Exogenous polyunsaturated fatty acids (PUFAs) promote changes in growth, phospholipid composition, membrane permeability and virulence phenotypes in Escherichia coli

Abstract

Background The utilization of exogenous fatty acids by Gram-negative bacteria has been linked to many cellular processes, including fatty acid oxidation for metabolic gain, assimilation into membrane phospholipids, and control of phenotypes associated with virulence. The expanded fatty acid handling capabilities have been demonstrated in several bacteria of medical importance; however, a survey of the polyunsaturated fatty acid responses in the model organism Escherichia coli has not been performed. The current study examined the impacts of exogenous fatty acids on E. coli. Results All PUFAs elicited higher overall growth, with several fatty acids supporting growth as sole carbon sources. Most PUFAs were incorporated into membrane phospholipids as determined by Ultra performance liquid chromatography-mass spectrometry, whereas membrane permeability was variably affected as measured by two separate dye uptake assays. Biofilm formation, swimming motility and antimicrobial peptide resistance were altered in the presence of PUFAs, with arachidonic and docosahexaenoic acids eliciting strong alteration to these phenotypes. Conclusions The findings herein add E. coli to the growing list of Gram-negative bacteria with broader capabilities for utilizing and responding to exogenous fatty acids. Understanding bacterial responses to PUFAs may lead to microbial behavioral control regimens for disease prevention.

Incorporation of Exogenous Fatty Acids Enhances the Salt Tolerance of Food Yeast Zygosaccharomyces rouxii

“…Recent studies also highlighted that exogenous fatty acids can be incorporated by cells and had a promotion effect on the growth of some bacteria, such as E. faecalis, Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, and Vibrio species …”

“…The method of the spotted assay can compare and analyze the cell survival intuitively, which showed that exogenous fatty acids were helpful for the salt tolerance of cells, and it was particularly noticeable for fatty acids C12:0, C16:0, C16:1, and C18:1 (Figure 2). Recent studies also highlighted that exogenous fatty acids can be incorporated by cells and had a promotion effect on the growth of some bacteria, such as E. faecalis, 16 Escherichia coli, 29 Staphylococcus aureus, 17 Acinetobacter baumannii, 30 and Vibrio species. 11 To further explore how exogenous fatty acids increased the salt tolerance of Z. rouxii, a comprehensive analysis of cellular physiological characterization in the presence of exogenous fatty acids was performed.…”

“…Fatty acids are simple compounds biosynthesized by the fatty acid synthase (FAS) through the sequential elongation of acetyl-CoA, and palmitic acid (C16:0) can be further elongated and desaturated. , In previous studies, fatty acids had great effects on the maintenance of the cell membrane structure, cell viability, and cell overall metabolism during adverse stress conditions. , Turk et al revealed that Debaryomyces hansenii can increase the sterol-to-phospholipid ratio and the unsaturation of fatty acids within the membrane to cope with high concentrations of NaCl stress. Li et al studied that metabolic adaptability shifts of cell membrane fatty acids can improve the acid stress resistance of Komagataeibacter hansenii, which showed that both fatty acid dehydrogenase ( des ) and cyclopropane fatty acid synthase ( cfa ) genes were activated under acid stress.…”

“…15 According to the analysis of the FAS inhibitor cerulenin and membrane-damaging antibiotic daptomycin, Saito et al 16 revealed that the supplementation of unsaturated fatty acids produced variable growth effects of Enterococcus faecalis and only host-derived unsaturated fatty acids provided stress protection. However, the current research on the exogenous fatty acids mainly focused on bacteria and was limited to a few specific fatty acids such as C18:1 17 and C18:2; 12 little attention has been paid to study yeasts and other fatty acids. Furthermore, whether cells can utilize exogenous fatty acids and how exogenous fatty acids affect the cells' stress resistance remain poorly understood.…”

Simulated docking reveals putative channels for the transport of long-chain fatty acids in Vibrio cholerae

“…cholerae, were only able to acquire up to 18 carbon length FAs (17). However, over the past decade several Gram-negative pathogens have been shown to assimilate and respond to exogenous PUFAs (18,19,20,21). In the case of V. cholerae, this increased uptake is likely due to its natural ecosystem of tropical climates where marine algae and protist are the bases of the aquatic food web.…”