title: Structure determination of Streptococcus suis serotype 9 capsular polysaccharide and assignment of functions of the cps locus genes involved in its biosynthesis.
abstract: Streptococcus suis serotype 9 is the most prevalent S. suis serotype in several European countries. In spite of its pathogenicity for pigs and increasing zoonotic potential, limited information is available on this serotype. Here we determined for the first time the chemical composition and structure of serotype 9 capsular polysaccharide (CPS), a major bacterial virulence factor and the antigen at the origin of S. suis classification into serotypes. Chemical and spectroscopic data gave the repeating unit sequence: [3)Glcol-6-P-3-[D-Gal(α1-2)]D-Gal(β1-3)D-Sug(β1-3)L-Rha(α1-)]n. Compared to previously characterized S. suis CPSs (serotypes 1, 1/2, 2 and 14), serotype 9 CPS does not contain sialic acid but contains a labile 4-keto sugar (2-acetamido-2,6-dideoxy-β-D-xylo-hexopyranos-4-ulose), one particular feature of this serotype. A correlation between S. suis serotype 9 CPS sequence and genes of this serotype cps locus encoding putative glycosyltransferases and polymerase responsible for the biosynthesis of the repeating unit was tentatively established. Knowledge of CPS structure and composition will contribute to better dissect the role of this bacterial component in the pathogenesis of S. suis serotype 9.
authors.affiliation: National Research Council, Ottawa, Ontario, Canada.
authors.forename: Evgueny
authors.initials: E
authors.lastname: Vinogradov
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Goyette-Desjardins
authors.affiliation: Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Okura
authors.affiliation: Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan; The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Gifu, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takamatsu
authors.affiliation: Laboratory of Research on Streptococcus suis, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada. Electronic address: mariela.segura@umontreal.ca.
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
mesh_terms: D016667:Bacterial Capsules / Q000737:chemistry*; D002240:Carbohydrate Sequence; D005798:Genes, Bacterial; D005810:Multigene Family; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000737:chemistry*; D065288:Serogroup; D017011:Streptococcus suis / Q000737:chemistry / Q000235:genetics*; D037521:Virulence Factors / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D011135:Polysaccharides, Bacterial; D037521:Virulence Factors
keywords: 4-Keto sugar; Capsular polysaccharide; Serotype 9; Streptococcus suis