Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 50: Statistical Physics of Biological Systems I (Joint Session BP/DY)
DY 50.5: Vortrag
Donnerstag, 23. März 2017, 16:00–16:15, ZEU 250
Quorum sensing in stochastic many-particle models of microbial populations — •Johannes Knebel1, Matthias Bauer2, Matthias Lechner1, Peter Pickl1, and Erwin Frey1 — 1Ludwigs-Maximilians Universitity, Munich — 2Max Planck Institute for Intelligent Systems, Tuebingen
Autoinducers are small signaling molecules that mediate intercellular communication in microbial populations and trigger coordinated gene expression via ``quorum sensing''. Elucidating the mechanisms that control autoinducer production is pertinent to understanding collective microbial behaviors such as virulence and bioluminescence. Recent experiments indicate that autoinducers can be heterogeneously produced in clonal populations. Here we ask how phenotypic heterogeneity is established and how the autoinducer concentration in the population is regulated at the same time. In our conceptual model, cells synthesize and excrete autoinducers, and replicate and adapt in this environment. The model reveals that heterogeneous autoinducer production is facilitated by the coupling of ecological and evolutionary dynamics through quorum sensing. To capture the emergent dynamics, we derived a macroscopic mean-field equation from the microscopic stochastic many-particle process in the spirit of the kinetic theory in statistical physics. This mean-field equation reduces to the continuous replicator equation when quorum sensing is absent and, notably, admits bimodal stationary distributions when quorum sensing is present. Our analysis explains phenotypic heterogeneity through quorum sensing and the observed phase transitions to homogeneity.