| Project/Area Number |
15591932
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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 |
Morphological basic dentistry
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
INOUE Tetsuyoshi OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Research Associate, 大学院・医歯学総合研究科, 助手 (20223258)
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| Co-Investigator(Kenkyū-buntansha) |
SHINGAKI Ryuji OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Research Associate, 大学院・医歯薬学総合研究科, 助手 (40294417)
KOKEGUCHI Susumu OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Assistant Professor, 大学院・医歯薬学総合研究科, 助教授 (10144776)
TAKASHIBA Shogo OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Professor, 大学院・医歯薬学総合研究科, 教授 (50226768)
FUKUI Kazuhiro OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Professor, 大学院・医歯薬学総合研究科, 教授 (70034171)
OHTA Hiroyuki Ibaraki University, Professor, 農学部, 教授 (80168947)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | biofilm / fimbriae / exopolysaccharide / adherence / cell-cell aggregation / Actinobacillus / leukotoxin / periodontal disease / ミクロコロニー / 初期付着 / 菌体表層多糖 |
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| Research Abstract |
<Observation of biofilm (BF) formation> In a wild-type strain of Actinobacillus actinomycetemcomitans (Aa), many fimbriae were produced in an early stage of BF formation, whereas, in mature stage, fimbriae production was repressed, and cell-cell aggregation was observed. Exopolysaccharide (EPS)-like structure was also observed on the cell surface. <BF formation and dye-binding ability> BF-positive strains had Congo red (CR)-binding ability, while BF-negative strains did not. A fimbriae-deficient strain showed CR-binding ability, suggesting that it indicates the presence of BF formation factors other than fimbriae. The dye-binding capacity disappeared by treatment with periodate, suggesting it reflects EPS biosynthesis. From genome sequence analysis, a gene cluster homolog involved in biosynthesis of Congo red-binding EPS was found in Aa genome. One of the genes was disrupted. However, BF formation was not affected. More detailed studies are needed to clarify the role of this gene cluster in BF formation. <Assay for cell-cell aggregation> Treatment with periodate or DNase completely inhibited cell-cell aggregation. From this result, it was assumed that in addtion of EPS, cell surface DNA was also involved in aggregation during BF formation. <Regulation of leukotoxin production> To examine the effects of catabolite repression-like mechanism on BF formation and leukotoxin production, attempts to isolate crp gene mutant were made. However, it colud not be obtained. The crp gene might be an essential gene in Aa. Toxin production was increased in an acidic condition, suggesting the reduction of microenvironmental pH in BF causes induction of toxin production.
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