licD2基因对肺炎链球菌毒力影响研究

发布时间：2018-05-21 02:20

本文选题：肺炎链球菌 + 毒力基因　；参考：《重庆医科大学》2005年硕士论文

【摘要】：肺炎链球菌(Streptococcus pneumoniae,S.pn)是全世界范围内引起感染和死亡的主要病原菌之一,是引起社区获得性肺炎、中耳炎和脑膜炎最常见的病原菌。一百多年来,科学家们不断探寻肺炎链球菌致病的机理,虽然揭示出许多肺炎链球菌感染的基本理论,然而到目前为止,人类对肺炎链球菌引发的疾病仍缺乏有效的预防手段。要彻底解决肺炎链球菌感染的问题,仍需深入探讨肺炎链球菌致病的分子机理。胆碱不仅是肺炎链球菌生长所需因子,在细胞分裂、转化和自溶等生物学特性中发挥作用,还是影响多种肺炎链球菌毒力因子的重要物质,在肺炎链球菌生理代谢和发病机制中发挥着重要作用。而 licD2基因是掌控胆碱代谢的重要遗传学位点,因此该基因对肺炎链球菌毒力具有重大影响。目的:构建 licD2 基因缺陷的肺炎链球菌菌株,探索该基因的缺陷是否影响细菌毒力。方法:采用基因克隆技术,在肺炎链球菌自杀质粒 pEVP3 中插入 licD2 基因片段。利用基因同源重组的原理,将重组自杀质粒整合到肺炎链球菌染色体中建立稳定的重组菌株。通过相对定量 RT-PCR 分析肺炎链球菌多种毒力因子表达情况,并利用动物体内试验观察 licD2 基因缺陷菌株毒力改变。结果:①构建了 pEVP3-licD2质粒,成功建立了 licD2 基因缺陷的肺炎链球菌菌株。②licD2 缺陷以后,肺炎链球菌转化能力明显下降甚至完全不能转化。③从体外培养细菌的毒力基因 mRNA 表达来看,缺陷型肺炎链球菌几种毒力因子的
[Abstract]:Streptococcus pneumoniae (S.pn) is one of the major pathogens causing infection and death worldwide. It is the most common pathogen causing community acquired pneumonia, otitis media and meningitis. In the past more than 100 years, scientists have been exploring the pathogenesis of Streptococcus pneumoniae, although it reveals a lot of Streptococcus pneumoniae. The basic theory of dyeing, however, is still lack of effective preventive measures for Streptococcus pneumoniae caused by Streptococcus pneumoniae. To solve the problem of Streptococcus pneumoniae infection, the molecular mechanism of Streptococcus pneumoniae still needs to be explored.
Choline is not only a necessary factor for the growth of Streptococcus pneumoniae, but also plays an important role in biological characteristics such as cell division, transformation and autolysis. It plays an important role in the physiological metabolism and pathogenesis of Streptococcus pneumoniae. The licD2 gene is an important genetics in control of choline metabolism. Therefore, the gene has a significant effect on the virulence of Streptococcus pneumoniae.
Aim: to construct licD2 gene defective Streptococcus pneumoniae and explore whether the gene's defects affect the bacterial virulence. Methods: gene cloning technique was used to insert licD2 gene fragment into the pEVP3 of Streptococcus pneumoniae suicide plasmid. The recombinant self killing plasmid was integrated into the chromosome of Streptococcus pneumoniae by the principle of homologous recombination. A relatively quantitative RT-PCR was used to analyze the expression of various virulence factors of Streptococcus pneumoniae and to observe the change of virulence of licD2 gene defective strains in vivo. Results: (1) a pEVP3-licD2 plasmid was constructed and a Streptococcus pneumoniae with licD2 gene defect was successfully established. (2) after the licD2 defect, pneumonia The ability to convert Streptococcus mutans to a significant decrease or even completely cannot be converted. (3) several virulence factors of Streptococcus pneumoniae from the expression of the virulence gene mRNA of the bacteria in vitro
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R378

【参考文献】