title: Serotype O:8 isolates in the Yersinia pseudotuberculosis complex have different O-antigen gene clusters and produce various forms of rough LPS.
abstract: In Yersinia pseudotuberculosis complex, the O-antigen of LPS is used for the serological characterization of strains, and 21 serotypes have been identified to date. The O-antigen biosynthesis gene cluster and corresponding O-antigen structure have been described for 18, leaving O:8, O:13 and O:14 unresolved. In this study, two O:8 isolates were examined. The O-antigen gene cluster sequence of strain 151 was near identical to serotype O:4a, though a frame-shift mutation was found in ddhD, while No. 6 was different to 151 and carried the O:1b gene cluster. Structural analysis revealed that No. 6 produced a deeply truncated LPS, suggesting a mutation within the waaF gene. Both ddhD and waaF were cloned and expressed in 151 and No. 6 strains, respectively, and it appeared that expression of ddhD gene in strain 151 restored the O-antigen on LPS, while waaF in No. 6 resulted in an LPS truncated less severely but still without the O-antigen, suggesting that other mutations occurred in this strain. Thus, both O:8 isolates were found to be spontaneous O-antigen-negative mutants derived from other validated serotypes, and we propose to remove this serotype from the O-serotyping scheme, as the O:8 serological specificity is not based on the O-antigen.
authors.affiliation: School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia.
authors.forename: Johanna J
authors.initials: JJ
authors.lastname: Kenyon
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Duda
authors.affiliation: Department of Chemical Sciences, University of Napoli, Napoli, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: De Felice
authors.affiliation: School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Cunneen
authors.affiliation: Department of Chemical Sciences, University of Napoli, Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
authors.affiliation: Department of Bacteriology and Immunology, Medicum, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Laitinen
authors.affiliation: Department of Bacteriology and Immunology, Medicum, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland Helsinki University Central Hospital Laboratory Diagnostics, Helsinki, Finland.
authors.forename: Mikael
authors.initials: M
authors.lastname: Skurnik
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
authors.affiliation: School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Reeves
authors.affiliation: Department of Agriculture Sciences, University of Napoli, Portici, Italy decastro@unina.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: De Castro
mesh_terms: D019295:Computational Biology; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology*; D015394:Molecular Structure; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D019081:O Antigens / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D065288:Serogroup; D012703:Serotyping; D013045:Species Specificity; D015011:Yersinia pseudotuberculosis / Q000235:genetics / Q000276:immunology*; D015012:Yersinia pseudotuberculosis Infections / Q000175:diagnosis*
chemical_list: D008070:Lipopolysaccharides; D019081:O Antigens
keywords: O-Antigen; O-specific polysaccharide; O:8 serotype; Yersinia pseudotuberculosis; serotyping