| Project/Area Number |
09670288
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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 |
Bacteriology (including Mycology)
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MORIYA Tetsuhiro Kyushu University, Medicine, Research Associate, 医学部, 助手 (10140790)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIMOTO Shuji Kyushu University, Medicine, Lecturer, 医学部, 講師 (30199369)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Vibrio cholerae / VNC / Nonculturable / Resuscitation / 培養不能型(VNC) / ビブリオ |
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| Research Abstract |
We constructed a nonculturable (viable but nonculturable : VNC) form of Vibrio cholerae under various conditions to clarify mode of life of pathogenic bacteria as infectious sources in the environment and analized their physiological characterizations. Furthermore, we tried to establish the method that could constantly resuscitate the VNC V.cholerae to grow on agar medium.
When V.cholerae was suspended into M9 salt and was kept at low temperature, the bacteria entered into a VNC state after about 1 month incubation, It was found that the terms for entering into the VNC were different from not only strains of V.cholerae but also various conditions surrounding the bacteria. Especially, both cell concentrations of V.cholerae and stages of cell growth affected the time for VNC.The bacteria in low cell concentration and middle log phase have quickly entered into the VNC state. V.cholerae showed longer survival in the water containing many impurities such as dust or living things rather than
… More
in clean water. This indicated reconfirmation of the fact that V.cholerae attached to the planktons in the environment and was able to survive for long time.
We confirmed that the VNC V.cholerae was resuscitate to form colonies by heat treatment in the presence of ammonium ions. This resuscitation method was effective to V.cholerae in the environment, since we could resuscitate VNC V.cholerae in the water sample collected near Dhaka in Bangladesh. We think that the resuscitation method will be useful to the bacteria other than V.cholerae. The rate of resuscitation from VNC, however, was not constant and we have to grope for the more sophisticated method for resuscitation.
From our data obtained, it is difficult to consider the VNC state "active mechanism for Survival", rather the VNC state seems to be the initial stage of process to "cell death" caused by the accumulation of various damages to cell components or functions. We are now investigate the possibility that the repair mechanism is induced by the stimuli such as heat treatments and repair the damages in the VNC V.cholerae. Less
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