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Glycerophosphate-containing O-specific polysaccharides (OPSs) were obtained by mild acidic degradation of lipopolysaccharides isolated from Escherichia coli type strain O81 and E. coli strain HS3-104 from horse feces. The structures of both OPSs and of the oligosaccharide derived from the strain O81 OPS by treatment with 48% HF were studied by monosaccharide analysis and one- and two-dimensional 1H- and 13C-NMR spectroscopy. Both OPSs had similar structures and differed only in the presence of a side-chain glucose residue in the strain HS3-104 OPS. The genes and the organization of the O-antigen biosynthesis gene cluster in both strains are almost identical with the exception of the gtr gene cluster responsible for glucosylations in the strain HS3-104, which is located elsewhere in the genome. [ABSTRACT FROM AUTHOR]

The lipopolysaccharide (LPS) of strains representing various serotypes of Yersinia enterocolitica and Y. enterocolitica-like bacteria was studied by deoxycholate-PAGE and silver staining analysis. Four main types of LPS were detected based on the O-polysaccharide (O-PS): (i) LPS with homopolymeric O-PS, (ii) LPS with ladder-forming heteropolymeric O-PS, (iii) LPS with single-length O-PS, and (iv) semi-rough LPS without O-PS. Within the first three types, several subvariants were detected. Selected serotypes representing all above LPS types are sensitive to bacteriophage ϕR1-37 indicating that they share the phage receptor, a hexasaccharide called outer core in Y. enterocolitica O:3. Whereas phage ϕR1-37-resistant mutants of homopolymeric O-PS have lost only the outer core, those of ladder-forming or single-length O-PS have lost also the O-PS suggesting that in the latter ones the outer core is bridging between O-PS and lipid A-core. This work forms a basis of further structural, biochemical and genetic studies of these LPSs. [ABSTRACT FROM AUTHOR]

Enterobacterial common antigen (ECA) is a characteristic surface component in bacteria belonging to the Enterobacteriaceae family. It is generally integrated in the outer membrane via a linkage to phosphatidylglycerol (ECA) and at the same time in some special cases via a linkage to lipopolysaccharide (ECA); the latter form is immunogenic. Yersinia enterocolitica O:3 expresses both ECA and ECA. To study whether ECA-immunogenicity of Y. enterocolitica O:3 is temperature-regulated, rabbits were immunized with ECA-expressing Y. enterocolitica O:3 bacteria grown at 22 and 37°C. To induce minimal amount of anti-LPS antibodies, immunization was performed with YeO3-c-trs8-R, an LPS mutant missing both O-polysaccharide and the outer core hexasaccharide. However, abundant antibodies specific for LPS core were still present in the obtained antisera such that the reactivity of ECA-specific antibodies could not be detected. To obtain 'monovalent' anti-ECA antisera, the sera were absorbed with ECA-negative bacteria. Absorption with live bacteria removed efficiently the anti-LPS antibodies, whereas this was not the case with boiled bacteria. Western blotting revealed that the specificity of the monovalent anti-ECA antiserum was different from that of a monoclonal anti-ECA antibody (mAb 898) as it did not react with ECAPG, and this suggested that in Y. enterocolitica O:3 ECA only one or two ECA repeat unit(s) is/are linked to LPS. Both ECA and ECA expression were found to be regulated by temperature and repressed at 37°C. [ABSTRACT FROM AUTHOR]