1 research outputs found
Effects of internal dynamics on chemotactic aggregation of bacteria
The effects of internal adaptation dynamics on the self-organized aggregation
of chemotactic bacteria are investigated by Monte Carlo (MC) simulations based
on a two-stream kinetic transport equation coupled with a reaction-diffusion
equation of the chemoattractant that bacteria produce. A remarkable finding is
a nonmonotonic behavior of the peak aggregation density with respect to the
adaptation time; more specifically, aggregation is the most enhanced when the
adaptation time is comparable to or moderately larger than the mean run time of
bacteria. Another curious observation is the formation of a trapezoidal
aggregation profile occurring at a very large adaptation time, where the biased
motion of individual cells is rather hindered at the plateau regimes due to the
boundedness of the tumbling frequency modulation. Asymptotic analysis of the
kinetic transport system is also carried out, and a novel asymptotic equation
is obtained at the large adaptation-time regime while the Keller-Segel type
equations are obtained when the adaptation time is moderate. Numerical
comparison of the asymptotic equations with MC results clarifies that
trapezoidal aggregation is well described by the novel asymptotic equation, and
the nonmonotonic behavior of the peak aggregation density is interpreted as the
transient of the asymptotic solutions between different adaptation time
regimes