ISOLATION OF RFB GENE CLUSTERS DIRECTING THE SYNTHESIS OF O POLYSACCHARIDES CONSISTING OF MANNOSE HOMOPOLYMERS AND SEROLOGICAL ANALYSIS OF LIPOPOLYSACCHARIDES

Four serotypes of two genera, Escherichia coli 08 and 09 and Klebsiell a 03 and 05, produce the 0 polysaccharides consisting of mannose homop olymers. Previously we reported the isolation and expression of E. col i 09 rfb in E. coli K-12 strains (Kido et al, J. Bacteriol., 171: 3629 -3633, 1989). In this study, R' plasmids carrying his-rfb region of th e other three strains were isolated and expressed in E. coli K-12 stra in. Serological study of lipopolysaccharides (LPS) synthesized in E. c oli K-12 strain was carried out. His-linked rfb genes from E. coli 09 and Klebsiella 03 directed the synthesis of 0 polysaccharides with the same antigenicity as those of the parental strains in E. coli K-12 st rain. On the other hand, rfb genes from E. coli 08 and Klebsiella 05 d irected the synthesis of 0 polysaccharides which were antigenically no t identical but partially common to those of the parental strains. A r ough strain derived from E. coli 08 synthesized LPS which showed the i dentical antigenicity as the wild strain when the his-rfb region of E. coli 08 was introduced. The results suggest that some genes located d istantly from his are additionally required to complete the synthesis of 0 polysaccharides of E. coli 08 and Klebsiella 05.