Chemical properties of O-antigenic lipopolysaccharides isolated from Vibrio parahaemolyticus O2 and O9, in particular, the separation and identification of 2-keto-3-deoxy-5-phosphoryl-octonate found in their strong acid-hydrolysates

Abstract

A degradation study was carried out on lipopolysaccharides (LPS) isolated from Vibrio parahaemolyticus O2 and O9. On Sephadex G-50 gel filtration of “degraded polysaccharide” (DPS) from the S-form strains, no such peak was observed that represents polymeric O-specific side chains with atached core which is generally eluted in void volume. The result suggests that the O-specificities of these V. parahaemolyticus are associated with the structure and composition of the core region of their LPS molecules and/or that their O-specific chains are very short.A Weissbach's periodate-thiobarbituric acid-reaction positive substance (X) was released from each of O2 and O9 LPS after strong acid hydrolysis (4N HCl, 100C, 45min). On High-voltage paper electrophoresis (HVPE), X was separated into two components, X1 and X2, with mobilities of 1.54 and 1.80, respectively, relative to that of 2-keto-3-deoxy-octonate (KDO). X1 was identified as 2-keto-3-deoxy-5-phosphoryl-KDO (5-O-phosphoryl-KDO) on HVPE using, as a control, authentic 5-O-phosphoryl-KDO isolated from Bordetella pertussis (phase I). After treatment with alkaline-phosphatase, X1 as well as the authentic 5-O-phosphoryl-KDO disappeared and KDO was detected.