铜绿假单胞菌耐药性相关基因的筛选鉴定及群体感应系统相关研究

发布时间：2018-01-17 16:24

  本文关键词：铜绿假单胞菌耐药性相关基因的筛选鉴定及群体感应系统相关研究　出处：《西北大学》2008年硕士论文　论文类型：学位论文

  更多相关文章： 铜绿假单胞菌 转座突变 耐药性 群体感应系统 溶血素

【摘要】： 铜绿假单胞菌(Pseudomonas aeruginosa)是一种条件致病菌,它可以在人群中引起严重的急性和慢性感染,成为医院常见的病原菌之一。由于铜绿假单胞菌具有较强的内在耐药性,给临床治疗带来很大困难(Bodey et al.,1983;Kohler etal.,2001)。因此寻找铜绿假单胞菌中的耐药基因、研究其耐药机制对于控制铜绿假单胞菌引起的感染有重要意义。 本研究通过使用七种抗生素对铜绿假单胞菌转座突变体文库进行筛选,对得到的对抗生素敏感程度提高3倍的敏感突变体及对抗生素敏感程度降低8倍的抗性突变体进行随机PCR及测序鉴定,通过与铜绿假单胞菌基因组进行比对,确定了转座子的插入位点及其所破坏的基因,发现了多个与抗生素耐药性相关的功能未知的新基因。 群体感应系统是细菌中广泛存在的通过感知群体密度来协调群体行为的一种机制,对病原菌致病过程起重要作用(Dong et al.,2001)。PA4350基因属于功能未知的Ⅳ类基因,与铜绿假单胞菌群体感应系统的转录调节基因lasR和rhlR基因的同源性接近50%,推测其可能参与群体感应系统的基因表达调控过程。通过研究发现PA4350基因与las和rhl系统互不产生影响,对多种毒性因子的表达也没有调节作用。 铜绿假单胞菌plcH基因负责编码溶血性磷脂酶C,后者是重要的毒性因子。通过溶血实验发现铜绿假单胞菌溶血现象与群体感应系统有关,进而以荧光素酶基因操纵子luxCDABE为报道子,对plcH基因与群体感应系统的关系进行研究。结果表明铜绿假单胞菌群体感应系统对plcH基因的表达有正调控作用。 本研究对于深入了解铜绿假单胞菌群体感应系统及其致病性,探索新的细菌耐药机制和开发治疗药物具有重要意义。
[Abstract]:Pseudomonas aeruginosa (Pseudomonas aeruginosa) is a conditional pathogen that can cause severe acute and chronic infections in people. Because Pseudomonas aeruginosa has strong intrinsic drug resistance, it brings great difficulties to clinical treatment, such as Bodey et al.1983.The results show that Pseudomonas aeruginosa is one of the most common pathogens in hospitals. Therefore, it is important to search for the drug-resistant gene of Pseudomonas aeruginosa and study its mechanism for controlling the infection caused by Pseudomonas aeruginosa. In this study, seven antibiotics were used to screen the transposable mutants of Pseudomonas aeruginosa (Pseudomonas aeruginosa). Random PCR and sequencing were performed to identify the susceptible mutants which were 3 times more sensitive to antibiotics and 8 times less sensitive to antibiotics. By comparing with the genome of Pseudomonas aeruginosa, the insertion site of transposon and its damaged genes were identified, and several new genes with unknown function related to antibiotic resistance were found. Colony sensing system is a kind of mechanism widely existing in bacteria to coordinate colony behavior through sensing population density, which plays an important role in pathogenic process of pathogenic bacteria Dong et al. PA4350 gene belongs to class 鈪，

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