Symes, Steven J.
Giles, David K.; Kim, Jisook
University of Tennessee at Chattanooga
Place of Publication
Aeromonas salmonicida is a Gram-negative bacterium that can infect a wide host range of fish populations, including salmonids and non-salmonids as well as freshwater and marine life. A. salmonicida causes the disease furunculosis, which can cause lethargy, intestinal inflammation, ulcers, hemorrhaging, and death. The infection is spread through fish-to-fish contact, and the presence of infection can have devastating effects on cultivated fish populations. The purpose of this study was to explore the ability of A. salmonicida to incorporate polyunsaturated fatty acids (PUFAs) into its lipid profile and test the phenotypic effects thereof. A. salmonicida cultures were grown in minimal media in the presence or absence of one of seven PUFAs Lipids were extracted from these cultures and analyzed for lipid modification by thin-layer chromatography and ultra performance liquid chromatography and tandem mass spectrometry, showing A. salmonicida capable of incorporating all seven of the PUFAs studied. Phenotypic effects were determined through the use of assays that tested for biofilm formation, membrane permeability, and antimicrobial peptide susceptibility. It was found that the PUFAs 18:2 and 22:6 caused significant (P < 0.01) decrease in biofilm formation. The PUFAs 18:3γ, 20:4, and 22:6 showed significant (P < 0.001) increases in membrane permeability as tested by the uptake of the hydrophobic compound crystal violet. Additionally, the PUFAs 18:3γ, 20:5, and 22:6 showed significant (P < 0.001) protection against the antimicrobial peptide polymyxin B. The prevalence of 22:6 in significant phenotypic effects could indicate a connection between the ability of A. salmonicida to utilize the long-chain PUFA and its role as a fish pathogen.
UTC Department of Chemistry and Physics,Dr. Symes, Dr. Giles, Dr. Kim, Joshua Herndon, Grote Chemistry Fund, Westbrook Research Scholarship, and the National Science Foundation
B. S.; 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 Science.
Aeromonas salmonicida; Bacterial diseases in fishes; Fishes -- Microbiology
Hofer, Rachel, "Lipid modification in Aeromonas salmonicida through exogenous polyunsaturated fatty acid incorporation" (2019). Honors Theses.