Biological circuits for signaling and synchronization in bacterial populations

To coordinate their behavior and virulence and to synchronize attacks against their hosts, bacteria communicate by producing and detecting signaling molecules (autoinducers). This communication is controlled by biological circuits called quorum sensing circuits. Recently quorum sensing circuits have been recognized as an alternative target for controlling bacterial virulence and infections without the use of antibiotics. Here we model the quorum sensing process as a state transition graph. Based on this model we develop a simulation tool for the quorum sensing process in open and confined spaces. We perform a number of numerical experiments with various strategies of quorum sensing circuit regulation and we study the effectiveness of quorum sensing inhibitors. We also use network graph theory to model the complete quorum sensing system of Pseudomonas aeruginosa and construct its state space, which turned out to be very large, hierarchical, modular and scale-free.