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 thin-layer chromatography and UPLC-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.

Exogenous polyunsaturated fatty acids (PUFAs) influence permeability, antimicrobial peptide resistance, biofilm formation and membrane phospholipid structure in an A‐layer and non‐A‐layer strain of Aeromonas salmonicida

“…The results of permeability testing using CV and EtBr showed significant ( p < .001) differences depending on fatty acid; however, there were several differences between hydrophobic compounds. The prevailing theme is that, regardless of A‐layer, several PUFAs caused elevated permeability, as has been observed with equivalent methodology in other Gram‐negative bacteria such as E. coli and Klebsiella pneumoniae (Herndon et al, 2020; Hobby et al, 2019). However, other Gram‐negative bacteria, such as Acinetobacter baumannii , Pseudomonas aeruginosa and several Vibrio spp ., display the opposite trend (Baker et al, 2018; Eder et al, 2017; Moravec et al, 2017; Smith et al, 2021), suggesting different coping mechanisms (e.g.…”

Metabolomics analysis of salt tolerance of Zygosaccharomyces rouxii and guided exogenous fatty acid addition for improved salt tolerance

“…Analysis of the changes in membrane fatty acid content after exogenous fatty acid addition indicated that exogenous fatty acids can help cells’ de novo biosynthesis of membrane fatty acids. The reason for the further increase in unsaturated fatty acids contents may be the strengthened synthesis of fatty acids from saturated to unsaturated to improve salt tolerance 35,36 …”

“…The reason for the further increase in unsaturated fatty acids contents may be the strengthened synthesis of fatty acids from saturated to unsaturated to improve salt tolerance. 35,36 Membrane fluidity is an important metric of membrane health, and it can be changed by growth condition changes. 37 As shown in Fig.…”