鼠疫耶尔森氏菌基因分型与适应性微进化研究

发布时间：2018-07-14 18:20

【摘要】：目的:细菌基因组进化的分子策略包括点突变、基因组重排和基因水平转移等。我们针对上述三种进化机制对鼠疫耶尔森氏菌(以下简称鼠疫菌)进行了系统的分析与研究,为研究鼠疫菌的进化规律和建立中国鼠疫菌基因分型系统提供科学依据。方法:采用抑制削减杂交技术寻找古典型鼠疫菌特有的序列;通过对鼠疫菌和假结核菌基因组中IS序列插入位点进行详细的比较基因组学分析,选择40个IS插入位点设计等位基因特异PCR引物进行PCR扩增。结果:发现了一个长383bp、天山山地灰旱獭、长尾黄鼠鼠疫自然疫源地鼠疫菌特有的DFR;根据40个IS插入位点的重排潜,将260株鼠疫菌分成33个基因型,这些菌株大多分布在13个基因型中,占89.2%(232/260)。这13个基因型与鼠疫菌的自然疫源地和生物型等密切相关;以260株鼠疫菌的差异片段(DFRs)谱、假基因谱和IS插入位点的重排谱为基础建立了中国鼠疫菌基因分型系统;应用该分型系统将中国902株鼠疫菌分成59个基因组型。结论:进一步证实鼠疫菌由假结核菌进化而来,天山山地灰旱獭、长尾黄鼠鼠疫自然疫源地可能是我国鼠疫菌和演化的源头之一,北天山西段的温泉县可能就是鼠疫菌从中亚地区传入我国的入口处。田鼠型鼠疫菌作为一个古老且独特分支,其致病性和演化规律与其他鼠疫菌存在显著差别。中国鼠疫菌基因分型系统简单可靠,基本上可以将中国各个鼠疫自然疫源地区分开。初步确定了中国鼠疫自然疫源地基因组型的分布状况,并提出了主要基因组型和次要基因组型的概念。在疫源地扩张和鼠疫菌微进化的过程中,主要基因组型发挥了主导作用。因此,我们根据主要基因组型推测出鼠疫菌的微进化规律。
[Abstract]:Objective: the molecular strategies of bacterial genome evolution include point mutation, genome rearrangement and horizontal gene transfer. We have systematically analyzed and studied Yersinia pestis (Yersinia pestis) based on the above three evolutionary mechanisms in order to provide a scientific basis for studying the evolutionary law of Yersinia pestis and establishing a genotyping system for Yersinia pestis in China. Methods: suppression subtractive hybridization technique was used to search for the unique sequence of Yersinia pestis, and the insertion sites of is sequence in the genome of Yersinia pestis and pseudotuberculum were analyzed in detail by comparative genomics. Forty allele-specific primers were selected for PCR amplification. Results: a strain of Yersinia pestis endemic to Yersinia pestis in natural foci of Yersinia pestis in Tianshan Mountain, Tianshan Mountain, was found, and 260 strains of Yersinia pestis were divided into 33 genotypes according to the rearrangement of 40 is insertion sites. Most of these strains were distributed in 13 genotypes, accounting for 89. 2% (232 / 260). The 13 genotypes were closely related to the natural foci and biotypes of Yersinia pestis, and the Chinese Yersinia pestis genotyping system was established on the basis of the differential fragment (DFRs) spectrum, pseudo gene spectrum and is insertion site rearrangement spectrum of 260 Yersinia pestis strains. Using this typing system, 902 strains of Yersinia pestis in China were divided into 59 genomes. Conclusion: it is further proved that Yersinia pestis evolved from pseudotuberculous bacillus. The natural foci of Yersinia pestis and Yersinia pestis in Tianshan Mountain may be one of the sources of Yersinia pestis and evolution in China. The hot spring county in the western part of North Tianshan Mountain may be the entrance of Yersinia pestis from Central Asia. As an ancient and unique branch of Yersinia pestis, the pathogenicity and evolutional law of Yersinia pestis are significantly different from those of other Yersinia pestis. Chinese Yersinia pestis genotyping system is simple and reliable. The distribution of genome type in plague natural foci in China was preliminarily determined, and the concepts of main genome type and secondary genome type were put forward. During the expansion of the foci and the microevolution of Yersinia pestis, the main genomes played a leading role. Therefore, we infer the microevolution of Yersinia pestis according to the main genome types.
【学位授予单位】：中国人民解放军军事医学科学院
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R378

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