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2005 Fiscal Year Final Research Report Summary

Study on the oxidative stress responses of a major periodontopathogenic bacteria

Research Project

Project/Area Number 16591831
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Morphological basic dentistry
Research InstitutionNagasaki University

Principal Investigator

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)

Co-Investigator(Kenkyū-buntansha) 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)
NAITO Mariko  Nagasaki University, Graduate School of Biomedical Sciences, Instructor, 大学院・医歯薬学総合研究科, 助手 (20244072)
SHOJI Mikio  Nagasaki University, Graduate School of Biomedical Sciences, Instructor, 大学院・医歯薬学総合研究科, 助手 (10336175)
Project Period (FY) 2004 – 2005
Keywordsanaerobe / periodontitis / Porphyromonas gingivalis / oxidative stress
Research Abstract

Inspection of genomic DNA sequence of the oral anaerobe Porphyromonas gingivalis reveals that the microorganism possesses the peroxide-sensing transcription activator OxyR, but not the superoxide-sensing transcription factor SoxR. Oxidative stress-responsive proteins in the microorganism were investigated using two dimensional gel electrophoresis and it was found that two proteins, SOD and AhpC were predominantly upregulated in oxidative conditions. In P. gingivalis oxyR mutant these two proteins were not induced by treatment with hydrogen peroxide under aerobic conditions. P.gingivalis sod and ahpC were positively regulated by OxyR. Putative -35 boxes of these promoters were found immediately adjacent to their putative OxyR binding sequences. Moreover, the promoter regions of sod and ahpC had the ability to bind P.gingivalis OxyR protein. These results demonstrate that P.gingivalis sod is one of the OxyR regulons, suggesting that OxyR functions as an intracellular redox sensor rather than a peroxide sensor in this organism.
The new protein (UstA) was also identified in this study. Expression of UstA was upregulated in stationary phase or by exposure to atmospheric oxygen. The UstA-encoding gene (ustA) was located upstream of a homologue of the usp gene. The ustA gene appeared to be transcribed in a monocistronic fashion. The ustA mutant grew slower than the wild type parent strain, resulting in a lower yield in stationary phase. Furthermore, in this mutant, the expression levels of SOD, Tpr, and Trx were markedly higher than those in the wild type. 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.

  • Research Products

    (4 results)

All 2006 2005

All Journal Article (4 results)

  • [Journal Article] Superoxide dismutase-encoding gene of the obligate anaerobe PorPhyromonas gingivalis is regulated by the redox-sensing transcription activator OxyR.2006

    • Author(s)
      Naoya ohara
    • Journal Title

      Microbiology-SGM 152・4

      Pages: 955-966

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Superoxide dismutase-encoding gene of the obligate anaerobe Porphyromonas gingivalis is regulated by the redox-sensing transcription activator OxyR.2006

    • Author(s)
      Ohara N.
    • Journal Title

      Microbiogy. 152

      Pages: 955-966

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Novel stationary-phase-upregulated protein of Porphyromonas gingivalis influences production of superoxide dismutase, thiol peroxidase and thioredoxin2005

    • Author(s)
      Yuichiro Kikuchi
    • Journal Title

      Microbiology-SGM 151・3

      Pages: 841-853

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] The novel stationary-phase-upregulated protein of Porphyromonas gingivalis influences the production of superoxide dismutase, thiol peroxidase and thioredoxin.2005

    • Author(s)
      Kikuchi Y.
    • Journal Title

      Microbiogy. 151

      Pages: 841-853

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 2007-12-13  

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