title: Silkworm pathogenic bacteria infection model for identification of novel virulence genes.
abstract: Silkworms are killed by injection of pathogenic bacteria, such as Staphylococcus aureus and Streptococcus pyogenes, into the haemolymph. Gene disruption mutants of S. aureus whose open reading frames were previously uncharacterized and that are conserved among bacteria were examined for their virulence in silkworms. Of these 100 genes, three genes named cvfA, cvfB, and cvfC were required for full virulence of S. aureus in silkworms. Haemolysin production was decreased in these mutants. The cvfA and cvfC mutants also had attenuated virulence in mice. S. pyogenes cvfA-disrupted mutants produced less exotoxin and had attenuated virulence in both silkworms and mice. These results indicate that the silkworm-infection model is useful for identifying bacterial virulence genes.
authors.affiliation: Graduate School of Pharmaceutical Sciences, University of Tokyo, 3-1, 7-Chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Chikara
authors.initials: C
authors.lastname: Kaito
authors.forename: Kenji
authors.initials: K
authors.lastname: Kurokawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Terao
authors.forename: Shigetada
authors.initials: S
authors.lastname: Kawabata
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Hamada
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sekimizu
mesh_terms: D000818:Animals; D012831:Bombyx / Q000382:microbiology*; D004195:Disease Models, Animal; D005260:Female; D005798:Genes, Bacterial; D006460:Hemolysin Proteins / Q000378:metabolism; D051379:Mice; D009154:Mutation; D016366:Open Reading Frames; D017434:Protein Structure, Tertiary; D013203:Staphylococcal Infections / Q000382:microbiology*; D013210:Staphylococcus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D013297:Streptococcus pyogenes / Q000235:genetics / Q000472:pathogenicity; D015996:Survival Rate; D014774:Virulence / Q000235:genetics
chemical_list: D006460:Hemolysin Proteins