Relatively simple methodology for the determination of configuration of unsaturation of bacterial monounsaturated fatty acids: application to the unsaturates of Legionella spp

D-Alanylcardiolipin, a major component of the unique lipid pattern of Vagococcus fluvialis

Motile group N streptococci, classified as Vagococcus fluvialis, have been isolated from cows' udders, human and animal feces, river water, and seawater. They possess an unusual membrane lipid and fatty acid pattern. We isolated and characterized 13 polar lipids, 8 of them also found in other gram-positive bacteria: mono- and dihexosyldiacylglycerol, an acylated and a glycerophosphate-substituted derivative of the latter, cardiolipin, phosphatidylglycerol, D-alanylphosphatidylglycerol, and L-lysylphosphatidylglycerol. Besides them, we characterized two rare compounds, bis(acylglycero)phosphate and alpha-D-glucopyranosylcardiolipin, and two compounds so far not detected in nature, D-alanylbis(acylglycero)phosphate and D-alanylcardiolipin. The concomitant occurrence of four aminoacyl phospholipids in one organism is another unique finding. Substituted cardiolipins represent a novel lipid class: in vagococci, D-alanylcardiolipin is a major membrane lipid component, contributing 11 and 26 mol% of total lipids in the exponential and stationary phases of growth, respectively. The vagococcal lipids contain even-numbered straight-chain saturated and cis-monounsaturated fatty acids, but the cis-monoenic acids belong to the omega-9 series and not the omega-7 series, found in enterococci, lactococci, and streptococci.

Determination of monounsaturated double-bond position and geometry in the cellular fatty acids of the pathogenic bacterium Francisella tularensis

The nonhydroxy fatty acid composition of Francisella tularensis is reported in detail. The double-bond configuration of the monounsaturated acids has been determined by capillary gas chromatography-mass spectrometry of the derivatized fatty acids. The monounsaturated fatty acids detected, in decreasing order of abundance, were 24:1 omega 15c, 18:1 omega 9c, 22:1 omega 13c, 20:1 omega 11c, 16:1 omega 7c, 26:1 omega 17c, and 14:1 omega 7c. The fatty acid profile found in F. tularensis, in particular the double-bond positions, represents a valuable taxonomic characteristic of this pathogenic bacterium.