Characterization and taxonomic significance of lipopolysaccharides of Leptospira interrogans serovar hardjo

Abstract

Lipopolysaccharides (LPSs) from Leptospira interrogans serovar hardjo (reference strain hardjoprajitno and strain hardjobovis) were prepared by the hot phenol-water procedure. High yields of LPSs were found in the phenol phase. Gel electrophoresis of the phenol phase LPSs showed similar patterns for all strains in contrast to the different patterns found in the water phase LPSs. Sugar composition was also similar among all strains with rhamnose as the predominant sugar. Mannosamine was detected by high performance thin layer and gas-liquid chromatography. 2-Keto-3-deoxyoctonic acid (KDO) was comparable with authentic KDO by paper chromatography. Periodate oxidation at near neutral pH with or without prior hydrolysis showed that most of the KDO was substituted. The fatty acid composition of strain hardjobovis LPS was slightly different from that of the reference strain hardjoprajitno. Myristic and 3-hydroxymyristic acid were not detected in any of the LPS preparations. In conjunction with genetic and other data, the two strains are sufficiently different to be regarded as members of two separate species sharing common antigens. There is sufficient evidence to rename the hardjoprajitno strain type L. interrogans hardjo-p, and the hardjobovis strain type L. borgpeterseni hardjo-b.