Division of Enteric Bacterial Infections, Center for Infectious Diseases, National Institute of Health Seoul 122-701, Korea.
J Microbiol Biotechnol. 2010 Feb;20(2):415-24.
The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:H7. A non-polar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the DeltaluxS mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally-defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxis-related genes (flhD; fliA, C, D, S, Z; cheA, Y, and Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.
本研究旨在探讨全局调控机制——群体感应与大肠杆菌 O157:H7 毒力因子表达之间的关系。我们通过非极性 luxS 缺失突变的方法，构建了韩国临床分离株 CI03J 的 DeltaluxS 突变株 ML03J。野生型和突变株的表型特征表明，ML03J 在 0.2%葡萄糖 LB 培养基中生长和代谢没有明显缺陷，产生功能缺陷的鞭毛，不能利用山梨糖；山梨糖利用的生物学意义尚不清楚。基于组学的分析表明，LuxS 参与了几个鞭毛/趋化性相关基因（flhD；fliA、C、D、S、Z；cheA、Y 和 Z）的转录激活、谷氨酸依赖型酸抗性基因（gadAB）的抑制以及志贺毒素、溶血素和 LEE 致病性岛中 SepD 等毒力因子的表达。
