铜绿假单胞菌中RND外排泵基因调节及功能研究

发布时间：2018-03-28 01:07

本文选题：铜绿假单胞菌　切入点：启动子　出处：《西北大学》2007年硕士论文

【摘要】： 铜绿假单胞菌(Pseudomonas aeruginosa，PA)感染是目前各种医院内感染中最广泛、最严重的问题之一。有报道指出它所引起的院内感染约占10％～35％，居病原菌之首。铜绿假单胞菌为一种条件致病菌，，因天然具有多重耐药性，临床治疗困难很大。通过研究其致病机理和耐药机制，人们试图了解并最终控制铜绿假单胞菌引起的感染。在铜绿假单胞菌的耐药性中起重要作用的因素是细胞膜的低通透性和在细胞膜上存在各种RND外排泵。分析铜绿假单胞菌基因组信息的结果表明，在铜绿假单胞菌中一共有12种已知的及可能的RND外排泵系统。本研究在基因转录水平对这12个已知及可能的RND外排泵进行了系统分析。将铜绿假单胞菌中所有编码RND泵基因的启动子都克隆到一个带有报告基因luxCDABE的低拷贝质粒上。通过检测报道子的发光量，来研究这些RND基因的表达和调节。将这些质粒转化到铜绿假单胞菌后，在各种条件下研究表达量的变化，揭示RND外排泵对不同化合物的外排功能。研究结果表明：庆大霉素能诱导RND外排泵J和I的表达，RND外排泵J能被四环素诱导，但是不能被属于同一类抗生素土霉素的诱导。12种RND外排泵中，有11种受到氨苄青霉素的诱导。有机溶剂如乙醚、乙酸乙酯不能诱导RND外排泵的表达。由基因PA4206、PA4207和PA4208组成的RND外排泵，不仅受抗生素的诱导，而且还受到金属离子如锌离子的调节。由基因PA2520、PA2521和PA2522组成的RND外排泵不仅能够向外排出锌离子、钴离子，而且还能向外排出抗生素如氯霉素；这些RND外排泵在向外排出的物质如抗生素，在结构上没有明显相关性，并且在某些情况下存在金属离子和抗生素的协同作用。
[Abstract]:Pseudomonas aeruginosaformis (PAA) infection is one of the most extensive and serious nosocomial infections at present. It has been reported that the nosocomial infection caused by Pseudomonas aeruginosa is about 103.35%, ranking first among pathogens. Pseudomonas aeruginosa is a conditional pathogen. Because of the natural multidrug resistance, clinical treatment is very difficult. Through the study of its pathogenesis and drug resistance mechanism, people try to understand and ultimately control the infection caused by Pseudomonas aeruginosa. The factors that play an important role in the drug resistance of Pseudomonas aeruginosa are the low permeability of cell membrane and the existence of various RND efflux pumps on the membrane. There are 12 known and possible RND efflux pump systems in Pseudomonas aeruginosa. In this study, 12 known and possible RND efflux pumps were systematically analyzed at the gene transcription level. The promoter of the RND pump gene was cloned into a low copy plasmid with the reporter gene luxCDABE. To study the expression and regulation of these RND genes. After these plasmids were transformed into Pseudomonas aeruginosa, the expression levels were studied under various conditions. The results showed that gentamycin could induce the expression of J and I of RND efflux pump J could be induced by tetracycline. But 11 of the 12 RND efflux pumps that cannot be induced by oxytetracycline belong to the same class of antibiotics, 11 of which are induced by ampicillin. Ethyl acetate could not induce the expression of RND efflux pump, and the RND efflux pump composed of PA4206, PA4207 and PA4208 was not only induced by antibiotics. The RND efflux pump composed of PA2520 + PA2521 and PA2522 can not only excrete zinc ions and cobalt ions, but also release antibiotics such as chloramphenicol. The effluents of these RND efflux pumps, such as antibiotics, have no obvious structural correlation, and in some cases there is a synergistic effect of metal ions and antibiotics.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R378.991

【参考文献】