An augmented Keller-Segel model for E. coli chemotaxis in fast-varying environments

This is a continuous study on E. coli chemotaxis under the framework of pathway-based meanfield theory (PBMFT) proposed in [G. Si, M. Tang and X. Yang, Multiscale Model. Simul., 12 (2014), 907–926], following the physical studies in [G. Si, T. Wu, Q. Quyang and Y. Tu, Phys. Rev. Lett., 109 (2012), 048101]. In this paper, we derive an augmented Keller-Segel system with macroscopic intercellular signaling pathway dynamics. It can explain the experimental observation of phase-shift between the maxima of ligand concentration and density of E. coli in fast-varying environments at the population level. This is a necessary complement to the original PBMFT where the phase-shift can only be modeled by moment systems. Formal analysis are given for the system in the cases of fast and slow adaption rates. Numerical simulations show the quantitative agreement of the augmented Keller-Segel model with the individual-based E. coli chemotaxis simulator.