Figure 3. Simulations of chemotaxis in different gradients.

(A) Concentration profiles of the gradients used in the simulations. (B) Chemotactic drift of cells in these gradients. The average position 〈X〉 of the cells is shown as a function of time. A population of 2000 cells starts moving from the left wall (x ₀ = 10 µm, y ₀ randomly distributed in (0, y_max)), and swims for 2000 s. (C) Relative CheY-P concentration as a function of time, averaged over 2000 cells in the same gradients. The gray line indicates the fully adapted state [CheY-P] = 1.0 in a medium without attractant. Relative adaptation rate k = 1. All cellular parameters are as described in Table 1.