d -Alanylcardiolipin, a Major Component of the Unique Lipid Pattern of Vagococcus fluvialis

Abstract

ABSTRACT 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 α- 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 ω-9 series and not the ω-7 series, found in enterococci, lactococci, and streptococci.