| Project/Area Number |
12490009
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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 |
広領域
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOGURE Kazuhiro The University of Tokyo, Ocean Research Institute, Marine Ecosystems Dynamics, Professor, 海洋研究所, 教授 (10161895)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Hiroyuki Japan Marine Science and Technology Center, Principal Investigator, 研究主幹 (30182645)
CHIURA Hiroshi International Christian University, Associate Professor, 教養学部, 準教授 (00103698)
MIZUNOE Yoshimitsu Kyushu University, Faculty of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (20157514)
ISHIHAMA Akira National Institute of Genetics, Professor Emeritus, 名誉教授 (80019869)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥14,300,000 (Direct Cost: ¥14,300,000)
Fiscal Year 2002: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2001: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | VNC / Bacteria / Physiology / Molecular level / Microbial Ecology / Stationary Phase / Culturability / Sigma Factor / 培養不能状態 / 酸素ストレス / ウイルス様粒子 / 化学合成生態系 / 密度勾配 / シグマファクター / 増殖期 / VNC状態 / 海洋細菌 / Percoll密度勾配 / 酸化的ストレス / 培養不能 / 発現 / 遺伝子 / ストレス |
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| Research Abstract |
The establishment of bacteriology is based on the development of pure culture technique by using agar plates. Although individual cells are tiny, the presence of the cell is seen as a colony after incubation under the suitable condition. This technique had made it possible not only to confirm the presence but also to enumerate the cells. Eventually, it started to be regarded that no colony means the absence or death of the cells. This idea has been the standard for virtually all the scientific fields of bacteriology for long time.
Microbial ecologists are the first group that had recognized the presence of non-culturable bacterial cells in nature. They found that only a small portion of bacteria were culturable by the standard method and the lack of culturability did not mean the absence of living cells.
The concept of Viable but Nonculturable (VNC) was proposed in 1985 by Prof. Rita R.Colwell. This idea is that cells may fall in non-culturable state while keeping certain metabolic activities. Under certain condition, those cells may return to the normal condition and start to show the culturability. If this is the case, all the culture-dependent diagnostic tests or detection method may miss the presence of potentially harmful microorganisms. Since the proposal, more than 40 bacteria have been reported to fall into VNC states. However this physiological state has seldom been precisely described at molecular level, which causes controversial discussions on its real state.
The purpose of this research was to clarify its physiological state at molecular level.
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