NOVEL SENSORY RESPONSES IN PSEUDOMONAS

芳香化合物包括污染物、致癌物和消毒剂。 许多细菌，包括一些病原体，都可以在这些细菌上生长。 化合物。芳香族物质可以通过细胞膜扩散，为此 细菌被认为没有特定的机制来 识别细胞外介质中芳香族物质的存在。最近， 然而，芳烃已被证明是一些细菌的化学引诱剂。 而假单胞菌已经被发现可以合成可诱导的化学受体 苯甲酸和其他一些芳香酸。拟议的研究将 探索苯甲酸化学感受的机制和分子基础。这个 恶臭假单胞菌苯甲酸化学受体基因片段将被克隆 并对其分子结构进行了检测。基因的数量和大小 由苯甲酸化学受体操纵子指定的产品将被分析 并将使用定点突变来定义和表征 操纵子的监管区域。生理学方法将是补充 分子方法，并用于检测细胞内的亚细胞位置。 苯甲酸化学感受器并确定感觉信息是如何 由化学感受器接收，流向其余的细胞趋化性 机械设备。因为苯甲酸盐是亲脂性的，并且具有芳香结构， 苯甲酸化学感受器很可能具有结构特征。 与那些研究得很好的化学感受器有很大的不同 其他细菌系统，也有可能是苯甲酸盐 化学感受器在细胞内有独特的位置。因此，这些研究 应提供有关细菌感觉行为的新信息 将军。这些研究也有望增加我们对 当细菌遇到芳香酸时发生的初始相互作用 在环境中，他们将扩大相对较小的银行 目前存在的关于基因组织的知识 假单胞菌。

Aromatic compounds include pollutants, carcinogens, and disinfectants. Many bacteria, including some pathogens, can grow on various of these compounds. Aromatics can diffuse through cell membranes and for this reason bacteria have been thought not to have specific mechanisms to recognize the presence of aromatics in the extracellular medium. Recently, however, aromatics have been shown to be chemoattractants for some bacteria and Pseudomonas has been found to synthesize inducible chemoreceptors for benzoate and a number of other aromatic acids. The proposed research will explore the mechanism and molecular basis of benzoate chemoreception. The benzoate chemoreceptor gene region from Pseudomonas putida will be cloned and its molecular organization examined. The number and sizes of gene products specified by the benzoate chemoreceptor operon will be analyzed and site-directed mutagenesis will be used to define and characterize the regulatory region of the operon. Physiological approaches will complement molecular approaches and be used to examine the subcellular location of the benzoate chemoreceptor and determine how sensory information that is received by the chemoreceptor flows to the rest of the cellular chemotaxis machinery. Because benzoate is lipophilic and has an aromatic structure, the benzoate chemoreceptor quite probably has structural characteristics that are very different from those of the well-studied chemoreceptors of other bacterial systems and it is also possible that the benzoate chemoreceptor has a unique intracellular location. Thus these studies should provide new information about bacterial sensory behavior in general. These studies will also be expected to increase our understanding of initial interactions that occur when bacteria encounter aromatic acids in the environment and they will augment the relatively small bank of knowledge that presently exists about the genetic organization of pseudomonads.