Participation of CheR and CheB in the chemosensory response of Campylobacter jejuni
Participation of CheR and CheB in the chemosensory response of Campylobacter jejuni
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DOI：
10.1099/mic.0.047399-0
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发表时间：
2011-05-01
期刊：
影响因子：
2.8
通讯作者：
Takai, Shinji
中科院分区：
文献类型：
--
作者：
Kanungpean, Doungjit;Kakuda, Tsutomu;Takai, Shinji
空肠弯曲杆菌是人类细菌性胃肠炎的主要病因，也是动物（尤其是家禽）肠道的共生细菌。趋化性是鸡源性嗜热厌氧菌定殖的重要决定因素。空肠。适应在趋化性的梯度感应机制中起着至关重要的作用。对C. jejuni揭示了编码推定的适应蛋白切布和切R的基因的存在。构建了切布、cheR和cheBR的框内缺失，并在群板上检查了所得突变体的化学感受行为。切布和切R蛋白显着影响趋化性，但不是必不可少的这种行为发生。在CheR存在下，在缺乏功能性切布的突变体中检测到两种甲基接受趋化蛋白（MCP）DocC和Tip 1在SDS-PAGE期间的移动性增加，推测是由于受体的稳定甲基化。使用组织培养的体外研究显示，cheR的缺失导致过度粘附和过度侵袭表型，而切布的缺失导致非粘附、非侵袭表型。此外，Delta cheBR突变体显示出显著降低的定殖鸡盲肠的能力。我们的数据表明，修饰的化学受体的CheBR系统参与调控的趋化性在C。空肠，尽管切布明显不受磷酸化控制。
Campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans and a commensal bacterium of the intestinal tracts of animals, especially poultry. Chemotaxis is an important determinant for chicken colonization of C. jejuni. Adaptation has a crucial role in the gradient-sensing mechanism that underlies chemotaxis. The genome sequence of C. jejuni reveals the presence of genes encoding putative adaptation proteins, CheB and CheR. In-frame deletions of cheB, cheR and cheBR were constructed and the chemosensory behaviour of the resultant mutants was examined on swarm plates. CheB and CheR proteins significantly influence chemotaxis but are not essential for this behaviour to occur. Increased mobility of two methyl-accepting chemotaxis proteins (MCPs), DocC and Tip1, during SDS-PAGE was detected in the mutants lacking functional CheB in the presence of CheR, presumably resulting from stable methylation of receptors. In vitro studies using tissue culture revealed that deletion of cheR resulted in hyperadherent and hyperinvasive phenotypes, while deletion of cheB resulted in nonadherent, noninvasive phenotypes. Furthermore, the Delta cheBR mutant showed significantly reduced ability to colonize chick caeca. Our data suggest that modification of chemoreceptors by the CheBR system is involved in regulation of chemotaxis in C. jejuni although CheB is apparently not controlled by phosphorylation.