Polyunsaturated fatty acids cause physiological and behavioral changes
in Vibrio alginolyticus and Vibrio fischeri
Vibrio alginolyticus and Vibrio (Aliivibrio) fischeri are Gram-negative
bacteria found globally in marine environments. During the past decade,
studies have shown that certain Gram-negative bacteria, including Vibrio
species (cholerae, parahaemolyticus, and vulnificus) are capable of
using exogenous polyunsaturated fatty acids (PUFAs) to modify the
phospholipids of their membrane. Moreover, exposure to exogenous PUFAs
has been shown to affect certain phenotypes that are important factors
of virulence. The purpose of this study was to investigate whether V.
alginolyticus and V. fischeri are capable of responding to exogenous
PUFAs by remodeling their membrane phospholipids and/or altering
behaviors associated with virulence. Thin-layer chromatography (TLC)
analyses and ultra-performance liquid chromatography-electrospray
ionization mass spectrometry (UPLC/ESI-MS) confirmed incorporation of
all PUFAs into membrane phosphatidylglycerol and
phosphatidylethanolamine. Several growth phenotypes were identified when
individual fatty acids were supplied in minimal media and as sole carbon
sources. Interestingly, several PUFAs acids inhibited growth of V.
fischeri. Significant alterations to membrane permeability were observed
depending on fatty acid supplemented. Strikingly, arachidonic acid
(20:4) reduced membrane permeability by approximately 35% in both V.
alginolyticus and V. fischeri. Biofilm assays indicated that fatty acid
influence was dependent on media composition and temperature. All fatty
acids caused decreased swimming motility in V. alginolyticus, while only
linoleic acid (18:2) significantly increased swimming motility in V.
fischeri. In summary, exogenous fatty acids cause a variety of changes
in V. alginolyticus and V. fischeri, thus adding these bacteria to a
growing list of Gram-negatives that exhibit versatility in fatty acid
utilization and highlighting the potential for environmental PUFAs to
influence phenotypes associated with planktonic, beneficial, and