摘要
目的 研究鼠疫耶尔森菌中国自然分离株 pgm位点及其侧翼序列的变异 ,了解不同疫源地菌株间的毒力差异 ,为鼠疫防治提供帮助。方法 比较分析现有 4株菌的 pgm位点及其侧翼序列的变异 ,采用PCR、等位基因特异性PCR扩增 2 6 0株中国自然分离株和 7株假结核耶尔森菌。结果 除锡林郭勒高原型和青海田鼠型菌株外 ,其他菌株均缺失了YP16 6 6的 70～ 87bp之间的 18bp碱基。 14 0 6bp处T的缺失仅存在于东方型菌株中。北天山东段型及西段A、B型 ,锡林郭勒高原型 ,青海田鼠型菌株的 pgm位点下游都没有IS10 0插入 ;锡林郭勒高原型和青海田鼠型菌株的色素沉着区有 1个IS2 85插入 ,在其下游 3kb区域还有 1个IS10 0插入。冈底斯山型和昆仑山A、B型菌株的 pgm位点上游侧翼区与其他菌株不同。36株菌的 pgm位点缺失 ,缺失的菌株主要集中在鄂尔多斯高原型 ,松辽平原B型 ,昆仑山A、B型 4种生态型菌株中。结论 北天山东段型及西段A、B型 ,锡林郭勒高原型 ,青海田鼠型菌株是中国鼠疫耶尔森菌中比较古老的菌株。锡林郭勒高原型和青海田鼠型菌株是一个独特的分支 ,建议归为第 4个生物型———田鼠型。北天山东段型及西段A、B型 ,锡林郭勒高原型 ,青海田鼠型菌株的 pgm位点 ,由于在其下游没有IS10 0插入 ,所以稳定、不易缺失?
Objective To study genetic variations of pgm locus and its flanking regions in Yersinia pestis isolated from Chinese natural focus so as to understand differences in virulence between different strains and to improve the prevention of plague. Methods We analysed the sequence variations of pgm locus and its flanking regions by using PCR-sequencing and allele-specific PCR among 260 strains of Y. pestis isolated from different foci and 7 strains of Yersinia pseudotuberculosis. Results For YP1666, only the strains of Xilin Gol grassland type and Microtus fuscus type had intact transmembrane helix, and the T-deletion at base 1406 was unique in strains of Orientalis. Same as Y. pseudotuberculosis, there was no IS100-insertion at the 3′ end of pgm locus of strains from Eastern section of North Tianshan Mountain type, Western section of North Tianshan Mountain type A and B, Xilin Gol grassland type and M. fuscus type. Only the strains of Xilin Gol grassland type and M. fuscus type had IS285-insertion in pigmentation segment and IS100-insertion at its downstream flanking region. pgm locus was deleted entirely from 36 strains, most of which came from Ordos plateau type, Song-liao plain type B , Kunlun Mountain type A and B. Conclusion Strains of Eastern section of North Tianshan Mountain type, Western section of North Tianshan Mountain type A and B, Xilin Gol grassland type and M. fuscus type are the oldest lineage of Chinese isolates. The pgm locus of the strains of these three types is very stable because there is no IS100-insertion at its 3′ terminal. We suggest that the strains of Xilin Gol grassland type and M. fuscus type should be grouped into a fourth biovar: Microtus. pgm locus is highly conserved among strains of different ecotypes, and its variations are well correlated with biovar, focus and ecotype, which indicates that pgm locus has played a role in strains′ adaptation to their environment.
出处
《解放军医学杂志》
CAS
CSCD
北大核心
2004年第4期300-306,共7页
Medical Journal of Chinese People's Liberation Army
基金
国家"8 63"基金 (编号 2 0 0 1AA2 2 30 61 )
国家自然科学基金 (编号30 371 2 84)资助课题
