mkl基因在海分枝杆菌抵抗宿主免疫中的作用  

The potential role of Mycobacterium marinum mkl gene in bacterial resistance to the host immunity

作　　者：华亦斐 王晴岚[1] 牛辰[1] 高谦[1] 

机构地区：[1]复旦大学基础医学院教育部/卫生部医学分子病毒学重点实验室,上海200032

出　　处：《微生物与感染》2015年第3期173-179,共7页Journal of Microbes and Infections

基　　金：国家自然科学基金(81271790;81201256)

摘　　要：本研究利用MycoMarT7噬菌体建立了海分枝杆菌随机突变库,鉴定获得1株转座子插在基因MMAR_0994(mkl)上的突变株。用野生株和突变株分别感染斑马鱼成鱼,通过观察斑马鱼的存活情况,研究mkl基因对海分枝杆菌毒力的影响;利用尾静脉注射感染孵出48h后的斑马鱼幼鱼,于荧光显微镜下观察突变株及野生株在幼鱼体内的播散情况,以检测mkl基因在细菌与宿主天然免疫相互作用中的功能;将野生株和突变株分别感染小鼠来源巨噬细胞,检测其在巨噬细胞内的增殖。此外,还检测了突变株对酸性环境的耐受情况。结果显示,mkl基因突变株感染斑马鱼成鱼后25d内没有鱼死亡;在斑马鱼幼鱼感染模型和细胞感染模型中,突变株的增殖明显减弱;突变株对酸性环境压力更敏感。以上结果提示,mkl基因在海分枝杆菌抵抗宿主免疫及致病中发挥重要作用。A Mycobacterium marinum random mutant library using MycoMarT7 phage system was constructed .After screening ,a mutant whose transposon insertion site was in MMAR_0994 （mkl） gene was obtained .The adult zebrafish were infected with the wild‐type and the mutant strains respectively and the survival rates of the zebrafish were compared .The potential impact of the mutant on host innate immune system was tested by infecting the 48‐hour post‐fertilization zebrafish larvae using caudal vein injection . In vivo distribution of the bacteria was monitored by following green fluorescence in the larvae .The impact of the mutant on mouse macrophage cell line was tested .In addition ,the acid tolerance level was also checked . The results showed that mkl mutant displayed attenuated virulence in the zebrafish infection model .The attenuated phenotypes in the zebrafish larvae and mouse macrophage cell line were observed .The invasion rates of the mutant and the wild‐type were similar .The growth of the mutant was more sensitive to low pH . These results indicated that mkl may play a functional role in the interaction with host immune system .

关 键 词：海分枝杆菌 mkl基因 巨噬细胞 斑马鱼感染模型 

分 类 号：R378.911[医药卫生—病原生物学]