Genetic and structural characterization of the core region of the lipopolysaccharide from Serratia marcescens N28b (serovar O4).

The gene cluster (waa) involved in Serratia marcescens N28b core lipopolysaccharide (LPS) biosynthesis was identified, cloned, and sequenced. Complementation analysis of known waa mutants from Escherichia coli K-12, Salmonella enterica, and Klebsiella pneumoniae led to the identification of five genes coding for products involved in the biosynthesis of a shared inner core structure: [L,D-HeppIIIalpha(1-->7)-L,D-HeppIIalpha(1-->3)-L,D-HeppIalpha(1-->5)-KdopI(4<--2)alphaKdopII] (L,D-Hepp, L-glycero-D-manno-heptopyranose; Kdo, 3-deoxy-D-manno-oct-2-ulosonic acid). Complementation and/or chemical analysis of several nonpolar mutants within the S.

The inner-core lipopolysaccharide biosynthetic waaE gene: function and genetic distribution among some Enterobacteriaceae.

To determine the function of the waaE gene in the biosynthesis of the inner-core LPS of Klebsiella pneumoniae, a waaE non-polar mutant has been constructed. Data obtained from the comparative chemical analysis of LPS samples obtained from the wild-type, the mutant strain and the complemented mutant demonstrated that the waaE gene is involved in substitution of alpha-L-glycero-D-manno-heptopyranose I (L,D-HeppI) at the O-4 position by a beta-D-glucopyranose (beta-D-Glcp) residue. In addition, DNA amplification and nucleotide sequence determination studies revealed that waaE homologues located between the waaA and coaD genes are present in clinical isolates of Enterobacteriaceae containing the structure beta-D-Glcp-(1-->4)-alpha-L,D-HeppI (K.

Genetic characterization of the Klebsiella pneumoniae waa gene cluster, involved in core lipopolysaccharide biosynthesis.

A recombinant cosmid containing genes involved in Klebsiella pneumoniae C3 core lipopolysaccharide biosynthesis was identified by its ability to confer bacteriocin 28b resistance to Escherichia coli K-12. The recombinant cosmid contains 12 genes, the whole waa gene cluster, flanked by kbl and coaD genes, as was found in E. coli K-12.

The role of the capsular polysaccharide of Aeromonas hydrophila serogroup O:34 in the adherence to and invasion of fish cell lines.

The ability of Aeromonas hydrophila serogroup O:34 strains grown under different conditions (capsulated and non-capsulated) to adhere to and invade two fish cell lines was compared. The level of adherence was slightly higher when the strains were grown under conditions promoting capsule formation than when the same strains were grown under conditions which did not promote capsule formation. However, the most significant difference among the wild-type strains grown under conditions promoting capsule formation was the ability to invade the fish cell lines, which was significantly higher than when the same strains were grown under conditions which did not promote capsule formation.