Giles, David K.
Spratt, Henry G.; Chapman, Elisa L.
University of Tennessee at Chattanooga
Place of Publication
Vibrio cholerae is a Gram-negative bacterium known as a waterborne pathogen. It is often found in marine conditions and can infect humans through ingestion. V. cholerae is responsible for cholera, a disease characterized by profuse diarrhea, vomiting, and other dehydration symptoms. Ultimately, severe cases can cause extreme electrolyte imbalances, shock, and acute renal failure which lead to death in a short period of time. Annually, V. cholerae causes approximately 3 million cases of cholera and 100,000 deaths worldwide. V. cholerae can persist in motile and biofilm lifestyles under aquatic and host conditions, a unique biphasic lifestyle that contributes to Vibrio’s survival and pathogenicity. Previous research has shown that V. cholerae responds to various fatty acids by altering behavior associated with virulence (biofilm formation, motility, and antibiotic resistance). This study aimed to identify V. cholerae genes that participate in fatty acid-mediated formation of biofilms, which are communities of bacteria formed for survival, persistence, and pathogenicity. Using a transposon library, bioinformatically selected mutants were evaluated for their ability to form biofilms in distinct physiological conditions with or without three polyunsaturated fatty acids (PUFAs). The candidate mutants were subjected to 3 physiologically relevant PUFAs (alpha-linoleic acid [18:3ɑ], arachidonic acid [20:4], and docosahexaenoic acid [22:6]). Each mutant’s growth characteristics and biofilm formation were assessed under marine (30°C, pH 8.1, 600mM NaCl) and human host (37°C, pH 7.1, 150mM NaCl) conditions. As indicated in preliminary research, temperature and salt induced changes in biofilm formation and growth among the selected mutants. Interestingly, transposon mutant VCA0785 displayed a decrease in biofilm production in marine and host conditions, indicating an importance of this gene in biofilm formation. VC1348 produced biofilm mimicking wild-type under marine conditions, but showed striking amounts of biofilm when PUFAs were available under host conditions. Interestingly 18:3ɑ elicited almost 10 times the amount of biofilm in host versus marine conditions. Under marine conditions, VC1710 displayed a stark decrease in biofilm formation in the presence of each fatty acid, with 22:6 causing opposite effects between conditions. Collectively, this study identified environment-specific alteration to fatty acid-mediated biofilm formation, as well as implicating some potential methyl-accepting chemotaxis proteins involved in signaling biofilm production in V. cholerae.
B. A.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Arts.
Biofilms; Unsaturated fatty acids; Vibrio cholerae
Gray, Isabel, "Fatty acid mediated alterations in biofilm formation with Vibrio cholerae" (2020). Honors Theses.