Biolog和PCR-DGGE技术解析椒江口沉积物微生物多样性

采用Biolog和PCR-DGGE技术对椒江口6个站位表层沉积物群落水平的微生物代谢功能和以16S rRNA基因标记的细菌遗传多样性进行分析,并对其代谢功能和群落结构与沉积物污染物等参数进行冗余梯度分析(Redundancy gradient analysis,RDA)和典范对应分析(Canonicalcorrespondence analysis,CCA).Biolog分析结果表明,微生物群落整体代谢活性由高到低的顺序为:潮间带(B1、B2)、入海口处(A3)>入海口内(A1、A2)>入海口外(A4);碳源代谢的Shannon-Wiener多样性指数范围为2.09～3.25,由高到低的顺序为:潮间带(B1、B2)、入海口处(A3)>河道内(A1)>近入海口处(A2)>入海口外(A4);潮间带、入海口处及河道内的微生物对各类碳源的相对利用率较平均,而近入海口处和入海口外的微生物群落对聚合物的相对利用率较高,对氨基酸类和胺类的相对利用率较低.DGGE图谱分析表明,细菌群落结构沿河口盐度梯度存在空间异质性,但两潮间带站位的相似度高(82.27%);遗传基因的Shannon-Wiener多样性指数范围为1.68～2.87,由高到低的顺序为:潮间带>入海口处>入海口外>近入海口处>河道内.群落代谢功能与理化因子的RDA显示,有机质和硝基苯的分布能较好地解释微生物群落代谢功能的变化;群落遗传结构与理化因子的CCA显示,硝基苯和多环芳烃的分布能较好地解释细菌群落遗传结构的变化.综上结果认为,椒江口沉积物的微生物代谢及遗传多样性符合典型的河口特征,但入海口内微生物沉积环境已表现出对某些化工污染物的响应.

Diversity of microorganisms in sediments of the Jiaojiang Estuary as estimated by Biolog and PCR-DGGE

Biolog and PCR-DGGE methods were used to estimate the catabolic and genetic diversity of microorganisms in the surface sediments at six sites in the Jiaojiang Estuary. The package CANOCO was used to determine the correlation between microbial diversity and physiochemical parameters. It was shown by Biolog that the microbial metabolic activity was in the order of intertidal zone and mouth of the estuary>within the mouth>outside the mouth.The values of Shannon-Wiener index for microbial carbon sources ranged from 2.09 to 3.25 in the order of intertidal zone and mouth of the estuary>within the river course > near the mouth > outside the mouth. The use efficiency of different carbon sources for microorganisms was similar in the intertidal zone, mouth of the estuary and within the estuary. However, different use efficiencies of carbon sources were observed near and outside the mouth, where the use efficiency of polymers for microorganisms was much higher than those of amino acids or amine. The DGGE results indicated high spatial heterogeneity of bacterial community structures along the salinity gradient and high similarity (82.27%) of the bacterial community structure between the two sampling sites in the intertidal zone. The values of Shannon-Wiener index for bacterial community structure ranged from 1.68 to 2.87 in the order of intertidal zone > mouth of the estuary > outside the mouth > near the mouth > within the river course. Redundancy gradient analysis (RDA) showed that the distribution of organic matter and nitrobenzene mainly explained the change of microbial catabolism. On the other hand, Canonical correspondence analysis (CCA) showed that the bacterial community structure might be significantly influenced by nitrobenzene and PAHs. Therefore, we concluded that the diversity of microbial catabolism and community structure in the surface sediments of Jiaojiang Estuary was influenced by both the estuarine physicochemical conditions and anthropogenic pollution.