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淡水湖泊T4类浮游病毒遗传多样性研究
Genetic Diversity of T4 Type Virioplankton in Freshwater Lakes
【作者】 黄慧珍;
【导师】 赵以军;
【作者基本信息】 华中师范大学 , 水生生物学, 2010, 硕士
【摘要】 浮游病毒是淡水水体种类和数目最多的生物类群,论文通过三种方法对武汉淡水湖泊中浮游病毒的多样性进行了研究。RAPD方法:通过不同湖泊的带型进行比较,能大致得到关于各水体病毒多样性的初步认识:对同一季节而言,随着营养水平的增加,种类和数量都呈现增加的趋势;通过对各湖泊冬夏两季抽动比较,发现每个湖泊则表现出不同的变化趋势。DGGE方法:根据11个湖泊冬夏两季样品基于g23基因的T4类浮游病毒的研究,发现夏季水样较易得到高效率的PCR产物,且其电泳图谱上显示出的条带也更多。DGGE结果也表明,随着营养水平的增高,病毒种类也呈现增加的趋势:在夏季电泳图上,可以显示出明显的相同条带,以及特异性条带。宏基因组法能得到关于各水体T4类浮游病毒的序列信息。从11个不同营养水平的湖泊的冬、夏两季样品中,共得到312条序列。将这些湖泊分为贫/中营养、轻度富营养、中度富营养以及重度富营养四组,组内发散度分析发现,营养水平的差异和季节变化都将对浮游病毒多样性产生影响;所有序列建立系统进化树,发现有7个特殊类群,即C1~C7,通过对这7个类群与部分其他无规律序列及海洋序列的进行系统进化分析,发现人为干扰也会对病毒群落结构产生影响。
【Abstract】 Virioplankton is the most diverse and abundant living form in freshwaters, and in this study, we checked its diversity in freshwater lakes of Wuhan mainly with 3 different methods.RAPD method:comparing profiles from different lakes, we know the general virioplankton diversity of different samples. To the same season, with the increase of nutrition, virioplankton seems to be more diverse and abundant. Each lake shows different trend from winter to summer.DGGE method:we amplified g23 gene of 22 samples (11 lakes, in winter and summer) to identify T4 virioplankton diversity, and get the following results. More efficient PCR products can be easily got in summer samples, and the bands from electrophoresis image of summer samplesare much more than bands of winter samples. The same result with RAPD is that diversity of virioplankton is higher in eutrophic samples. Summer image showed significant universal and special bands.Metagenome method:312 sequences were aquired from 11 different nutrient condition lakes in summer and winter. We divide all the lakes into 4 different goups according to their nutrient level. Average evolutionary divergence over sequence pairs within groups alalysis showde that nutrient level and seasonal change can do great to virioplankton community structure in lakes. Furthermore, the phylogenetic analysis of all the sequences revealed 7 special clusters, C1-C7, and proved that anthropology forcing could influence the genetic diversity of T4 phage in some freshwater lakes.
【Key words】 Vinoplankton; T4; Genetic diversity; RAPD; DGGE; Metagenome; g23 gene;