鼠疫耶尔森菌生物型变异遗传基础的研究和新生物型--田鼠型的提出

目的 探究鼠疫耶尔森菌生物型变异的遗传基础。方法 通过全基因组序列的比较分析,鉴定可能与生物型变异相关的基因突变,采用DNA测序和位点特异性PCR的方法,分析基因突变在鼠疫耶尔森菌自然分离株中的分布。结果 田鼠鼠疫自然疫源地菌株在毒力、生化表型和分子特征上与其他型别鼠疫耶尔森菌相差很大。所有脱氮阴性菌株的napA基因发生了突变,所有甘油利用阴性菌株的glpD基因发生了突变,所有阿拉伯糖利用阴性菌株的araC基因发生了突变。结论 提出了一个新的生物型——田鼠型;相应糖醇代谢相关基因发生突变是4个生物型变异的遗传基础。

Molecular mechanism of biovar conversion of Yersinia pestis and the proposition of a new biovar:Microtus

Objective To study the genetic basis for biovar conversion of Y. pestis. Methods In silico comparative genomic analysis was conducted and some critical genetic variations of Yersinia pestis were comparatively analyzed by means of PCR and DNA sequencing. Results A 93bp in-frame deletion in glpD gene results in the glycerol negative characteristic of Orientalis strains. A point mutation in the napA gene may cause the negative characteristic of nitrate reduction in Mediaevalis and Microus strains. A 122-bp frameshift deletion in the araC gene may lead to the arabinose negative phenotype of Microus strains. Conclusion In this study, Microtus strains with their unique pathogenic, biochemical and molecular features, were proposed as a novel biovar Microtus. In the light of its differential ability to ferment glycerol and arabinose and to reduce nitrate, Y. pestis can be classified into four biovars-Antiqua(glycerol positive, arabinose positive and nitrate positive), Mediaevalis(glycerol positive, arabinose positive and nitrate negative), Orientalis(glycerol negative, arabinose positive and nitrate positive), and Microtus(glycerol positive, arabinose negative and nitrate negative).