luxR基因调控嗜水气单胞菌耐药性的分子机制初探

Molecular Mechanism of luxR Regulation of Drug Resistance of Aeromonas hydrophila

中文关键词: 嗜水气单胞菌  LuxR调控蛋白  耐药  转录组

英文关键词: Aeromonas hydrophila  LuxR regulatory protein  Drug resistance  Transcriptome

中文摘要:

      LuxR家族蛋白是一类在革兰氏阴性细菌中发挥重要作用的调控蛋白，参与细菌多项重要生理活动。采用RNAi技术构建嗜水气单胞菌(Aeromonas hydrophila) luxR05735稳定沉默菌株luxR05735-RNAi，并利用qRT-PCR检测基因沉默效果。结果显示，与野生株相比，沉默株中luxR05735的表达量降低了96.8%。药物敏感性实验表明，与野生株相比，luxR05735-RNAi对庆大霉素、诺氟沙星、卡那霉素、吡哌酸的耐药性显著降低。对野生株与沉默株luxR05735-RNAi的转录组数据进行分析发现，表达差异显著的基因共有1286个，其中，上调基因353个，下调基因933个；显著富集的通路4条，分别是核糖体通路、精氨酸生物合成通路、硫代谢通路、硒化合物代谢通路；在这4条通路中可能与嗜水气单胞菌耐药性相关的重要功能基因包括metE、glnA、rplB、rplX、rpsA、rpsJ等，这些功能基因编码的蛋白主要与细菌的生物成膜及核糖体蛋白合成相关。综合以上研究结果，可以推测嗜水气单胞菌的luxR05735通过调控细菌的生物膜形成相关基因及核糖体蛋白相关基因的表达，从而调控细菌对药物的耐受性。

英文摘要:

      LuxR family proteins play a key role in various important physiological activities of gram-negative bacteria. In this study, RNAi technology was used to construct a stable silenced strain Aeromonas hydrophila luxR05735-RNAi. The expression of luxR05735 in wild-type strain and luxR05735- RNAi was detected by qRT-PCR. The results showed that the expression of luxR05735 in strain luxR05735- RNAi was reduced by 96.8% compared to that of the wild-type strain. Drug sensitivity tests showed that luxR05735-RNAi significantly reduced bacterial resistance to gentamicin, norfloxacin, kanamycin, and pipemidic acid compared with the wild-type strain. The transcriptome analysis of the wild-type strain and luxR05735-RNAi revealed that there were 1286 genes with significant differences in expression, of which 353 genes were up-regulated and 933 genes were down-regulated. There are four significantly enriched pathways, which are ribosome, arginine biosynthesis, sulfur metabolism and selenocompound metabolism. In the four pathways, some important functional genes, including metE, glnA, rplB, rplX, rpsA, rpsJ were found to be associated with drugs resistance of A. hydrophila. These genes encode the proteins that were mainly involved in bacteria biofilm formation and ribosomal protein synthesis. It can be speculated from the above results that the luxR05735 of A. hydrophila regulates the expression of the genes that encode bacteria biofilm formation and ribosomal protein synthesis, and then further regulates the drugs resistance of A. hydrophila.