摘要 玄武湖是南京市公园内的风景旅游湖泊，由于近些年工农业生产的发展和人类各种干扰的增加，湖水富营养化程度严重。本论文使用基于16S rDNA的PCR一DGGE(变性梯度凝胶电泳)技术，对南京玄武湖细菌群落结构的多样性做了分析和研究。用SDS一蛋白酶K法提取水样细菌总DNA，并进行纯化后分别进行 16S rDNA的V3高变区PCR，而后经35%一65%变性梯度凝胶电泳(DDGE)分离，在凝胶成像系统下观察各样品的DGGE变性梯度凝胶条带，不同类型的细菌观察到的DGGE条带位置不同。研究结果表明，不同污染程度下细菌多样性具有一定差异。富营养程度越严重的水域微生物种群较丰富。此研究有助于我们更深入地掌握玄武湖湖泊微生物的分布特征及其在湖泊生态系统中的功能与作用，对实施湖泊生态环境的改善具有重要的意义。

关键词：细菌群落结构，16S r DNA；PCR；变性梯度凝胶电泳(DGGE)

ABSTRACT Xuanwu lake is a scenic city Park lakes，as recent industrial and agricultural production and human interaction that increase in magnitude of lake eutrophication .The paper-based 16s rDNA of PCR-DGGE. (denaturing gradient gel electrophoresis) Microbial diversity of the xuanwu lake was analyzed and studied. SDS-proteinase K method with water samples of the total bacterial DNA，and were separately purified 16s rDNA V3 areas of PCR， then 35%一65% by denaturing gradient gel electrophoresis (DDGE) separation，the gel imaging systems to observe the sample DGGE denaturing gradient gel bands，  different types of bacteria DGGE bands observed in different Positions. The results show that bacterial diversity in the different degree of pollution with some differences. This study will help us better grasp the distribution of microorganisms lake and its lake ecosystems function and effect on lake depth to improve the ecological environment of great significance.

Key words：bacterial community structure，16S r DNA；PCR；Denaturing Gradient Gel EleetroPhoresis(DGGE)