Phenol-extracted lipopeptidopoly-saccharide (LPPS) complex from Listeria monocytogenes

Endotoxin phenol extraction method with subsequent ultracentrifugation and/or chromatographic analysis on Sepharose 2 B column were used to obtain biologically active isolate that turned out to contain polysaccharide, peptide and lipid fractions. The raw phenol extract formed 15% and the LPPS complex, obtained from it by ultracentrifugation, 0.17% of bacterial biomass. The LPPS complex contained 11 amino acids representing about 11% of its dry weight. Similarly as in factor Ei and in analogous extracts isolated by other authors the prevailing amino acids were glutamic acid, aspartic acid and lysine. The LPPS complex contained 1.26% of hexosamine, further hexoses, methyl pentoses and ribose. KDO was not detected. Further this complex consisted of 3% of freely-bound and 5% of firmly-bound lipids, beta-hydroxymyrist acid was not detectable. The composition of fatty acids in the firmly-bound lipid fraction of the LPPS complex differed quantitatively from that both in factor Ei and bacterial cell bodies. The tightness of lipid bonds during purification and the biological role of the Listeria lipids are discussed. On the basis of detected chemical and biological properties, both compatible and incompatible with peptidoglycan, a specific character of endotoxin-like isolates from L. monocytogenes is assumed.