大肠埃希菌密度感应调节子qseC基因失活突变株构建及其生物学特性  

Construction of quorum sensing regulator C gene inactivation mutant of Escherichia coli and its biological characteristics

作　　者：周青帅 赵行行 李冬梅 崔古贞 陈峥宏[2] 任玮 齐晓岚[1] 洪伟[1] ZHOU Qingshuai;ZHAO Xingxing;LI Dongmei;CUI Guzhen;CHEN Zhenghong;REN Wei;QI Xiaolan;HONG Wei(不详;Key Laboratory of Ministry of Education for Endemic and Ethnic Diseases&Key Laboratory of Medical Molecular Biology of Guizhou Province,Guizhou Medical University,Guiyang 550004,China)

机构地区：[1]贵州医科大学地方病与少数民族疾病教育部重点实验室&贵州省医学分子生物学重点实验室,贵阳550004 [2]贵州医科大学贵州省普通高等学校病原生物学特色重点实验室,贵阳550004 [3]贵州医科大学免疫学教研室,贵阳550004

出　　处：《实用医学杂志》2022年第3期288-294,共7页The Journal of Practical Medicine

基　　金：国家自然科学基金(编号:32170134,U1812403);贵州省自然科学基金重点项目(编号:[2020]1Z067)。

摘　　要：目的密度感应系统与细菌生长状态、毒力改变、生物膜形成、运动能力改变以及参与细菌和宿主的免疫反应和对药物的抗性等相关。大肠埃希菌密度调节子C(Escherichia coli quorum sensing regulator C,qseC)是其密度感应系统的受体,探究其对大肠埃希菌生理、生化特征的影响。方法使用嗜热二型内含子基因打靶系统(Thermotargetron)构建大肠埃希菌HMS174菌株qseC基因失活突变株,测定其生长速率、溶血能力、生物膜形成和运动能力等表型的变化,以及对酸碱和6种抗生素的敏感性。结果成功构建了大肠埃希菌HMS174 qseC627s位点的打靶载体,该载体基因失活效率为100%。对比大肠埃希菌HMS174与ΔqseC627s突变株的表型发现,突变株生长速率和最大生物量降低、溶血能力丧失、生物膜形成能力降低、运动能力减弱、对酸、碱的耐受能力降低。抗生素敏感性测定结果表明,ΔqseC627s对氯霉素、氨苄青霉素、四环素、阿莫西林、甲硝唑耐受性降低。结论大肠埃希菌HMS174中qseC基因缺失后,突变株表型和对抗外界压力因素发生了显著改变。Objective The quorum sensing system is related to bacterial growth profile,virulence,biofilm formation,motility,host immune responses,and resistance to antibiotics.The quorum sensing Escherichia coli(E.coli)regulator C(qseC)is the receptor of the E.coli quorum sensing system,and its effects on the physiological and biochemical characteristics of E.coli were not well understood.Methods In the present work,we used the Thermotargetron gene targeting system(based on thermophilic mobile groupⅡintron)to inactivate the qseC gene in E.coli strain HMS174.The phenotypic changes ofΔqseC627 s strain,including growth rate,hemolysis,biofilm formation,motility,tolerance to the acidic and alkaline environment,and resistance to antibiotics,were investigated.The present work will draw a clearer picture of the physiological functions of the qseC gene in E.coli.Results The qseC627 s locus of E.coli HMS174 was chosen as TeI3 c/4 c insertion site,the gene inactivation efficiency was100%.Targeting plasmid was cured by successively transferred in LB medium,and the plasmid cure efficiency was100%.Compared to the wild-type strain,the mutantΔqseC627 s showed reduced growth rate,maximum bacterial density,biofilm formation ability,motility,hemolytic ability,and tolerance to the acidic and alkaline.Furthermore,compared to the wild type strain,the antibiotic susceptibility assay showed thatΔqseC627 s was more resistant to chloramphenicol,ampicillin,tetracycline,amoxicillin,and metronidazole.Conclusions After the inactivation of the qseC gene in E.coli HMS174,the phenotype and resistance to external stress of theΔqseC were significantly changed.

关 键 词：大肠埃希菌 密度感应系统 Thermotargetron 突变株表型 

分 类 号：R387.2[医药卫生—医学寄生虫学]