Physics of bacterial chemotaxis: From molecular mechansims to cellular behaviors

More than 40 years ago, Berg and Brown discovered that E. coli cells perform a run-and-tumble style random walk biased towards higher concentrations of attractants. Around the same time, a phenomenological model of chemotaxis was proposed by Keller and Segel based on a drift-diffusion equation. Since then, much progress has been made in uncovering the molecular mechanism of this cellular navigation system. In this talk, we will discuss some of our recent work in developing an ab initio theory [1-2] to understand bacterial chemotaxis behaviors based on molecular mechanisms of the chemotaxis signaling pathway [3] and how theoretical predictions compare with quantitative microfluidics-based experiments [4,5].

[1] “A pathway-based mean-field model for Escherichia coli chemotaxis”, G. Si, T. Wu, Q. Ouyang, Yuhai Tu, Phys. Rev. Lett., 109, 048101-048105, 2012.

[2] “Behaviors and strategies of bacterial navigation in chemical and nonchemical gradients”, Bo Hu, Yuhai Tu, Plos Comp. Bio., 10 (6), e1003672, 2014.

[3] “Quantitative modeling of bacterial chemotaxis: signal amplification and accurate adaptation”, Yuhai Tu, Annu. Rev. Biophys., 42: 337-59, 2013.

[4] “Frequency-dependent Escherichia coli chemotaxis behavior”, X. Zhu, G. Si, N. Deng, Q. Ouyang, T. Wu, Z. He, L. Jiang, C. Lou, and Yuhai Tu, Phys. Rev. Lett., 108, 128101, 2012.

[5] “Barrier Crossing in Escherichia coli Chemotaxis”, Zhaojun Li, Qiuxian Cai, Xuanqi Zhang, Guangwei Si, Qi Ouyang, Chunxiong Luo, and Yuhai Tu, Phys. Rev. Lett. 2017. 118: 098101.