"Low Energy Shock in E. coli"

“大肠杆菌中的低能量冲击”

• 批准号: 9317013
• 负责人: Kim Lewis
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-02-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9317013&HistoricalAwards=false
• 关键词: Low; Energy; Shock; E.; coli

Lewis 9317013 Addition of uncouplers to E. coli causes a low energy shock response that is accompanied by induction of multidrug resistance pumps. A Summary of the objectives aimed at identifying the components of the response and understanding their interactions is given below. 1. Expression of a target gene. Regulatory mutations in emrD, a multidrug resistance gene, that lead to constitutive expression will be used to determine the upstream site controlling uncoupler- dependent expression. 2. The signal. Expression of emrD in an ATPase mutant in response to an uncoupler will be measured to determine whether the signal originates prior to, or after ATP synthesis. Changes in pmf will be measured in parallel to determine the quantitative requirements for the inducing signal. 3. The sensor. Regulatory mutations leading to constitutive expression of emrD will be used to clone the regulator genes. It is expected that one of the genes will code for the receptor that senses uncoupling. 4. Are other MDR's target genes of low energy shock? Five more putative MDR's have been found in E. coli. the possibility that they are also induced by uncoupling will be studied using Northern blotting. Significance: it is of general importance in understanding cell metabolism to learn how the cell senses its energy status and activates a response mechanism. %%% Cells obtain energy through respiration. This is a process of oxidation of various nutrients such as sugars by oxygen. Respiration takes place in the cell membrane. The energy released in the course of respiration is stored in the form of a "high energy" molecule, ATP. A large number of toxic substances affects the membrane and leads to an "Energy Shock", or loss of energy- producing capability. We found that the cell responds to such toxins by inducing the synthesis of a special class of proteins, multiple drug resistance pumps, that extrude the toxins from the cell. How does a cell sense the presence of t oxins? What is the mechanism for the induction of the multidrug resistance pumps? These are the questions that will be studied in this project. ***

向大肠杆菌添加解偶联剂可引起低能量冲击反应，并伴有多药耐药泵的诱导。下文概述了旨在确定应对措施的组成部分并了解其相互作用的目标。1. 目标基因的表达。emrD是一种多药耐药基因，其调控突变可导致组成性表达，将用于确定控制解偶联依赖性表达的上游位点。2. 这个信号。emrD在ATP酶突变体中对解偶联剂的表达将被测量，以确定信号是在ATP合成之前还是之后产生的。将并行测量pmf的变化，以确定对感应信号的定量要求。3. 传感器。导致emrD组成表达的调控突变将用于克隆调控基因。预计其中一个基因将编码感知解偶联的受体。4. 其他耐多药的靶基因是低能休克吗？在大肠杆菌中又发现了五种假定的耐多药耐药。它们也可能由解偶联诱导的可能性将用Northern印迹法进行研究。意义：了解细胞如何感知自身能量状态并激活反应机制，对理解细胞代谢具有普遍意义。细胞通过呼吸获得能量。这是一个各种营养物质如糖被氧气氧化的过程。呼吸作用发生在细胞膜上。在呼吸过程中释放的能量以“高能”分子ATP的形式储存起来。大量的有毒物质影响到膜，导致“能量冲击”，或失去产生能量的能力。我们发现细胞对这些毒素的反应是通过诱导合成一种特殊的蛋白质，多种耐药泵，将毒素从细胞中挤出来。细胞如何感知t毒素的存在？诱导多药耐药泵的机制是什么？这些都是本项目将要研究的问题。＊＊＊