| Project/Area Number |
14370585
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Nagasaki University |
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Principal Investigator |
NAKAYAMA Koji Nagasaki University, Graduate School of Biomedical Sciences, Professor, 大学院・医歯薬学総合研究科, 教授 (80150473)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Naoya Nagasaki University, Graduate School of Biomedical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (70223930)
NAITO Mariko Nagasaki University, Graduate School of Biomedical Sciences, Research Associate, 大学院・医歯薬学総合研究科, 助手 (20244072)
SHOJI Mikio Nagasaki University, Graduate School of Biomedical Sciences, Research Associate, 大学院・医歯薬学総合研究科, 助手 (10336175)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥13,900,000 (Direct Cost: ¥13,900,000)
Fiscal Year 2004: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2003: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Keywords | Oral Anaerobic Bacteria / Porphyromonas gingivalis / Stationary phase / Oxidative stress / Universal stress protein / 歯周病 / 口腔嫌気性細菌 / 環境因子 / タンパク発現 |
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| Research Abstract |
Porphyromonas gingivals, an obligate anaerobic bacterium, is implicated as a major pathogen in the development and progression of chronic periodontitis. Although expression of several virulence factors of the bacterium has been found to be affected by environmental stress such as entrance into the stationary growth phase and heat, there is relatively little information on the mechanisms that may operate in the bacterium in response to environmental stress. In this study, we investigated the new protein (UstA) that was initially identified following the two dimensional gel analysis. Expression of UstA was upregulated in stationary phase or by exposure to atmospheric oxygen. N-terminal sequencing and database analysis with the P.gingivalis genome sequence revealed that the UstA-encoding gene (ustA) was located upstream of a homologue of the usp gene encoding the universal stress protein on the chromosome. The ustA gene appeared to be transcribed in a monocistronic fashion as revealed by primer extension and Northern blot analysis. To elucidate the role of UstA in the bacterium, chromosomal mutants carrying a disruption of the ustA gene were constructed. The ustA mutant grew slower than the wild type parent strain in rich medium, resulting in a lower yield in stationary phase. Furthermore, in this mutant, the expression levels of the P.gingivalis homologues of superoxide dismutase, thiol peroxidase, and thioredoxin were markedly higher than those in the wild type especially in stationary phase. The ustA mutant was more resistant to diamide, a thiol-specific oxidant, than the wild type. In addition, the ustA mutation suppressed hypersensitivities of the oxyR mutant to diamide, metronidazole, and mitomycin C. These results suggest that UstA may play a significant role in oxidative stress responses in the bacterium.
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