Figure 1.

Example simulation: QS biofilm in the case of high nutrient conditions, and no EPS consumption. The colour scale (E) in the subfigures represents the fraction of downregulated cells in the biofilm (M₀/(M₀ + M₁)). AHL concentration lines are shown in black and white, equidistantly distributed between zero and the maximum AHL value at each time. A non-dimensional value of AHL = 1.0 is required for upregulation. (A) shows the QS biofilm, before induction occurs (t = 5.0, max AHL = 0.44). In (B), the downstream colonies have upregulated (t = 6.0, max AHL = 1.71). (C) shows the biofilm after induction has occurred (t = 8.0, max AHL = 14.1).