微囊藻毒素与自然水体中细菌VIVIFORM状态的相关性

THE STUDIES ON THE RELATIONSHIP BETWEEN MICROCYSTIN-LR AND VIVIFORM STATE OF BACTERIUM IN NATURAL BODIES OF WATER

细菌VIVIFORM状态是直接关系到自然水体水质评价和环境保护的生态现象 ,其形成机理相当复杂 ,但环境胁迫是主要诱因。通过人为改变湖水中的微囊藻毒素 (MC LR)水平 ,对水体中蓝藻毒素与细菌VIVIFORM状态之间的相关性进行了分析。结果表明 ,较高的毒素水平对水体中细菌种群总量没有明显的影响 ,但能刺激VIVIFORM细菌转化成可培养状态 ,从而证实了自然水体中蓝藻毒素与水细菌VIVIFORM状态之间存在直接的相关性。

The bacterial viviform state is an important ecological problem which is relative to water quality accessment and environmental protection in natural water bodies. Though the reasons why it was formed are unclear and complicated,the direct effects came from the environmental stress factors including nutrient starvation,temperature changes and algal toxins stress etc. The rates of bacterial viviform states in different samping stations of Xili reservoir were investigated,the results showed: the bacteral total number was similar between the station of Dongjiang river entrance and the internal reseroir,but the rates of bacterial viviform state were lower in Dongjiang river entrance. It was deduced that environmental stress factors (such as high light intensity,water pollution and oxygen stress etc.)induced bacterial cell tybe transformation from culturable state to viviform cell. It was found that there were some relationship between blue-green bloom and bacterial viviform state in natural water bodies by studying on eutrophic water bodies in Lake Wenshanhu,Lake Xili and Lake Kinneret etc. The algal toxin is an important environmental factor in water bodies of blue-green bloom,the further experiments which studied on the influence of microcystins-LR on the viviform state of bacterium was done by using artificially induced microcystin-LR concentration gradients. The results showed microcystin-LR had no obvious effect on the aquatic bacterial population,but it could stimulated the bacterial cell transformation from viviform state to culturable state. It indicates that there is the direct relationship between microcystin-LR and the viviform state of bacterium in natural bodies of water. The further research on the molecular mechanism of microcystin-LR stimulating cell type transformation is onging.