E. coli Superdiffusion and Chemotaxis-Search Strategy, Precision, and Motility
E. coli Superdiffusion and Chemotaxis-Search Strategy, Precision, and Motility
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DOI：
10.1016/j.bpj.2009.04.065
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发表时间：
2009-08-19
影响因子：
3.4
通讯作者：
Dobnikar, J.
中科院分区：
文献类型：
--
作者：
Matthaeus, F.;Jagodic, M.;Dobnikar, J.
大肠杆菌运动的特征是一系列连续的翻滚和游泳事件。在没有化学梯度的情况下，个人游泳的长度通常被认为是指数分布的。然而，最近有实验表明，游泳长度分布具有幂定律的形式，这表明细菌可能执行超扩散的Levy-Walk运动。在大肠杆菌中，趋化信号传递途径中的关键酶之一Cher的水平可以通过随机波动来诱导。我们使用趋化信号通路的数学模型来研究在没有和存在化学梯度的情况下，这些波动对大肠杆菌行为的影响。我们发现，Cher波动的种群在没有化学吸引剂的情况下执行Levy-Walks，因此在营养稀少的环境中可能具有优势。稀疏环境中更有效的搜索策略通常伴随着更大的运动性，在化学吸引剂存在的情况下也是如此。这种策略的权衡是降低了感测和跟踪梯度的精度，以及对绝对化学吸引剂水平的较慢适应。
Escherichia coli motion is characterized by a sequence of consecutive tumble-and-swim events. In the absence of chemical gradients, the length of individual swims is commonly believed to be distributed exponentially. However, recently there has been experimental indication that the swim-length distribution has the form of a power-law, suggesting that bacteria might perform superdiffusive Levy-walk motion. In E coli, the power-law behavior can be induced through stochastic fluctuations in the level of CheR, one of the key enzymes in the chemotaxis signal transmission pathway. We use a mathematical model of the chemotaxis signaling pathway to study the influence of these fluctuations on the E. coli behavior in the absence and presence of chemical gradients. We find that the population with fluctuating CheR performs Levy-walks in the absence of chemoattractants, and therefore might have an advantage in environments where nutrients are sparse. The more efficient search strategy in sparse environments is accompanied by a generally larger motility, also in the presence of chemoattractants. The tradeoff of this strategy is a reduced precision in sensing and following gradients, as well as a slower adaptation to absolute chemoattractant levels.