National Agricultural Research Center, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Can J Microbiol. 2010 Apr;56(4):333-41. doi: 10.1139/w10-019.
Bacterial culture based on the use of plate media is an effective method for investigating bacterial populations in the environment. To improve the culturability of bacteria from freshwater lakes, we developed a new medium, FW70, which contains sodium pyruvate, casamino acids, and lake water and is solidified using gellan gum. To test the importance of these components, we prepared a series of media in which one or more of the components was absent. Water was sampled 31 times from 3 Japanese lakes and was passed through a membrane filter (pore size = 0.45 microm) to remove fast-growing microbes before the water was spread onto the plates. In most cases, significantly larger numbers of bacterial colonies were detected on FW70 than on other media. Furthermore, to test the practicality of FW70, we compared it with standard nutrient agar and R2A agar. In all cases, the culturability was significantly greater on FW70 than on standard nutrient agar or R2A agar. Some isolates recovered by means of FW70 belonged to bacteria that had not previously been classified. These results suggest that FW70 improves the culturability of freshwater bacteria and can be used for the isolation of novel bacteria as a result of the filtration step.
基于平板培养基使用的细菌培养是调查环境中细菌种群的有效方法。为了提高淡水湖中细菌的可培养性，我们开发了一种新的培养基 FW70，其中含有丙酮酸钠、水解酪蛋白和湖水，并使用结冷胶固化。为了测试这些成分的重要性，我们制备了一系列培养基，其中一种或多种成分缺失。从 3 个日本湖泊中采集了 31 次水样，并在将水样铺到平板上之前，通过膜过滤器（孔径=0.45 微米）过滤水样以去除快速生长的微生物。在大多数情况下，FW70 上检测到的细菌菌落数量明显多于其他培养基。此外，为了测试 FW70 的实用性，我们将其与标准营养琼脂和 R2A 琼脂进行了比较。在所有情况下，FW70 上的可培养性均显著高于标准营养琼脂或 R2A 琼脂。通过 FW70 回收的一些分离株属于以前未分类的细菌。这些结果表明，FW70 提高了淡水细菌的可培养性，并可以通过过滤步骤用于分离新型细菌。
