肝螺杆菌与幽门螺杆菌的功能基因组比较分析(修改).docVIP

南方医科大学成人高等教育毕业论文 题目：作者姓名：专业：年级：级专升本: 肝螺杆菌(Helicobacter hepaticus，Hhh株ATCC51449的全基因组测序已经完成。分析发现Hh有和幽门螺杆菌(Hp)一样的尿素酶、鞭毛蛋白和粘附素同源基因，而编码趋化蛋白及细胞致死性肿胀毒素CDT)的特性则与空肠弯曲菌类似。Hh缺乏大多数与Hp同源的定植和毒力因子如cag致病岛。此外Hh还有一个与霍乱弧菌相似的致病岛HHGI1。上述基因特点该菌肠道定植的适应性与致病潜能。 关键词: 肝螺杆菌 幽门螺杆菌 基因组 Analysis of functional genome of Helicobacter hepaticus in comparison with that of Helicobacter pylori. NIU Ling-yun，LI Jing BAI Yang，WANG Ji-de*. * Department of Digestive Medicine，Nanfang hospital，Southern Medical University，Guangzhou 510515,China Abstract: Helicobacter hepaticus (H. hepaticus) is one of the five hepatic pathogenic helicobacters identified up to now. Genomic sequence of H. hepaticus ATCC51449 has beem published. Homologue genes to H. pylori including urease, flagellin protein and adhesions have been found in H. hepaticus. Other functional genes such as chemotactic protein and cytolethal distending toxin (CDT) are similar to that encoded by campylobacter jejuni. H. hepatius does not encode some well known colonization or virulent factors of H. pylori such as cag pathogenicity island. On the contrary, it contains a specific cluster of gene designated as HHGI1 (Helicobacter hepaticus genomic island) that encodes a protein similar to the Hcp (hemolysin-coregulated protein) of Vibrio cholerae. The genomic features of H. hepaticus may reflect the capacity of colonisation and pathogenicity of this bacterium. Key Word: Helicobacter hepaticus, Helicobacter pylori, Genome 自1989年提出螺杆菌属以来，已经正式命名了20种，根据它们喜好的定居部位，可被分为胃螺杆菌和肠肝螺杆菌。肝螺杆菌(Helicobacter Hepaticus，Hh)［1-3］[4-5]，此外肝螺杆菌的感染还可在某些免疫缺陷小鼠中诱导炎症性肠病(IBD)的发生[6-7]。一株肝螺杆菌(ATCC51449)的基因组序列已经公布，是含有1799146个碱基对的环状染色体，可以编码1875种蛋白质，它缺乏大多数已知的Hp毒力因子同源物，如粘附素，VacAcag致病岛蛋白，但是含有与空肠弯曲菌(Campylobacter jejuni, Cj)同源的粘附素PEB1和细胞致死性肿胀毒素(Cytolethal distending toxin,CDT)HHGI1和其它几个基因小岛，它们的特点是G+C含量与其余的基因有所不同。目前研究表明肝螺杆菌具有很少的特征性标志，只有一些基因有特点，如16sRNA基因可以编码18kDa的致免疫蛋白[8]，cdtABC可以编码CDT，ureABC的部分序列编码尿素酶结构亚单位[9]。本文以Hp为比较，就该菌的基因组作一简要分析，以利于明确该菌潜在的致病产物与机制。 1.肝螺杆菌基因的一般特性 肝螺杆菌ATCC51449含有179914