| Project/Area Number |
11672086
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Periodontal dentistry
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| Research Institution | KYOSHU UNIVERSITY |
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Principal Investigator |
YONEDA Masahiro Faculty of Dental Science, Kyusyu Univ.Research Associate, 歯学部・附属病院, 助手 (10253460)
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| Co-Investigator(Kenkyū-buntansha) |
HIROFUJI Takao Faculty of Dental Science, Kyusyu Univ.Assistant Professor, 歯学部・附属病院, 講師 (10189897)
NAKAYAMA Koji Faculty of Dentistry, Nagasaki Univ.Professor, 歯学部, 教授 (80150473)
MAEDA Katsumasa Faculty of Dental Science, Kyusyu Univ.Professor, 大学院・歯学研究院, 教授 (00117243)
HAMACHI Takafumi Faculty of Dental Science, Kyusyu Univ.Research Asociate, 大学院・歯学研究院, 助手 (80198811)
ANAN Hisashi Faculty of Dental Science, Kyusyu Univ.Assistant Professor, 歯学部・附属病院, 講師 (80158732)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Porphyromonas gingivalis / Bacteroides forsythus / mixed infection / gingipains / P.gingivalis / B.forsythus / gingipain |
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| Research Abstract |
Several microorganisms including Porphyromonas gingivalis and Bacteroides forsythus have been implicated to be etiologically important agents of periodontal disease. In this study, we determined the ability of periodontopathogenic microorganisms to synergistically cause tissue destruction in a murine abscess model. Although all bacterial combinations used in this study produced larger sizes of abscesses than that of monoinfection of each bacterium, the combination of P.gingivalis-B.forsythus showed a synergistic effect on the abscess formation. Since these two bacteria have been frequently found together in lesions of periodontitis, these results suggested the significance of their coinfection in the progression of periodontitis. P.gingivalis produces extracellular and cell-associated cysteine proteinases (gingipains) which appear to be involved in its virulence. The rgpA rgpB double and kgp mutants induced significantly smaller abscess than the wild type. Moreover, the rgpA rgpB kgp triple (gingipain-null) mutant hardly showed lesion formation at the experimental conditions used in this study, indicating that these genes encoding gingipains were important for virulence of P.gingivalis. Mixed infection of these P.gingivalis mutants with B.forsythus showed an additive effect rather than a synergistic effect, indicating that the gingipains of P.gingivalis may play an important role in this synergism.
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