Quorum-Sensing Synchronization of Synthetic Toggle Switches: A Design Based on Monotone Dynamical Systems Theory
Fig 6
Bistability regions for S and A toggles (top), and a reduced SR toggle design discovered from the bistability region (bottom).
(Top panel). The region between two blue color coded LP-bifurcation loci corresponds to a bistability region for the A toggle model Eqs (9) and (10) at d = 0. A red filled circle corresponds to a cusp point (CP). For the S toggle model, bistability exists for all parameter values a1 ≥ 0 and a2 ≥ 0 at d = 0. Other fixed parameter values are given in Eqs (11)–(14). (Bottom panel). The reduced SR toggle is obtained from the original S toggle (Fig 1) after removal of genes lacI and tetR from the corresponding plasmids bearing promoters PY and PX, respectively. This reduction procedure corresponds to setting zero values a1 = a2 = 0 as discussed in the main text.