Electronic Thesis and Dissertation Repository


Master of Science


Microbiology and Immunology


Dr. Gregor Reid


Lactobacilli are Gram-positive bacteria used in fermented foods. Many species are commensal microbiota members that confer host benefits. This thesis investigated lactobacilli mitigation of organophosphate and neonicotinoid pesticide toxicity in mammals and insects, respectively. Lactobacillus rhamnosus GG (LGG) and GR-1 (LGR-1) were found to sequester, but not metabolize, organophosphate pesticides (parathion and chlorpyrifos) in solution. For LGG, this sequestration reduced organophosphate pesticide absorption in a Caco-2 intestinal Transwell model and promoted survival of Drosophila melanogaster lethally exposed to chlorpyrifos. Supplementation of mice with LGR-1 was found to alter host xenobiotic metabolism in the liver, and consequently chlorpyrifos metabolism following acute exposure. Drosophila supplemented with L. plantarum, a species indigenous to the fly, elicited an immune response that was correlated with increased survival following imidacloprid (neonicotinoid) exposure. Taken together, these experiments suggest that humans and honeybees could benefit from simple and affordable dietary supplementation with Lactobacillus strains to offset pesticide exposure.