Chemotaxis to aromatic acids by Gram-negative bacteria

芳香族化合物作为植物的主要聚合成分（木质素）和人类工业活动的有毒副产物在生物圈中大量存在。虽然我们对细菌如何降解芳香族化合物已经有了一定的了解，但对于细菌如何检测环境中芳香族化合物的存在却知之甚少。包括假单胞菌在内的一些活动细菌对芳香化合物有很强的行为吸引力。本项目将研究恶臭假单胞菌对芳香酸苯甲酸酯趋化的机理基础。我们的目的是了解受体如何检测这些芳香酸的功能，并阐明引诱剂识别和生物降解之间的关系。计划进行遗传和生化实验，以确定对苯甲酯的特定行为反应所需的基因，并表达和表征这些基因编码的蛋白质。还将分析趋化基因和选定的苯甲酸酯降解基因的调控，特别侧重于定义基因表达所需的DNA序列和调控蛋白。由于趋化性是代谢的重要前奏，因此所提出的工作可能导致开发出改进的策略来生物降解选定的有毒化合物。苯甲酸盐受体蛋白也可能具有独特的结构特征。

Aromatic compounds are abundant in the biosphere as a major polymeric component of plants (lignin) and as toxic by-products of human industrial activities. Although a reasonable amount is known about how aromatics are degraded by bacteria, not much is known about how bacteria detect the presence of aromatic compounds in the environment. Several genera of motile bacteria, including Pseudomonas, have a strong behavioral attraction to aromatic compounds. This project will study the mechanistic basis for chemotaxis to the aromatic acid, benzoate, by Pseudomonas putida. Our intent is to understand how the receptor that detects these aromatic acids functions and to elucidate the relationship between attractant recognition and biodegradation. Genetic and biochemical experiments are planned to identify the genes necessary for specific behavioral responses to benzoate, and to express and characterize the proteins encoded by these genes. The regulation of the chemotaxis genes and of selected benzoate degradation genes will also be analyzed, with a particular focus on defining DNA sequences and regulatory proteins that are required for gene expression. Since chemotaxis is an important prelude to metabolism, the proposed work could lead to the development of improved strategies for the biodegradation of selected toxic compounds. The receptor protein for benzoate may also have distinctive structural characteristics.