title: Cloning and expression of serum opacity factor in fish pathogenic Streptococcus dysgalactiae and its application to discriminate between fish and mammalian isolates.
abstract: Lancefield group C Streptococcus dysgalactiae (GCSD) is known as a causative agent of bovine mastitis and cardiopulmonary diseases in humans. Recently, GCSD has been isolated from diseased fish in Japan. Almost all culture supernatants and sodium dodecyl sulfate extracts obtained from GCSD isolated from farmed fish possessed serum opacity activity. Serum opacity factor (SOF) is a bifunctional cell-associated protein that causes serum opacification. In this study, a gene coding SOF, which was named sof-FD, was identified from GCSD isolated from fish. The amino acid sequence of sof-FD showed 40.1-46.5% identity to those of other SOFs from mammalian strains of S. dysgalactiae and Streptococcus pyogenes. Repetitive fibronectin binding domains were also observed in sof-FD, the structures of which were similar to those of other SOFs, as previously reported. The amino acid sequence of SOF was identical among fish isolates. A primer set targeting the sof-FD gene was designed and applied to a PCR assay for discriminating fish isolates from mammalian isolates.
authors.affiliation: Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Nishiki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Horikiri
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Itami
authors.forename: Terutoyo
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001431:Bacteriological Techniques / Q000379:methods; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D005353:Fibronectins / Q000378:metabolism; D005393:Fish Diseases / Q000382:microbiology*; D005399:Fishes; D006801:Humans; D007564:Japan; D008322:Mammals; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000032:analysis* / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013290:Streptococcal Infections / Q000145:classification / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D017931:DNA Primers; D005353:Fibronectins; C021908:opacity factor; D010447:Peptide Hydrolases