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''Porphyromonas gingivalis'' belongs to the phylum Bacteroidetes and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar. It is found in the oral cavity, where it is implicated in certain forms of periodontal disease, as well as the upper gastrointestinal tract, respiratory tract, and in the colon. It has also been isolated from women with bacterial vaginosis. Collagen degradation observed in chronic periodontal disease results in part from the collagenase enzymes of this species. It has been shown in an ''in vitro'' study that ''P. gingivalis'' can invade human gingival fibroblasts and can survive in them in the presence of considerable concentrations of antibiotics.〔http://www.ncbi.nlm.nih.gov/pubmed/22949096〕 ''P. gingivalis'' also invades gingival epithelial cells in high numbers, in which cases both bacteria and epithelial cells survive for extended periods of time. High levels of specific antibodies can be detected in patients harboring ''P. gingivalis''. In addition, ''P. gingivalis'' has been linked to rheumatoid arthritis. It contains the enzyme peptidyl-arginine deiminase, which is involved in citrullination. Patients with rheumatoid arthritis have an increased incidence of periodontal disease and antibodies against the bacterium are significantly more common in these patients. ''P. gingivalis'' is divided into K-serotypes based upon capsular antigenicity of the various types.〔American Academy of Periodontology 2010 In-Service Exam, question A-85〕 == Genome == The genome of ''P. gingivalis'' has been described in 2003 and revealed 1,990 open reading frames (i.e. protein-coding sequences), encoded by 2,343,479 bp, with an average G+C content of 48.3%. An estimated 463 genes are essential. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Porphyromonas gingivalis」の詳細全文を読む スポンサード リンク
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