恩诺沙星对大肠杆菌全基因组表达谱的影响

Effect of Enrofloxacin on Gene Expression Profiles of Escherichia coli

为探索恩诺沙星(Enrofloxacin)压力下大肠杆菌(Escherichia coli,E.coli)生理状态的变化,从而为进一步研究细菌对药物压力的应答机制提供参考,作者将E.coli接种于加入恩诺沙星(浓度为1/2 MIC)的液体LB中,绘制生长曲线,分别以光镜和电镜进行形态学观察,取5 h培养菌,进行表达谱差异分析。结果显示,加入恩诺沙星后细菌生长速度明显降低(P<0.01),菌体形态呈长丝状,基因芯片检测发现519个差异点,其中239个上调,而280个下调,表达变化3倍以上的基因66个,其中34个上调,32个下调,主要涉及SOS应答、细胞分裂、压力应答、物质合成、新陈代谢、转录调控等生物学功能。上述结果表明,在恩诺沙星压力下,细菌启动SOS应答,细胞分裂被抑制,细菌生理机制发生了复杂的变化。

In order to explore the changes of physiology of Escherichia coli （E. coli） under the pressure of enrofloxacin, and to provide references for further study on resistance and response mechanisms to drug pressure of bacteria, E. coli ATCC25922 were inoculated in liquid LB medium containing enrofloxacin （the concentration was 1/2 MIC）, shaking cultured at 37 ℃. The growth curve of E. coli was drawn, and then light microscope and electron microscope were used respectively for morphological observation. The changes of expression profiles of the bacteria after shaking culture for 5 h at 37℃ were analyzed by the microarray. The results showed that the growth rate of E. coli obviously decreased and morphology was filamentous after addition of enrofloxacin. The microarray analysis showed that, fluorescence intensity of 519 hybridization dots were obviously changed comparing with control group, in which 239 up-regulated and 280 down- regulated. There were 34 genes with a ≥3-fold up-regulation and 32 genes with a ≥3-fold down- regulation. These genes were involved in many biological processes such as SOS response, cell division, stress response, biosynthesis, metabolism, transport and regulation of transcription. All results suggest that under the pressure of enrofloxacin, the SOS response of the bacteria was started, cell division was inhibited, and the physiological mechanism may undergo extensive and complex changes.