Laboratory of Soil Microbiology, Department of Agronomy, Cornell University, Ithaca, New York 14853.
Appl Environ Microbiol. 1986 Jul;52(1):114-8. doi: 10.1128/aem.52.1.114-118.1986.
The populations of six bacterial genera fell rapidly after their addition to sterile lake water but not after their addition to buffer. The decline in numbers of two species that were studied further, Klebsiella pneumoniae and Micrococcus flavus, occurred even when the buffer was added to sterile lake water. The inhibition of K. pneumoniae by substances in lake water varied with the season of the year, and the rate and extent of decline of both species were different in sterile samples of different lakes. The extent of reduction in the density of K. pneumoniae was independent of initial population size and was diminished by the addition of 10 mug of glucose per ml of lake water. The toxin was removed from lake water by dialysis and by a cation-exchange resin but not by an anion-exchange resin, and it was destroyed by heating. The inhibition of K. pneumoniae was not evident in lake water buffered at a pH value above 8.0. We suggest that toxins may be important in determining the composition of the bacterial community of lakes.
在添加到无菌湖水后，六个细菌属的种群数量迅速下降，但在添加到缓冲液后则没有下降。进一步研究的两种物种，肺炎克雷伯菌和黄色微球菌，数量的下降甚至发生在将缓冲液添加到无菌湖水时。湖水物质对肺炎克雷伯菌的抑制作用随一年中的季节而变化，并且两种物种在不同无菌湖样本中的下降速度和程度也不同。肺炎克雷伯菌密度的降低程度与初始种群大小无关，并且通过每毫升湖水添加 10 微克葡萄糖而降低。毒素可通过透析和阳离子交换树脂从湖水中去除，但不能通过阴离子交换树脂去除，并且毒素可被加热破坏。在 pH 值高于 8.0 的缓冲的湖水中，肺炎克雷伯菌的抑制作用不明显。我们认为，毒素可能在决定湖泊细菌群落的组成方面起着重要作用。
