基于SBT分型技术的广州地区嗜肺军团菌群体遗传学研究

发布时间：2018-04-30 21:37

本文选题：军团菌 + 群体遗传学　；参考：《辽宁大学》2012年硕士论文

【摘要】：嗜肺军团菌(Legionellapneumophila)广泛存在于各种水生环境中，例如江、河、湖泊、冷却水塔、空调、喷泉、加湿器等。嗜肺军团菌是军团病的致病因子，吸入军团菌污染的水汽可发生军团病的感染，经常引起散发病例，以及社区获得的暴发疫情。本研究针对广州地区分离的116株嗜肺军团菌，采用序列分型方法(Sequence-based-technology，SBT)方法进行分型研究，旨在了解广州地区水环境中嗜肺军团菌的群体遗传学特征，为我国军团病的分子流行病学研究提供依据。对116分离株的7个等位基因进行PCR扩增测序，获得各个分离株的等位基因谱(allelicprofile)和序列型(sequencetype，ST)。随后以等位基因谱和ST型为基础，利用Bionumerics6.6，eBURST，START2.0，SplitsTree4.0，RDP3.0，ClonalFrame等软件，对广州地区军团菌的群体遗传学结构进行深入分析。Bionumerics6.6软件对116分离株SBT分型，共确定了30个ST型，其中有16个为新ST型；eBURST对ST型的克隆群(ClonalComplex，CCs)分析，共得到2个克隆群和22个单一ST型(singletons)；在CC1中ST-1被鉴定为祖先。利用START2.0分别对30个ST和116分离株计算连锁不平衡，116株分离样品得到ISA=0.6969(p0.001)，，30个ST得到的ISA=0.3259(p0.001)；SplitsTree4.0对30个ST型和116分离株的拼接序列构建分裂树，均得到网状树，以上结果表明嗜肺军团菌中存在重组。利用RDP3.0对30个ST型和116分离株的拼接序列进行重组事件估算，30个ST型预测到5个重组事件，而116分离株预测3个可能的重组事件。ClonalFrame计算重组与突变的比例r/m=0.9(0.95%[0.2-1.9])；表明嗜肺军团菌中虽然存在重组，但不足以影响其群体遗传学结构。本研究还结合欧洲军团菌感染工作组(EuropeanWorkingGroupforLegionellaInfections，EWGLI)对全世界军团菌的研究数据，初步分析了世界军团菌的种群结构。综合以上分析可以确定广州水环境分离的116分离株的种群结构为克隆化(Clonal)。
[Abstract]:This study is aimed to understand the population genetics characteristics of basophilic bacteria in the water environment of Guangzhou , and to provide the basis for the molecular epidemiology study of the disease in Guangzhou . Based on the alleles spectrum and ST type , we analyzed the population genetics structure of legionum in Guangzhou area by using software of Bionumerics6 . 6 , eburst , START2 . 0 , SplitsTree 4.0 , RDP3 . 0 , ClonalFrame and so on .
Two clones were obtained and 22 single ST - type ( singletons ) were obtained by eburst ' s analysis of ST - type clones ( CCs ) .
In CC1 , ST - 1 was identified as an ancestor . Using START2.0 , the linkage disequilibrium was calculated for 30 ST and 116 isolates , and 116 isolates were ISA = 0.6969 ( p0.001 ) and 30 ST - derived ISA = 0.3259 ( p0.001 ) ;
By using RDP3.0 to estimate the recombination events , 30 ST - type and 116 isolates were used to estimate the recombination events , while 116 isolates predicted three possible recombination events .
In this study , the population structure of the world military community was preliminarily analyzed . The population structure of 116 isolates from Guangzhou water environment was determined to be Clonal .

【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R378

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