Disrupting Microbial Communication Leads to a 2D Percolation Transition.

Bacteria often converse with each other to coordinate macro-scale expressions such as pathogenic infections, production of biofilms, production of antibiotics and bioluminescence. Empirical evidence suggests that bacteria are capable of conducting these conversations at length scales far exceeding the size of themselves. We observe that by disrupting this large-scale communication, the conversations within these microbes follow a pattern similar to a percolation transition. In experiments, we have one bacterial species that is capable of communication (sender) and another species that is capable of producing an enzyme capable of disrupting this communication (degrader). We spatially distribute the senders and gradually increase the amount of degraders to observe a critical density at which the large-scale communication is suppressed. Using experimental image analysis and reaction-diffusion modeling, we were able to calculate critical exponents and confirmed that this transition is a 2D percolation universality class. Our results suggest that, even for systems as complex and diverse as a heterogeneous microbial community, statistical mechanical models can still be a powerful tool for extracting robust, universal quantitative features.