Universal Response-Adaptation Relation in Bacterial Chemotaxis
Universal Response-Adaptation Relation in Bacterial Chemotaxis
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DOI：
10.1128/jb.02171-14
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发表时间：
2015-01-01
影响因子：
3.2
通讯作者：
Sourjik, Victor
中科院分区：
文献类型：
--
作者：
Krembel, Anna K.;Neumann, Silke;Sourjik, Victor
细菌的趋化性策略依赖于化学浓度的时间比较，其中维持当前游泳方向的概率由最近过去经历的刺激变化来调节。这种比较所需的短期记忆是由适应系统提供的，该系统通过趋化性受体的活性依赖性甲基化来运作。先前的理论研究表明，梯度中的有效导航需要一个明确的适应率，因为记忆时间尺度需要与细菌直线运行的持续时间相匹配。在这里，我们表明，大肠杆菌的趋化途径确实表现出的响应幅度和适应时间之间的普遍关系，不依赖于化学配体的类型。我们的研究结果表明，不同配体的适应率的这种对齐是通过化学受体之间的合作相互作用，而不是通过微调个别受体的甲基化率。这一观察结果说明了一个尚未认识到的功能，受体群集细菌趋化性。
The bacterial strategy of chemotaxis relies on temporal comparisons of chemical concentrations, where the probability of maintaining the current direction of swimming is modulated by changes in stimulation experienced during the recent past. A short-term memory required for such comparisons is provided by the adaptation system, which operates through the activity-dependent methylation of chemotaxis receptors. Previous theoretical studies have suggested that efficient navigation in gradients requires a well-defined adaptation rate, because the memory time scale needs to match the duration of straight runs made by bacteria. Here we demonstrate that the chemotaxis pathway of Escherichia coli does indeed exhibit a universal relation between the response magnitude and adaptation time which does not depend on the type of chemical ligand. Our results suggest that this alignment of adaptation rates for different ligands is achieved through cooperative interactions among chemoreceptors rather than through fine-tuning of methylation rates for individual receptors. This observation illustrates a yet-unrecognized function of receptor clustering in bacterial chemotaxis.