Barrier Crossing in Escherichia coli Chemotaxis.


We study cell navigation in spatiotemporally complex environments by developing a microfluidic racetrack device that creates a traveling wave with multiple peaks and a tunable wave speed. We find that while the population-averaged chemotaxis drift speed increases with wave speed for low wave speed, it decreases sharply for high wave speed. This reversed dependence of population-averaged chemotaxis drift speed on wave speed is caused by a "barrier-crossing" phenomenon, where a cell hops backwards from one peak attractant location to the peak behind by crossing an unfavorable (barrier) region with low attractant concentrations. By using a coarse-grained model of chemotaxis, we map bacterial motility in an attractant field to the random motion of an overdamped particle in an effective potential. The observed barrier-crossing phenomenon of living cells and its dependence on the spatiotemporal profile of attractant concentration are explained quantitatively by Kramers reaction rate theory.

DOI: 10.1103/PhysRevLett.118.098101

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@article{Li2017BarrierCI, title={Barrier Crossing in Escherichia coli Chemotaxis.}, author={Zhaojun Li and Qiuxian Cai and Xuanqi Zhang and Guangwei Si and Qi Ouyang and Chunxiong Luo and Yuhai Tu}, journal={Physical review letters}, year={2017}, volume={118 9}, pages={098101} }