Transport and Chemoreception of Aromatic Compounds by Pseudomonas putida

恶臭假单胞菌对芳香族化合物的转运和化学感受

• 批准号: 9603551
• 负责人: Caroline Harwood
• 金额: $ 10万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9603551&HistoricalAwards=false
• 关键词: Transport; Chemoreception; Aromatic; Compounds; Pseudomonas

Harwood 9603551 Aromatic compounds are abundant in the environment as major constituents of the woody tissues of green plants. Large quantities of aromatic pollutants have also been released into the environment as industrial waste products. Many of these compounds can be broken down by bacteria, and a reasonable amount is known about the enzymology of aromatic compound biodegradation. By contrast, little is known about how bacteria seek and acquire aromatic substrates from the environment; processes that are governed by chemotaxis and transport. This project will examine these poorly understood aspects of biodegradation by the bacterium Pseudomonas putida. Studies will focus on PcaK, a protein that appears to have dual functions as a 4-hydroxybenzoate chemoreceptor and permease. The pcaK gene is coordinately regulated with genes for the biodegradation of 4-hydroxybenzoate. PcaK accumulates 4-hydroxybenzoate against a concentration gradient and is the first example of a transport protein for aromatic acids. The PcaK protein also appears to function as a chemoreceptor because P. putida pcaK mutants are not attracted to 4-hydroxybenzoate or related compounds in chemotaxis assays. PcaK is not homologous to known bacterial chemoreceptors, and thus appears to represent a new kind of chemoreceptor. Research will explore the hypothesis that PcaK can initiate sensory signaling required for chemotactic responses to aromatic compounds by a mechanism distinct from known bacterial chemotaxis systems. Studies will be carried out to define proteins that interact with PcaK to effect transmission of sensory information to the flagella of P. putida to cause chemotactic responses. The goal of the project is to understand how bacteria sense and respond to the presence of environmental pollutants in their environment. This could aid in elucidating the role of chemotaxis in recruiting swimming bacteria to particular environmental sites, including those contaminated with pollutants. The res earch should lead to an increased understanding of the role of bacterial behavioral responses in the biodegradation of human industrial wastes.

哈伍德9603551 芳香族化合物作为绿色植物木质组织的主要成分在环境中大量存在。 大量的芳香族污染物也作为工业废物释放到环境中。 这些化合物中的许多可以被细菌分解，并且已知关于芳香族化合物生物降解的酶学的合理量。 相比之下，人们对细菌如何从环境中寻找和获得芳香底物知之甚少;这一过程受趋化性和运输的控制。 这个项目将研究这些知之甚少的方面的生物降解细菌恶臭假单胞菌。 研究将集中在PcaK，一种蛋白质，似乎具有双重功能，作为4-羟基苯甲酸酯化学受体和通透酶。 pcaK基因与4-羟基苯甲酸的生物降解基因协同调控。 PcaK针对浓度梯度积累4-羟基苯甲酸酯，并且是芳香酸转运蛋白的第一个例子。 PcaK蛋白似乎也起化学受体的作用，因为恶臭假单胞菌pcaK突变体在趋化性测定中不被4-羟基苯甲酸酯或相关化合物吸引。 PcaK与已知的细菌化学感受器不同源，因此似乎代表了一种新的化学感受器。 研究将探索PcaK可以启动芳香族化合物的趋化反应所需的感觉信号的假设，其机制不同于已知的细菌趋化系统。 将进行研究以确定与PcaK相互作用的蛋白质，从而影响将感觉信息传递到恶臭假单胞菌鞭毛以引起趋化反应。 该项目的目标是了解细菌如何感知和应对环境污染物的存在。 这可能有助于阐明趋化性在将游泳细菌招募到特定环境场所（包括受污染物污染的场所）中的作用。 研究结果应导致对细菌行为反应在人类工业废物生物降解中的作用的进一步理解。