title: Comparative genome analysis and identification of competitive and cooperative interactions in a polymicrobial disease.
abstract: Polymicrobial diseases are caused by combinations of multiple bacteria, which can lead to not only mild but also life-threatening illnesses. Periodontitis represents a polymicrobial disease; Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, called 'the red complex', have been recognized as the causative agents of periodontitis. Although molecular interactions among the three species could be responsible for progression of periodontitis, the relevant genetic mechanisms are unknown. In this study, we uncovered novel interactions in comparative genome analysis among the red complex species. Clustered regularly interspaced short palindromic repeats (CRISPRs) of T. forsythia might attack the restriction modification system of P. gingivalis, and possibly work as a defense system against DNA invasion from P. gingivalis. On the other hand, gene deficiencies were mutually compensated in metabolic pathways when the genes of all the three species were taken into account, suggesting that there are cooperative relationships among the three species. This notion was supported by the observation that each of the three species had its own virulence factors, which might facilitate persistence and manifestations of virulence of the three species. Here, we propose new mechanisms of bacterial symbiosis in periodontitis; these mechanisms consist of competitive and cooperative interactions. Our results might shed light on the pathogenesis of periodontitis and of other polymicrobial diseases.
authors.affiliation: Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Endo
authors.affiliation: Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Takayasu
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Nachiko
authors.initials: N
authors.lastname: Ogata
authors.affiliation: 1] Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan [2] Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nozawa
authors.affiliation: 1] Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan [2] Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Aikawa
authors.affiliation: Department of Lifetime Oral Health Care Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Arakawa
authors.affiliation: 1] Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan [2] Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan [3] Section of Microbial Genomics and Ecology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Fumito
authors.initials: F
authors.lastname: Maruyama
authors.affiliation: Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Izumi
authors.affiliation: 1] Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan [2] Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakagawa
mesh_terms: D041963:Bacteroidetes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D016680:Genome, Bacterial; D006801:Humans; D010518:Periodontitis / Q000382:microbiology; D010802:Phylogeny; D016966:Porphyromonas gingivalis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D013559:Symbiosis; D048373:Treponema denticola / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology