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目的研究我国土拉弗朗西斯菌(土拉菌)亚种类型及各菌株之间的遗传进化关系。方法对于来源于我国北方地区的10株土拉菌,采用2种型特异引物C1C4和RD1进行PCR,根据扩增产物片段长度来判断所属亚种;同时,使用fopA、tul4和16SrRNA引物,进行3种特异基因的PCR,然后测序;这10株土拉菌及网上已公布基因组序列的3株B型土拉菌、1株subsp.novicida,应用MEGA4软件,进行3种特异基因为基础的系统进化分析。结果采用2种型特异引物C1C4和RD1,鉴定10株土拉菌均为B型亚种;根据MEGA4构建的进化树,我国10株土拉菌可以分为2种基因型,410108、410109和410111为B1型,另外7株土拉菌为B2型;而国外的3株B型土拉菌归为B3型。结论我国北方地区分离的土拉菌可能以B型为主,对于土拉菌B型亚种的起源,我国土拉菌可能早于欧美国家。3种基因为基础的系统进化分析可作为土拉菌基因分型的一种可靠方法。
Objective To study the subtypes of Francisella tularensis (Tula Streptomyces) and the genetic evolution among the strains in China. Methods For 10 strains of Toxoplasma from northern China, two types of primers C1C4 and RD1 were used for PCR, and their corresponding subspecies were identified according to their length. Meanwhile, fopA, tul4 and 16SrRNA primers were used for 3 And then sequenced. The ten strains of Tulara and the three genotypes T-type of Tulara published on the Internet and one strain of subsp. Novicida were sequenced. Three species-specific gene-based phylogenetic analyzes were performed using MEGA4 software analysis. Results Two kinds of specific primers C1C4 and RD1 were used to identify ten strains of Tulare, all of which were B subtype. According to the phylogenetic tree constructed by MEGA4, ten strains of Tulacan could be divided into two genotypes: 410108, 410109 and 410111 For the B1 type, the other 7 strains of Tula B2 for the type; while the three strains of T-B in foreign countries classified as B3. Conclusion The Tulara isolated in northern China may be mainly B type. For the origin of Tula subtype B, the Tulara may be earlier than the European and American countries. Three gene-based phylogenetic analyzes can be used as a reliable method for genotyping Tulara.