title: Gene expression profile and pathogenicity of biofilm-forming Prevotella intermedia strain 17.
abstract: BACKGROUND
  Prevotella intermedia (P. intermedia), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. P. intermedia strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials in vitro from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays.
  
  
  RESULTS
  Strain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (sigmaE; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media.
  
  
  CONCLUSIONS
  These results demonstrate that the capacity to form biofilm in P. intermedia contribute to their resistance against host innate defence responses.
authors.affiliation: Department of Bacteriology, Osaka Dental University, Osaka, Japan. yamanaka@cc.osaka-dent.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamanaka
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Furukawa
authors.forename: Chiho
authors.initials: C
authors.lastname: Matsumoto-Mashimo
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yamane
authors.forename: Chieko
authors.initials: C
authors.lastname: Sugimori
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nambu
authors.forename: Naoki
authors.initials: N
authors.lastname: Mori
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nishikawa
authors.forename: Clay B
authors.initials: CB
authors.lastname: Walker
authors.forename: Kai-Poon
authors.initials: KP
authors.lastname: Leung
authors.forename: Hisanori
authors.initials: H
authors.lastname: Fukushima
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D016866:Bacteroidaceae Infections / Q000276:immunology / Q000382:microbiology*; D018441:Biofilms; D002478:Cells, Cultured; D055113:Chronic Periodontitis / Q000276:immunology / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000382:microbiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D010587:Phagocytosis; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism; D018713:Prevotella intermedia / Q000737:chemistry / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D011135:Polysaccharides, Bacterial