本文關(guān)鍵詞：銅綠假單胞菌耐藥性相關(guān)基因的篩選鑒定及群體感應(yīng)系統(tǒng)相關(guān)研究　出處：《西北大學(xué)》2008年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 銅綠假單胞菌 轉(zhuǎn)座突變 耐藥性 群體感應(yīng)系統(tǒng) 溶血素

【摘要】： 銅綠假單胞菌(Pseudomonas aeruginosa)是一種條件致病菌,它可以在人群中引起嚴(yán)重的急性和慢性感染,成為醫(yī)院常見的病原菌之一。由于銅綠假單胞菌具有較強(qiáng)的內(nèi)在耐藥性,給臨床治療帶來很大困難(Bodey et al.,1983;Kohler etal.,2001)。因此尋找銅綠假單胞菌中的耐藥基因、研究其耐藥機(jī)制對于控制銅綠假單胞菌引起的感染有重要意義。 本研究通過使用七種抗生素對銅綠假單胞菌轉(zhuǎn)座突變體文庫進(jìn)行篩選,對得到的對抗生素敏感程度提高3倍的敏感突變體及對抗生素敏感程度降低8倍的抗性突變體進(jìn)行隨機(jī)PCR及測序鑒定,通過與銅綠假單胞菌基因組進(jìn)行比對,確定了轉(zhuǎn)座子的插入位點及其所破壞的基因,發(fā)現(xiàn)了多個與抗生素耐藥性相關(guān)的功能未知的新基因。 群體感應(yīng)系統(tǒng)是細(xì)菌中廣泛存在的通過感知群體密度來協(xié)調(diào)群體行為的一種機(jī)制,對病原菌致病過程起重要作用(Dong et al.,2001)。PA4350基因?qū)儆诠δ芪粗蘑纛惢?與銅綠假單胞菌群體感應(yīng)系統(tǒng)的轉(zhuǎn)錄調(diào)節(jié)基因lasR和rhlR基因的同源性接近50%,推測其可能參與群體感應(yīng)系統(tǒng)的基因表達(dá)調(diào)控過程。通過研究發(fā)現(xiàn)PA4350基因與las和rhl系統(tǒng)互不產(chǎn)生影響,對多種毒性因子的表達(dá)也沒有調(diào)節(jié)作用。 銅綠假單胞菌plcH基因負(fù)責(zé)編碼溶血性磷脂酶C,后者是重要的毒性因子。通過溶血實驗發(fā)現(xiàn)銅綠假單胞菌溶血現(xiàn)象與群體感應(yīng)系統(tǒng)有關(guān),進(jìn)而以熒光素酶基因操縱子luxCDABE為報道子,對plcH基因與群體感應(yīng)系統(tǒng)的關(guān)系進(jìn)行研究。結(jié)果表明銅綠假單胞菌群體感應(yīng)系統(tǒng)對plcH基因的表達(dá)有正調(diào)控作用。 本研究對于深入了解銅綠假單胞菌群體感應(yīng)系統(tǒng)及其致病性,探索新的細(xì)菌耐藥機(jī)制和開發(fā)治療藥物具有重要意義。
[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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