title: Identification of the genes involved in the biofilm-like structures on actinomyces oris K20, a clinical isolate from an apical lesion.
abstract: BACKGROUND
  Although the production of biofilm is thought to be crucial in the pathogenesis of abscess formations caused by oral resident microorganisms, the particular mechanisms are still unknown. The aim of this study was to identify gene(s) responsible for maintaining the cell surface-associated meshwork-like structures, which are found in some biofilm-producing bacteria, in a clinical isolate of Actinomyces oris K20.
  
  
  METHODS
  Random insertional mutagenesis by using transposon EZ-Tn5 was performed against the strain K20. Transposon insertion mutants were screened by scanning electron microscopy for the absence of cell surface-associated meshwork-like structures. The disrupted genes by the transposon insertion were determined by direct genome sequencing with the transposon-end primers.
  
  
  RESULTS
  Five mutants without the meshwork-like structures were identified from 175 mutants. Sequencing of flanking regions of transposon insertion revealed that 3 mutants had a gene encoded polysaccharide deacetylase, Spo0J containing ParB-like nuclease domain, and hypothetical protein, respectively. The other 2 mutants had an insertion in a noncoding region and an unidentified region, respectively.
  
  
  CONCLUSIONS
  Our findings indicated that these genes might be involved in the formation of meshwork-like structures on Actinomyces oris K20.
authors.affiliation: Department of Bacteriology, Osaka Dental University, Osaka, Japan. mashimo@cc.osaka-dent.ac.jp
authors.forename: Chiho
authors.initials: C
authors.lastname: Mashimo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kamitani
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nambu
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yamane
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamanaka
authors.forename: Chieko
authors.initials: C
authors.lastname: Sugimori-Shinozuka
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tatami
authors.forename: Junichi
authors.initials: J
authors.lastname: Inoue
authors.forename: Maki
authors.initials: M
authors.lastname: Kamei
authors.forename: Shosuke
authors.initials: S
authors.lastname: Morita
authors.forename: Kai-Poon
authors.initials: KP
authors.lastname: Leung
authors.forename: Hisanori
authors.initials: H
authors.lastname: Fukushima
mesh_terms: D000190:Actinomyces / Q000235:genetics*; D000196:Actinomycosis / Q000382:microbiology*; D000581:Amidohydrolases / Q000235:genetics; D001431:Bacteriological Techniques; D018441:Biofilms; D002874:Chromosome Mapping; D019915:DNA Primase / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D016254:Mutagenesis, Insertional / Q000235:genetics; D010483:Periapical Diseases / Q000382:microbiology*
chemical_list: D004251:DNA Transposable Elements; D008565:Membrane Proteins; D019915:DNA Primase; D000581:Amidohydrolases; C022427:polysaccharide deacetylase