Isolation and characterization of the lipopolysaccharide of Thiocapsa roseopersicina.

The lipopolysaccharide from Thiocapsa roseopersicina was isolated by phenol/water, being found in the water phase. It is cleaved into a polysaccharide moiety (degraded polysaccharide) and lipid A by hydrolysis with 10% acetic acid (100 degree C, 3 h). D-Mannose, L-rhamnose, 3-amino-3, 6-dideoxy-D-galactose and D-glucose are the major constituents of the degraded polysaccharide. 2-O-Methyl-L-rhamnose, 3-O-methyl-D-mannose, D-galactose, glucosamine and quinovosamine are minor constituents. D-Glycer-D-manno-heptose (tentatively identified) and 3-deoxy-D-manno-octulosonic acid were detected in only small amounts. Conspicuously, lipid A from T. roseopersicina contains a neutral sugar, D-mannose, in addition to D-glucosamine, as had been observed with lipid A from Chromatium vinosum D. Major fatty acids are beta-hydroxymyristic and lauric acids. Only trace amounts of phosphorus were found indicating this lipid A to be free of phosphate. The lipopolysaccharide of T. roseopersicina represents the O-antigen of the strain. It reacts with antisera prepared against living or heat-killed cells in passive hemagglutination.