GENETIC ANALYSIS OF RICKETTSIA PROWAZEKII

普氏立克次体是流行性斑疹伤寒的病原体。 人类的一种通过声音传播的疾病。了解这种专有性的生物学 胞内细菌寄生虫及其致病因素 毒力一直受到与生长相关的困难的阻碍 在鸡蛋和细胞培养中，不可能控制立克次体 真核细胞内的生长条件，以及缺乏基因 系统。立克次体突变株几乎不存在，基因转移 机制尚未确定。因此，为了调查 普罗瓦泽基的一些基本属性，我们选择了 应用重组DNA技术将普氏根瘤菌DNA克隆到 大肠杆菌是宿主。通过这种方式，立克次体基因、基因产物和 监管机制可以在高度透明的环境中进行检查和操纵 可管理的系统。克隆银行将使用各种不同的 设计不同大小的质粒和粘粒载体和克隆方法 和克隆DNA的拷贝数。通过这种方式，克隆的可能性 任何特定的基因都会被增强。克隆人银行将由以下人员筛选 检测立克次体抗原存在的免疫学方法。在……里面 此外，还将使用直接选择技术分离立克次体 补充已知的大肠杆菌营养缺乏性突变的基因。立克次体 在大肠杆菌中筛选表达的基因包括细胞质酶， 膜结合活性和普氏弧菌表面抗原。克隆人 表达立克次体活性将为 生化研究和精确定义的普罗瓦泽克乳杆菌DNA片段 立克次体基因结构与表达的研究。

Rickettsia prowazekii is the etiologic agent of epidemic typhus, a louseborne disease of man. Understanding the biology of this obligate intracellular bacterial parasite, and the factors which contribute to its virulence has been hampered by the difficulties associated with growing rickettsiae in eggs and cell cultures, the impossibility of controlling growth conditions within a eukaryotic cell, and the absence of a genetic system. Rickettsial mutants are practically nonexistent and gene transfer mechanisms have not been identified. Accordingly, in order to investigate some of the fundamental attributes of R. prowazekii, we have elected to apply recombinant DNA techniques and clone R. prowazekii DNA into Escherichia coli hosts. In this way rickettsial genes, gene products, and regulatory mechanisms can be examined and manipulated in a highly manageable system. Clone banks will be established using a variety of plasmid and cosmid vectors and cloning methods designed to vary the size and copy number of the cloned DNA. In this way, the probability of cloning any specific gene is enhanced. Clone banks will be screened by immunological methods to detect the presence of rickettsial antigens. In addition, direct selection techniques will be used to isolate rickettsial genes complementing known E. coli auxotrophic mutations. The rickettsial genes to be screened for expression in E. coli include cytoplasmic enzymes, membrane-bound activities and R. prowazekii surface antigens. Clones expressing rickettsial activities will provide gene products for biochemical studies and precisely defined R. prowazekii DNA segments for studies on rickettsial gene structure and expression.