Microbial community analysis for evaluating water quality improvement in reservoirs installed with destratification system

采用变性梯度凝胶电泳（DGGE）和聚合酶链反应（PCR）技术，研究了津井湖水体中设置分层系统后，水体中细菌和藻类微生物群落的季节变化。为了以图形化的方式表达群落的季节变化，应用多维尺度（MDS）。MDS地图揭示了一个周期性的变化的社区和一个独特的分歧，从路径在一个突然的藻华后，一场大风暴。由于在排除蓝藻的分析中分歧消失，群落的主要部分可能独立于突然的藻华。利用激发发射矩阵光谱（EEMS）和PCR-DGGE技术研究了不同采样点水体中溶解性有机物（DOM）的产生与细菌群落变化的关系，结果表明，不同采样点水体中细菌群落的差异性明显小于不同采样月水体中细菌群落的差异性。 ...更多信息 在分批培养试验中，对藻华的分解和降解进行了研究。从Tsukui湖采集的藻华的溶解表明溶解的有机碳和260 nm处的紫外吸光度在5天内迅速增加。根据溶解，来自腐殖酸和蛋白质类物质的几个荧光峰出现在EEM中。DGGE主要条带的系统发育分析表明，与γ-变形菌门、CFB类群和α-变形菌门关系密切的细菌可能在水华的溶解和降解过程中发挥了重要作用。将铜绿微囊藻（Microcystis aeruginosa）纯培养物分别接种于灭菌和未灭菌的津井湖水中。真细菌的存在对溶藻后DOM的形成有影响。来自腐殖类物质的荧光在未消毒的湖水中增加，随后减少，而在消毒的水中没有观察到这种变化。少

Seasonal change of microbial community including bacteria and algae in Tsukui Lake, where destratification system was installed, was investigated by denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR). In order to express graphically the seasonal change of the community based on the dissimilarity index, multi-dimensional scaling (MDS) was applied. The MDS map revealed a cyclic change of the community and a distinctive divergence from the path during a sudden algal bloom after a heavy storm. Since the divergence disappeared in an analysis excluding cyanobacteria, the major part of the community might be independent of the sudden algal bloom. Dissimilarity of microbial communities was much lower among three different sampling sites than among the sampling months.Excitation emission matrix spectroscopy (EEMS) and PCR-DGGE were applied to elucidate the relationship between production of dissolved organic matter (DOM) and bacterial community change during the l … More ysis of algal bloom followed by their degradation in a batch incubation test. The lysis of the algal bloom collected from Tsukui Lake was indicated by rapid increases of dissolved organic carbon and UV absorbance at 260 nm within five days In accordance with the lysis, several fluorescence peaks derived from humic- and protein-like substances appeared in the EEM. Phylogenetic analysis of the major DGGE bands showed that bacteria closely related to y-Proteobacteria, CFB group and a-Proteobacteria probably played important roles in the lysis and degradation of algal bloom.The phenomena of algal lysis and DOM formation were investigated also in laboratory. Pure culture of Microcystis aeruginosa was inoculated into sterilized and non-sterilized Tsukui lake water. The existence of eubacteria differed the DOM formation after the algal lysis. The fluorescence derived from humic-like substances increased and subsequently decreased in the non-sterilized lake water, while such a variation was not observed in the sterilized water. Less