title: Stimulation of growth of Porphyromonas gingivalis by cell extracts from Tannerella forsythia.
abstract: OBJECTIVE
  In order to examine if Tannerella forsythia stimulates the growth of Porphyromonas gingivalis, an in vitro study was performed.
  
  
  BACKGROUND
  P. gingivalis and T. forsythia are often isolated simultaneously from active periodontitis sites, indicating that these bacteria somewhat interact in the periodontal environment. We reported previously that mixed infection of P. gingivalis and T. forsythia synergistically induced lesion formation in a murine abscess model, and gingipains of P. gingivalis played an important role in this synergism. One of the possible mechanisms of this synergism is growth promotion by coinfection of the two bacteria.
  
  
  METHODS
  Cell extracts of T. forsythia were added to the nutrition-decreased medium and the promotion of growth of P. gingivalis was examined.
  
  
  RESULTS
  Sonicated extract of T. forsythia stimulated growth of P. gingivalis in nutrition-decreased medium in a dose-dependent manner. Proteins appeared to be the nature of growth-promoting factor, and the cell extract of T. forsythia had no stimulating effect on the growth of P. gingivalis strain devoid of gingipain activities.
  
  
  CONCLUSIONS
  A product or a component of T. forsythia seemed to stimulate growth of P. gingivalis under nutrition-limited conditions. Gingipains are considered to play an important role in digestion or uptake of this growth-promoting factor. The interaction between T. forsythia and P. gingivalis in growth may be in part related with the synergistic virulence in a murine model.
authors.affiliation: Section of General Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan. yoneda@college.fdcnet.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoneda
authors.forename: Toru
authors.initials: T
authors.lastname: Yoshikane
authors.forename: Noriko
authors.initials: N
authors.lastname: Motooka
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamada
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hisama
authors.forename: Toru
authors.initials: T
authors.lastname: Naito
authors.forename: Ichizo
authors.initials: I
authors.lastname: Okada
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yoshinaga
authors.forename: Keitaro
authors.initials: K
authors.lastname: Hidaka
authors.forename: Koichi
authors.initials: K
authors.lastname: Imaizumi
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Maeda
authors.forename: Takao
authors.initials: T
authors.lastname: Hirofuji
mesh_terms: D000818:Animals; D016866:Bacteroidaceae Infections / Q000382:microbiology*; D001439:Bacteroides / Q000502:physiology*; D002417:Cattle; D010510:Periodontal Diseases / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000254:growth & development*