Ordal G W
Crit Rev Microbiol. 1985;12(2):95-130. doi: 10.3109/10408418509104426.
Bacterial chemotaxis is a primitive behavioral system that shows great promise for being amenable to a description of its molecular mechanism. In Gram-negatives like Escherichia coli, addition of amino acid attractant begins a series of events, starting with binding to certain intrinsic membrane proteins, the MCPs, and ending with a period of smooth swimming. Immediately, methyl-esterification of these MCPs begins and continues during this period. By contrast in the Gram-positive Bacillus subtilis, demethylation of MCPs occurs during the same period. At least two other mechanisms for mediating chemotaxis toward the attractants oxygen and phosphotransferase sugars exist in E. coli, and in these, changes in methylation of MCPs plays no role. Moreover, chemotaxis away from many repellents by B. subtilis appears to involve different mechanisms. Many of the repellents include drugs and toxicants, many of them man-made, so that chemoreceptors could not have specifically evolved; yet the bacteria are often exquisitely sensitive to them. Indeed, the B. subtilis membrane seems to act like a generalized antenna for noxious membrane-active substances.
细菌趋化性是一种原始的行为系统，极有可能适合对其分子机制进行描述。在像大肠杆菌这样的革兰氏阴性菌中，添加氨基酸引诱剂会引发一系列事件，始于与某些内在膜蛋白（即MCPs）的结合，终于一段平稳游动期。在此期间，这些MCPs会立即开始并持续进行甲基酯化。相比之下，在革兰氏阳性菌枯草芽孢杆菌中，MCPs在此期间会发生去甲基化。大肠杆菌中至少还存在另外两种介导对引诱剂氧气和磷酸转移酶糖类的趋化性的机制，在这些机制中，MCPs甲基化的变化不起作用。此外，枯草芽孢杆菌对许多驱避剂的趋避似乎涉及不同机制。许多驱避剂包括药物和毒物，其中许多是人造的，因此化学感受器不可能专门进化而来；然而细菌通常对它们极其敏感。实际上，枯草芽孢杆菌的膜似乎就像一个对有害膜活性物质的通用天线。
