpha-HSO ratios were 5.2-10.5-fold greater in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells. RT-PCR showed significantly higher expression of 5alphaR1 (p < 0.001), and lower expression of 20alpha-HSO (p < 0.001), 3alpha-HSO2 (p < 0.001), 3alpha-HSO3 (p < 0.001) in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells.
Conclusion: The findings provide the first evidence that the 5alphaR activity (leading to the conversion of progesterone to the cancer promoting 5alpha-pregnanes) is significantly higher in the tumorigenic MCF-7, MDA-MB-231 and T-47D breast cell lines than in the nontumorigenic MCF-10A cell line. The higher 5alphaR activity coincides with significantly greater expression of 5alphaR1. On the other hand, the activities of 20alpha-HSO and 3alpha-HSO are higher in the MCF-10A cells than in MCF-7, MDA-MB-231 and T-47D cells; these differences in activity correlate with significantly higher expression of 20alpha-HSO, 3alpha-HSO2 and 3alpha-HSO3 in MCF-10A cells. Changes in progesterone metabolizing enzyme expression (resulting in enzyme activity changes) may be responsible for stimulating breast cancer by increased production of tumor-promoting 5alpha-pregnanes and decreased production of anti-cancer 20alpha--and 3alpha-4-pregnenes.
2003-03-22T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/8
info:doi/10.1186/1471-2407-3-9
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC154104/
Biology Publications
Scholarship@Western
20-alpha-Hydroxysteroid Dehydrogenase
3-Hydroxysteroid Dehydrogenases
3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)
Breast Neoplasms
Cell Line
Tumor
Cholestenone 5 alpha-Reductase
Female
Humans
Progesterone
Cell Line, Tumor
Oncology
oai:ir.lib.uwo.ca:cjsotl_rcacea-1014
2012-11-06T21:34:45Z
publication:biologypub
publication:cjsotl_rcacea
publication:biology
publication:faculties
The Effect of Performance Feedback on Student Help-Seeking and Learning Strategy Use: Do Clickers Make a Difference?
Dawson, Debra L
Meadows, Ken N.
Haffie, Tom
Two studies were performed to investigate the impact of students’ clicker performance feedback on their help-seeking behaviour and use of other learning strategies. In study 1, we investigated the relationship between students’ clicker performance, self-efficacy, help-seeking behavior, and academic achievement. We found that there was a significant positive correlation between their clicker performance and their course grades, and help-seeking behavior was negatively and significantly related to clicker and course performance but only for participants with high self-efficacy. In study 2, we expanded our focus to determine if participants modified a number of learning strategies as a result of receiving clicker performance feedback as well as attempting to replicate the clicker-course performance relationship found in study 1. Although participants reported an increase in their use of various learning strategies as a result of using the clickers, changes in learning strategy use was not significantly related to clicker or term test performance. The relationship between clicker and course performance was replicated. The results suggest that clicker-based feedback alone may not be sufficient to lead to a successful change in learning strategy use and that students may need more specific instruction on self-regulation and effective learning strategy use in order to improve their learning.
Deux études ont évalué l’impact de la rétroaction sur la performance des étudiants indiquée par télévoteur sur leur comportement de recherche d’aide et sur les autres stratégies d’apprentissage utilisées. Dans la première étude, les chercheurs se sont penchés sur la relation entre la performance indiquée par télévoteur, le sentiment d’auto-efficacité, la recherche d’aide et la réussite scolaire. Nous avons trouvé une corrélation positive significative entre la performance indiquée par télévoteur et les notes de cours. De plus, nous avons également découvert un lien négatif significatif entre le comportement en matière de recherche d’aide, le télévoteur et la performance dans le cours, mais uniquement chez les participants ayant un sentiment d’auto-efficacité élevé. Dans la deuxième étude, nous avons élargi notre approche pour déterminer si les participants avaient modifié plusieurs stratégies d’apprentissage après avoir obtenu une rétroaction sur leur performance par télévoteur. Nous avons de plus tenté de répliquer la relation entre le télévoteur et la performance dans cours découverte lors de la première étude. Bien que les participants aient déclaré avoir utilisé davantage de stratégies d’apprentissage après avoir utilisé le télévoteur, nous n’avons pas trouvé de lien significatif entre les changements relatifs à ces stratégies et le télévoteur ou le test de performance de mi-semestre. Nous avons répliqué le lien entre le télévoteur et la performance dans le cours. Les résultats suggèrent que la rétroaction offerte par le télévoteur n’est pas suffisante en soi pour entraîner un changement fructueux en matière de stratégies d’apprentissage et que les étudiants ont besoin d’instructions plus spécifiques sur l’autorégulation et sur les stratégies d’apprentissage efficaces pour mieux apprendre.
2010-06-21T17:25:43Z
article
application/pdf
https://ir.lib.uwo.ca/cjsotl_rcacea/vol1/iss1/6
info:doi/10.5206/cjsotl-rcacea.2010.1.6
The Canadian Journal for the Scholarship of Teaching and Learning
Scholarship@Western
clickers
active learning
learning strategies
help-seeking
academic achievement
oai:ir.lib.uwo.ca:biologypub-1008
2009-11-21T00:34:41Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Induction of Protein Body Formation in Plant Leaves by Elastin-like Polypeptide Fusions
Conley, Andrew J.
Joensuu, Jussi J.
Menassa, Rima
Brandle, Jim E,
Background: Elastin-like polypeptides are synthetic biopolymers composed of a repeating pentapeptide 'VPGXG' sequence that are valuable for the simple non-chromatographic purification of recombinant proteins. In addition, elastin-like polypeptide fusions have been shown to enhance the accumulation of a range of different recombinant proteins in plants, thus addressing the major limitation of plant-based expression systems, which is a low production yield. This study's main objectives were to determine the general utility of elastin-like polypeptide protein fusions in various intracellular compartments and to elucidate elastin-like polypeptide's mechanism of action for increasing recombinant protein accumulation in the endoplasmic reticulum of plants.
Results: The effect of elastin-like polypeptide fusions on the accumulation of green fluorescent protein targeted to the cytoplasm, chloroplasts, apoplast, and endoplasmic reticulum was evaluated. The endoplasmic reticulum was the only intracellular compartment in which an elastin-like polypeptide tag was shown to significantly enhance recombinant protein accumulation. Interestingly, endoplasmic reticulum-targeted elastin-like polypeptide fusions induced the formation of a novel type of protein body, which may be responsible for elastin-like polypeptide's positive effect on recombinant protein accumulation by excluding the heterologous protein from normal physiological turnover. Although expressed in the leaves of plants, these novel protein bodies appeared similar in size and morphology to the prolamin-based protein bodies naturally found in plant seeds. The elastin-like polypeptide-induced protein bodies were highly mobile organelles, exhibiting various dynamic patterns of movement throughout the cells, which were dependent on intact actin microfilaments and a functional actomyosin motility system.
Conclusion: An endoplasmic reticulum-targeted elastin-like polypeptide fusion approach provides an effective strategy for depositing large amounts of concentrated heterologous protein within the limited space of the cell via storage in stable protein bodies. Furthermore, encapsulation of recombinant proteins into physiologically inert organelles can function to insulate the protein from normal cellular mechanisms, thus limiting unnecessary stress to the host cell. Since elastin-like polypeptide is a mammalian-derived protein, this study demonstrates that plant seed-specific factors are not required for the formation of protein bodies in vegetative plant tissues, suggesting that the endoplasmic reticulum possesses an intrinsic ability to form protein body-like accretions in eukaryotic cells when overexpressing particular proteins.
2009-08-07T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/9
info:doi/10.1186/1741-7007-7-48
http://www.biomedcentral.com/1741-7007/7/48
Biology Publications
Scholarship@Western
Analysis of Variance
Chloroplasts
Cytoplasm
Electroporation
Endoplasmic Reticulum
Extracellular Fluid
Gene Expression Regulation
Plant
Heat-Shock Proteins
Ligase Chain Reaction
Luminescent Agents
Luminescent Proteins
Microfilaments
Peptides
Plant Leaves
Polymerase Chain Reaction
Protein Transport
Recombinant Fusion Proteins
Rhizobium radiobacter
Talin
Tobacco
Gene Expression Regulation, Plant
Biology
oai:ir.lib.uwo.ca:geographypub-1135
2010-05-15T22:50:56Z
publication:biologypub
publication:earth
publication:geography
publication:biology
publication:geographypub
publication:faculties
publication:earthpub
Desert Potholes: Ephemeral Aquatic Microsystems
Chan, Marjarie A.
Moser, Katrina
Davis, Jim M.
Southam, Gordon
Hughes, Kebbi
Graham, Tim
An enigma of the Colorado Plateau high desert is the “pothole”, which ranges from shallow ephemeral puddles to deeply carved pools. The existence of prokaryotic to eukaryotic organisms within these pools is largely controlled by the presence of collected rainwater. Multivariate statistical analysis of physical and chemical limnologic data variables measured from potholes indicates spatial and temporal variations, particularly in water depth, manganese, iron, nitrate and sulfate concentrations and salinity. Variation in water depth and salinity are likely related to the amount of time since the last precipitation, whereas the other variables may be related to redox potential. The spatial and temporal variations in water chemistry affect the distribution of organisms, which must adapt to daily and seasonal extremes of fluctuating temperature (0–60 °C), pH changes of as much as 5 units over 12 days, and desiccation. For example, many species become dormant when potholes dry, in order to endure intense heat, UV radiation, desiccation and freezing, only to flourish again upon rehydration. But the pothole organisms also have a profound impact on the potholes. Through photosynthesis and respiration, pothole organisms affect redox potential, and indirectly alter the water chemistry. Laboratory examination of dried biofilm from the potholes revealed that within 2 weeks of hydration, the surface of the desiccated, black biofilm became green from cyanobacterial growth, which supported significant growth in heterotrophic bacterial populations. This complex biofilm is persumably responsible for dissolving the cement between the sandstone grains, allowing the potholes to enlarge, and for sealing the potholes, enabling them to retain water longer than the surrounding sandstone. Despite the remarkable ability of life in potholes to persist, desert potholes may be extremely sensitive to anthropogenic effects. The unique limnology and ecology of Utah potholes holds great scientific value for understanding water–rock–biological interactions with possible applications to life on other planetary bodies.
2005-09-01T07:00:00Z
article
https://ir.lib.uwo.ca/geographypub/128
info:doi/10.1007/s10498-004-6274-8
http://dx.doi.org/10.1007/s10498-004-6274-8
Geography & Environment Publications
Scholarship@Western
potholes
desert
Colorado Plateau
sandstone
Utah
microorganisms
redox
biofilm
cyanobacteria
limnology
Geography
oai:ir.lib.uwo.ca:biochempub-1106
2015-05-13T16:48:57Z
publication:biologypub
publication:biochempub
publication:biology
publication:pmid
publication:biochem
publication:faculties
NIP/DuoxA is essential for Drosophila embryonic development and regulates oxidative stress response.
Xie, Xiaojun
Hu, Jack
Liu, Xiping
Qin, Hanjuan
Percival-Smith, Anthony
Rao, Yong
Li, Shawn S C
NIP/DuoxA, originally cloned as a protein capable of binding to the cell fate determinant Numb in Drosophila, was recently identified as a modulator of reactive oxygen species (ROS) production in mammalian systems. Despite biochemical and cellular studies that link NIP/DuoxA to the generation of ROS through the dual oxidase (Duox) enzyme, the in vivo function of NIP/DuoxA has not been characterized to date. Here we report a genetic and functional characterization of nip in Drosophila melanogaster. We show that nip is essential for Drosophila development as nip null mutants die at the 1(st) larval instar. Expression of UAS-nip, but not UAS-Duox, rescued the lethality. To understand the function of nip beyond the early larval stage, we generated GAL4 inducible UAS-RNAi transgenes. da(G32)-GAL4 driven, ubiquitous RNAi-mediated silencing of nip led to profound abnormality in pre-adult development, crinkled wing and markedly reduced lifespan at 29 degrees C. Compared to wild type flies, da-GAL4 induced nip-RNAi transgenic flies exhibited significantly reduced ability to survive under oxidative stress and displayed impaired mitochondrial aconitase function. Our work provides in vivo evidence for a critical role for nip in the development and oxidative stress response in Drosophila.
2010-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biochempub/104
https://ir.lib.uwo.ca/context/biochempub/article/1106/viewcontent/ijbsv06p0252.pdf
Biochemistry Publications
Scholarship@Western
Aging
Animals
Animals
Genetically Modified
Drosophila
Drosophila melanogaster
Embryonic Development
Larva
Oxidative Stress
Proteins
RNA Interference
Reactive Oxygen Species
Transgenes
Wing
Biochemistry
Biology
oai:ir.lib.uwo.ca:biologypub-1009
2010-07-13T23:33:17Z
publication:biologypub
publication:biology
publication:faculties
Not So Fast: Inflation in Impact Factors Contributes to Apparent Improvements in Journal Quality
Neff, Bryan D.
Olden, Julian D.
The Institute for Scientific Information (ISI) impact factor has become an important standard for assessing journal quality. Here we propose that impact factors may be subject to inflation analogous to changes in monetary prices in economics. The possibility of inflation came to light as a result of the observation that papers published today tend to cite more papers than those published a decade ago. We analyzed citation data from 75,312 papers from 70 ecological journals published during 1998—2007. We found that papers published in 2007 cited an average of seven more papers than those published a decade earlier. This increase accounts for about 80% of the observed impact factor inflation rate of 0.23. In examining the 70 journals we found that nearly 50% showed increases in their impact factors, but at rates lower than the background inflation rate. Therefore, although those journals appear to be increasing in quality as measured by the impact factor, they are actually failing to keep pace with inflation.
2010-06-01T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/10
info:doi/10.1525/bio.2010.60.6.9
http://dx.doi.org/10.1525/bio.2010.60.6.9
Biology Publications
Scholarship@Western
Impact factor
Journal quality
Scholarly publishing
Citation analysis
Bibliometrics
Ecology
Inflation
Merit
Life Sciences
oai:ir.lib.uwo.ca:biologypub-1010
2010-08-13T23:39:14Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Brassinosteroid-mediated Stress Tolerance in Arabidopsis Shows Interactions with Abscisic Acid, Ethylene and Salicylic Acid Pathways
Divi, Uday K.
Rahman, Tawhidur
Krishna, Priti
BACKGROUND: Brassinosteroids (BRs) play crucial roles in plant development and also promote tolerance to a range of abiotic stresses. Although much has been learned about their roles in plant development, the mechanisms by which BRs control plant stress responses and regulate stress-responsive gene expression are not fully known. Since BR interacts with other plant hormones, it is likely that the stress tolerance conferring ability of BR lies in part in its interactions with other stress hormones.
RESULTS: Using a collection of Arabidopsis mutants that are either deficient in or insensitive to abscisic acid (ABA), ethylene (ET), jasmonic acid (JA) and salicylic acid (SA), we studied the effects of 24-epibrassinloide (EBR) on basic thermotolerance and salt tolerance of these mutants. The positive impact of EBR on thermotolerance in proportion to wild type was evident in all mutants studied, with the exception of the SA-insensitive npr1-1 mutant. EBR could rescue the ET-insensitive ein2 mutant from its hypersensitivity to salt stress-induced inhibition of seed germination, but remained ineffective in increasing the survival of eto1-1 (ET-overproducer) and npr1-1 seedlings on salt. The positive effect of EBR was significantly greater in the ABA-deficient aba1-1 mutant as compared to wild type, indicating that ABA masks BR effects in plant stress responses. Treatment with EBR increased expression of various hormone marker genes in both wild type and mutant seedlings, although to different levels.
CONCLUSIONS: These results together indicate that the redox-sensitive protein NPR1 (NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1), a master regulator of SA-mediated defense genes, is likely a critical component of EBR-mediated increase in thermotolerance and salt tolerance, but it is not required for EBR-mediated induction of PR-1 (PATHOGENESIS-RELATED1) gene expression; that BR exerts anti-stress effects independently as well as through interactions with other hormones; that ABA inhibits BR effects during stress; and that BR shares transcriptional targets with other hormones.
2010-07-19T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/11
info:doi/10.1186/1471-2229-10-151
http://dx.doi.org/10.1186/1471-2229-10-151
Biology Publications
Scholarship@Western
Stress tolerance
Arabidopsis
Abscisic acid
Ethylene
Salicylic acid
Biology
oai:ir.lib.uwo.ca:biologypub-1011
2010-12-13T07:55:20Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Preferences for Active and Aggressive Intervention among Patients with Advanced Cancer
Maida, Vincent
Peck, Jonathan
Ennis, Marguerite
Brar, Navjot
Maida, Alexandria R.
BACKGROUND: Intrinsic to "Patient-Centered Care" is being respectful and responsive to individual patient preferences, expressed needs, and personal values. Establishing a patient's preferences for active and aggressive intervention is imperative and foundational to the development of advance care planning. With the increasing awareness and acceptance of palliative philosophies of care, patients with advanced cancer are increasingly transitioning from active and aggressive medical management (AAMM) to conservative palliative management (CPM).
METHODS: A cross-sectional study based on a prospective and sequential case series of patients referred to a regional palliative medicine consultative program was assembled between May 1, 2005 and June 30, 2006. Patients and/or their substitute decision makers (SDM) completed a questionnaire, at baseline, that assessed their preferences for AAMM en route to their eventual deaths. Seven common interventions constituting AAMM were surveyed: cardiopulmonary resuscitation (CPR) & mechanical ventilation (MV), chemotherapy, antibiotics, anticoagulants, blood transfusions, feeding tubes, and artificial hydration. Multivariable analyses were conducted on the seven interventions individually as well as on the composite score that summed preferences for the seven interventions.
RESULTS: 380 patients with advanced cancer agreed to participate in the study. A trend to desire a mostly conservative palliative approach was noted as 42% of patients desired one or fewer interventions. At baseline, most patients and their SDM's were relatively secure about decisions pertaining to the seven interventions as the rates of being "undecided" ranged from a high of 23.4% for chemotherapy to a low of 3.9% for feeding tubes. Multivariable modeling showed that more AAMM was preferred by younger patients (P < 0.0001), non-Caucasians (P = 0.042), patients with higher baseline Palliative Performance Scale scores (P = 0.0002) and where a SDM was involved in the decision process (p = 0.027). Non-statistically significant trends to prefer more AAMM was observed with male gender (p = 0.077) and higher levels of the Charlson Comorbidity index (p = 0.059). There was no association between treatment preferences and cancer class.
CONCLUSIONS: Although the majority of patients with advanced cancer in this study expressed preferences for CPM, younger age, higher baseline PPSv2, and involvement of SDMs in the decision process were significantly associated with preferences for AAMM.
2010-10-28T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/12
info:doi/10.1186/1471-2407-10-592
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2988029/
Biology Publications
Scholarship@Western
Cancer
Intervention
Palliative care
Biology
oai:ir.lib.uwo.ca:biologypub-1012
2011-05-30T20:51:56Z
publication:biologypub
publication:biochempub
publication:biology
publication:pmid
publication:biochem
publication:faculties
Mutations in the P3 Protein of Soybean mosaic virus G2 Isolates Determine Virulence on Rsv4-Genotype Soybean
Chowda-Reddy, R. V.
Sun, Haiyue
Chen, Hongyan
Poysa, Vaino
Ling, Hong
Gijzen, Mark
Wang, Aiming
Two Soybean mosaic virus (SMV) G2 isolates, L and L-RB, sharing high-sequence similarly but differing in ability to break Rsv4-mediated resistance in soybean, were investigated. Infectious clones corresponding to these two isolates and their chimeric clones resulting from swapping different regions of genomic cDNA between L and L-RB were constructed. Only L-RB or chimeras containing the middle fragment of L-RB cDNA showed virulence on Rsv4-genotype soybean. Sequence comparison analysis revealed that the middle genomic region of L and L-RB encodes four different amino acids. Point mutagenesis demonstrated that a single amino acid substitution (Q1033K) in the P3 protein determined virulence toward Rsv4 resistance. In addition, six new SMV Rsv4 resistance-breaking isolates, variants of the second passage on Williams 82 infected with the chimeras or mutants noninfectious on soybean carrying Rsv4, were obtained. Sequencing data indicated that these new isolates contain either the Q1033K mutation or a new substitution (G1054R) in P3. Site-directed mutagenesis confirmed the virulence role of the G1054R mutation on Rsv4-genotype soybean. Taken together, these data suggest that P3 of the SMV G2 strain is an avirulent determinant for Rsv4 and one single nucleotide mutation in P3 may be sufficient to compromise its elicitor function.
2011-01-01T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/13
info:doi/10.1094/MPMI-07-10-0158
http://dx.doi.org/10.1094/MPMI-07-10-0158
Biology Publications
Scholarship@Western
Amino Acid Substitution
Base Sequence
Chimera
Molecular Cloning
Complementary DNA
Viral DNA
Molecular Sequence Data
Mosaic Viruses
Mutagenesis
Site-Directed
Mutation
Plant Diseases
Sequence Alignment
Sequence Homology
Amino Acid
Sequence Homology
Nucleic Acid
Soybeans
Virulence
Cloning, Molecular
DNA, Complementary
DNA, Viral
Mutagenesis, Site-Directed
Sequence Homology, Amino Acid
Sequence Homology, Nucleic Acid
Biochemistry, Biophysics, and Structural Biology
Biology
oai:ir.lib.uwo.ca:biologypub-1013
2011-08-25T23:18:55Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
PEX11β Induces Peroxisomal Gene Expression and Alters Peroxisome Number during Early Xenopus laevis Development
Fox, Mark A.
Walsh, Logan A.
Nieuwesteeg, Michelle
Damjanovski, Sashko
BACKGROUND: Peroxisomes are organelles whose roles in fatty acid metabolism and reactive oxygen species elimination have contributed much attention in understanding their origin and biogenesis. Many studies have shown that de novo peroxisome biogenesis is an important regulatory process, while yeast studies suggest that total peroxisome numbers are in part regulated by proteins such as Pex11, which can facilitate the division of existing peroxisomes. Although de novo biogenesis and divisions are likely important mechanisms, the regulation of peroxisome numbers during embryonic development is poorly understood. Peroxisome number and function are particularly crucial in oviparous animals such as frogs where large embryonic yolk and fatty acid stores must be quickly metabolized, and resulting reactive oxygen species eliminated. Here we elucidate the role of Pex11β in regulating peroxisomal gene expression and number in Xenopus laevis embryogenesis.
RESULTS: Microinjecting haemagglutinin (HA) tagged Pex11β in early embryos resulted in increased RNA levels for peroxisome related genes PMP70 and catalase at developmental stages 10 and 20, versus uninjected embryos. Catalase and PMP70 proteins were found in punctate structures at stage 20 in control embryos, whereas the injection of ectopic HA-Pex11β induced their earlier localization in punctate structures at stage 10. Furthermore, the peroxisomal marker GFP-SKL, which was found localized as peroxisome-like structures at stage 20, was similarly found at stage 10 when co-microinjected with HA-Pex11β.
CONCLUSIONS: Overexpressed Pex11β altered peroxisomal gene levels and induced the early formation of peroxisomes-like structures during development, both of which demonstrate that Pex11β may be a key regulator of peroxisome number in early Xenopus embryos.
2011-04-28T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/14
info:doi/10.1186/1471-213X-11-24
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095563/
Biology Publications
Scholarship@Western
PEX11β
Peroxisomal gene expression
Peroxisome number
Xenopus laevis
Biology
oai:ir.lib.uwo.ca:biologypub-1014
2011-08-25T23:25:57Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
IGF-1 Increases Invasive Potential of MCF 7 Breast Cancer Cells and Induces Activation of Latent TGF-β1 Resulting in Epithelial to Mesenchymal Transition
Walsh, Logan A.
Damjanovski, Sashko
INTRODUCTION: TGF-β signaling has been extensively studied in many developmental contexts, amongst which is its ability to induce epithelial to mesenchymal transitions (EMT). EMTs play crucial roles during embryonic development and have also come under intense scrutiny as a mechanism through which breast cancers progress to become metastatic. Interestingly, while the molecular hallmarks of EMT progression (loss of cell adhesion, nuclear localization of β-catenin) are straightforward, the cellular signaling cascades that result in an EMT are numerous and diverse. Furthermore, most studies describing the biological effects of TGF-β have been performed using high concentrations of active, soluble TGF-β, despite the fact that TGF-β is produced and secreted as a latent complex.
METHODS: MCF-7 breast cancer cells treated with recombinant IGF-1 were assayed for metalloproteinase activity and invasiveness through a matrigel coated transwell invasion chamber. IGF-1 treatments were then followed by the addition of latent-TGF-β1 to determine if elevated levels of IGF-1 together with latent-TGF-β1 could cause EMT.
RESULTS: Results showed that IGF-1 - a molecule known to be elevated in breast cancer is a regulator of matrix metalloproteinase activity (MMP) and the invasive potential of MCF-7 breast cancer cells. The effects of IGF-1 appear to be mediated through signals transduced via the PI3K and MAPK pathways. In addition, increased IGF-1, together with latent TGF-β1 and active MMPs result in EMT.
CONCLUSIONS: Taken together our data suggest a novel a link between IGF-1 levels, MMP activity, TGF-β signaling, and EMT in breast cancer cells.
2011-05-02T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/15
info:doi/10.1186/1478-811X-9-10
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104381/
Biology Publications
Scholarship@Western
IGF-1
MCF 7
Breast cancer
TGF-β1
Epithelial transition
Mesenchymal transition
Biology
oai:ir.lib.uwo.ca:biologypub-1015
2011-08-29T23:40:20Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Analysis of Common Bean Expressed Sequence Tags Identifies Sulfur Metabolic Pathways Active in Seed and Sulfur-rich Proteins Highly Expressed in the Absence of Phaseolin and Major Lectins
Yin, Fuqiang
Pajak, Agnieszka
Chapman, Ralph
Sharpe, Andrew
Huang, Shangzhi
Marsolais, Frédéric
BACKGROUND: A deficiency in phaseolin and phytohemagglutinin is associated with a near doubling of sulfur amino acid content in genetically related lines of common bean (Phaseolus vulgaris), particularly cysteine, elevated by 70%, and methionine, elevated by 10%. This mostly takes place at the expense of an abundant non-protein amino acid, S-methyl-cysteine. The deficiency in phaseolin and phytohemagglutinin is mainly compensated by increased levels of the 11S globulin legumin and residual lectins. Legumin, albumin-2, defensin and albumin-1 were previously identified as contributing to the increased sulfur amino acid content in the mutant line, on the basis of similarity to proteins from other legumes.
RESULTS: Profiling of free amino acid in developing seeds of the BAT93 reference genotype revealed a biphasic accumulation of gamma-glutamyl-S-methyl-cysteine, the main soluble form of S-methyl-cysteine, with a lag phase occurring during storage protein accumulation. A collection of 30,147 expressed sequence tags (ESTs) was generated from four developmental stages, corresponding to distinct phases of gamma-glutamyl-S-methyl-cysteine accumulation, and covering the transitions to reserve accumulation and dessication. Analysis of gene ontology categories indicated the occurrence of multiple sulfur metabolic pathways, including all enzymatic activities responsible for sulfate assimilation, de novo cysteine and methionine biosynthesis. Integration of genomic and proteomic data enabled the identification and isolation of cDNAs coding for legumin, albumin-2, defensin D1 and albumin-1A and -B induced in the absence of phaseolin and phytohemagglutinin. Their deduced amino acid sequences have a higher content of cysteine than methionine, providing an explanation for the preferential increase of cysteine in the mutant line.
CONCLUSION: The EST collection provides a foundation to further investigate sulfur metabolism and the differential accumulation of sulfur amino acids in seed of common bean. Identification of sulfur-rich proteins whose levels are elevated in seed lacking phaseolin and phytohemagglutinin and sulfur metabolic genes may assist the improvement of protein quality.
2011-05-26T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/16
info:doi/10.1186/1471-2164-12-268
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3115882/
Biology Publications
Scholarship@Western
Bean
Sulphur
Metabolic pathways
Seed
Phaseolin
Lectins
Biology
oai:ir.lib.uwo.ca:biologypub-1016
2011-09-06T00:30:25Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Vision Impairs the Abilities of Bats to Avoid Colliding with Stationary Obstacles
Orbach, Dara N.
Fenton, Brock
BACKGROUND: Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as "distress calls" of other bats, contributed to probabilities of collision.
METHODOLOGY/PRINCIPAL FINDINGS: To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions.
CONCLUSIONS/SIGNIFICANCE: Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments.
2010-11-09T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/17
info:doi/10.1371/journal.pone.0013912
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2976695/
Biology Publications
Scholarship@Western
Analysis of Variance
Animals
Chiroptera
Cyclonic Storms
Echolocation
Flight
Animal
Light
Space Perception
Ocular Vision
Animal Vocalization
Female
Flight, Animal
Male
Vision, Ocular
Vocalization, Animal
Biology
oai:ir.lib.uwo.ca:biologypub-1017
2011-09-06T00:35:16Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
In Silico Identification of Carboxylate Clamp Type Tetratricopeptide Repeat Proteins in Arabidopsis and Rice As Putative Co-Chaperones of Hsp90/Hsp70
Prasad, Bishun D.
Goel, Shilpi
Krishna, Priti
The essential eukaryotic molecular chaperone Hsp90 operates with the help of different co-chaperones, which regulate its ATPase activity and serve as adaptors to recruit client proteins and other molecular chaperones, such as Hsp70, to the Hsp90 complex. Several Hsp90 and Hsp70 co-chaperones contain the tetratricopeptide repeat (TPR) domain, which interacts with the highly conserved EEVD motif at the C-terminal ends of Hsp90 and Hsp70. The acidic side chains in EEVD interact with a subset of basic residues in the TPR binding pocket called a 'carboxylate clamp'. Since the carboxylate clamp residues are conserved in the TPR domains of known Hsp90/Hsp70 co-chaperones, we carried out an in silico search for TPR proteins in Arabidopsis and rice comprising of at least one three-motif TPR domain with conserved amino acid residues required for Hsp90/Hsp70 binding. This approach identified in Arabidopsis a total of 36 carboxylate clamp (CC)-TPR proteins, including 24 novel proteins, with potential to interact with Hsp90/Hsp70. The newly identified CC-TPR proteins in Arabidopsis and rice contain additional protein domains such as ankyrin, SET, octicosapeptide/Phox/Bem1p (Phox/PB1), DnaJ-like, thioredoxin, FBD and F-box, and protein kinase and U-box, indicating varied functions for these proteins. To provide proof-of-concept of the newly identified CC-TPR proteins for interaction with Hsp90, we demonstrated interaction of AtTPR1 and AtTPR2 with AtHsp90 in yeast two-hybrid and in vitro pull down assays. These findings indicate that the in silico approach used here successfully identified in a genome-wide context CC-TPR proteins with potential to interact with Hsp90/Hsp70, and further suggest that the Hsp90/Hsp70 system relies on TPR co-chaperones more than it was previously realized.
2010-09-15T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/18
info:doi/10.1371/journal.pone.0012761
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939883/
Biology Publications
Scholarship@Western
Amino Acid Motifs
Arabidopsis
Gene Expression Regulation
Plant
HSP70 Heat-Shock Proteins
HSP90 Heat-Shock Proteins
Molecular Chaperones
Molecular Sequence Data
Oryza sativa
Phylogeny
Plant Proteins
Protein Binding
Gene Expression Regulation, Plant
Biology
oai:ir.lib.uwo.ca:biologypub-1018
2011-09-06T01:34:56Z
publication:biologypub
publication:rwkex
publication:psychiatrypub
publication:rwkex_researcharticles
publication:biology
publication:pmid
publication:faculties
publication:psychiatry
Ontogenetic De Novo Copy Number Variations (CNVs) as a Source of Genetic Individuality: Studies on Two Families with MZD Twins for Schizophrenia
Maiti, Sujit
Kumar, Kiran Halagur Bhoge Gowda
Castellani, Christina A.
O'Reilly, Richard
Singh, Shiva M.
Genetic individuality is the foundation of personalized medicine, yet its determinants are currently poorly understood. One issue is the difference between monozygotic twins that are assumed identical and have been extensively used in genetic studies for decades. Here, we report genome-wide alterations in two nuclear families each with a pair of monozygotic twins discordant for schizophrenia evaluated by the Affymetrix 6.0 human SNP array. The data analysis includes characterization of copy number variations (CNVs) and single nucleotide polymorphism (SNPs). The results have identified genomic differences between twin pairs and a set of new provisional schizophrenia genes. Samples were found to have between 35 and 65 CNVs per individual. The majority of CNVs (~80%) represented gains. In addition, ~10% of the CNVs were de novo (not present in parents), of these, 30% arose during parental meiosis and 70% arose during developmental mitosis. We also observed SNPs in the twins that were absent from both parents. These constituted 0.12% of all SNPs seen in the twins. In 65% of cases these SNPs arose during meiosis compared to 35% during mitosis. The developmental mitotic origin of most CNVs that may lead to MZ twin discordance may also cause tissue differences within individuals during a single pregnancy and generate a high frequency of mosaics in the population. The results argue for enduring genome-wide changes during cellular transmission, often ignored in most genetic analyses.
2011-03-02T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/19
info:doi/10.1371/journal.pone.0017125
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3047561/
Biology Publications
Scholarship@Western
Chromosomes
Human
DNA Copy Number Variations
Demography
Family
Humans
Individuality
Inheritance Patterns
Middle Aged
Mosaicism
Pedigree
Repetitive Sequences
Nucleic Acid
Schizophrenia
Monozygotic Twins
Aged
Aged, 80 and over
Chromosomes, Human
Female
Male
Repetitive Sequences, Nucleic Acid
Twins, Monozygotic
Biology
Medical Genetics
Psychiatry and Psychology
oai:ir.lib.uwo.ca:biologypub-1019
2011-09-06T01:55:15Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Drinking and Flying: Does Alcohol Consumption Affect the Flight and Echolocation Performance of Phyllostomid Bats?
Orbach, Dara N.
Veselka, Nina
Dzal, Yvonne
Lazure, Louis
Fenton, M. Brock
BACKGROUND: In the wild, frugivorous and nectarivorous bats often eat fermenting fruits and nectar, and thus may consume levels of ethanol that could induce inebriation. To understand if consumption of ethanol by bats alters their access to food and general survival requires examination of behavioural responses to its ingestion, as well as assessment of interspecific variation in those responses. We predicted that bats fed ethanol would show impaired flight and echolocation behaviour compared to bats fed control sugar water, and that there would be behavioural differences among species.
METHODOLOGY/PRINCIPAL FINDINGS: We fed wild caught Artibeus jamaicensis, A. lituratus, A. phaeotis, Carollia sowelli, Glossophaga soricina, and Sturnira lilium (Chiroptera, Phyllostomidae) sugar water (44 g of table sugar in 500 ml of water) or sugar water with ethanol before challenging them to fly through an obstacle course while we simultaneously recorded their echolocation calls. We used bat saliva, a non-invasive proxy, to measure blood ethanol concentrations ranging from 0 to >0.3% immediately before flight trials. Flight performance and echolocation behaviour were not significantly affected by consumption of ethanol, but species differed in their blood alcohol concentrations after consuming it.
CONCLUSIONS/SIGNIFICANCE: The bats we studied display a tolerance for ethanol that could have ramifications for the adaptive radiation of frugivorous and nectarivorous bats by allowing them to use ephemeral food resources over a wide span of time. By sampling across phyllostomid genera, we show that patterns of apparent ethanol tolerance in New World bats are broad, and thus may have been an important early step in the evolution of frugivory and nectarivory in these animals.
2010-02-01T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/20
info:doi/10.1371/journal.pone.0008993
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813879/
Biology Publications
Scholarship@Western
Alcohol Drinking
Analysis of Variance
Animals
Central Nervous System Depressants
Chiroptera
Echolocation
Ethanol
Flight
Animal
Species Specificity
Time Factors
Female
Flight, Animal
Male
Ecology and Evolutionary Biology
oai:ir.lib.uwo.ca:biologypub-1020
2011-09-06T02:59:46Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Amyloid Beta Resistance in Nerve Cell Lines Is Mediated by the Warburg Effect
Newington, Jordan T.
Pitts, Andrea
Chien, Andrew
Arseneault, Robert
Schubert, David
Cumming, Robert C.
Amyloid beta (Aβ) peptide accumulation in the brains of patients with Alzheimer's disease (AD) is closely associated with increased nerve cell death. However, many cells survive and it is important to understand the mechanisms involved in this survival response. Recent studies have shown that an anti-apoptotic mechanism in cancer cells is mediated by aerobic glycolysis, also known as the Warburg effect. One of the major regulators of aerobic glycolysis is pyruvate dehydrogenase kinase (PDK), an enzyme which represses mitochondrial respiration and forces the cell to rely heavily on glycolysis, even in the presence of oxygen. Recent neuroimaging studies have shown that the spatial distribution of aerobic glycolysis in the brains of AD patients strongly correlates with Aβ deposition. Interestingly, clonal nerve cell lines selected for resistance to Aβ exhibit increased glycolysis as a result of activation of the transcription factor hypoxia inducible factor 1. Here we show that Aβ resistant nerve cell lines upregulate Warburg effect enzymes in a manner reminiscent of cancer cells. In particular, Aβ resistant nerve cell lines showed elevated PDK1 expression in addition to an increase in lactate dehydrogenase A (LDHA) activity and lactate production when compared to control cells. In addition, mitochondrial derived reactive oxygen species (ROS) were markedly diminished in resistant but not sensitive cells. Chemically or genetically inhibiting LDHA or PDK1 re-sensitized resistant cells to Aβ toxicity. These findings suggest that the Warburg effect may contribute to apoptotic-resistance mechanisms in the surviving neurons of the AD brain. Loss of the adaptive advantage afforded by aerobic glycolysis may exacerbate the pathophysiological processes associated with AD.
2011-04-26T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/21
info:doi/10.1371/journal.pone.0019191
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3082554/
Biology Publications
Scholarship@Western
Amyloid beta-Peptides
Animals
Glycolysis
L-Lactate Dehydrogenase
Lactic Acid
Mitochondria
Models
Biological
Neurons
PC12 Cells
Protein-Serine-Threonine Kinases
Rats
Reactive Oxygen Species
Models, Biological
Cell and Developmental Biology
Oncology
Physiology
oai:ir.lib.uwo.ca:biologypub-1021
2012-02-24T02:12:22Z
publication:biologypub
publication:biochempub
publication:obsgyn
publication:biology
publication:obsgynpub
publication:paed
publication:pmid
publication:biochem
publication:faculties
publication:paedpub
Retinoic Acid Is a Key Regulatory Switch Determining the Difference between Lung and Thyroid Fates in Xenopus laevis
Wang, Jean H.
Deimling, Steven J.
D'Alessandro, Nicole E.
Zhao, Lin
Possmayer, Fred
Drysdale, Thomas A.
BACKGROUND: The lung and thyroid are derived from the anterior endoderm. Retinoic acid and Fgf signalling are known to be essential for development of the lung in mouse but little is known on how the lung and thyroid are specified in Xenopus.
RESULTS: If either retinoic acid or Fgf signalling is inhibited, there is no differentiation of the lung as assayed by expression of sftpb. There is no change in expression of thyroid gland markers when retinoic acid signalling is blocked after gastrulation and when Fgf signalling is inhibited there is a short window of time where pax2 expression is inhibited but expression of other markers is unaffected. If exogenous retinoic acid is given to the embryo between embryonic stages 20 and 26, the presumptive thyroid expresses sftpb and sftpc, specific markers of lung differentiation and expression of key thyroid transcription factors is lost. When the presumptive thyroid is transplanted into the posterior embryo, it also expresses sftpb, although pax2 expression is not blocked.
CONCLUSIONS: After gastrulation, retinoic acid is required for lung but not thyroid differentiation in Xenopus while Fgf signalling is needed for lung but only for early expression of pax2 in the thyroid. Exposure to retinoic acid can cause the presumptive thyroid to switch to a lung developmental program.
2011-12-20T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/22
info:doi/10.1186/1471-213X-11-75
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3268113/
Biology Publications
Scholarship@Western
Retinoic acid
Lung
Thyroid
Xenopus laevis
Biochemistry, Biophysics, and Structural Biology
Biology
Obstetrics and Gynecology
Pediatrics
oai:ir.lib.uwo.ca:biologypub-1024
2015-04-17T20:26:04Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Biological relevance of CNV calling methods using familial relatedness including monozygotic twins
Castellani, Christina A
Singh, Shiva M
Locke, Elizabeth O
Studies involving the analysis of structural variation including Copy Number Variation (CNV) have recently exploded in the literature. Furthermore, CNVs have been associated with a number of complex diseases and neurodevelopmental disorders. Common methods for CNV detection use SNP, CNV, or CGH arrays, where the signal intensities of consecutive probes are used to define the number of copies associated with a given genomic region. These practices pose a number of challenges that interfere with the ability of available methods to accurately call CNVs. It has, therefore, become necessary to develop experimental protocols to test the reliability of CNV calling methods from microarray data so that researchers can properly discriminate biologically relevant data from noise.
2014-04-21T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/23
info:doi/doi:10.1186/1471-2105-15-114
https://ir.lib.uwo.ca/context/biologypub/article/1024/viewcontent/1471_2105_15_114.pdf
Biology Publications
Scholarship@Western
Microarrays; Copy number variation; Genetic relatedness; CNV calling methods; Monozygotic twins
Biology
oai:ir.lib.uwo.ca:biologypub-1025
2015-09-14T19:55:06Z
publication:biologypub
publication:wheprobiotics
publication:biology
publication:pmid
publication:westernheadseast
publication:institutes
publication:faculties
Harnessing Microbiome and Probiotic Research in Sub-Saharan Africa: Recommendations from an African Workshop
Reid, Gregor
To augment capacity-building for microbiome and probiotic research in Africa, a workshop was held in Nairobi, Kenya, at which researchers discussed human, animal, insect, and agricultural microbiome and probiotics/prebiotics topics. Five recommendations were made to promote future basic and translational research that benefits Africans.
2014-04-16T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/24
info:doi/doi:10.1186/2049-2618-2-12
https://ir.lib.uwo.ca/context/biologypub/article/1025/viewcontent/2049_2618_2_12.pdf
Biology Publications
Scholarship@Western
human
animal
insect
and agricultural microbiome
probiotics
prebiotics
Microbiology
oai:ir.lib.uwo.ca:biologypub-1026
2018-03-06T16:03:13Z
publication:biologypub
publication:biochempub
publication:biology
publication:pmid
publication:biochem
publication:faculties
Unifying the analysis of high-throughput sequencing datasets: characterizing RNA-seq, 16S rRNA gene sequencing and selective growth experiments by compositional data analysis.
Fernandes, Andrew D
Reid, Jennifer Ns
Macklaim, Jean M
McMurrough, Thomas A
Edgell, David R
Gloor, Gregory B
BACKGROUND: Experimental designs that take advantage of high-throughput sequencing to generate datasets include RNA sequencing (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-seq), sequencing of 16S rRNA gene fragments, metagenomic analysis and selective growth experiments. In each case the underlying data are similar and are composed of counts of sequencing reads mapped to a large number of features in each sample. Despite this underlying similarity, the data analysis methods used for these experimental designs are all different, and do not translate across experiments. Alternative methods have been developed in the physical and geological sciences that treat similar data as compositions. Compositional data analysis methods transform the data to relative abundances with the result that the analyses are more robust and reproducible.
RESULTS: Data from an in vitro selective growth experiment, an RNA-seq experiment and the Human Microbiome Project 16S rRNA gene abundance dataset were examined by ALDEx2, a compositional data analysis tool that uses Bayesian methods to infer technical and statistical error. The ALDEx2 approach is shown to be suitable for all three types of data: it correctly identifies both the direction and differential abundance of features in the differential growth experiment, it identifies a substantially similar set of differentially expressed genes in the RNA-seq dataset as the leading tools and it identifies as differential the taxa that distinguish the tongue dorsum and buccal mucosa in the Human Microbiome Project dataset. The design of ALDEx2 reduces the number of false positive identifications that result from datasets composed of many features in few samples.
CONCLUSION: Statistical analysis of high-throughput sequencing datasets composed of per feature counts showed that the ALDEx2 R package is a simple and robust tool, which can be applied to RNA-seq, 16S rRNA gene sequencing and differential growth datasets, and by extension to other techniques that use a similar approach.
2014-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/25
info:doi/doi: 10.1186/2049-2618-2-15
https://ir.lib.uwo.ca/context/biologypub/article/1026/viewcontent/fernandesRNAseq2014.pdf
Biology Publications
Scholarship@Western
compositional data
differential abundance
centered log-ratio transformation
Dirichlet distribution
Monte Carlo sampling
RNA-seq
microbiome
16S rRNA gene sequencing
high-throughput sequencing
Medical Biochemistry
oai:ir.lib.uwo.ca:biologypub-1028
2015-09-14T20:09:02Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Long-Term Genomic and Epigenomic Dysregulation as a Consequence of Prenatal Alcohol Exposure: A Model for Fetal Alcohol Spectrum Disorders
Kleiber, Morgan L
Diehl, Eric J
Laufer, Benjamin I
Mantha, Katarzyna
Chokroborty-Hoque, Aniruddho
Alberry, Bonnie
Singh, Shiva M
There is abundant evidence that prenatal alcohol exposure leads to a range of behavioral and cognitive impairments, categorized under the term fetal alcohol spectrum disorders (FASDs). These disorders are pervasive in Western cultures and represent the most common preventable source of neurodevelopmental disabilities. The genetic and epigenetic etiology of these phenotypes, including those factors that may maintain these phenotypes throughout the lifetime of an affected individual, has become a recent topic of investigation. This review integrates recent data that has progressed our understanding FASD as a continuum of molecular events, beginning with cellular stress response and ending with a long-term "footprint" of epigenetic dysregulation across the genome. It reports on data from multiple ethanol-treatment paradigms in mouse models that identify changes in gene expression that occur with respect to neurodevelopmental timing of exposure and ethanol dose. These studies have identified patterns of genomic alteration that are dependent on the biological processes occurring at the time of ethanol exposure. This review also adds to evidence that epigenetic processes such as DNA methylation, histone modifications, and non-coding RNA regulation may underlie long-term changes to gene expression patterns. These may be initiated by ethanol-induced alterations to DNA and histone methylation, particularly in imprinted regions of the genome, affecting transcription which is further fine-tuned by altered microRNA expression. These processes are likely complex, genome-wide, and interrelated. The proposed model suggests a potential for intervention, given that epigenetic changes are malleable and may be altered by postnatal environment. This review accentuates the value of mouse models in deciphering the molecular etiology of FASD, including those processes that may provide a target for the ammelioration of this common yet entirely preventable disorder.
2014-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/26
info:doi/doi: 10.3389/fgene.2014.00161
https://ir.lib.uwo.ca/context/biologypub/article/1028/viewcontent/fgene_05_00161.pdf
Biology Publications
Scholarship@Western
DNA methylation
epigenetics
fetal alcohol spectrum disorders
gene expression
histone modifications
microRNA
mouse models
neurodevelopment
Biology
oai:ir.lib.uwo.ca:biologypub-1029
2015-09-16T16:42:16Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Exploring the Complexity of Intellectual Disability in Fetal Alcohol Spectrum Disorders
Chokroborty-Hoque, Aniruddho
Alberry, Bonnie
Singh, Shiva M.
Brain development in mammals is long lasting. It begins early during embryonic growth and is finalized in early adulthood. This progression represents a delicate choreography of molecular, cellular, and physiological processes initiated and directed by the fetal genotype in close interaction with environment. Not surprisingly, most aberrations in brain functioning including intellectual disability (ID) are attributed to either gene(s), or environment or the interaction of the two. The ensuing complexity has made the assessment of this choreography, ever challenging. A model to assess this complexity has used a mouse model (C57BL/6J or B6) that is subjected to prenatal alcohol exposure. The resulting pups show learning and memory deficits similar to patients with fetal alcohol spectrum disorder (FASD), which is associated with life-long changes in gene expression. Interestingly, this change in gene expression underlies epigenetic processes including DNA methylation and miRNAs. This paradigm is applicable to ethanol exposure at different developmental times (binge at trimesters 1, 2, and 3 as well as continuous preference drinking (70%) of 10% alcohol by B6 females during pregnancy). The exposure leads to life-long changes in neural epigenetic marks, gene expression, and a variety of defects in neurodevelopment and CNS function. We argue that this cascade may be reversed postnatally via drugs, chemicals, and environment including maternal care. Such conclusions are supported by two sets of results. First, antipsychotic drugs that are used to treat ID including psychosis function via changes in DNA methylation, a major epigenetic mark. Second, post-natal environment may improve (with enriched environments) or worsen (with negative and maternal separation stress) the cognitive ability of pups that were prenatally exposed to ethanol as well as their matched controls. In this review, we will discuss operational epigenetic mechanisms involved in the development of intellectual ability/disability in response to alcohol during prenatal or post-natal development. In doing so, we will explore the potential of epigenetic manipulation in the treatment of FASD and related disorders implicated in ID.
2014-08-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/27
info:doi/doi: 10.3389/fped.2014.00090
https://ir.lib.uwo.ca/context/biologypub/article/1029/viewcontent/fped_02_00090.pdf
Biology Publications
Scholarship@Western
neurodevelopment
fetal alcohol spectrum disorders
mouse models
epigenetics
stress
environmental enrichment
intellectual disability
gene expression
Biology
oai:ir.lib.uwo.ca:biologypub-1030
2015-09-16T17:46:32Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Olanzapine-Induced Methylation Alters Cadherin Gene Families and Associated Pathways Implicated in Psychosis
Melka, Melkaye G.
Castellani, Christina A
Rajakumar, Nagalingam
O'Reilly, Richard
Singh, Shiva M
BACKGROUND: The complex aetiology of most mental disorders involves gene-environment interactions that may operate using epigenetic mechanisms particularly DNA methylation. It may explain many of the features seen in mental disorders including transmission, expression and antipsychotic treatment responses. This report deals with the assessment of DNA methylation in response to an antipsychotic drug (olanzapine) on brain (cerebellum and hippocampus), and liver as a non-neural reference in a rat model. The study focuses on the Cadherin/protocadherins encoded by a multi-gene family that serve as adhesion molecules and are involved in cell-cell communication in the mammalian brain. A number of these molecules have been implicated in the causation of schizophrenia and related disorders.
RESULTS: The results show that olanzapine causes changes in DNA methylation, most specific to the promoter region of specific genes. This response is tissue specific and involves a number of cadherin genes, particularly in cerebellum. Also, the genes identified have led to the identification of several pathways significantly affected by DNA methylation in cerebellum, hippocampus and liver. These included the Gα12/13 Signalling (p = 9.2E-08) and Wnt signalling (p = 0.01) pathways as contributors to psychosis that is based on its responsiveness to antipsychotics used in its treatment.
CONCLUSION: The results suggest that DNA methylation changes on the promoter regions of the Cadherin/protocadherin genes impact the response of olanzapine treatment. These impacts have been revealed through the identified pathways and particularly in the identification of pathways that have been previously implicated in psychosis.
2014-09-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/28
info:doi/doi:10.1186/1471-2202-15-112
https://ir.lib.uwo.ca/context/biologypub/article/1030/viewcontent/1471_2202_15_112.pdf
Biology Publications
Scholarship@Western
Animals
Antipsychotic Agents
Benzodiazepines
Cadherins
Cerebellum
DNA Methylation
Hippocampus
Immunoprecipitation
Liver
Male
Promoter Regions
Genetic
Psychotic Disorders
Rats
Sprague-Dawley
Promoter Regions, Genetic
Rats, Sprague-Dawley
Biology
Psychiatry and Psychology
oai:ir.lib.uwo.ca:biologypub-1031
2015-09-17T17:33:39Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
The Relative Influence of Habitat Amount and Configuration on Genetic Structure Across Multiple Spatial Scales
Millette, Katie L
Keyghobadi, Nusha
Despite strong interest in understanding how habitat spatial structure shapes the genetics of populations, the relative importance of habitat amount and configuration for patterns of genetic differentiation remains largely unexplored in empirical systems. In this study, we evaluate the relative influence of, and interactions among, the amount of habitat and aspects of its spatial configuration on genetic differentiation in the pitcher plant midge, Metriocnemus knabi. Larvae of this species are found exclusively within the water-filled leaves of pitcher plants (Sarracenia purpurea) in a system that is naturally patchy at multiple spatial scales (i.e., leaf, plant, cluster, peatland). Using generalized linear mixed models and multimodel inference, we estimated effects of the amount of habitat, patch size, interpatch distance, and patch isolation, measured at different spatial scales, on genetic differentiation (F ST) among larval samples from leaves within plants, plants within clusters, and clusters within peatlands. Among leaves and plants, genetic differentiation appears to be driven by female oviposition behaviors and is influenced by habitat isolation at a broad (peatland) scale. Among clusters, gene flow is spatially restricted and aspects of both the amount of habitat and configuration at the focal scale are important, as is their interaction. Our results suggest that both habitat amount and configuration can be important determinants of genetic structure and that their relative influence is scale dependent.
2015-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/29
info:doi/doi: 10.1002/ece3.1325
https://ir.lib.uwo.ca/context/biologypub/article/1031/viewcontent/ece30005_0073.pdf
Biology Publications
Scholarship@Western
Dispersal
gene flow
habitat structure
isolation
landscape genetics
Biology
oai:ir.lib.uwo.ca:biologypub-1032
2016-11-11T20:54:05Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Sex Differences in Spatial Memory in Brown-Headed Cowbirds: Males Outperform Females on a Touchscreen Task
Guigueno, Mélanie F
MacDougall-Shackleton, Scott A.
Sherry, David F.
Spatial cognition in females and males can differ in species in which there are sex-specific patterns in the use of space. Brown-headed cowbirds are brood parasites that show a reversal of sex-typical space use often seen in mammals. Female cowbirds, search for, revisit and parasitize hosts nests, have a larger hippocampus than males and have better memory than males for a rewarded location in an open spatial environment. In the current study, we tested female and male cowbirds in breeding and non-breeding conditions on a touchscreen delayed-match-to-sample task using both spatial and colour stimuli. Our goal was to determine whether sex differences in spatial memory in cowbirds generalizes to all spatial tasks or is task-dependant. Both sexes performed better on the spatial than on the colour touchscreen task. On the spatial task, breeding males outperformed breeding females. On the colour task, females and males did not differ, but females performed better in breeding condition than in non-breeding condition. Although female cowbirds were observed to outperform males on a previous larger-scale spatial task, males performed better than females on a task testing spatial memory in the cowbirds' immediate visual field. Spatial abilities in cowbirds can favour males or females depending on the type of spatial task, as has been observed in mammals, including humans.
2015-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/30
info:doi/10.1371/journal.pone.0128302
https://ir.lib.uwo.ca/context/biologypub/article/1032/viewcontent/pone.0128302.pdf
Biology Publications
Scholarship@Western
brown-headed cowbirds
spatial cognition
spatial memory
sex differences
Biology
oai:ir.lib.uwo.ca:biologypub-1033
2015-09-17T20:12:21Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Accurate Alternative Measurements for Female Lifetime Reproductive Success in Drosophila Melanogaster
Nguyen, Trinh T X
Moehring, Amanda
Fitness is an individual's ability to survive and reproduce, and is an important concept in evolutionary biology. However, accurately measuring fitness is often difficult, and appropriate fitness surrogates need to be identified. Lifetime reproductive success, the total progeny an organism can produce in their lifetime, is thought to be a suitable proxy for fitness, but the measure of an organism's reproductive output across a lifetime can be difficult or impossible to obtain. Here we demonstrate that the short-term measure of reproductive success across five days provides a reasonable prediction of an individual's total lifetime reproductive success in Drosophila melanogaster. However, the lifetime reproductive success of a female that has only mated once is not correlated to the lifetime reproductive success of a female that is allowed to mate multiple times, demonstrating that these measures should not serve as surrogates nor be used to make inferences about one another.
2015-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/31
info:doi/doi: 10.1371/journal.pone.0116679
https://ir.lib.uwo.ca/context/biologypub/article/1033/viewcontent/moehringnguyen.pdf
Biology Publications
Scholarship@Western
Biology
oai:ir.lib.uwo.ca:biologypub-1034
2016-11-11T20:55:57Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
DNA Methylation Differences in Monozygotic Twin Pairs Discordant for Schizophrenia Identifies Psychosis Related Genes and Networks
Castellani, Christina A.
Laufer, Benjamin I.
Melka, Melkaye G.
Diehl, Eric J.
O'Reilly, Richard L.
Singh, Shiva M.
Background
Despite their singular origin, monozygotic twin pairs often display discordance for complex disorders including schizophrenia. It is a common (1%) and often familial disease with a discordance rate of ~50% in monozygotic twins. This high discordance is often explained by the role of yet unknown environmental, random, and epigenetic factors. The involvement of DNA methylation in this disease appears logical, but remains to be established.
Methods
We have used blood DNA from two pairs of monozygotic twins discordant for schizophrenia and their parents in order to assess genome-wide methylation using a NimbleGen Methylation Promoter Microarray.
Results
The genome-wide results show that differentially methylated regions (DMRs) exist between members representing discordant monozygotic twins. Some DMRs are shared with parent(s) and others appear to be de novo. We found twenty-seven genes affected by DMR changes that were shared in the affected member of two discordant monozygotic pairs from unrelated families. Interestingly, the genes affected by pair specific DMRs share specific networks. Specifically, this study has identified two networks; “cell death and survival” and a “cellular movement and immune cell trafficking”. These two networks and the genes affected have been previously implicated in the aetiology of schizophrenia.
Conclusions
The results are compatible with the suggestion that DNA methylation may contribute to the discordance of monozygotic twins for schizophrenia. Also, this may be accomplished by the direct effect of gene specific methylation changes on specific biological networks rather than individual genes. It supports the extensive genetic, epigenetic and phenotypic heterogeneity implicated in schizophrenia.
2015-05-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/32
info:doi/10.1186/s12920-015-0093-1
https://ir.lib.uwo.ca/context/biologypub/article/1034/viewcontent/s12920_015_0093_1.pdf
Biology Publications
Scholarship@Western
Monozygotic twins
Schizophrenia
DNA Methylation
MeDIP
Methylation Array
Biology
oai:ir.lib.uwo.ca:biologypub-1035
2015-09-21T19:54:45Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Saponin-Permeabilization is Not a Viable Alternative to Isolated Mitochondria for Assessing Oxidative Metabolism in Hibernation
Staples, James
Mathers, Katherine E.
Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liver energy metabolism typically assessed in isolated mitochondria. We studied the ground squirrel (Ictidomys tridecemlineatus Mitchell), a hibernating mammal that shows profound and acute whole-animal metabolic suppression in the transition from winter euthermia to torpor. This reversible metabolic suppression is also reflected in the metabolism of isolated liver mitochondria. In this study we compared euthermic and torpid animals using saponin permeabilized tissue and mitochondria isolated from the same livers. As previously demonstrated, isolated mitochondria have state 3 respiration rates, fueled by succinate, that are suppressed by 60-70% during torpor. This result holds whether respiration is standardized to mitochondrial protein, cytochrome a content or citrate synthase activity. In contrast, saponin-permeabilized liver tissue, show no such suppression in torpor. Neither citrate synthase activity nor VDAC content differ between torpor and euthermia, indicating that mitochondrial content remains constant in both permeabilized tissue and isolated mitochondria. In contrast succinate dehydrogenase activity is suppressed during torpor in isolated mitochondria, but not in permeabilized tissue. Mechanisms underlying metabolic suppression in torpor may have been reversed by the permeabilization process. As a result we cannot recommend saponin permeabilization for assessing liver mitochondrial function under conditions where acute changes in metabolism are known to occur.
2015-07-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/33
info:doi/doi: 10.1242/?bio.011544
https://ir.lib.uwo.ca/context/biologypub/article/1035/viewcontent/858.full.pdf
Biology Publications
Scholarship@Western
Metabolism
Hibernation Mitochondrial respiration
Metabolic suppression
Permeabilized tissue
Biology
oai:ir.lib.uwo.ca:biologypub-1036
2016-11-11T20:57:23Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Insights into the Origin of DNA Methylation Differences between Monozygotic Twins Discordant for Schizophrenia
Melka, Melkaye G.
Castellani, Christina A.
O'Reilly, Richard
Singh, Shiva M.
BACKGROUND: DNA methylation differences between monozygotic twins discordant for schizophrenia have been previously reported. However, the origin of methylation differences between monozygotic twins discordant for schizophrenia is not clear. The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics.
METHODS: Methylation differences in rat brain regions and also in two pairs of unrelated monozygotic twins discordant for schizophrenia have been studied using genome-wide DNA methylation arrays at Arraystar Inc. (Rockville, Maryland, USA). The identified gene promoters showing significant alterations to DNA methylation were then further characterized using ingenuity pathway analysis (Ingenuity System Inc, CA, USA).
RESULTS: Pathway analysis of the most significant gene promoter hyper/hypomethylation revealed a significant enrichment of DNA methylation changes in biological networks and pathways directly relevant to neural development and psychiatric disorders. These included HIPPO signaling (p = 3.93E-03) and MAPK signaling (p = 4.27E-03) pathways involving hypermethylated genes in schizophrenia-affected patients as compared to their unaffected co-twins. Also, a number of significant pathways and networks involving genes with hypomethylated gene promoters have been identified. These included CREB signaling in neurons (p = 1.53E-02), Dopamine-DARPP32 feedback in cAMP signaling (p = 7.43E-03) and Ephrin receptors (p = 1.13E-02). Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02).
CONCLUSION: The findings highlight the significance of antipsychotic drugs on DNA methylation in schizophrenia patients. The unique pathways affected by DNA methylation in the two pairs of monozygotic twins suggest that patient-specific pathways are responsible for the disease; suggesting that patient-specific treatment strategies may be necessary in treating the disorder. The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients.
2015-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/34
info:doi/10.1186/s40303-015-0013-5
https://ir.lib.uwo.ca/context/biologypub/article/1036/viewcontent/melkam15.pdf
Biology Publications
Scholarship@Western
DNA methylation
monozygotic twins
schizophrenia
Biology
oai:ir.lib.uwo.ca:biologypub-1037
2016-11-11T21:02:51Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Strategies for Precision Modulation of Gene Expression by Epigenome Editing: An Overview
Laufer, Benjamin I.
Singh, Shiva M.
Genome editing technology has evolved rather quickly and become accessible to most researchers. It has resulted in far reaching implications and a number of novel designer systems including epigenome editing. Epigenome editing utilizes a combination of nuclease-null genome editing systems and effector domains to modulate gene expression. In particular, Zinc Finger, Transcription-Activator-Like Effector, and CRISPR/Cas9 have emerged as modular systems that can be modified to allow for precision manipulation of epigenetic marks without altering underlying DNA sequence. This review contains a comprehensive catalog of effector domains that can be used with components of genome editing systems to achieve epigenome editing. Ultimately, the evidence-based design of epigenome editing offers a novel improvement to the limited attenuation strategies. There is much potential for editing and/or correcting gene expression in somatic cells toward a new era of functional genomics and personalized medicine.
2015-09-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/35
info:doi/10.1186/s13072-015-0023-7
https://ir.lib.uwo.ca/context/biologypub/article/1037/viewcontent/s13072_015_0023_7.pdf
Biology Publications
Scholarship@Western
Regulation of gene expression
Functional genomics
Stem cells
dCas9
CRISPR/Cas9
Zinc Finger
Transcription-Activator-Like Effector (TALE)
Synthetic biology
Biology
oai:ir.lib.uwo.ca:biologypub-1038
2016-07-28T17:42:01Z
publication:biologypub
publication:biology
publication:faculties
Compost Application Affects Metal Uptake in Plants Grown in Urban Garden Soils and Potential Human Health Risk
Murray, Hollydawn
Pinchin, Trevor A
Macfie, Sheila M
Purpose This study explores the effect of varying organic matter content on the potential human health risk of consuming vegetables grown in urban garden soils.
Materials and methods Metal accumulation among edible tissues of green bean (Phaseolus vulgaris L.), lettuce (Lactuca sativa L.) and carrot (Daucus carota L.) was determined for plants grown in five urban garden soils amended with 0, 9, or 25% (v/v) compost. Potential risk to human health was assessed by calculating a bioconcentration factor and a hazard quotient.
Results and discussion Overall, the consumption of lettuce and green bean pods grown in some urban gardens posed a potential human health risk due to unacceptably high concentrations of cadmium or lead. In many cases, compost amendment increased the accumulation of metals in the vegetables. Even in soils considered uncontaminated by current guidelines, some hazard quotients exceeded the threshold value of 1. The compost used in this study had a high fulvic acid to humic acid ratio, which may explain increased concentrations of metals in plants grown in compost-amended soils.
Conclusions These results indicate a need to include soil characteristics, specifically organic matter quality, when setting threshold criteria for metal content of urban garden soils.
2011-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/38
info:doi/10.1007/s11368-011-0359-y
https://ir.lib.uwo.ca/context/biologypub/article/1038/viewcontent/Murray_et_al_revised_Dec_15.pdf
Biology Publications
Scholarship@Western
Fulvic acid
Humic acid
Metal contamination
Organic matter
Risk assessment
Urban gardens
Biology
oai:ir.lib.uwo.ca:biologypub-1039
2016-07-28T17:34:00Z
publication:biologypub
publication:biology
publication:faculties
Production of Organic Acids and Adsorption of Cd on Roots of Durum Wheat (Triticum turgidum L. var. durum)
Adeniji, Bolaji A.
Budimir-Hussey, Mackenzie T.
Macfie, Sheila M.
A number of isolines of durum wheat (Triticum turgidum var durum) differ in their translocation of Cd. In the field, the high isolines accumulate twice the Cd in leaves and grain when compared to the low isolines. The hypothesis that differential accumulation of Cd is associated with differential production of organic acids was tested by measuring Cd content in tissues, Cd partitioning within the root, and organic acids in tissues. In solution culture, the high and low isolines of W9261-BG did not differ in any of the variables measured. Within W9260-BC, the low isoline had half the Cd in its shoot, 30% more tightly-bound Cd in the root and higher concentrations of fumaric, malic, and succinic acids in the root compared to the high isoline. Differential Cd accumulation may be linked to differential adsorption and retention of Cd in the roots of the low Cd-accumulating isolines, possibly via chelation with organic acids.
2010-04-13T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/39
info:doi/10.1007/s11738-010-0498-6
https://ir.lib.uwo.ca/context/biologypub/article/1039/viewcontent/Adeniji_et_al._Feb_6.pdf
Biology Publications
Scholarship@Western
Cadmium
LMWOAs
Triticum turgidum
Isolines
Adsorption
Biology
oai:ir.lib.uwo.ca:biologypub-1040
2016-07-28T17:36:32Z
publication:biologypub
publication:biology
publication:faculties
Site- and Species-Specific Patterns of Metal Bioavailability in Edible Plants
Murray, Hollydawn
Thompson, Karen
Macfie, Sheila
Differences in metal uptake between plant species and soil types were compared to assess the safe use of mildly contaminated soils for the growth of edible food crops. Accumulation of metals in five plant species grown in each of three field soils and a commercial soil were evaluated in a controlled environment room. Metal bioavailability varied more with plant species than with type of soil. Among a number of physical and chemical soil properties that were determined, high metal content and low percent organic matter were the best predictors of increased metal bioavailability. Contamination levels of metals measured in soil and vegetable samples were used to calculate bioconcentration factors and hazard quotients. The results indicated significant differences between plant species. The most metal-accumulating species was carrot and the most mobile element was cadmium. Some hazard quotients exceeded the threshold value of 1, even in soils considered uncontaminated by current guidelines. Overall, these results reinforce the need to include soil characteristics when setting threshold guidelines for metal content of agricultural soils and indicate the need for species-specific planting guidelines.
2009-07-15T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/37
info:doi/10.1139/B09-019
https://ir.lib.uwo.ca/context/biologypub/article/1040/viewcontent/Murray_et_al_revised_MS.pdf
Biology Publications
Scholarship@Western
cadmium
copper
lead
zinc
plant uptake
risk assessment
hazard quotient
Biology
oai:ir.lib.uwo.ca:biologypub-1041
2016-07-29T15:03:49Z
publication:biologypub
publication:biology
publication:faculties
Species-Specific Relationship between Transpiration and Cadmium Translocation in Lettuce, Barley and Radish
Akhter, Mst. Fardausi
Macfie, Sheila
Cadmium (Cd) may accumulate in plants to levels that are of concern in human diets. Our ability to predict the accumulation of Cd in plants is restricted by our poor understanding of the physiological processes that control Cd accumulation and translocation. A hydroponic experiment was carried out to test the hypothesis that the amount of Cd taken up and translocated to aboveground tissues is proportional to the volume of water transpired in lettuce (Lactuca sativa L.), barley (Hordeum vulgare L.) and radish (Raphanus sativus L.). Transpiration was measured as mass of water lost. Increased transpiration caused increased accumulation of Cd in plants; however, the proportion of total Cd translocated to the leaves ranged from 85% in lettuce to 66% in radish to only 21% in barley. Thus, factors controlling species-specific internal distribution of Cd are more important than transpiration in translocating Cd to aboveground tissues.
2012-03-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/36
info:doi/10.5539/jps.v1n1p2
https://ir.lib.uwo.ca/context/biologypub/article/1041/viewcontent/Akhter_and_Macfie_2012.pdf
Biology Publications
Scholarship@Western
Cadmium
Root: Shoot partitioning
Transpiration
Translocation
Biology
oai:ir.lib.uwo.ca:biologypub-1042
2016-07-29T18:53:52Z
publication:biologypub
publication:biology
publication:faculties
Possible Radiation-Induced Damage to the Molecular Structure of Wooden Artifacts Due to Micro-Computed Tomography, Handheld X-Ray Fluorescence, and X-Ray Photoelectron Spectroscopic Techniques
Kozachuk, Madalena
Suda, Alexandra
Ellis, Lisa
Walzak, Mary
Biesinger, Mark
Macfie, Sheila
Hudson, Robert
Nelson, Andrew
Martin, Ronald
Heginbotham, Arlen
This study was undertaken to ascertain whether radiation produced by X-ray photoelectron spectroscopy (XPS), micro-computed tomography (μCT) and/or portable handheld X-ray fluorescence (XRF) equipment might damage wood artifacts during analysis. Changes at the molecular level were monitored by Fourier transform infrared (FTIR) analysis. No significant changes in FTIR spectra were observed as a result of μCT or handheld XRF analysis. No substantial changes in the collected FTIR spectra were observed when XPS analytical times on the order of minutes were used. However, XPS analysis collected over tens of hours did produce significant changes in the FTIR spectra.
2016-05-20T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/40
info:doi/10.5334/jcms.126
https://ir.lib.uwo.ca/context/biologypub/article/1042/viewcontent/kozachuk_etal_2016.pdf
Biology Publications
Scholarship@Western
X-ray Analysis
FTIR
Wooden Artifacts
Damage
Biology
oai:ir.lib.uwo.ca:biologypub-1043
2016-08-03T18:18:57Z
publication:biologypub
publication:biology
publication:faculties
Pb Distribution in Bones from the Franklin Expedition: Synchrotron X-Ray Fluorescence and Laser Ablation/Mass Spectroscopy
Martin, Ronald
Naftel, Steven
Macfie, Sheila
Jones, Keith
Nelson, Andrew J.
Synchrotron micro-X-ray Fluorescence has been used to map the metal distribution in selected bone fragments representative of remains associated with the Franklin expedition. In addition, laser ablation mass spectroscopy using a 25 μm diameter circular spot was employed to compare the Pb isotope distributions in small regions within the bone fragments. The X-ray Fluorescence mapping shows Pb to be widely distributed in the bone while the Pb isotope ratios obtained by laser ablation within small areas representative of bone with different Pb exchange rates do not show statistically significant differences. These results are inconsistent with the hypothesis that faulty solder seals in tinned meat were the principle source of Pb in the remains of the expedition personnel.
2013-02-07T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/42
info:doi/10.1007/s00339-013-7579-5
https://ir.lib.uwo.ca/context/biologypub/article/1043/viewcontent/Martin_etal_2013.pdf
Biology Publications
Scholarship@Western
lead
Franklin expedition
synchrotron
bone
Biology
oai:ir.lib.uwo.ca:biologypub-1044
2016-08-03T16:02:57Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Accumulation of Cadmium in Near-Isogenic Lines of Durum Wheat (Triticum Turgidum L. Var Durum): the Role of Transpiration
Quinn, C. J.
Mohammad, A.
Macfie, Sheila M.
Concentrations of cadmium in the grain of durum wheat (Triticum turgidum L. var durum) are often above the internationally acceptable limit of 0.2 mg kg−1. Cultivars that vary in concentrations of cadmium in the grain have been identified but the physiology behind differential accumulation has not been determined. Three pairs of near-isogenic lines (isolines) of durum wheat that vary in aboveground cadmium accumulation (8982-TL ‘high’ and ‘low’, W9260-BC ‘high’ and ‘low’, and W9261-BG ‘high’ and ‘low’) were used to test the hypothesis that the greater amounts of cadmium in shoots of the ‘high’ isolines are correlated with greater volumes of water transpired. In general, cadmium content was positively correlated with transpiration only in the ‘low’ isolines. Although shoots of the ‘high’ isolines of W9260-BC and W9261-BG contained higher concentrations of cadmium than did their corresponding ‘low’ isolines, they did not transpire larger volumes of water. In addition, isolines of 8982-TL transpired less water than did the other pairs of isolines yet both ‘high’ and ‘low’ isolines of 8982-TL contained higher amounts of cadmium than did the other pairs. The difference between ‘high’ and ‘low’ isolines appears to be related to the relative contribution of transpiration to cadmium translocation to the shoot. Increased transpiration was associated with increased cadmium content in the ‘low’ isolines but in the ‘high’ isolines increased cadmium in the shoot occurred independently of the volume of water transpired.
2011-10-05T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/41
info:doi/ 10.1007/s12298-011-0086-2
https://ir.lib.uwo.ca/context/biologypub/article/1044/viewcontent/Quinn_etal_2011.pdf
Biology Publications
Scholarship@Western
cadmium
durum wheat
near-isogenic lines
transpiration
Triticum turgidum
Biology
oai:ir.lib.uwo.ca:biologypub-1045
2016-08-08T18:54:48Z
publication:biologypub
publication:biology
publication:faculties
Localization and Chemical Speciation of Cadmium in the Roots of Barley and Lettuce
Akhter, Mst. Fardausi
Omelon, Christopher R.
Gordon, Robert A.
Moser, Desmond
Macfie, Sheila
Plants have the potential to accumulate toxic amounts of cadmium (Cd), and understanding how and where Cd is stored in plants is important for ensuring food safety. Previous experiments have determined that a greater amount of Cd is translocated into the leaves of lettuce (Lactuca sativa) as compared to barley leaves (Hordeum vulgare). Preferential retention of Cd in root of barley would explain this difference. Hence, the purpose of this study was to determine the localization and coordination environment of Cd (i.e., the ligands to which Cd was bound) in the different root tissues of lettuce and barley using histochemical staining, electron microscopy and micro X-ray spectroscopy. Retention of Cd in barley roots could be explained by accumulation of Cd at the endodermis, comparatively higher amounts of Cd sequestered in the symplast of cortical cells and binding to xylem cell walls. Increased translocation of Cd to lettuce shoots seemed to be due to a less effective barrier at the endodermis and less sequestration of Cd in the cortex. Regardless of the tissue type, most of the Cd2+ was bound to S ligands in the roots of barley, possibly reflecting accumulation of Cd–phytochelatin and Cd–S molecules in the vacuoles. In lettuce roots, Cd was more evenly distributed among ligands containing S, O and NO3 groups, which is indicative of proportionately more Cd binding to the cell walls, relative to barley. These results will be useful in uncovering the mechanisms of differential Cd-tolerance and sequestration in lettuce and barley.
2014-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/43
info:doi/10.1016/j.envexpbot.2013.12.005
https://ir.lib.uwo.ca/context/biologypub/article/1045/viewcontent/Akhter_et_al_Nov_28_EEB.pdf
Biology Publications
Scholarship@Western
Cadmium
Electron spectroscopy
X-ray spectroscopy
Chemical speciation
Hordeum vulgare
Lactuca sativa
Biology
oai:ir.lib.uwo.ca:biologypub-1046
2016-08-08T18:57:46Z
publication:biologypub
publication:biology
publication:faculties
Reduced Translocation of Cadmium from Roots Is Associated with Increased Production of Phytochelatins and Their Precursors
Akhter, Mst. Fardausi
McGarvey, Brian
Macfie, Sheila
Cadmium (Cd) is a non-essential trace element and its environmental concentrations are approaching toxic levels, especially in some agricultural soils. Understanding how and where Cd is stored in plants is important for ensuring food safety. In this study, we examined two plant species that differ in the distribution of Cd among roots and leaves. Lettuce and barley were grown in nutrient solution under two conditions: chronic (4 weeks) exposure to a low, environmentally relevant concentration (1.0 μM) of Cd and acute (1 h) exposure to a high concentration (5.0 mM) of Cd. Seedlings grown in solution containing 1.0 μM CdCl2 did not show symptoms of toxicity and, at this concentration, 77% of the total Cd was translocated to leaves of lettuce, whereas only 24% of the total Cd was translocated to barley leaves. We tested the hypothesis that differential accumulation of Cd in roots and leaves is related to differential concentrations of phytochelatins (PCs), and its precursor peptides. The amounts of PCs and their precursor peptides in the roots and shoots were measured using HPLC. Each of PC2–4 was synthesized in the barley root upon chronic exposure to Cd and did not increase further upon acute exposure. In the case of lettuce, no PCs were detected in the root given either Cd treatment. The high amounts of PCs produced in barley root could have contributed to preferential retention of Cd in barley roots.
2012-12-15T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/44
info:doi/10.1016/j.jplph.2012.07.011
https://ir.lib.uwo.ca/context/biologypub/article/1046/viewcontent/Akhter_et_al_JPP_Aug_1_JPP.pdf
Biology Publications
Scholarship@Western
Cadmium
Hordeum vulgare
Lactuca sativa
Phytochelatin
Translocation
Biology
oai:ir.lib.uwo.ca:biologypub-1047
2016-08-25T19:31:59Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Does the Response of Insect Herbivores to Cadmium Depend on Their Feeding Strategy?
Konopka, Joanna K.
Hanyu, Kazushi
Macfie, Sheila
McNeil, Jeremy N.
Phytoremediation has been proposed for the elimination of toxic metals in soil, yet little attention has been given to the performance of insects that feed on contaminant-tolerant plants. We tested the performance of two herbivores with different feeding behaviors, the cabbage looper, Trichoplusia ni, and the green peach aphid, Myzus persicae, reared on cadmium-tolerant Brassica juncea plants that contained different concentrations of cadmium. We also tested the performance of the aphid parasitoid Aphidius colemani developing in aphids reared on plants with different levels of cadmium. The hypothesis tested was that the chewing insect would be more negatively affected than the sucking insect, because of the localization of cadmium within the host plant, and that the aphid parasitoid would not be affected. We also compared the performance of T. ni on artificial diet with different levels of cadmium. Neither the phloem-feeding aphid nor its parasitoid was affected by cadmium in the host plant. The effects of cadmium on the foliage-feeding cabbage looper varied, with negative effects on development observed in experiments with artificial diet but not in those using natural host plants. These data, together with information available in the literature, support the idea that the effects of toxic metals present in a host plant may be influenced by a herbivore’s feeding strategy. However, a wide range of chewing and sucking species needs to be tested to confirm this hypothesis.
2013-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/45
info:doi/10.1007/s10886-013-0273-4
https://ir.lib.uwo.ca/context/biologypub/article/1047/viewcontent/Konopka_etal_2013_penultimate__1_.pdf
Biology Publications
Scholarship@Western
Cadmium
Phytoremediation
Feeding strategy
Oviposition
Myzus persicae
Trichoplusia ni
Aphidius colemani
Brassica juncea
Biology
oai:ir.lib.uwo.ca:biologypub-1048
2016-08-26T18:46:54Z
publication:biologypub
publication:biology
publication:faculties
It Takes an Individual Plant to Raise a Community: TRFLP Analysis of the Rhizosphere Microbial Community of Two Pairs of High- and Low-Metal-Accumulating Plants
Columbus, Melanie P.
Macfie, Sheila
We used terminal restriction fragment length polymorphism (TRFLP) analysis to look at the microbial community profiles of the rhizosphere surrounding two pairs of high- and low-metal (Cd)-accumulating plants (Brassica and Triticum). Unexpectedly, the microbial community did not vary with soil type, time, plant type, or metal-accumulating ability of the plant. Instead, when a plant's metal-accumulating ability was well matched to the level of metal contamination in the soil, the microbial populations in the rhizosphere were different than those of the seed endophytes and bulk soil. Unmatched plants had the same microbial community as bulk soil. The plant interaction with the soil, therefore, is essential to forming the bacterial community in the rhizosphere.
2014-11-15T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/46
info:doi/10.1016/j.soilbio.2014.11.002
https://ir.lib.uwo.ca/context/biologypub/article/1048/viewcontent/Columbus_and_Macfie_2015.pdf
Biology Publications
Scholarship@Western
microbial community
rhizosphere
TRFLP
cadmium
Biology
oai:ir.lib.uwo.ca:biologypub-1049
2016-10-20T17:09:10Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Metabolic Flexibility: Hibernation, Torpor, and Estivation.
Staples, James F
Many environmental conditions can constrain the ability of animals to obtain sufficient food energy, or transform that food energy into useful chemical forms. To survive extended periods under such conditions animals must suppress metabolic rate to conserve energy, water, or oxygen. Amongst small endotherms, this metabolic suppression is accompanied by and, in some cases, facilitated by a decrease in core body temperature-hibernation or daily torpor-though significant metabolic suppression can be achieved even with only modest cooling. Within some ectotherms, winter metabolic suppression exceeds the passive effects of cooling. During dry seasons, estivating ectotherms can reduce metabolism without changes in body temperature, conserving energy reserves, and reducing gas exchange and its inevitable loss of water vapor. This overview explores the similarities and differences of metabolic suppression among these states within adult animals (excluding developmental diapause), and integrates levels of organization from the whole animal to the genome, where possible. Several similarities among these states are highlighted, including patterns and regulation of metabolic balance, fuel use, and mitochondrial metabolism. Differences among models are also apparent, particularly in whether the metabolic suppression is intrinsic to the tissue or depends on the whole-animal response. While in these hypometabolic states, tissues from many animals are tolerant of hypoxia/anoxia, ischemia/reperfusion, and disuse. These natural models may, therefore, serve as valuable and instructive models for biomedical research.
2016-03-15T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/48
http://www.comprehensivephysiology.com/WileyCDA/CompPhysArticle/refId-c140064.html
Biology Publications
Scholarship@Western
Biology
oai:ir.lib.uwo.ca:biologypub-1051
2016-10-20T18:22:42Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Matching cellular metabolic supply and demand in energy-stressed animals.
Staples, James F
Buck, Leslie T
Certain environmental stressors can impair cellular ATP production to the point of harming or even killing an animal. Some exceptional animals employ strategies that maintain the balance between ATP production and consumption, allowing them to tolerate prolonged exposure to stressors such as hypoxia and anoxia. Anoxia- and hypoxia-tolerant animals reduce ATP consumption by ion-motive ATPases while concomitant reductions in passive ion flux reduce the demand for ion pumping and maintain transmembrane ion gradients. Reductions in gene transcription and protein turnover decrease ATP demand in hibernating and hypoxia-tolerant animals. Proton leak uncouples mitochondrial substrate oxidation from ATP synthesis and accounts for a considerable proportion of cellular energy demand, but there is little evidence that the proton permeability of inner mitochondrial membranes decreases in animals that tolerate energy stress. Indeed in some cases proton leak increases, possibly reducing reactive oxygen species production. Because substrate oxidation is important to the control of cellular metabolism, the downregulation of ATP supply pathways contributes significantly to metabolic suppression under energy stress. Mechanisms that coordinate the downregulation of both ATP supply and demand pathways include AMP kinase and ATP-sensitive ion channels. Strategies employed by animals tolerant to one energy stress often convey "cross-tolerance" to completely different stresses.
2009-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/49
http://www.sciencedirect.com/science/article/pii/S1095643309000373
Biology Publications
Scholarship@Western
Adenosine Triphosphate
Animals
Anoxia
Energy Metabolism
Stress
Physiological
Stress, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1050
2016-10-18T19:16:36Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Metabolic suppression in mammalian hibernation: the role of mitochondria.
Staples, James F
Hibernation evolved in some small mammals that live in cold environments, presumably to conserve energy when food supplies are low. Throughout the winter, hibernators cycle spontaneously between torpor, with low metabolism and near-freezing body temperatures, and euthermia, with high metabolism and body temperatures near 37°C. Understanding the mechanisms underlying this natural model of extreme metabolic plasticity is important for fundamental and applied science. During entrance into torpor, reductions in metabolic rate begin before body temperatures fall, even when thermogenesis is not active, suggesting active mechanisms of metabolic suppression, rather than passive thermal effects. Mitochondrial respiration is suppressed during torpor, especially when measured in liver mitochondria fuelled with succinate at 37°C in vitro. This suppression of mitochondrial metabolism appears to be invoked quickly during entrance into torpor when body temperature is high, but is reversed slowly during arousal when body temperature is low. This pattern may reflect body temperature-sensitive, enzyme-mediated post-translational modifications of oxidative phosphorylation complexes, for instance by phosphorylation or acetylation.
2014-06-15T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/47
https://ir.lib.uwo.ca/context/biologypub/article/1050/viewcontent/StaplesJEBCommentary2014.pdf
Biology Publications
Scholarship@Western
Animals
Cell Respiration
Hibernation
Mammals
Mitochondria
Biology
oai:ir.lib.uwo.ca:biologypub-1052
2016-10-20T18:26:43Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Mitochondrial metabolism in hibernation and daily torpor: a review.
Staples, James F
Brown, Jason C L
Hibernation and daily torpor involve substantial decreases in body temperature and metabolic rate, allowing birds and mammals to cope with cold environments and/or limited food. Regulated suppression of mitochondrial metabolism probably contributes to energy savings: state 3 (phosphorylating) respiration is lower in liver mitochondria isolated from mammals in hibernation or daily torpor compared to normothermic controls, although data on state 4 (non-phosphorylating) respiration are equivocal. However, no suppression is seen in skeletal muscle, and there is little reliable data from other tissues. In both daily torpor and hibernation, liver state 3 substrate oxidation is suppressed, especially upstream of electron transport chain complex IV. In hibernation respiratory suppression is reversed quickly in arousal even when body temperature is very low, implying acute regulatory mechanisms, such as oxaloacetate inhibition of succinate dehydrogenase. Respiratory suppression depends on in vitro assay temperature (no suppression is evident below approximately 30 degrees C) and (at least in hibernation) dietary polyunsaturated fats, suggesting effects on inner mitochondrial membrane phospholipids. Proton leakiness of the inner mitochondrial membrane does not change in hibernation, but this also depends on dietary polyunsaturates. In contrast proton leak increases in daily torpor, perhaps limiting reactive oxygen species production.
2008-09-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/50
http://link.springer.com/article/10.1007/s00360-008-0282-8
Biology Publications
Scholarship@Western
Animals
Basal Metabolism
Body Temperature
Hibernation
Mitochondria
Liver
Mitochondrial Membranes
Respiration
Mitochondria, Liver
Biology
oai:ir.lib.uwo.ca:biologypub-1053
2016-10-25T19:58:55Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Regulation of mitochondrial metabolism during hibernation by reversible suppression of electron transport system enzymes.
Mathers, Katherine E
McFarlane, Sarah V
Zhao, Lin
Staples, James F
Small hibernators cycle between periods of torpor, with body temperature (T b) approximately 5 °C, and interbout euthermia (IBE), where T b is approximately 37 °C. During entrance into a torpor bout liver mitochondrial respiration is rapidly suppressed by 70 % relative to IBE. We compared activities of electron transport system (ETS) complexes in intact liver mitochondria isolated from 13-lined ground squirrels (Ictidomys tridecemlineatus) sampled during torpor and IBE to investigate potential sites of this reversible metabolic suppression. Flux through complexes I-IV and II-IV was suppressed by 40 and 60 %, respectively, in torpor, while flux through complexes III-IV and IV did not differ between torpor and IBE. We also measured maximal enzyme activity of ETS enzymes in homogenized isolated mitochondria and whole liver tissue. In isolated mitochondria, activities of complexes I and II were significantly lower in torpor relative to IBE, but complexes III, IV, and V did not differ. In liver tissue, only activity of complex II was suppressed during torpor relative to IBE. Despite the significant differences in both ETS flux and maximal activity, the protein content of complexes I and II did not differ between torpor and IBE. These results suggest that the rapid, reversible suppression of mitochondrial metabolism is due to regulatory changes, perhaps by post-translational modification during entrance into a torpor bout, and not changes in ETS protein content.
2016-08-06T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/51
http://link.springer.com/article/10.1007%2Fs00360-016-1022-0
Biology Publications
Scholarship@Western
Biology
oai:ir.lib.uwo.ca:biologypub-1054
2016-11-07T14:53:01Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Saponin-Permeabilization is Not a Viable Alternative to Isolated Mitochondria for Assessing Oxidative Metabolism in Hibernation
Mathers, Katherine E.
Staples, James F.
Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liver energy metabolism typically assessed in isolated mitochondria. We studied the ground squirrel (Ictidomys tridecemlineatus Mitchell), a hibernating mammal that shows profound and acute whole-animal metabolic suppression in the transition from winter euthermia to torpor. This reversible metabolic suppression is also reflected in the metabolism of isolated liver mitochondria. In this study we compared euthermic and torpid animals using saponin permeabilized tissue and mitochondria isolated from the same livers. As previously demonstrated, isolated mitochondria have state 3 respiration rates, fueled by succinate, that are suppressed by 60-70% during torpor. This result holds whether respiration is standardized to mitochondrial protein, cytochrome a content or citrate synthase activity. In contrast, saponin-permeabilized liver tissue, show no such suppression in torpor. Neither citrate synthase activity nor VDAC content differ between torpor and euthermia, indicating that mitochondrial content remains constant in both permeabilized tissue and isolated mitochondria. In contrast succinate dehydrogenase activity is suppressed during torpor in isolated mitochondria, but not in permeabilized tissue. Mechanisms underlying metabolic suppression in torpor may have been reversed by the permeabilization process. As a result we cannot recommend saponin permeabilization for assessing liver mitochondrial function under conditions where acute changes in metabolism are known to occur.
2015-05-15T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/52
info:doi/10.1242/bio.011544
https://ir.lib.uwo.ca/context/biologypub/article/1054/viewcontent/Biology_Open_2015_Mathers_bio.011544.pdf
Biology Publications
Scholarship@Western
Hibernation
Metabolic suppression
Metabolism
Mitochondrial respiration
Permeabilized tissue
Biology
oai:ir.lib.uwo.ca:biologypub-1055
2016-10-25T20:09:13Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Parallel ionoregulatory adjustments underlie phenotypic plasticity and evolution of Drosophila cold tolerance.
MacMillan, Heath A
Ferguson, Laura V
Nicolai, Annegret
Donini, Andrew
Staples, James F
Sinclair, Brent J
Low temperature tolerance is the main predictor of variation in the global distribution and performance of insects, yet the molecular mechanisms underlying cold tolerance variation are poorly known, and it is unclear whether the mechanisms that improve cold tolerance within the lifetime of an individual insect are similar to those that underlie evolved differences among species. The accumulation of cold-induced injuries by hemimetabolous insects is associated with loss of Na(+) and K(+) homeostasis. Here we show that this model holds true for Drosophila; cold exposure increases haemolymph [K(+)] in D. melanogaster, and cold-acclimated flies maintain low haemolymph [Na(+)] and [K(+)], both at rest and during a cold exposure. This pattern holds across 24 species of the Drosophila phylogeny, where improvements in cold tolerance have been consistently paired with reductions in haemolymph [Na(+)] and [K(+)]. Cold-acclimated D. melanogaster have low activity of Na(+)/K(+)-ATPase, which may contribute to the maintenance of low haemolymph [Na(+)] and underlie improvements in cold tolerance. Modifications to ion balance are associated with both phenotypic plasticity within D. melanogaster and evolutionary differences in cold tolerance across the Drosophila phylogeny, which suggests that adaptation and acclimation of cold tolerance in insects may occur through similar mechanisms. Cold-tolerant flies maintain haemolymph osmolality despite low haemolymph [Na(+)] and [K(+)], possibly through modest accumulations of organic osmolytes. We propose that this could have served as an evolutionary route by which chill-susceptible insects developed more extreme cold tolerance strategies.
2015-02-01T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/53
http://jeb.biologists.org/content/218/3/423
Biology Publications
Scholarship@Western
Acclimatization
Adaptation
Physiological
Animals
Biological Evolution
Cold Temperature
Drosophila melanogaster
Hemolymph
Phylogeny
Sodium-Potassium-Exchanging ATPase
Water-Electrolyte Balance
Adaptation, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1058
2016-10-25T20:22:11Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Identification, expression, and taxonomic distribution of alternative oxidases in non-angiosperm plants.
Neimanis, Karina
Staples, James F
Hüner, Norman P A
McDonald, Allison E
Alternative oxidase (AOX) is a terminal ubiquinol oxidase present in the respiratory chain of all angiosperms investigated to date, but AOX distribution in other members of the Viridiplantae is less clear. We assessed the taxonomic distribution of AOX using bioinformatics. Multiple sequence alignments compared AOX proteins and examined amino acid residues involved in AOX catalytic function and post-translational regulation. Novel AOX sequences were found in both Chlorophytes and Streptophytes and we conclude that AOX is widespread in the Viridiplantae. AOX multigene families are common in non-angiosperm plants and the appearance of AOX1 and AOX2 subtypes pre-dates the divergence of the Coniferophyta and Magnoliophyta. Residues involved in AOX catalytic function are highly conserved between Chlorophytes and Streptophytes, while AOX post-translational regulation likely differs in these two lineages. We demonstrate experimentally that an AOX gene is present in the moss Physcomitrella patens and that the gene is transcribed. Our findings suggest that AOX will likely exert an influence on plant respiration and carbon metabolism in non-angiosperms such as green algae, bryophytes, liverworts, lycopods, ferns, gnetophytes, and gymnosperms and that further research in these systems is required.
2013-09-10T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/56
http://www.sciencedirect.com/science/article/pii/S0378111913005696?np=y
Biology Publications
Scholarship@Western
Amino Acid Sequence
Base Sequence
Binding Sites
Computational Biology
Databases
Genetic
Evolution
Molecular
Iron
Mitochondrial Proteins
Molecular Sequence Data
Oxidoreductases
Plant Proteins
Plants
Protein Binding
Sequence Alignment
Viridiplantae
Databases, Genetic
Evolution, Molecular
Biology
oai:ir.lib.uwo.ca:biologypub-1057
2016-10-25T20:19:16Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Are long chain acyl CoAs responsible for suppression of mitochondrial metabolism in hibernating 13-lined ground squirrels?
Cooper, Alex N
Brown, Jason C L
Staples, James F
Hibernation in 13-lined ground squirrels (Ictidomys tridecemlineatus) is associated with a substantial suppression of whole-animal metabolism. We compared the metabolism of liver mitochondria isolated from torpid ground squirrels with those from interbout euthermic (IBE; recently aroused from torpor) and summer euthermic conspecifics. Succinate-fuelled state 3 respiration, calculated relative to mitochondrial protein, was suppressed in torpor by 48% and 44% compared with IBE and summer, respectively. This suppression remains when respiration is expressed relative to cytochrome c oxidase activity. We hypothesized that this suppression was caused by inhibition of succinate transport at the dicarboxylate transporter (DCT) by long-chain fatty acyl CoAs that may accumulate during torpor. We predicted, therefore, that exogenous palmitoyl CoA would inhibit respiration in IBE more than in torpor. Palmitoyl CoA inhibited respiration ~70%, in both torpor and IBE. The addition of carnitine, predicted to reverse palmitoyl CoA suppression by facilitating its transport into the mitochondrial matrix, did not rescue the respiration rates in IBE or torpor. Liver mitochondrial activities of carnitine palmitoyl transferase did not differ among IBE, torpor and summer animals. Although palmitoyl CoA inhibits succinate-fuelled respiration, this suppression is likely not related exclusively to inhibition of the DCT, and may involve additional mitochondrial transporters such as the adenine-nucleotide transporter.
2014-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/55
http://www.sciencedirect.com/science/article/pii/S1096495914000207
Biology Publications
Scholarship@Western
Acyl Coenzyme A
Animals
Electron Transport Complex IV
Hibernation
Mitochondria
Liver
Mitochondrial Proteins
Oxygen Consumption
Sciuridae
Seasons
Mitochondria, Liver
Biology
oai:ir.lib.uwo.ca:biologypub-1056
2016-10-25T20:13:30Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Substrate-specific changes in mitochondrial respiration in skeletal and cardiac muscle of hibernating thirteen-lined ground squirrels.
Brown, Jason C L
Staples, James F
During torpor, the metabolic rate (MR) of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is considerably lower relative to euthermia, resulting in part from temperature-independent mitochondrial metabolic suppression in liver and skeletal muscle, which together account for ~40% of basal MR. Although heart accounts for very little (
2014-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/54
http://link.springer.com/article/10.1007/s00360-013-0799-3
Biology Publications
Scholarship@Western
Animals
Cell Respiration
Citrate (si)-Synthase
Female
Hibernation
Male
Mitochondria
Muscle
Muscle
Skeletal
Myocardium
Sciuridae
Succinate Dehydrogenase
Mitochondria, Muscle
Muscle, Skeletal
Biology
oai:ir.lib.uwo.ca:biologypub-1059
2016-10-25T20:25:04Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Changes in the mitochondrial phosphoproteome during mammalian hibernation.
Chung, Dillon J
Szyszka, Beata
Brown, Jason C L
Hüner, Norman P A
Staples, James F
Mammalian hibernation involves periods of substantial suppression of metabolic rate (torpor) allowing energy conservation during winter. In thirteen-lined ground squirrels (Ictidomys tridecemlineatus), suppression of liver mitochondrial respiration during entrance into torpor occurs rapidly (within 2 h) before core body temperature falls below 30°C, whereas reversal of this suppression occurs slowly during arousal from torpor. We hypothesized that this pattern of rapid suppression in entrance and slow reversal during arousal was related to changes in the phosphorylation state of mitochondrial enzymes during torpor catalyzed by temperature-dependent kinases and phosphatases. We compared mitochondrial protein phosphorylation among hibernation metabolic states using immunoblot analyses and assessed how phosphorylation related to mitochondrial respiration rates. No proteins showed torpor-specific changes in phosphorylation, nor did phosphorylation state correlate with mitochondrial respiration. However, several proteins showed seasonal (summer vs. winter) differences in phosphorylation of threonine or serine residues. Using matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry, we identified three of these proteins: F1-ATPase α-chain, long chain-specific acyl-CoA dehydrogenase, and ornithine transcarbamylase. Therefore, we conclude that protein phosphorylation is likely a mechanism involved in bringing about seasonal changes in mitochondrial metabolism in hibernating ground squirrels, but it seems unlikely to play any role in acute suppression of mitochondrial metabolism during torpor.
2013-05-15T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/57
http://physiolgenomics.physiology.org/content/45/10/389.long
Biology Publications
Scholarship@Western
Animals
Body Temperature
Electrophoresis
Gel
Two-Dimensional
Female
Hibernation
Male
Mammals
Mitochondria
Liver
Mitochondrial Proteins
Oxygen Consumption
Phosphoproteins
Phosphorylation
Proteome
Proteomics
Sciuridae
Seasons
Serine
Spectrometry
Mass
Matrix-Assisted Laser Desorption-Ionization
Threonine
Electrophoresis, Gel, Two-Dimensional
Mitochondria, Liver
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Biology
oai:ir.lib.uwo.ca:biologypub-1060
2016-10-25T20:28:18Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
The effects of hibernation on the contractile and biochemical properties of skeletal muscles in the thirteen-lined ground squirrel, Ictidomys tridecemlineatus.
James, Rob S
Staples, James F
Brown, Jason C L
Tessier, Shannon N
Storey, Kenneth B
Hibernation is a crucial strategy of winter survival used by many mammals. During hibernation, thirteen-lined ground squirrels, Ictidomys tridecemlineatus, cycle through a series of torpor bouts, each lasting more than a week, during which the animals are largely immobile. Previous hibernation studies have demonstrated that such natural models of skeletal muscle disuse cause limited or no change in either skeletal muscle size or contractile performance. However, work loop analysis of skeletal muscle, which provides a realistic assessment of in vivo power output, has not previously been undertaken in mammals that undergo prolonged torpor during hibernation. In the present study, our aim was to assess the effects of 3 months of hibernation on contractile performance (using the work loop technique) and several biochemical properties that may affect performance. There was no significant difference in soleus muscle power output-cycle frequency curves between winter (torpid) and summer (active) animals. Total antioxidant capacity of gastrocnemius muscle was 156% higher in torpid than in summer animals, suggesting one potential mechanism for maintenance of acute muscle performance. Soleus muscle fatigue resistance was significantly lower in torpid than in summer animals. Gastrocnemius muscle glycogen content was unchanged. However, state 3 and state 4 mitochondrial respiration rates were significantly suppressed, by 59% and 44%, respectively, in mixed hindlimb skeletal muscle from torpid animals compared with summer controls. These findings in hindlimb skeletal muscles suggest that, although maximal contractile power output is maintained in torpor, there is both suppression of ATP production capacity and reduced fatigue resistance.
2013-07-15T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/58
http://jeb.biologists.org/content/216/14/2587.long
Biology Publications
Scholarship@Western
Adenosine Triphosphate
Analysis of Variance
Animals
Antioxidants
Biomechanical Phenomena
Cell Respiration
Female
Glycogen
Hibernation
Male
Muscle Contraction
Muscle
Skeletal
Sciuridae
Seasons
Time Factors
Muscle, Skeletal
Biology
oai:ir.lib.uwo.ca:biologypub-1061
2016-10-25T20:31:37Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Adaptations to hibernation in lung surfactant composition of 13-lined ground squirrels influence surfactant lipid phase segregation properties.
Suri, Lakshmi N M
Cruz, Antonio
Veldhuizen, Ruud A W
Staples, James F
Possmayer, Fred
Orgeig, Sandra
Perez-Gil, Jesus
Pulmonary surfactant lines the entire alveolar surface, serving primarily to reduce the surface tension at the air-liquid interface. Surfactant films adsorb as a monolayer interspersed with multilayers with surfactant lipids segregating into different phases or domains. Temperature variation, which influences lipid physical properties, affects both the lipid phase segregation and the surface activity of surfactants. In hibernating animals, such as 13-lined ground squirrels, which vary their body temperature, surfactant must be functional over a wide range of temperatures. We hypothesised that surfactant from the 13-lined ground squirrel, Ictidomys tridecemlineatus, would undergo appropriate lipid structural re-arrangements at air-water interfaces to generate phase separation, sufficient to attain the low surface tensions required to remain stable at both low and high body temperatures. Here, we examined pressure-area isotherms at 10, 25 and 37°C and found that surfactant films from both hibernating and summer-active squirrels reached their highest surface pressure on the Wilhelmy-Langmuir balance at 10°C. Epifluorescence microscopy demonstrated that films of hibernating squirrel surfactant display different lipid micro-domain organisation characteristics than surfactant from summer-active squirrels. These differences were also reflected at the nanoscale as determined by atomic force microscopy. Such re-arrangement of lipid domains in the relatively more fluid surfactant films of hibernating squirrels may contribute to overcoming collapse pressures and support low surface tension during the normal breathing cycle at low body temperatures.
2013-08-01T07:00:00Z
article
https://ir.lib.uwo.ca/biologypub/59
http://www.sciencedirect.com/science/article/pii/S0005273613000680
Biology Publications
Scholarship@Western
Adaptation
Physiological
Animals
Hibernation
Lipids
Microscopy
Atomic Force
Pulmonary Surfactants
Sciuridae
Surface Properties
Surface Tension
Temperature
Adaptation, Physiological
Microscopy, Atomic Force
Biology
oai:ir.lib.uwo.ca:biologypub-1062
2016-10-19T15:58:47Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Regulation of succinate-fuelled mitochondrial respiration in liver and skeletal muscle of hibernating thirteen-lined ground squirrels.
Brown, Jason C L
Chung, Dillon J
Cooper, Alex N
Staples, James F
Hibernating ground squirrels (Ictidomys tridecemlineatus) alternate between two distinct metabolic states throughout winter: torpor, during which metabolic rate (MR) and body temperature (Tb) are considerably suppressed, and interbout euthermia (IBE), during which MR and Tb briefly return to euthermic levels. Previous studies showed suppression of succinate-fuelled respiration during torpor in liver and skeletal muscle mitochondria; however, these studies used only a single, saturating succinate concentration. Therefore, they could not address whether mitochondrial metabolic suppression occurs under physiological substrate concentrations or whether differences in the kinetics of mitochondrial responses to changing substrate concentration might also contribute to mitochondrial metabolic regulation during torpor. The present study confirmed that succinate oxidation is reduced during torpor in liver and skeletal muscle at 37 and 10°C over a 100-fold range of succinate concentrations. At 37°C, this suppression resulted from inhibition of succinate dehydrogenase (SDH), which had a greater affinity for oxaloacetate (an SDH inhibitor) during torpor. At 10°C, SDH was not inhibited, suggesting that SDH inhibition initiates but does not maintain mitochondrial suppression during torpor. Moreover, in both liver and skeletal muscle, mitochondria from torpid animals maintained relatively higher respiration rates at low succinate concentrations, which reduces the extent of energy savings that can be achieved during torpor, but may also maintain mitochondrial oxidative capacity above some lower critical threshold, thereby preventing cellular and/or mitochondrial injury during torpor and facilitating rapid recruitment of oxidative capacity during arousal.
2013-05-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/60
https://ir.lib.uwo.ca/context/biologypub/article/1062/viewcontent/BrownJEB2013.pdf
Biology Publications
Scholarship@Western
Animals
Cell Respiration
Female
Hibernation
Kinetics
Liver
Mitochondria
Liver
Mitochondria
Muscle
Muscle
Skeletal
Oxaloacetic Acid
Sciuridae
Succinate Dehydrogenase
Succinic Acid
Temperature
Mitochondria, Liver
Mitochondria, Muscle
Muscle, Skeletal
Biology
oai:ir.lib.uwo.ca:biologypub-1064
2016-10-19T16:00:52Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Metabolism of brain cortex and cardiac muscle mitochondria in hibernating 13-lined ground squirrels Ictidomys tridecemlineatus.
Gallagher, Kirsten
Staples, James F
During bouts of torpor, mitochondrial metabolism is known to be suppressed in the liver and skeletal muscle of hibernating mammals. This suppression is rapidly reversed during interbout euthermic (IBE) phases, when whole-animal metabolic rate and body temperature (T(b)) return spontaneously to euthermic levels. Such mitochondrial suppression may contribute significantly to energy savings, but the capacity of other tissues to suppress mitochondrial metabolism remains unclear. In this study we compared the metabolism of mitochondria from brain cortex and left ventricular cardiac muscle between animals sampled while torpid (stable T(b) near 5°C) and in IBE (stable T(b) near 37°C). Instead of isolating mitochondria using the traditional methods of homogenization and centrifugation, we permeabilized tissue slices with saponin, allowing energetic substrates and inhibitors to access mitochondria. No significant differences in state 3 or state 4 respiration were observed between torpor and IBE in either tissue. In general, succinate produced the highest oxidation rates followed by pyruvate and then glutamate, palmitoyl carnitine, and β-hydroxybutyrate. These findings suggest that there is no suppression of mitochondrial metabolism or change in substrate preference in these two tissues despite the large changes in whole-animal metabolism seen between torpor and IBE.
2013-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/62
https://ir.lib.uwo.ca/context/biologypub/article/1064/viewcontent/GallagherPBZ2013.pdf
Biology Publications
Scholarship@Western
Animals
Cell Respiration
Cerebral Cortex
Heart Ventricles
Hibernation
Manitoba
Mitochondria
Mitochondria
Muscle
Myocardium
Reactive Oxygen Species
Saponins
Sciuridae
Seasons
Mitochondria, Muscle
Biology
oai:ir.lib.uwo.ca:biologypub-1063
2016-10-25T20:37:08Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Selective mobilization of saturated fatty acids in isolated adipocytes of hibernating 13-lined ground squirrels Ictidomys tridecemlineatus.
Price, Edwin R
Armstrong, Christopher
Guglielmo, Christopher G
Staples, James F
Fatty acids are not mobilized from adipocyte triacylglycerols uniformly but rather some are preferentially mobilized while others are preferentially retained. In many vertebrate species, the pattern of differential mobilization is determined by the physical and chemical properties of each fatty acid. Fatty acids with shorter chains and more double bonds tend to be more readily mobilized than others, a pattern observed both in whole-animal studies and in isolated adipocytes. Several hibernating species seem to break this pattern, however, and retain 18:2ω6 (linoleic acid) while mobilizing saturated fatty acids such as 18:0. We sought to confirm this pattern in adipocytes of a hibernator, the 13-lined ground squirrel Ictidomys tridecemlineatus, and to investigate mobilization patterns for the first time at hibernation temperature. We isolated adipocytes from summer active and winter torpid squirrels and incubated them with 1 μM norepinephrine at 4°C (7 h) and 37°C (90 min). We measured the proportion of each fatty acid in the adipose tissue and in the buffer at the end of incubation. Patterns of mobilization were similar in both seasons and incubation temperatures. Saturated fatty acids (18:0 and 16:0) were highly mobilized relative to the average, while some unsaturated fatty acids (notably, 18:1ω9 and 18:2ω6) were retained. We conclude that hibernators have unique mechanisms at the level of adipose tissue that preferentially mobilize saturated fatty acids. Additionally, we found that adipocytes from hibernating squirrels produced more glycerol than those from summer squirrels (regardless of temperature), indicating a higher lipolytic capacity in hibernating squirrels.
2013-03-01T08:00:00Z
article
https://ir.lib.uwo.ca/biologypub/61
http://www.journals.uchicago.edu/doi/pdfplus/10.1086/668892
Biology Publications
Scholarship@Western
Adipocytes
Animals
Fatty Acids
Flame Ionization
Gas Chromatography-Mass Spectrometry
Hibernation
Lipid Mobilization
Manitoba
Sciuridae
Seasons
Temperature
Biology
oai:ir.lib.uwo.ca:biologypub-1065
2016-11-07T17:04:11Z
publication:biologypub
publication:biology
publication:faculties
Tomato Whole Genome Transcriptional Response to Tetranychus urticae Identifies Divergence of Spider Mite-Induced Responses Between Tomato and Arabidopsis
Martel, Catherine
Zhurov, Vladimir
Navarro, Marie
Martinez, Manuel
Cazaux, Marc
Auger, Philippe
Migeon, Alain
Santamaria, M. Estrella
Wybouw, Nicky
Diaz, Isabel
Van Leeuwen, Thomas
Navajas, Maria
Grbic, Miodrag
Grbic, Vojislava
The two-spotted spider mite Tetranychus urticae is one of the most significant mite pests in agriculture, feeding on more than 1,100 plant hosts, including model plants Arabidopsis thaliana and tomato, Solanum lycopersicum. Here, we describe timecourse tomato transcriptional responses to spider mite feeding and compare them with Arabidopsis in order to determine conserved and divergent defense responses to this pest. To refine the involvement of jasmonic acid (JA) in mite-induced responses and to improve tomato Gene Ontology annotations, we analyzed transcriptional changes in the tomato JA-signaling mutant defenseless1 (def-1) upon JA treatment and spider mite herbivory. Overlay of differentially expressed genes (DEG) identified in def-1 onto those from the timecourse experiment established that JA controls expression of the majority of genes differentially regulated by herbivory. Comparison of defense responses between tomato and Arabidopsis highlighted 96 orthologous genes (of 2,133 DEG) that were recruited for defense against spider mites in both species. These genes, involved in biosynthesis of JA, phenylpropanoids, flavonoids, and terpenoids, represent the conserved core of induced defenses. The remaining tomato DEG support the establishment of tomato-specific defenses, indicating profound divergence of spider mite-induced responses between tomato and Arabidopsis.
2015-03-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/63
info:doi/10.1094/MPMI-09-14-0291-FI
https://ir.lib.uwo.ca/context/biologypub/article/1065/viewcontent/MPMI_09_14_0291_FI.pdf
Biology Publications
Scholarship@Western
Tetranychus urticae
spider mite
Arabidopsis thaliana
Solanum lycopersicum
transcriptional responses
Biology
oai:ir.lib.uwo.ca:biologypub-1067
2017-07-06T18:38:48Z
publication:biologypub
publication:biology
publication:faculties
A cross-seasonal perspective on local adaptation: Metabolic 1 plasticity mediates responses to winter in a thermal-2 generalist moth
Sinclair, Brent J.
Williams, Caroline M
Chick, Wesley D
2014-11-20T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/64
https://ir.lib.uwo.ca/context/biologypub/article/1067/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
Biology
Entomology
oai:ir.lib.uwo.ca:biologypub-1068
2017-07-07T19:11:32Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Identification of cold-responsive genes in a New Zealand alpine stick insect using RNA-Seq.
Dunning, Luke T
Dennis, Alice B
Park, Duckchul
Sinclair, Brent J
Newcomb, Richard D
Buckley, Thomas R
The endemic New Zealand alpine stick insect Micrarchus nov. sp. 2 regularly experiences sub-zero temperatures in the wild. 454-based RNA-Seq was used to generate a de novo transcriptome and differentiate between treatments to investigate the genetic basis of cold tolerance. Non cold-treated individuals were compared to those exposed to 0°C for 1 h followed by a 1 h recovery period at 20°C. We aligned 607,410 Roche 454 reads, generating a transcriptome of 5235 contigs. Differential expression analysis ranked candidate cold responsive genes for qPCR validation by P-value. The top nine up-regulated candidates, together with eight a priori targets identified from previous studies, had their relative expression quantified using qPCR. Three candidate cold responsive genes from the RNA-Seq data were verified as significantly up-regulated, annotated as: prolyl 4-hydroxylase subunit alpha-1 (P4HA1), staphylococcal nuclease domain-containing protein 1 (snd1) and cuticular protein analogous to peritrophins 3-D2 (Cpap3-d2). All three are novel candidate genes, illustrating the varied response to low temperature across insects.
2013-03-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/80
info:doi/10.1016/j.cbd.2012.10.005
https://ir.lib.uwo.ca/context/biologypub/article/1068/viewcontent/Identification_of_cold_responsive_genes_in_a_New_Zealand_alpine_stick_insect_using_RNA_Seq.pdf
Biology Publications
Scholarship@Western
Animals
Cold Shock Proteins and Peptides
Female
Gene Expression Profiling
Insect Proteins
Insects
Models
Statistical
New Zealand
RNA
Messenger
Real-Time Polymerase Chain Reaction
Sequence Alignment
Sequence Analysis
RNA
Transcriptome
Models, Statistical
RNA, Messenger
Sequence Analysis, RNA
Biology
oai:ir.lib.uwo.ca:biologypub-1070
2017-07-07T17:20:53Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
The overwintering biology of the acorn weevil, Curculio glandium in southwestern Ontario.
Udaka, Hiroko
Sinclair, Brent J
The acorn weevil, Curculio glandium, is a widespread predator of acorns in eastern North America that overwinters in the soil as a larva. It is possible that low temperatures limit its northern geographic range, so we determined the cold tolerance strategy, seasonal variation in cold tolerance, and explored the physiological plasticity of overwintering larvae. Weevil larvae were collected from acorns of red and bur oak from Pelee Island, southwestern Ontario in fall 2010 and 2011. C. glandium larvae are freeze avoidant and larvae collected from bur oak acorns had lower supercooling points (SCPs: -7.6±0.36°C, LT50: -7.2°C) than those collected from red oak acorns (SCPs: -6.1±0.40°C, LT50: -6.1°C). In the winter of 2010-2011, SCPs and water content decreased, however these changes did not occur in 2011-2012, when winter soil temperatures fluctuated greatly in the absence of the buffering effect of snow. To examine whether larvae utilize cryoprotective dehydration, larvae from red oak acorns were exposed to -5°C in the presence of ice for seven days. These conditions decreased the SCP without affecting water content, suggesting that SCP and water content are not directly coupled. Finally, long-term acclimation at 0°C for six weeks slightly increased cold tolerance but also did not affect water content. Thus, although larval diet affects cold tolerance, there is limited plasticity after other treatments. The soil temperatures we observed were not close to lethal limits, although we speculate that soil temperatures in northerly habitats, or in years of reduced snow cover, has the potential to cause mortality in the field.
2014-08-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/65
info:doi/10.1016/j.jtherbio.2014.02.019
https://ir.lib.uwo.ca/context/biologypub/article/1070/viewcontent/the_overwintering_biology_of_the_acorn_weevil__Curclio_glandium_in_Southwestern_Ontario_figures_and_post_print.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Freezing
Larva
Water
Weevils
Biology
oai:ir.lib.uwo.ca:biologypub-1072
2017-07-06T19:55:16Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Increased abundance of frost mRNA during recovery from cold stress is not essential for cold tolerance in adult Drosophila melanogaster.
Udaka, H
Percival-Smith, A
Sinclair, B J
Frost (Fst) is a candidate gene associated with the response to cold in Drosophila melanogaster because Fst mRNA accumulation increases during recovery from low temperature exposure. We investigated the contribution of Fst expression to chill-coma recovery time, acute cold tolerance and rapid cold hardening (RCH) in adult D. melanogaster by knocking down Fst mRNA expression using GAL4/UAS-mediated RNA interference. In this experiment, four UAS-Fst and one tubulin-GAL4 lines were used. We predicted that if Fst is essential for cold tolerance phenotypes, flies with low Fst mRNA levels should be less cold tolerant than flies with normal levels of cold-induced Fst mRNA. Cold-induced Fst abundance and recovery time from chill-coma were not negatively correlated in male or female flies. Survival of 2 h exposures to sub-zero temperatures in Fst knockdown lines was not lower than that in a control line. Moreover, a low temperature pretreatment increased survival of severe cold exposure in flies regardless of Fst abundance level during recovery from cold stress, suggesting that Fst expression is not essential for RCH. Thus, cold-induced Fst accumulation is not essential for cold tolerance measured as chill-coma recovery time, survival to acute cold stress and RCH response in adult D. melanogaster.
2013-10-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/66
info:doi/10.1111/imb.12044
https://ir.lib.uwo.ca/context/biologypub/article/1072/viewcontent/MS_RNAifly_final_pre_submission_Nov23__2_.pdf
Biology Publications
Scholarship@Western
Aging
Animals
Cold Temperature
Drosophila Proteins
Drosophila melanogaster
Female
Male
Phenotype
RNA Interference
RNA
Messenger
Stress
Physiological
RNA, Messenger
Stress, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1071
2017-07-07T19:13:04Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Cold tolerance of the eastern subterranean termite, Reticulitermes flavipes (Isoptera: Rhinotermitidae), in Ontario.
Clarke, Matthew W
Thompson, Graham J
Sinclair, Brent J
We characterized the cold tolerance of natural populations of the Eastern subterranean termite (Reticulitermes flavipes (Kollar) [Isoptera, Rhinotermitidae]) in southwestern Ontario, Canada. We measured cold tolerance in workers from six colonies of termites established from Pelee Island in Lake Erie, and Point Pelee National Park. The mean critical thermal minimum, at which termites entered chill coma, ranged from 8.1 to 5.7°C. Mean supercooling points (SCP, the temperature at which individuals freeze) ranged from -4 to -4.6°C, and did not differ significantly between colonies, nor was SCP dependent on body size. Individuals survived brief exposure to low temperatures, as long as they did not freeze, but internal ice formation was always lethal, suggesting a freeze avoiding strategy. The LT50 (temperature at which 50% of individuals were killed by a 1 h exposure) was -5.1°C, but all individuals could survive -2°C for at least 72 h. Low temperature acclimation (12°C, 7 d) or hardening (4°C, 2 h) had no impact on the SCP, but acclimation did slightly increase the critical thermal minimum, making the termites less cold tolerant. We conclude that R. flavipes is not particularly cold tolerant, and likely relies on burrowing deep into the soil to avoid exposure to temperature to extremes.
2013-08-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/81
info:doi/10.1603/EN12348
https://ir.lib.uwo.ca/context/biologypub/article/1071/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Cold Temperature
Cold-Shock Response
Introduced Species
Isoptera
Ontario
Biology
Entomology
Other Ecology and Evolutionary Biology
oai:ir.lib.uwo.ca:biologypub-1073
2017-07-06T20:07:18Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Insects in fluctuating thermal environments.
Colinet, Hervé
Sinclair, Brent J
Vernon, Philippe
Renault, David
All climate change scenarios predict an increase in both global temperature means and the magnitude of seasonal and diel temperature variation. The nonlinear relationship between temperature and biological processes means that fluctuating temperatures lead to physiological, life history, and ecological consequences for ectothermic insects that diverge from those predicted from constant temperatures. Fluctuating temperatures that remain within permissive temperature ranges generally improve performance. By contrast, those which extend to stressful temperatures may have either positive impacts, allowing repair of damage accrued during exposure to thermal extremes, or negative impacts from cumulative damage during successive exposures. We discuss the mechanisms underlying these differing effects. Fluctuating temperatures could be used to enhance or weaken insects in applied rearing programs, and any prediction of insect performance in the field-including models of climate change or population performance-must account for the effect of fluctuating temperatures.
2015-01-07T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/67
info:doi/10.1146/annurev-ento-010814-021017
https://ir.lib.uwo.ca/context/biologypub/article/1073/viewcontent/Manuscript_FINAL_PDF.pdf
Biology Publications
Scholarship@Western
Animals
Climate Change
Environment
Insects
Temperature
Biology
oai:ir.lib.uwo.ca:biologypub-1075
2017-07-06T20:18:31Z
publication:biologypub
publication:biology
publication:faculties
Freeze tolerance of Cyphoderris monstrosa (Orthoptera: Prophalangopsidae)
Toxopeus, Jantina
Lebenzon, Jacqueline
Mckinnon, Alexander H
Sinclair, Brent J.
The great grig, Cyphoderris monstrosa Uhler (Orthoptera: Prophalangopsidae), is a large (20-30 mm, >1 g), nocturnal ensiferan that in habits montane coniferous forests in northwestern North America. C. monstrosa overwinters as a late-instar nymph, but its cold tolerance strategy has not previously been reported. We collected nymphs from near Kamloops, British Columbia, in late spring to determine their cold tolerance strategy. C. monstrosa nymphs were active at low temperatures until they froze at -4.6 ± 0.3 °C. The nymphs survived internal ice formation (i.e. are freeze tolerant), had a lethal temperature between -9 and -12 °C, and could survive for between five and ten days at -6 °C. Isolated C. monstrosa gut, Malpighian tubules and hind femur muscle tissues froze at temperatures similar to whole nymphs, and likely inoculate freezing in vivo. Hemolymph osmolality was 358 ± 51 mOsm, with trehalose and proline comprising approximately 10 % of that total. Glycerol was not detectable in hemolymph from field-fresh nymphs, but accumulated after freezing and thawing. The control of ice formation and presence of hemolymph cryoprotectants may contribute to C. monstrosa freeze tolerance and overwintering survival.
2016-12-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/69
info:doi/10.4039/tce.2016.21
https://ir.lib.uwo.ca/context/biologypub/article/1075/viewcontent/Freeze_tolerance_of_C._monstrosa.pdf
Biology Publications
Scholarship@Western
Biology
Entomology
Molecular Biology
oai:ir.lib.uwo.ca:biologypub-1074
2017-07-06T20:12:29Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
An invitation to measure insect cold tolerance: Methods, approaches, and workflow.
Sinclair, Brent J
Coello Alvarado, Litza E
Ferguson, Laura V
Insect performance is limited by the temperature of the environment, and in temperate, polar, and alpine regions, the majority of insects must face the challenge of exposure to low temperatures. The physiological response to cold exposure shapes the ability of insects to survive and thrive in these environments, and can be measured, without great technical difficulty, for both basic and applied research. For example, understanding insect cold tolerance allows us to predict the establishment and spread of insect pests and biological control agents. Additionally, the discipline provides the tools for drawing physiological comparisons among groups in wider studies that may not be focused primarily on the ability of insects to survive the cold. Thus, the study of insect cold tolerance is of a broad interest, and several reviews have addressed the theories and advances in the field. Here, however, we aim to clarify and provide rationale for common practices used to study cold tolerance, as a guide for newcomers to the field, students, and those wishing to incorporate cold tolerance into a broader study. We cover the 'tried and true' measures of insect cold tolerance, the equipment necessary for these measurement, and summarize the ecological and biological significance of each. Finally, we suggest a framework and workflow for measuring cold tolerance and low temperature performance in insects.
2015-10-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/68
info:doi/10.1016/j.jtherbio.2015.11.003
https://ir.lib.uwo.ca/context/biologypub/article/1074/viewcontent/TB_2015_105_Revision_1_V0.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Cold Temperature
Entomology
Insects
Thermometry
Biology
oai:ir.lib.uwo.ca:biologypub-1076
2017-07-07T13:44:26Z
publication:biologypub
publication:biology
publication:faculties
Thermal Biology and immersion tolerance of the Beringian pseudoscorpion Wyochernes 4 asiaticus
Anthony, Susan E
Buddle, Christopher M
Sinclair, Brent J
Wyochernes asiaticus (Arachnida: Pseudoscorpiones: Chernetidae) is a pseudoscorpion distributed across Beringia, the areas of Yukon, Alaska and Siberia that remained unglaciated at the last glacial maximum. Along with low temperatures, its streamside habitat suggests that submergence during flood events is an important physiological challenge for this species. We collected W. asiaticus in midsummer from 66.8N Yukon Territory, Canada, and measured thermal and immersion tolerance. Wyochernes asiaticus is freeze-avoidant, with a mean supercooling point of -6.9 C. It remains active at low temperatures (mean critical thermal minimum, CTmin, is -3.6 C) and has a critical thermal maximum (CTmax) of 37.8 C, which is lower than other arachnids and consistent with its restriction to high latitudes. Fifty per cent of W. asiaticus individuals survived immersion in oxygen-depleted water for 17 days, suggesting that this species has high tolerance to immersion during flooding events. To our knowledge, these are the first data on the environmental physiology of any pseudoscorpion and a new addition to our understanding of the biology of polar microarthropods.
2015-12-02T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/70
info:doi/10.1007/s00300-015-1849-y
https://ir.lib.uwo.ca/context/biologypub/article/1076/viewcontent/POBI_D_15_00282_R1__1_.pdf
Biology Publications
Scholarship@Western
Pseudoscorpion
Microarthropod
Cold tolerance
Critical thermal limits
Immersion
Biology
oai:ir.lib.uwo.ca:biologypub-1080
2017-07-07T17:35:09Z
publication:biologypub
publication:biology
publication:faculties
The relative importance of number, duration, and intensity of cold stress events in determining survival and energetics of an overwintering insect
Marshall, Katie E
Sinclair, Brent J
The relationship between abiotic stress and fitness in an individual is usually described by the intensity and duration of stress. Yet in natural systems, variability in abiotic stress is common. Since individuals have physiological and fitness responses to single bouts of stress, frequency of stress may also determine the lifetime success of an organism. However, the majority of laboratory studies have focused only on the effects of single stress events. We investigated the relative importance of stress parameters including duration, intensity and number of cold events on the short-term physiology and long-term fitness in the freeze-avoiding eastern spruce budworm Choristoneura fumiferana (Lepidoptera: Tortricidae, Clemens). We exposed overwintering 2nd-instar larvae of C. fumiferana to −5 °C, −10 °C, −15 °C or −20 °C, for either a single exposure of 120 h or repeated 12 h exposures (3, 6 or 10 exposures). Changes in short-term physiology were quantified by cryoprotectant content, energetic stores and supercooling point. Long-term fitness effects were measured by rearing individuals after overwintering and recording successful eclosion as adults, development time from 2nd instar to adult, and adult size. We found that long-term survival of C. fumiferana was most strongly affected by the number of low-temperature stress events rather than intensity or duration, despite increased investment into cryoprotection at the expense of glycogen reserves. Sublethal measures such as adult size were unaffected by low-temperature stress. Thus, we show that frequency of stress is an important, yet frequently neglected, parameter in the study of the effects of abiotic stress. The responses we documented here suggest that frequency of stress may be an additional important parameter for modelling the effects of abiotic stress on populations.
2014-10-29T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/74
info:doi/10.1111/1365-2435.12328
https://ir.lib.uwo.ca/context/biologypub/article/1080/viewcontent/submittedrevision__2_.pdf
Biology Publications
Scholarship@Western
abiotic stress; chilling injury; eastern spruce budworm; fluctuating thermal regimes; freeze avoidance; repeated cold exposure
Biology
oai:ir.lib.uwo.ca:biologypub-1077
2017-07-07T13:50:49Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Ion and water balance in Gryllus crickets during the first twelve hours of cold exposure.
Des Marteaux, Lauren E
Sinclair, Brent J
Insects lose ion and water balance during chilling, but the mechanisms underlying this phenomenon are based on patterns of ion and water balance observed in the later stages of cold exposure (12 or more hours). Here we quantified the distribution of ions and water in the hemolymph, muscle, and gut in adult Gryllus field crickets during the first 12h of cold exposure to test mechanistic hypotheses about why homeostasis is lost in the cold, and how chill-tolerant insects might maintain homeostasis to lower temperatures. Unlike in later chill coma, hemolymph [Na(+)] and Na(+) content in the first few hours of chilling actually increased. Patterns of Na(+) balance suggest that Na(+) migrates from the tissues to the gut lumen via the hemolymph. Imbalance of [K(+)] progressed gradually over 12h and could not explain chill coma onset (a finding consistent with recent studies), nor did it predict survival or injury following 48h of chilling. Gryllus veletis avoided shifts in muscle and hemolymph ion content better than Gryllus pennsylvanicus (which is less chill-tolerant), however neither species defended water, [Na(+)], or [K(+)] balance during the first 12h of chilling. Gryllus veletis better maintained balance of Na(+) content and may therefore have greater tissue resistance to ion leak during cold exposure, which could partially explain faster chill coma recovery for that species.
2016-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/71
info:doi/10.1016/j.jinsphys.2016.03.007
https://ir.lib.uwo.ca/context/biologypub/article/1077/viewcontent/IP_D_16_00018R1__1_.pdf
Biology Publications
Scholarship@Western
Chill tolerance
Gryllus
Homeostasis
Insect
Ion balance
Biology
oai:ir.lib.uwo.ca:biologypub-1079
2017-07-07T13:59:53Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Editorial overview: Environmental physiology: Insect environmental physiology
Sinclair, Brent J.
2014-10-01T07:00:00Z
editorial
application/pdf
https://ir.lib.uwo.ca/biologypub/73
info:doi/10.1016/j.cois.2014.08.009
https://ir.lib.uwo.ca/context/biologypub/article/1079/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
Animal Sciences
Biology
Cell Biology
Entomology
Molecular Genetics
oai:ir.lib.uwo.ca:biologypub-1078
2017-07-07T13:55:22Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Linking energetics and overwintering in temperate insects.
Sinclair, Brent J
Overwintering insects cannot feed, and energy they take into winter must therefore fuel energy demands during autumn, overwintering, warm periods prior to resumption of development in spring, and subsequent activity. Insects primarily consume lipids during winter, but may also use carbohydrate and proteins as fuel. Because they are ectotherms, the metabolic rate of insects is temperature-dependent, and the curvilinear nature of the metabolic rate-temperature relationship means that warm temperatures are disproportionately important to overwinter energy use. This energy use may be reduced physiologically, by reducing the slope or elevation of the metabolic rate-temperature relationship, or because of threshold changes, such as metabolic suppression upon freezing. Insects may also choose microhabitats or life history stages that reduce the impact of overwinter energy drain. There is considerable capacity for overwinter energy drain to affect insect survival and performance both directly (via starvation) or indirectly (for example, through a trade-off with cryoprotection), but this has not been well-explored. Likewise, the impact of overwinter energy drain on growing-season performance is not well understood. I conclude that overwinter energetics provides a useful lens through which to link physiology and ecology and winter and summer in studies of insect responses to their environment.
2015-12-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/72
info:doi/10.1016/j.jtherbio.2014.07.007
https://ir.lib.uwo.ca/context/biologypub/article/1078/viewcontent/TB_D_14_00088R1__1_.pdf
Biology Publications
Scholarship@Western
Adaptation
Physiological
Animals
Climate
Energy Metabolism
Insects
Seasons
Adaptation, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1081
2017-07-07T14:19:06Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Cold hardiness and deacclimation of overwintering Papilio zelicaon pupae
Williams, Caroline M
Annegret, Nicolai
Sinclair, Brent J
Ferguson, Laura V
Bernards, Mark A
Hellmann, Jessica J
Seasonally-acquired cold tolerance can be reversed at warm temperatures, leaving temperate ectotherms vulnerable to cold snaps. However, deacclimation, and its underlying mechanisms, has not been well-explored in insects. Swallowtail butterflies are widely distributed but in some cases their range is limited by low temperature and their cold tolerance is seasonally acquired, implying that they experience mortality resulting from deacclimation. We investigated cold tolerance and hemolymph composition of Anise swallowtail (Papilio zelicaon) pupae during overwintering in the laboratory, and after four days exposure to warm temperatures in spring. Overwintering pupae had supercooling points around − 20.5 °C and survived brief exposures to − 30 °C, suggesting partial freeze tolerance. Overwintering pupae had hemolymph osmolality of approximately 920 mOsm, imparted by high concentrations of glycerol, K+ and Na+. After exposure to spring warming, supercooling points increased to approximately − 17 °C, and survival of a 1 h exposure to − 20 °C decreased from 100% to 0%. This deacclimation was associated with decreased hemolymph osmolality and reduced glycerol, trehalose, Na+ and Ca2 + concentrations. We compared cold tolerance of pupae to weather conditions at and beyond the species' northern range boundary. Minimum temperatures at the range boundary approached the lower lethal temperature of pupae, and were colder north of the range, suggesting that cold hardiness may set northern range limits. Minimum temperatures following warm snaps were likely to cause mortality in at least one of the past three years. Cold snaps in the spring are increasing in frequency as a result of global climate change, so are likely to be a significant source of mortality for this species, and other temperate ectotherms.
2014-12-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/75
info:doi/10.1016/j.cbpa.2014.08.002
https://ir.lib.uwo.ca/context/biologypub/article/1081/viewcontent/Cold_hardiness_and_deacclimation_of_overwintering_Papilio_zelicaon_pupae.pdf
Biology Publications
Scholarship@Western
Climate change
Cold tolerance
Cryoprotectant
Deacclimation
Insect
Hemolymph
Lepidoptera
Winter
Biology
Entomology
Life Sciences
Other Ecology and Evolutionary Biology
oai:ir.lib.uwo.ca:biologypub-1084
2017-07-07T14:36:58Z
publication:biologypub
publication:biology
publication:faculties
Overwintering in New Zealand stick insects
Dennis, Alice B
Dunning, Luke T
Dennis, Christopher J
Sinclair, Brent J
Buckley, Thomas R
Stick insects are found in a variety of habitats throughout New Zealand, including at least four species that occur at high altitudes. Here they face physiological challenges that differ from their typically warmer lowland habitats, but their strategies to deal with harsh winter conditions are not known. Autumn and winter field surveys, coupled with caging experiments, were conducted to determine which life stages are overwintering in montane and lowland habitats. Data loggers were placed for approximately one year at each site to measure the leaf litter and canopy microhabitat temperatures. From this, we have found that alpine and lowland stick insects persist in a variety of life stages throughout the year despite multiple exposure to freezing temperatures.
2013-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/78
info:doi/10.1080/00779962.2013.784235
https://ir.lib.uwo.ca/context/biologypub/article/1084/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
insect cold tolerance
microclimate
Phasmatodea
Niveaphasma annulata
Micrarchus
Biology
Entomology
Other Ecology and Evolutionary Biology
oai:ir.lib.uwo.ca:biologypub-1082
2017-07-07T14:23:17Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Cross-tolerance and cross-talk in the cold: relating low temperatures to desiccation and immune stress in insects.
Sinclair, Brent J
Ferguson, Laura V
Salehipour-shirazi, Golnaz
MacMillan, Heath A
Multiple stressors, both abiotic and biotic, often are experienced simultaneously by organisms in nature. Responses to these stressors may share signaling pathways ("cross-talk") or protective mechanisms ("cross-tolerance"). Temperate and polar insects that must survive the winter experience low temperatures accompanied by additional abiotic stressors, such as low availability of water. Cold and desiccation have many similar effects at a cellular level, and we present evidence that the cellular mechanisms that protect against cold stress also protect against desiccation, and that the responses to cold and dehydration likely evolved as cross-tolerance. By contrast, there are several lines of evidence suggesting that low temperature stress elicits an upregulation of immune responses in insects (and vice versa). Because there is little mechanistic overlap between cold stress and immune stress at the cellular level, we suggest that this is cross-talk. Both cross-talk and cross-tolerance may be adaptive and likely evolved in response to synchronous stressors; however, we suggest that cross-talk and cross-tolerance may lead to different responses to changes in the timing and severity of multiple stress interactions in a changing world. We present a framework describing the potentially different responses of cross-tolerance and cross-talk to a changing environment and describe the nature of these impacts using interaction of cold-desiccation and cold-immunity in overwintering insects as an example.
2013-10-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/76
info:doi/10.1093/icb/ict004
https://ir.lib.uwo.ca/context/biologypub/article/1082/viewcontent/revised_version_ICB_build__1_.pdf
Biology Publications
Scholarship@Western
Adaptation
Biological
Animals
Cold Temperature
Insects
Models
Biological
Receptor Cross-Talk
Signal Transduction
Water Loss
Insensible
Adaptation, Biological
Models, Biological
Water Loss, Insensible
Biology
oai:ir.lib.uwo.ca:biologypub-1083
2017-07-07T14:28:30Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Ontogenetic variation in cold tolerance plasticity in Drosophila: is the Bogert effect bogus?
Mitchell, Katherine A
Sinclair, Brent J
Terblanche, John S
Ontogenetic variation in plasticity is important to understanding mechanisms and patterns of thermal tolerance variation. The Bogert effect postulates that, to compensate for their inability to behaviourally thermoregulate, less-mobile life stages of ectotherms are expected to show greater plasticity of thermal tolerance than more-mobile life stages. We test this general prediction by comparing plasticity of thermal tolerance (rapid cold-hardening, RCH) between mobile adults and less-mobile larvae of 16 Drosophila species. We find an RCH response in adults of 13 species but only in larvae of four species. Thus, the Bogert effect is not as widespread as expected.
2013-03-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/77
info:doi/https://link.springer.com/article/10.1007%2Fs00114-013-1023-8
https://ir.lib.uwo.ca/context/biologypub/article/1083/viewcontent/NAWI_D_12_00388.pdf
Biology Publications
Scholarship@Western
Adaptation
Physiological
Animals
Cold Temperature
Drosophila
Larva
Species Specificity
Adaptation, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1085
2017-07-07T19:15:17Z
publication:biologypub
publication:biology
publication:faculties
Cold truths: how winter drives responses of terrestrial organisms to climate change
Williams, Caroline M
Henry, Hugh A.L.
Sinclair, Brent J
Winter is a key driver of individual performance, community composition, and ecological interactions in terrestrial habitats. Although climate change research tends to focus on performance in the growing season, climate change is also modifying winter conditions rapidly. Changes to winter temperatures, the variability of winter conditions, and winter snow cover can interact to induce cold injury, alter energy and water balance, advance or retard phenology, and modify community interactions. Species vary in their susceptibility to these winter drivers, hampering efforts to predict biological responses to climate change. Existing frameworks for predicting the impacts of climate change do not incorporate the complexity of organismal responses to winter. Here, we synthesise organismal responses to winter climate change, and use this synthesis to build a framework to predict exposure and sensitivity to negative impacts. This framework can be used to estimate the vulnerability of species to winter climate change. We describe the importance of relationships between winter conditions and performance during the growing season in determining fitness, and demonstrate how summer and winter processes are linked. Incorporating winter into current models will require concerted effort from theoreticians and empiricists, and the expansion of current growing-season studies to incorporate winter.
2015-02-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/82
info:doi/10.1111/brv.12105
https://ir.lib.uwo.ca/context/biologypub/article/1085/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
Snow
frost
cold
extreme events
average temperatures
freeze-thaw cycles
sub-lethal impacts
energetics
hibernation
Biology
Ecology and Evolutionary Biology
Entomology
oai:ir.lib.uwo.ca:biologypub-1086
2017-07-07T15:07:05Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Divergent transcriptional responses to low temperature among populations of alpine and lowland species of New Zealand stick insects (Micrarchus).
Dunning, Luke T
Dennis, Alice B
Sinclair, Brent J
Newcomb, Richard D
Buckley, Thomas R
In widespread and genetically structured populations, temperature variation may lead to among-population differentiation of thermal biology. The New Zealand stick insect genus Micrarchus contains four species that inhabit different thermal environments, two of which are geographically widespread. RNA-Seq and quantitative PCR were used to investigate the transcriptional responses to cold shock among lowland and alpine species to identify cold-responsive transcripts that differ between the species and to determine whether there is intraspecific geographical variation in gene expression. We also used mitochondrial DNA, nuclear 28S ribosomal DNA and transcriptome-wide SNPs to determine phylogeographic structure and the potential for differences in genetic backgrounds to contribute to variation in gene expression. RNA-Seq identified 2160 unigenes that were differentially expressed as a result of low-temperature exposure across three populations from two species (M. hystriculeus and M. nov. sp. 2), with a majority (68% ± 20%) being population specific. This extensive geographical variation is consistent across years and is likely a result of background genetic differences among populations caused by genetic drift and possibly local adaptation. Responses to cold shock shared among alpine M. nov. sp. 2 populations included the enrichment of cuticular structure-associated transcripts, suggesting that cuticle modification may have accompanied colonization of low-temperature alpine environments and the development of a more cold-hardy phenotype.
2014-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/79
info:doi/10.1111/mec.12767
https://ir.lib.uwo.ca/context/biologypub/article/1086/viewcontent/auto_convert.pdf
Biology Publications
Scholarship@Western
Adaptation
Physiological
Animals
Cold Temperature
Cold-Shock Response
DNA
Mitochondrial
Genetics
Population
Insects
Molecular Sequence Data
New Zealand
Phylogeny
Phylogeography
Polymorphism
Single Nucleotide
RNA
Ribosomal
28S
Sequence Analysis
DNA
Transcriptome
Adaptation, Physiological
DNA, Mitochondrial
Genetics, Population
Polymorphism, Single Nucleotide
RNA, Ribosomal, 28S
Sequence Analysis, DNA
Biology
Ecology and Evolutionary Biology
Entomology
oai:ir.lib.uwo.ca:biologypub-1087
2018-05-09T20:42:22Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Thermal preference and performance in a sub-Antarctic caterpillar: A test of the coadaptation hypothesis and its alternatives.
Haupt, Tanya M
Sinclair, Brent J
Chown, Steven L
Physiological ecologists have long assumed that thermoregulatory behaviour will evolve to optimise physiological performance. The coadaptation hypothesis predicts that an animal's preferred body temperature will correspond to the temperature at which its performance is optimal. Here we use a strong inference approach to examine the relationship between thermal preference and locomotor performance in the caterpillars of a wingless sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae). The coadaptation hypothesis and its alternatives (suboptimal is optimal, thermodynamic effect, trait variation) are tested. Compared to the optimal movement temperature (22.5°C for field-fresh caterpillars and 25, 20, 22.5, 25 and 20°C following seven day acclimations to 0, 5, 10, 15 and 5-15°C respectively), caterpillar thermal preference was significantly lower (9.2°C for field-fresh individuals and 9.4, 8.8, 8.1, 5.2 and 4.6°C following acclimation to 0, 5, 10, 15 and 5-15°C, respectively). Together with the low degree of asymmetry observed in the performance curves, and the finding that acclimation to high temperatures did not result in maximal performance, all, but one of the above hypotheses (i.e. 'trait variation') was rejected. The thermal preference of P. marioni caterpillars more closely resembles temperatures at which survival is high (5-10°C), or where feeding is optimal (10°C), than where locomotion speed is maximal, suggesting that thermal preference may be optimised for overall fitness rather than for a given trait.
2017-04-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/83
info:doi/10.1016/j.jinsphys.2016.12.006
https://ir.lib.uwo.ca/context/biologypub/article/1087/viewcontent/Haupt_2017.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Antarctic Regions
Cold Temperature
Islands
Larva
Locomotion
Moths
Thermotolerance
Biology
oai:ir.lib.uwo.ca:biologypub-1088
2018-05-11T17:13:07Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Does cold activate the Drosophila melanogaster immune system?
Salehipour-Shirazi, Golnaz
Ferguson, Laura V
Sinclair, Brent J
Cold exposure appears to activate aspects of the insect immune system; however, the functional significance of the relationship between cold and immunity is unclear. Insect success at low temperatures is shaped in part by interactions with biotic stressors, such as pathogens, thus it is important to understand how and why immunity might be activated by cold. Here we explore which components of the immune system are activated, and whether those components differ among different kinds of cold exposure. We exposed Drosophila melanogaster to both acute (2h, -2°C) and sustained (10h, -0.5°C) cold, and measured potential (antimicrobial peptide expression, phenoloxidase activity, haemocyte counts) and realised (survival of fungal infection, wound-induced melanisation, bacterial clearance) immunity following recovery. Acute cold increased circulating haemocyte concentration and the expression of Turandot-A and diptericin, but elicited a short-term decrease in the clearance of gram-positive bacteria. Sustained cold increased the expression of Turandot-A, with no effect on other measures of potential or realised immunity. We show that measures of potential immunity were up-regulated by cold, whereas realised immunity was either unaffected or down-regulated. Thus, we hypothesize that cold-activation of potential immunity in Drosophila may be a compensatory mechanism to maintain stable immune function during or after low temperature exposure.
2017-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/84
info:doi/10.1016/j.jinsphys.2016.10.009
https://ir.lib.uwo.ca/context/biologypub/article/1088/viewcontent/Salehipour_Shirazi_2017.pdf
Biology Publications
Scholarship@Western
Animals
Cold Temperature
Drosophila melanogaster
Female
Immune System
Biology
oai:ir.lib.uwo.ca:biologypub-1089
2018-05-11T17:18:47Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Cold tolerance of third-instar Drosophila suzukii larvae.
Jakobs, Ruth
Ahmadi, Banafsheh
Houben, Sarah
Gariepy, Tara D
Sinclair, Brent J
Drosophila suzukii is an emerging global pest of soft fruit; although it likely overwinters as an adult, larval cold tolerance is important both for determining performance during spring and autumn, and for the development of temperature-based control methods aimed at larvae. We examined the low temperature biology of third instar feeding and wandering larvae in and out of food. We induced phenotypic plasticity of thermal biology by rearing under short days and fluctuating temperatures (5.5-19°C). Rearing under fluctuating temperatures led to much slower development (42.1days egg-adult) compared to control conditions (constant 21.5°C; 15.7days), and yielded larger adults of both sexes. D. suzukii larvae were chill-susceptible, being killed by low temperatures not associated with freezing, and freezing survival was not improved when ice formation was inoculated externally via food or silver iodide. Feeding larvae were more cold tolerant than wandering larvae, especially after rearing under fluctuating temperatures, and rearing under fluctuating temperatures improved survival of prolonged cold (0°C) to beyond 72h in both larval stages. There was no evidence that acute cold tolerance could be improved by rapid cold-hardening. We conclude that D. suzukii has the capacity to develop at low temperatures under fluctuating temperatures, but that they have limited cold tolerance. However, phenotypic plasticity of prolonged cold tolerance must be taken into account when developing low temperature treatments for sanitation of this species.
2017-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/85
info:doi/10.1016/j.jinsphys.2016.10.008
https://ir.lib.uwo.ca/context/biologypub/article/1089/viewcontent/Jakobs_2017.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Cold Temperature
Drosophila
Female
Larva
Male
Biology
oai:ir.lib.uwo.ca:biologypub-1090
2018-05-11T17:25:37Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Editorial overview: Global change biology: Linking pattern and process to prediction and policy.
Koštál, Vladimir
Sinclair, Brent J
2016-10-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/86
info:doi/10.1016/j.cois.2016.08.008
https://ir.lib.uwo.ca/context/biologypub/article/1090/viewcontent/Kostal_2016.pdf
Biology Publications
Scholarship@Western
Biology
oai:ir.lib.uwo.ca:biologypub-1091
2018-05-11T17:29:47Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Can we predict the effects of multiple stressors on insects in a changing climate?
Kaunisto, Sirpa
Ferguson, Laura V
Sinclair, Brent J
The responses of insects to climate change will depend on their responses to abiotic and biotic stressors in combination. We surveyed the literature, and although synergistic stressor interactions appear common among insects, the thin taxonomic spread of existing data means that more multi-stressor studies and new approaches are needed. We need to move beyond descriptions of the effects of multiple stressors to a mechanistic, predictive understanding. Further, we must identify which stressor interactions, and species' responses to them, are sufficiently generalizable (i.e. most or all species respond similarly to the same stressor combination), and thus predictable (for new combinations of stressors, or stressors acting via known mechanisms). We discuss experimental approaches that could facilitate this shift toward predictive understanding.
2016-10-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/87
info:doi/10.1016/j.cois.2016.07.001
https://ir.lib.uwo.ca/context/biologypub/article/1091/viewcontent/Kaunisto_2016.pdf
Biology Publications
Scholarship@Western
Biology
oai:ir.lib.uwo.ca:biologypub-1093
2018-05-11T17:36:36Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Similar metabolic rate-temperature relationships after acclimation at constant and fluctuating temperatures in caterpillars of a sub-Antarctic moth.
Chown, Steven L
Haupt, Tanya M
Sinclair, Brent J
Temperature compensation in whole-animal metabolic rate is one of the responses thought, controversially, to characterize insects from low temperature environments. Temperature compensation may either involve a change in absolute values of metabolic rates or a change in the slope of the metabolic rate - temperature relationship. Moreover, assessments of compensation may be complicated by animal responses to fluctuating temperatures. Here we examined whole animal metabolic rates, at 0 °C, 5 °C, 10 °C and 15 °C, in caterpillars of the sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae), following one week acclimations to 5 °C, 10 °C and 15 °C, and fluctuating temperatures of 0-10 °C, 5-15 °C, and 10-20 °C. Over the short term, temperature compensation was found following acclimation to 5 °C, but the effect size was small (3-14%). By comparison with caterpillars of 13 other lepidopteran species, no effect of temperature compensation was present, with the relationship between metabolic rate and temperature having a Q10 of 2 among species, and no effect of latitude on temperature-corrected metabolic rate. Fluctuating temperature acclimations for the most part had little effect compared with constant temperatures of the same mean value. Nonetheless, fluctuating temperatures of 5-15 °C resulted in lower metabolic rates at all test temperatures compared with constant 10 °C acclimation, in keeping with expectations from the literature. Absence of significant responses, or those of large effect, in metabolic rates in response to acclimation, may be a consequence of the unpredictable temperature variation over the short-term on sub-Antarctic Marion Island, to which P. marioni is endemic.
2016-02-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/90
info:doi/10.1016/j.jinsphys.2015.11.010
https://ir.lib.uwo.ca/context/biologypub/article/1093/viewcontent/Chown_2016.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Antarctic Regions
Environment
Kinetics
Moths
Temperature
Biology
oai:ir.lib.uwo.ca:biologypub-1092
2018-05-11T17:33:41Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Reproductive arrest and stress resistance in winter-acclimated Drosophila suzukii.
Toxopeus, Jantina
Jakobs, Ruth
Ferguson, Laura V
Gariepy, Tara D
Sinclair, Brent J
Overwintering insects must survive the multiple-stress environment of winter, which includes low temperatures, reduced food and water availability, and cold-active pathogens. Many insects overwinter in diapause, a developmental arrest associated with high stress tolerance. Drosophila suzukii (Diptera: Drosophilidae), spotted wing drosophila, is an invasive agricultural pest worldwide. Its ability to overwinter and therefore establish in temperate regions could have severe implications for fruit crop industries. We demonstrate here that laboratory populations of Canadian D. suzukii larvae reared under short-day, low temperature, conditions develop into dark 'winter morph' adults similar to those reported globally from field captures, and observed by us in southern Ontario, Canada. These winter-acclimated adults have delayed reproductive maturity, enhanced cold tolerance, and can remain active at low temperatures, although they do not have the increased desiccation tolerance or survival of fungal pathogen challenges that might be expected from a more heavily melanised cuticle. Winter-acclimated female D. suzukii have underdeveloped ovaries and altered transcript levels of several genes associated with reproduction and stress. While superficially indicative of reproductive diapause, the delayed reproductive maturity of winter-acclimated D. suzukii appears to be temperature-dependent, not regulated by photoperiod, and is thus unlikely to be 'true' diapause. The traits of this 'winter morph', however, likely facilitate overwintering in southern Canada, and have probably contributed to the global success of this fly as an invasive species.
2016-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/88
info:doi/10.1016/j.jinsphys.2016.03.006
https://ir.lib.uwo.ca/context/biologypub/article/1092/viewcontent/Toxopeus_2016.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Diapause
Insect
Drosophila
Female
Larva
Male
Ontario
Photoperiod
Pupa
Seasons
Stress
Physiological
Diapause, Insect
Stress, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1094
2018-05-03T14:37:02Z
publication:biologypub
publication:biology
publication:faculties
Further support for thermal ecosystem engineering by wandering albatross on Marion Island
Chown, Steven L
Shaw, Justine D
Haupt, Tanya M
Sinclair, Brent J
On sub-Antarctic Marion Island, wandering albatross (Diomedea exulans) nests support high abundances of tineid moth, Pringleophaga marioni, caterpillars. Previous work proposed that the birds serve as thermal ecosystem engineers by elevating nest temperatures relative to ambient, thereby promoting growth and survival of the caterpillars. However, only 17 days of temperature data were presented previously, despite year-long nest occupation by birds. Previous sampling was also restricted to old and recently failed nests, though nests from which chicks have recently fledged are key to understanding how the engineering effect is realized. Here we build on previous work by providing nest temperature data for a full year and by sampling all three nest types. For the full duration of nest occupancy, temperatures within occupied nests are significantly higher, consistently by c. 7°C, than those in surrounding soils and abandoned nests, declining noticeably when chicks fledge. Caterpillar abundance is significantly higher in new nests compared to nests from which chicks have fledged, which in turn have higher caterpillar abundances than old nests. Combined with recent information on the life history of P. marioni, our data suggest that caterpillars are incidentally added to the nests during nest construction, and subsequently benefit from an engineering effect.
2016-02-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/89
info:doi/10.1017/S0954102015000383
https://ir.lib.uwo.ca/context/biologypub/article/1094/viewcontent/Haupt_2016.pdf
Biology Publications
Scholarship@Western
abundance
detritivore
development
microclimate
soil
biology
survival
thermal biology
Biology
oai:ir.lib.uwo.ca:biologypub-1095
2018-05-08T14:26:38Z
publication:biologypub
publication:biology
publication:faculties
Winter warming effects on overwinter survival, energy use, and spring emergence of Cerotoma trifurcata (Coleoptera: Chrysomelidae)
Berzitis, Emily A
Hager, Heather A
Sinclair, Brent J
Hallett, Rebecca H
Newman, Jonathan A
Bean leaf beetle Cerotoma trifurcata (Förster) (Coleoptera: Chrysomelidae) is a pest of soybean in the U.S.A. and is becoming a concern in Canada. The projected increase in winter temperatures under climate change could affect overwinter survival, timing of spring emergence and, ultimately, the severity of this pest. We assessed the potential effects of warmer winters in field experiments performed in three consecutive years. Three warming levels were applied: (i) heated approximately 4 °C above ambient; (ii) unheated with snow cover left intact; and (iii) unheated with snow cover removed. Survival and date of emergence were assessed in all years, and beetle lipid content was analyzed in 1 year to determine rates of energy use. Overwinter survival was 6.5–14.5% among years. Winter warming inconsistently affected overwinter survival: increasing survival in one winter, decreasing survival in the warmest winter and having no effect in one winter. Beetles that received supplemental winter warming emerged approximately 2 weeks earlier in spring, and lipid content did not differ among treatment groups. Earlier spring emergence may allow for the production of an additional generation per year of C. trifurcata under future climate change. However, further experiments are required to establish the relationship between overwinter survival and subsequent beetle population growth to determine potential pest status and best management practices under future climate conditions.
2016-10-17T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/91
info:doi/10.1111/afe.12196
https://ir.lib.uwo.ca/context/biologypub/article/1095/viewcontent/Berzitis_2017__1_.pdf
Biology Publications
Scholarship@Western
Bean leaf beetle
climate change
overwintering energetics
phenology
soybean pest
temperature increase
Biology
oai:ir.lib.uwo.ca:biologypub-1096
2018-05-10T14:08:05Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Can we predict ectotherm responses to climate change using thermal performance curves and body temperatures?
Sinclair, Brent J
Marshall, Katie E
Sewell, Mary A
Levesque, Danielle L
Willett, Christopher S
Slotsbo, Stine
Dong, Yunwei
Harley, Christopher D G
Marshall, David J
Helmuth, Brian S
Huey, Raymond B
Thermal performance curves (TPCs), which quantify how an ectotherm's body temperature (Tb ) affects its performance or fitness, are often used in an attempt to predict organismal responses to climate change. Here, we examine the key - but often biologically unreasonable - assumptions underlying this approach; for example, that physiology and thermal regimes are invariant over ontogeny, space and time, and also that TPCs are independent of previously experienced Tb. We show how a critical consideration of these assumptions can lead to biologically useful hypotheses and experimental designs. For example, rather than assuming that TPCs are fixed during ontogeny, one can measure TPCs for each major life stage and incorporate these into stage-specific ecological models to reveal the life stage most likely to be vulnerable to climate change. Our overall goal is to explicitly examine the assumptions underlying the integration of TPCs with Tb , to develop a framework within which empiricists can place their work within these limitations, and to facilitate the application of thermal physiology to understanding the biological implications of climate change.
2016-11-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/92
info:doi/10.1111/ele.12686
https://ir.lib.uwo.ca/context/biologypub/article/1096/viewcontent/Sinclair_2016.pdf
Biology Publications
Scholarship@Western
Adaptation
Physiological
Animals
Body Temperature Regulation
Climate Change
Environment
Models
Biological
Time Factors
Adaptation, Physiological
Models, Biological
Biology
oai:ir.lib.uwo.ca:biologypub-1097
2018-05-11T17:58:34Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Paradoxical acclimation responses in the thermal performance of insect immunity.
Ferguson, Laura V
Heinrichs, David E
Sinclair, Brent J
Winter is accompanied by multiple stressors, and the interactions between cold and pathogen stress potentially determine the overwintering success of insects. Thus, it is necessary to explore the thermal performance of the insect immune system. We cold-acclimated spring field crickets, Gryllus veletis, to 6 °C for 7 days and measured the thermal performance of potential (lysozyme and phenoloxidase activity) and realised (bacterial clearance and melanisation) immune responses. Cold acclimation decreased the critical thermal minimum from -0.5 ± 0.25 to -2.1 ± 0.18 °C, and chill coma recovery time after 72 h at -2 °C from 16.8 ± 4.9 to 5.2 ± 2.0 min. Measures of both potential and realised immunity followed a typical thermal performance curve, decreasing with decreasing temperature. However, cold acclimation further decreased realised immunity at low, but not high, temperatures; effectively, immune activity became paradoxically specialised to higher temperatures. Thus, cold acclimation induced mismatched thermal responses between locomotor and immune systems, as well as within the immune system itself. We conclude that cold acclimation in insects appears to preferentially improve cold tolerance over whole-animal immune performance at low temperatures, and that the differential thermal performance of physiological responses to multiple pressures must be considered when predicting ectotherms' response to climate change.
2016-05-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/93
info:doi/10.1007/s00442-015-3529-6
https://ir.lib.uwo.ca/context/biologypub/article/1097/viewcontent/Ferguson_2016__1_.pdf
Biology Publications
Scholarship@Western
Acclimatization
Animals
Climate Change
Cold Temperature
Hot Temperature
Immune System
Immunity
Orthoptera
Seasons
Stress
Physiological
Temperature
Stress, Physiological
Biology
oai:ir.lib.uwo.ca:biologypub-1098
2018-05-11T14:09:52Z
publication:biologypub
publication:biology
publication:faculties
Overwintering biology of the carob moth Apomyelois ceratoniae (Lepidoptera: Pyralidae)
Ahmadi, Banafsheh
Moharramipour, Saeid
Sinclair, Brent J
The pomegranate fruit moth, Apomyelois ceratoniae (Zeller), is the most important pest of pomegranate orchards in Iran, where infestations lead to 20%–80% fruit loss. A. ceratoniae overwinters as larvae in several instars. The success in overwintering determines the fruit loss in the following season, thus overwintering physiology of A. ceratoniae could provide insights into population prediction. To this end, overwintering strategy and some seasonal physiological and biochemical changes were investigated in the field-collected larvae of A. ceratoniae. The lowest supercooling point was recorded in November (−14.6 ± 0.9 °C) and the highest in both October and March (−10.2 ± 0.9 °C). The median lethal temperature (LT50) of larvae was higher than supercooling point, suggesting that A. ceratoniae is chill-susceptible. Overwintering larvae had slightly higher concentrations of glycerol and sorbitol compared to summer larvae. There were no significant seasonal changes in body water content or hemolymph osmolality. Current winter temperatures in Iranian orchards are higher than the cold tolerance thresholds of A. ceratoniae, suggesting that overwintering mortality is not a key factor in determining A. ceratoniae populations.
2015-11-07T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/94
info:doi/10.1080/09670874.2015.1102984
https://ir.lib.uwo.ca/context/biologypub/article/1098/viewcontent/Ahmadi_2016__1_.pdf
Biology Publications
Scholarship@Western
cold hardiness
cryoprotectants
osmolality
supercooling point
water content
Biology
oai:ir.lib.uwo.ca:biologypub-1100
2019-12-18T14:14:03Z
publication:biologypub
publication:rwkex
publication:rwkex_researcharticles
publication:biology
publication:pmid
publication:faculties
The effect of cold acclimation on active ion transport in cricket ionoregulatory tissues.
Des Marteaux, Lauren E
Khazraeenia, Soheila
Yerushalmi, Gil Y
Donini, Andrew
Li, Natalia G
Sinclair, Brent J
Cold-acclimated insects defend ion and water transport function during cold exposure. We hypothesized that this is achieved via enhanced active transport. The Malpighian tubules and rectum are likely targets for such transport modifications, and recent transcriptomic studies indicate shifts in Na+-K+ ATPase (NKA) and V-ATPase expression in these tissues following cold acclimation. Here we quantify the effect of cold acclimation (one week at 12 °C) on active transport in the ionoregulatory organs of adult Gryllus pennsylvanicus field crickets. We compared primary urine production of warm- and cold-acclimated crickets in excised Malpighian tubules via Ramsay assay at a range of temperatures between 4 and 25 °C. We then compared NKA and V-ATPase activities in Malpighian tubule and rectal homogenates from warm- and cold-acclimated crickets via NADH-linked photometric assays. Malpighian tubules of cold-acclimated crickets excreted fluid at lower rates at all temperatures compared to warm-acclimated crickets. This reduction in Malpighian tubule excretion rates may be attributed to increased NKA activity that we observed for cold-acclimated crickets, but V-ATPase activity was unchanged. Cold acclimation had no effect on rectal NKA activity at either 21 °C or 6 °C, and did not modify rectal V-ATPase activity. Our results suggest that an overall reduction, rather than enhancement of active transport in the Malpighian tubules allows crickets to maintain hemolymph water balance during cold exposure, and increased Malpighian tubule NKA activity may help to defend and/or re-establish ion homeostasis.
2018-02-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/95
info:doi/10.1016/j.cbpa.2017.11.005
https://ir.lib.uwo.ca/context/biologypub/article/1100/viewcontent/Des_Marteaux_et_al_2018___CBPA__revision_1_v1_.pdf
http://creativecommons.org/licenses/by-nc-nd/4.0/
Biology Publications
Scholarship@Western
Acclimatization
Animals
Cold Temperature
Gryllidae
Ion Transport
Malpighian Tubules
Rectum
Sodium-Potassium-Exchanging ATPase
Transcriptome
Vacuolar Proton-Translocating ATPases
Biology
oai:ir.lib.uwo.ca:biologypub-1101
2019-12-18T14:19:00Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Effects of cold acclimation on rectal macromorphology, ultrastructure, and cytoskeletal stability in Gryllus pennsylvanicus crickets.
Des Marteaux, Lauren E
Stinziano, Joseph R
Sinclair, Brent J
Cold-acclimated insects maintain ion and water balance in the cold, potentially by reducing permeability or increasing diffusion distance across ionoregulatory epithelia such as the rectum. We explored whether cold acclimation induces structural modifications that minimize water and ion diffusion across the rectum and maintain rectal cell integrity. We investigated rectal structure and cytoskeletal stability in chill-susceptible adult Gryllus pennsylvanicus crickets acclimated for one week to either warm (25 °C) or cold (12 °C) conditions. After acclimation, we used light and transmission electron microscopy to examine rectal macromorphology and rectal pad paracellular ultrastructure. We also used fluorescence microscopy and a filamentous-actin (F-actin) specific phalloidin stain to compare the polymerization state of the actin cytoskeleton for each of the acclimation groups before and after a cold shock (1 h at -4 °C). Cold acclimation did not alter rectal pad cell density, or the thickness of the rectal pads, muscle, or cuticle. The tortuosity and width of the rectal pad paracellular channels also did not differ between warm- and cold-acclimated crickets. Rectal pad cells had clear basal and apical regions with differing densities of F-actin. Cold shock reduced the density of F-actin in warm-acclimated crickets, whereas cold-acclimated crickets appeared to have unchanged (basal) or enhanced (apical) F-actin density after cold shock. This suggests that while cold acclimation does not modify rectal permeability through structural modifications to increase diffusion distance for water and ions, cold-acclimated crickets have a modified cytoskeleton that resists the depolymerising effects of cold shock.
2018-01-01T08:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/96
info:doi/10.1016/j.jinsphys.2017.11.004
https://ir.lib.uwo.ca/context/biologypub/article/1101/viewcontent/Des_Marteaux_et_al_2018___JIP__revision_1_v1_.pdf
http://creativecommons.org/licenses/by-nc-nd/4.0/
Biology Publications
Scholarship@Western
Acclimatization
Animals
Cold Temperature
Cytoskeleton
Female
Gryllidae
Microscopy
Confocal
Microscopy
Electron
Transmission
Microscopy
Fluorescence
Rectum
Microscopy, Confocal
Microscopy, Electron, Transmission
Microscopy, Fluorescence
Biology
oai:ir.lib.uwo.ca:biologypub-1102
2019-12-18T14:26:21Z
publication:biologypub
publication:biology
publication:pmid
publication:faculties
Insect Immunity Varies Idiosyncratically During Overwintering.
Ferguson, Laura V
Sinclair, Brent J
Overwintering insects face multiple stressors, including pathogen and parasite pressures that shift with seasons. However, we know little of how the insect immune system fluctuates with season, particularly in the overwintering period. To understand how immune activity changes across autumn, winter, and spring, we tracked immune activity of three temperate insects that overwinter as larvae: a weevil (Curculio sp., Coleoptera), gallfly (Eurosta solidaginis, Diptera), and larvae of the lepidopteran Pyrrharctia isabella. We measured baseline circulating hemocyte numbers, phenoloxidase activity, and humoral antimicrobial activity, as well as survival of fungal infection and melanization response at 12°C and 25°C to capture any potential plasticity in thermal performance. In Curculio sp. and E. solidaginis, hemocyte concentrations remained unchanged across seasons and antimicrobial activity against Gram-positive bacteria was lowest in autumn; however, Curculio sp. were less likely to survive fungal infection in autumn, whereas E. solidaginis were less likely to survive infection during the winter. Furthermore, hemocyte concentrations and antimicrobial activity decreased in P. isabella overwintering beneath snow cover. Overall, seasonal changes in activity were largely species dependent, thus it may be difficult to create generalizable predictions about the effects of a changing climate on seasonal immune activity in insects. However, we suggest that the relationship between the response to multiple stressors (e.g., cold and pathogens) drives changes in immune activity, and that understanding the physiology underlying these relationships will inform our predictions of the effects of environmental change on insect overwintering success.
2017-06-01T07:00:00Z
article
application/pdf
https://ir.lib.uwo.ca/biologypub/97
info:doi/10.1002/jez.2067
https://ir.lib.uwo.ca/context/biologypub/article/1102/viewcontent/Ferguson___Sinclair_JEZ_A.pdf
Biology Publications
Scholarship@Western
Animals
Coleoptera
Diptera
Hemocytes
Immunity
Humoral
Larva
Lepidoptera
Monophenol Monooxygenase
Seasons
Immunity, Humoral
Biology
839679/oai_dc/100//