Electronic Thesis and Dissertation Repository


Master of Science


Microbiology and Immunology


David Heinrichs


Upon colonization, Staphylococcus aureus must withstand the actions of many host defense mechanisms, including the unsaturated free fatty acids (uFFAs) secreted in sebum. Linoleic acid, a representative uFFA, is toxic to S. aureus at concentrations ≥50 µM; however, we selected for mutants capable of growing at elevated concentrations of linoleic acid. Five mutants had single nucleotide polymorphisms (SNPs) in the cvfA gene encoding an RNase that is a component of the RNA degradosome, and expression of the SNP-containing cvfA genes from a plasmid engendered S. aureus with high level resistance to linoleic acid. The SNPs were located within a region of the protein with unknown function, between the RNA-binding and catalytic domains. We have confirmed that at least one of the SNPs does not impact CvfA catalytic activity. Further research is required to determine the mechanism by which SNPs in cvfA confer increased resistance to uFFAs.

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