title: A gene cluster for the synthesis of serotype g-specific polysaccharide antigen in Aggregatibacter actinomycetemcomitans.
abstract: Aggregatibacter actinomycetemcomitans is an important pathogen related to aggressively progressive periodontal breakdown in adolescents and adults. The species can be divided into six serotypes (a-f) according to their surface carbohydrate antigens. Recently, a new serotype g of A. actinomycetemcomitans was proposed. The aim of the present study was to sequence the gene cluster associated with the biosynthesis of the serotype g-specific polysaccharide antigen and develop serotype-specific primers for PCR assay to identify serotype g strains of A. actinomycetemcomitans. The serotype-specific polysaccharide (SSPS) gene cluster of the NUM-Aa 4039 strain contained 21 genes in 21,842-bp nucleotides. The similarity of the SSPS gene cluster sequence was 96.7 % compared with that of the serotype e strain. Seventeen serotype g genes showed more than 90 % homology both in nucleotide and amino acids to the serotype e strain. Three additional genes with 1,579 bp in NUM-Aa 4039 were inserted into the corresponding ORF13 of the serotype e strain. The serotype g-specific primers were designed from the insertion region of NUM-Aa 4039. Serotypes of the a-f strains were not amplified by serotype-specific g primers; only NUM-Aa 4039 showed an amplicon band. The NUM-Aa 4039 strain was three genes in the SSPS gene cluster different from those of serotype e strain. The specific primers derived from these different regions are useful for identification and distribution of serotype g strain among A. actinomycetemcomitans from clinical samples.
authors.affiliation: Department of Oral Microbiology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba, 271-8587, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Tsuzukibashi
authors.forename: Masanori
authors.initials: M
authors.lastname: Saito
authors.forename: Taira
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Koji
authors.initials: K
authors.lastname: Umezawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Nagahama
authors.forename: Takachika
authors.initials: T
authors.lastname: Hiroi
authors.forename: Masatomo
authors.initials: M
authors.lastname: Hirasawa
authors.forename: Kazuko
authors.initials: K
authors.lastname: Takada
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics* / Q000378:metabolism; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics; D055113:Chronic Periodontitis / Q000382:microbiology; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012703:Serotyping
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial