对E.弱吸引梯度
Theoretical results for chemotactic response and drift of E. coli in a weak attractant gradient
摘要：
大肠杆菌（Escherichia coli，E.大肠杆菌）在自然环境中以一系列直线运动，被引起方向改变的翻滚打断。它通过延长在源的方向上运行的持续时间来对化学引诱物执行趋化性。当引诱剂浓度存在空间梯度时，这种偏差产生朝向其来源的漂移速度，而在均匀浓度下，大肠杆菌适应，在甲基天冬氨酸的情况下几乎完美。最近，微流控实验已经测量了大肠杆菌在精确控制的引诱剂梯度中的漂移速度，但没有通用的理论表达式。有了这个动机，我们在这里研究了一个解析解模型，基于Barkai-Leibler模型，最初引入解释完美的适应。严格的数学表达式得到的趋化反应函数和漂移速度在弱梯度的限制和假设下，完全随机翻滚。理论预测与实验结果相比，有利的，特别是在高浓度。我们进一步表明，信号转导网络减弱了浓度漂移的依赖性，从而提高了灵敏度的范围。
英文摘要：
The bacterium Escherichia coli (E. coli) moves in its natural environment in a series of straight runs, interrupted by tumbles which cause change of direction. It performs chemotaxis towards chemo-attractants by extending the duration of runs in the direction of the source. When there is a spatial gradient in the attractant concentration, this bias produces a drift velocity directed towards its source, whereas in a uniform concentration, E.coli adapts, almost perfectly in case of methyl aspartate. Recently, microfluidic experiments have measured the drift velocity of E.coli in precisely controlled attractant gradients, but no general theoretical expression for the same exists. With this motivation, we study an analytically soluble model here, based on the Barkai-Leibler model, originally introduced to explain the perfect adaptation. Rigorous mathematical expressions are obtained for the chemotactic response function and the drift velocity in the limit of weak gradients and under the assumption of completely random tumbles. The theoretical predictions compare favorably with experimental results, especially at high concentrations. We further show that the signal transduction network weakens the dependence of the drift on concentration, thus enhancing the range of sensitivity.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
