大肠杆菌O157：H7narX与narP缺失株的构建及其对细胞粘附与A／E损伤的观察

Construction of narX and narP mutants and their effect on adhesion and A/E lesion in E. coli O157:H7

目的大肠杆菌O157∶H7是一种重要的可以引起人类严重疾病的肠出血性大肠杆菌(enterohaemorrhagic E.coli,EHEC)血清型。为获得narX与narP缺失株并观察其对细胞粘附与A/E(attaching and effacing)损伤的影响。方法本研究采用λRed重组技术,利用PCR产物,通过Bet和Exo蛋白促进同位交换的方法,构建参与呼吸系统调控的narX和narP突变株。结果成功构建了narX和narP突变株,通过细胞粘附实验和免疫荧光染色,发现两个突变株对EBL细胞的粘附力都有明显下降,而在A/E损伤形成能力方面,只有narX突变株有明显下降。结论 narX和narP均对细胞的粘附有影响,narX对细胞A/E损伤有影响。进一步的机制还需深入的实验研究来证明。

E. coli O157 ： H7 is one of the most important serotypes of EHEC causing diseases in human. To obtain narX and narP mutants and investigate their effect on adhesion and A/E lesion in E. coli O157, narX and narP mutants were constructed by ）,-Red recombineering technology promoted by Bet and Exo proteins using PCR products. By using bacterial in- fection assays and immunofluorescence microscopy, it was found that the adhesion ability were decreased both in narX and narP mutant. In addition, the A/E lesion formation was only down-regulated in narX mutant. In conclusion, narX and narP gene might impact the adhesion and narX could influence A/E lesion formation.