鼠疫耶尔森氏菌密度感应系统与毒力关系研究

发布时间：2018-02-23 20:52

本文关键词： 鼠疫菌密度感应系统 DNA芯片转录谱抗体谱信号分子　出处：《中国人民解放军军事医学科学院》2005年博士论文　论文类型：学位论文

【摘要】：背景:鼠疫是由鼠疫耶尔森氏菌(简称鼠疫菌)引起的自然疫源性烈性传染病。鼠疫菌独特的致病能力,一直是鼠疫研究工作者关注的焦点。密度感应系统(quorum sensing, QS)是一种细胞密度依赖性的细菌胞间信号传递系统,通过这种机制细菌可以协调基因的表达,从而使细菌可以适应环境、产生毒力因子等,使细胞的活动具有组织性,成为类似于多细胞生物的群体性活动。本文报道了鼠疫菌密度感应系统在鼠疫菌毒力中的作用。方法:结合基因突变技术、高效液相分离、质潜鉴定和细胞凋亡分析实验,从鼠疫菌野生株和QS突变株分离鉴定QS系统的信号分子及其对巨噬细胞的作用;利用全基因组芯片,比较分析QS突变株与野生株转录谱差异,鉴定QS系统调控元;利用鼠疫菌毒力相关蛋白的蛋白芯片,分析QS系统在体内对毒力相关蛋白表达的影响;通过一系列表型实验,比较QS突变株在体外、细胞和动物毒力表型的差异。结果:从鼠疫菌的培养上清中,分离鉴定了两种信号分子,C6-HSL和C8-HSL,并证实了两种信号分子的合成基因。巨噬细胞毒性实验证实,这两种信号分子对小鼠巨噬细胞均具有促凋亡作用。QS系统调控了大量与细菌的基础生理功能和毒力相关的基因,并在体内影响了大量毒力蛋白的表达。细胞和动物实验结果显示,QS突变株在巨噬细胞内的生存能力下降,对小鼠的毒力减弱。结论:鼠疫菌QS系统合成了两个信号分子,C6-HSL和C8-HSL。信号分子直接作为毒力因子发挥作用。QS系统调控大量基因的表达,包括一些与鼠疫菌基本生理功能和鼠疫菌毒力相关的基因,QS突变株中这些基因的表达变化,导致各毒力表型改变,动物毒力减弱。
[Abstract]:Background: Yersinia pestis is a natural infectious disease caused by Yersinia pestis. Quorum sensing (QSs) is a cell-density dependent intercellular signaling system through which bacteria can coordinate gene expression and make bacteria adapt to the environment. The production of virulence factors makes the activity of cells organized and becomes a group activity similar to that of multicellular organisms. This paper reports the role of the density sensing system of Yersinia pestis in the virulence of Yersinia pestis. Methods: the signal molecules of QS system were isolated from wild strains and QS mutants of Yersinia pestis by means of gene mutation, high performance liquid phase separation, cytoplasmic potential identification and apoptosis analysis. Compare and analyze the difference of transcription spectrum between QS mutant and wild strain, identify QS system regulator; analyze the effect of QS system on virulence related protein expression in vivo by using protein chip of virulence related protein of Yersinia pestis; through a series of phenotypic experiments, To compare the virulence phenotype of QS mutant in vitro. Results: two signaling molecules, C6-HSL and C8-HSL, were isolated and identified from the culture supernatant of Yersinia pestis. Both of these signaling molecules can promote apoptosis of mouse macrophages. QS system regulates a large number of genes related to the basic physiological function and virulence of bacteria. The results of cell and animal experiments showed that the survival ability of QS mutant in macrophages was decreased, and the virulence to mice was weakened. Conclusion: two signaling molecules, C6-HSL and C8-HSLL, were synthesized by the QS system of Yersinia pestis. The signaling molecules directly act as virulence factors. QS system regulates the expression of a large number of genes. The expression of these genes in the QS mutants related to the basic physiological function of Yersinia pestis and virulence of Yersinia pestis caused the phenotypic changes of virulence and weakened the virulence of animals.
【学位授予单位】：中国人民解放军军事医学科学院
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R378

【引证文献】