Figure 6. Simulations of a toggle switch design with quorum sensing molecules produces patterns.

(A) Example construction of the toggle switch design with quorum sensing. The toggle switch is composed of two genes lacI and araC encoding repressors, which are up-regulated by their respective signaling molecules (C4-HSL and 3-OHC14-HSL) and down-regulated by each other. Additionally, each repressor down-regulates each other’s activators. In order to implement degradation, the repressors are tagged for enzymatic degradation and constitutive expression of aiiA produces an enzymes that degrades the signaling molecules. (B) Simulation of system (12) with initial conditions u(0, x, y) = v(0, x, y) = 100nM and no leakiness or cross talk. The parameter values are D_C4 = D_C14 = .001mm²/min, a_lacI = a_araC = 10nM/min, a₂ = 20nM/min, and γ = .5 min⁻¹.