Genetic Analyzes of Biosynthesis Mechanism of Capsular Polysaccharide as a Pathogenic Determinant.

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In these two years, we have been studying on the biosynthesis mechanisms of bacterial capsular polysaccharide (CPS) which has been regarded as one of the bacterial pathogenic determinants. The cps gene cluster of K pneumoniae Chedid (K2 : O1), which is involved in the biosynthesis of serotype K2 CPS,has been subcloned into M13 phages, mp 18 and mp 19, and the entire nucleotide sequence, about 24-kb, was determined in the term of this project. This investigation provided us many important new findings and information about the structure of the Klebsiella cps cluster and its regulation. At least 19 putative open reading frames (ORFs) were identified in the sequenced area, and several genes similar to the cpsG,cpsB,gnd, and galF were found in this region. The region implicated in the synthesis of serotype K2 CPS was localized in the central portion of the sequenced area, and it was suggested that the expression of genes in this region still continue even in the stationary phase by the function of a gene locating in the upstream region of the ORF3. However, the functions of several genes are still unknown, therefore we are planning to continue the analyzes of their roles in the biosynthesis of CPS in the next term of investigation.