Exogenous polyunsaturated fatty acid (PUFA) scavenging affects phospholipid profiles and virulence phenotypes in Vibrio cholerae and Vibrio parahaemolyticus

摘要

AIM: This research had two primary objectives. First, this study sought to determine whether or not exposing Vibrio cholerae and Vibrio parahaemolyticus to polyunsaturated fatty acids (PUFAs) would lead to changes in their respective phospholipid profiles. Secondly, if membrane remodeling occurred, this study sought to determine the impact of membrane modifications on bacterial fitness by evaluating their effect on membrane permeability, biofilm formation, and response to stresses. METHODS: The Bligh and Dyer method was used to extract bacterial lipids, which were subsequently analyzed via thin-layer chromatography (TLC). The effect of fatty acids on bacterial fitness was assessed using stress, biofilm, and crystal violet (CV) assays. Stresses used include: lactic acid, hydrogen peroxide, and the antimicrobial peptide polymyxin B (PMB). RESULTS: TLC of isolated phospholipids from V. cholerae and V. parahaemolyticus grown in the presence of PUFAs indicated structural changes, suggesting incorporation of exogenous fatty acids into membrane lipids. CV uptake tests revealed fatty acid-dependent changes in permeability of up to 30% in V. cholerae and 20% in V. parahaemolyticus. V. parahaemolyticus displayed increased sensitivity to oxidative stress for all PUFAs, while exposure to docosahexaenoic acid (22:6) enhanced its resilience. The susceptibility of both V. cholerae and V. parahaemolyticus to PMB was increased. Following exposure to multiple PUFAs, biofilm assays revealed a reduced capacity for biofilm formation in V. cholerae for all fatty acids except 22:6. Furthermore, V. parahaemolyticus exhibited an increase of over 30% in biofilm activity. Significant exceptions to this behavior were 22:6 and 18:3γ which decreased biofilm production in V. parahaemolyticus by 30% and 70%, respectively. These results implicate fatty acids as important resources for bacterial membrane remodeling that may affect environmental persistence and host virulence in Vibrio species.