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目的对癌症和癌前病变患者幽门螺杆菌进行sabA基因遗传信息多态性的研究。方法采用特异引物聚合酶链反应(PCR)及测序和比较基因组方法分析42株国内癌症及癌前病变患者幽门螺杆菌的sabA基因CT双核苷酸重复序列调节区多态性。结果 sabA基因调节区的阳性检测率为85%,功能性sabA基因占所有测序菌株的55%。对随机挑选的18株检测阳性菌株进行测序分析,结果显示在碱基水平及氨基酸水平存在显著的遗传多态性。对sabA基因调节区的氨基酸序列聚类分析中发现,本研究菌株与国际已经完成测序的7株幽门螺杆菌可以明显的分为两个组,即中国组与西方组。结论 sabA基因CT双核苷酸重复序列调节区在中国菌株中普遍存在,且在翻译水平有很显著的多态性。聚类分析发现含有功能性sabA基因的幽门螺杆菌菌株多态性存在明显的地域性分布差异。
Objective To study the genetic polymorphism of sabA gene of Helicobacter pylori in cancer and precancerous lesions. Methods Polymorphism of CT dinucleotide repeat regulatory region of sabA gene in Helicobacter pylori of 42 Chinese patients with cancer and precancerous lesions was analyzed by polymerase chain reaction (PCR), sequencing and comparative genomic analysis. Results The positive detection rate of sabA gene regulatory region was 85% and the functional sabA gene accounted for 55% of all sequencing strains. Sequencing analysis of 18 randomly selected positive strains showed that there were significant genetic polymorphisms at the base level and amino acid level. Cluster analysis of the amino acid sequence of the regulatory region of sabA gene revealed that the seven isolates of Helicobacter pylori which were successfully sequenced from the international community could be divided into two groups: Chinese group and western group. Conclusion The saf ampicillin double nucleotide sequence of sabA gene is common in Chinese isolates and has a significant polymorphism at translation level. Cluster analysis showed that there are significant differences in the geographical distribution of H. pylori strains containing functional sabA gene.