Research on physiology and ecology of pathogenic bacteri in viable but nonculturable state

活非培养状态病原菌生理生态学研究

基本信息

批准号：
10490012
负责人：
KOGURE Kazuhiro
金额：
$ 8.32万
依托单位：
Ocean Research Institute, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10490012/
关键词：
Viable but Nonculturable Stress Physiological activity Natural bacterial population 細菌水界検出 VBNC

项目摘要

Under stressed conditions, some bacteria fall into a physiological state in which cells fail to grow by conventional culture method but still maintain certain metabolic activities. A considerable part of natural bacteria detected under the microscopy are mataintaining metabolic activity, but unable to be cultured. The purpose of the present project is to clarify the physiological basis and ecological implication of so called "viable but nonculturable state" (VNC) of bacteria The results are summarized as follows. First, some bacteria, such as Escherichia coli, Vibrio cholerae, V. parahaemolyticus were placed in the stressed condition and were induced to fall into the VNC state. Biochemical components such as contents of DNA, RNA and protein, and metabolica activities such as respiratory activity or esterase activity were measured. These parameters were analyzed together for contracting models of VNC state. Second, effect of transient temperature up-shift on bacterial cells stressed by low nutrient and low temperature were investigated. It was found that as short as 20 minutes exposure at room temperature was effective to suppress further decrease of viable counts. Conditions affecting this process were checked and molecular basis of this phenomenon has been investigated. Third, distribution and fluctuation of natural bacteiral population that are not detected by conventional culture methods were clarified by the combination of molecular techniques and modern optical devices. In addition, the investigators have made efforts to present and discuss on the issue of VNC phenomenon. It is quite clear that during the last two years, many bacteriologists, biologists and scientists in Japan have been aware of this issue for the first time through the activitis of the members.

在压力条件下，一些细菌属于一种生理状态，在这种状态下，细胞无法通过常规培养方法生长，但仍保持某些代谢活性。在显微镜下检测到的自然细菌的相当一部分是成分的代谢活性，但无法培养。本项目的目的是阐明所谓的“可行但不可培养的状态”（VNC）的生理基础和生态含义，结果总结如下。首先，将一些细菌（例如大肠杆菌，弧菌霍乱，V。parahayticus）置于应力条件下，并被诱导落入VNC状态。测量了生化成分，例如DNA，RNA和蛋白质的含量，以及呼吸活性或酯酶活性等代谢活性。将这些参数共同分析，以用于VNC状态的合同模型。其次，研究了瞬时温度上班对低营养和低温压力的细菌细胞的影响。发现在室温下接触20分钟的时间很短，可以有效抑制可行计数的进一步减少。检查了影响此过程的条件，并研究了该现象的分子基础。第三，通过分子技术和现代光学设备的组合阐明了未通过常规培养方法检测到的天然双病毒种群的分布和波动。此外，研究人员已经努力就VNC现象问题提出和讨论。很明显，在过去的两年中，日本许多细菌学家，生物学家和科学家通过成员的活动性首次意识到了这个问题。