Sinorhizobial chemotaxis: a departure from the enterobacterial paradigm.
Sinorhizobial chemotaxis: a departure from the enterobacterial paradigm.
复制标题
中国根瘤菌趋化性：偏离肠细菌范式。
作者：
R. Schmitt
活动细菌表现出令人惊讶的复杂感官行为。通过监测环境中化学成分的变化，它们向食物来源（引诱剂）迁移，并逃离有毒化学物质（驱虫剂）。这种行为被称为趋化性，包括对来自感知环境的受体的信号进行信息处理，并将信号转导到鞭毛马达，以相应地调节其旋转。自从大约40年前Julius Adler的开创性工作（Adler, 1965）以来，趋化性的遗传、生化和生物物理研究主要集中在肠杆菌上，主要是大肠杆菌和沙门氏菌，因此对“在分子水平上理解简单行为”的目标做出了巨大贡献（Parkinson, 1987）。今天，肠杆菌的感觉通路和信号转导链的所有核心成分以及这些蛋白质之间的相互作用已经被确定（最近的综述见Bren & Eisenbach, 2000； Falke等，1997;Grebe & Stock, 1998; Macnab, 1996）。然而，鞭毛运动力学和调控的许多受体功能、信号放大和信号处理的分子细节仍不清楚。最近对非肠道甚至古细菌化学感觉系统的兴趣扩大了我们的视野，揭示了一个普遍主题的迷人变化（评论见Armitage & Schmitt, 1997; Manson et al., 1998; Marwan & Oesterhelt, 2000）。在细菌和古细菌之间观察到的一致性表明，原核化学感觉系统的起源较早——早在30亿年前。现今系统之间的差异表明了分化的进化和适应不同栖息地的需要。对于研究者来说，这种对既定方案的背离提出了一个有趣的挑战，因为它可能隐藏了迄今为止尚未解决的问题的新答案。
Motile bacteria display a surprisingly sophisticated sensory behaviour. By monitoring changes in the chemical composition of their environment, they migrate towards food sources (attractants) and flee from noxious chemicals (repellents). This behaviour, named chemotaxis, involves information processing of signals from receptors that sense the environment, and signal transduction to the flagellar motor to modulate its rotation accordingly. Since the pioneering work of Julius Adler almost 40 years ago (Adler, 1965), genetic, biochemical and biophysical studies of chemotaxis have been focussed mostly on enterobacteria, essentially on Escherichia coli and Salmonella, thus contributing greatly to the goal of ‘understanding a simple behaviour at the molecular level ’ (Parkinson, 1987). Today, the enterobacterial sensory pathway and all central components of the signal transduction chain as well as interactions between these proteins have been identified (for recent reviews see Bren & Eisenbach, 2000; Falke et al., 1997; Grebe & Stock, 1998; Macnab, 1996). However, many molecular details of receptor function, signal amplification and signal processing, of flagellar motor mechanics and regulation are still not understood. The more recent interest in non-enteric and even archaeal chemosensory systems has expanded our view and revealed fascinating variations on a general theme (for reviews see Armitage & Schmitt, 1997; Manson et al., 1998; Marwan & Oesterhelt, 2000). Concurrences observed between bacteria and archaea suggest an early origin of the prokaryotic chemosensory system – as long as 3 billion years ago. Differences between present-day systems point to a diverging evolution and the need for adaptation to different habitats. For the investigator, this departure from the established scheme poses an interesting challenge, as it may conceal new answers to hitherto unsolved questions.
DOI：
10.1073/pnas.96.18.10134
发表时间：
1999-08
影响因子：
11.1
作者：
Dennis R. Thomas;David G.A. Morgan;D. DeRosier
通讯作者：
Dennis R. Thomas;David G.A. Morgan;D. DeRosier
DOI：
10.1073/pnas.95.1.201
发表时间：
1998-01-06
影响因子：
11.1
作者：
Scharf, BE;Fahrner, KA;Berg, HC
通讯作者：
Berg, HC