Chemical properties of lipopolysaccharide (LPS) isolated from Vibrio anguillarum PT514

Vibrio anguillarum, one of the causative agents of fish vibriosis, is serologically and biochemically divided into three groups (A, B and C). The chemical composition and molecular architecture of lipopolysaccharide (LPS) isolated from V. anguillarum PT514, which belongs to serogroup B, were investigated. The LPS contained glucose (Glc), fructose (Fru), L-glycero-D-mannoheptose (L-D Hep), glucosamine (GlcN) and 4-amino-4, 6-dideoxyglucose as sugar constituents in molar ratios of 8.9:0.7:3.0:1.1:1.6. Sephadex G-50 gel-chromatography of a degraded polysaccharide fraction separated from the LPS by 5% acetic acid hydrolysis suggested that the O-specific polysaccharide region consists of, in average, as much as 29 moles of Glc per 3 moles of L-D Hep, while the core polysaccharide contains at least Glc, L-D Hep and GlcN in molar ratios of 3.2:3.0:0.2. Fru and 4-amino-4, 6-dideoxyglucose components were released from LPS on weak-acid hydrolysis, indicating that PT514 LPS is distinguishable from those of Vibrio anguillarum belonging to the other serogroups. 2-Keto-3-deoxyoctonate (KDO), a common sugar constituent of gram-negative bacterial LPS, was not detected by Weissbach's color reaction under the conventional hydrolysis condition, but O-phosphoryl KDO was found in the strong-acid hydrolysate (4M HCl, 100C, 45min). This substance was identical, at least in high-voltage paper electrophoresis, to 5-O-phosphoryl KDO. Lipid A isolated from the LPS contained C12:0, C14:0, C16:0, C16:1, C18:1, 3-OHC12:0 and 3-OHC14:0. The LPS showed endotoxic activity in limulus lysate assay to the same extent as those of V. cholerae NIH 41 (Ogawa) and 569B (Inaba).