Lipidomic analysis reveals differences inBacteroidesspecies driven largely by plasmalogens, glycerophosphoinositols and certain sphingolipids

Abstract

There has been increasing interest in bacterial lipids in recent years due, in part, to their emerging role as molecular signalling molecules. Bacteroides thetaiotaomicron is an important member of the mammalian gut microbiota that has been shown to produce sphingolipids (SP) that pass through the gut epithelial barrier to impact host SP metabolism and signal into host inflammation pathways. B. thetaiotaomicron also produces a novel family of N-acyl amines (called glycine lipids) that are potent ligands of host Toll-like receptor 2 (TLR2). Here, we specifically examine the lipid signatures of 4 species of gut associated Bacteroides. In total we identify 170 different lipids and we report that the range and diversity of Bacteroides lipids is species-specific. Multi-variate analysis reveals that the differences in the lipid signatures are largely driven by the presence/absence of plasmalogens, glycerophosphoinositols and certain SP. Moreover, we show that, in B. thetaiotaomicron, mutations altering either SP or glycine lipid biosynthesis results in significant changes in the levels of other lipids suggesting the existence of compensatory mechanisms required to maintain the functionality of the bacterial membrane.

Lipidome of the Bacteroides Genus Containing New Peptidolipid and Sphingolipid Families Revealed by Multiple-Stage Mass Spectrometry

“…thetaiotaomicron were also reported. ,, Recently, a more comprehensive structural study of the lipid species in B. fragilis group was reported, but many lipid structures remain undefined and the coverage is incomplete. − Here, we apply linear ion trap multiple-stage mass spectrometry (LIT MS n ) approaches with high-resolution (HR) mass spectrometry together with chemical reactions, GC/MS analysis to characterize the structures of the lipids extracted from B. thetaiotaomicron, B.…”