关键词: 鼠疫菌, 大质粒, 分布

Abstract: Objective To study the characteristics and the geographic distribution of Yersinia pesits strains with the largest plasmids in China.Methods According to the methods of Kado and Liu,the plasmids were extracted from 2 026 Y.pestis strains from the plague natural foci and analyzed by Agar Gel Electrophoresis.Results The strains with the largest plasmid are carried three kinds,and the relative molecular weight are 52×10⁶,65×10⁶ and 90×10⁶.Strains with 52×10⁶ plasmid are distributed in the southern and northern foothills of the Qilian Mountains and areas around the Qinghai Lake.Strains with 52×10⁶ plasmid are only found in the Naqu areas of the northern Tibetan Plateau and the part areas of Yushu,Qumalai County and Geermu City.Strains with 65×10⁶ plasmid are distributed in the other plague natural foci in China.Conclusion The studies of characteristics and the geographical distribution of strains with the largest plasmid are of great significance to analyze the space construction of the plague natural foci and the genetics characteristics of Y.pestis in China.