Stochastic Mechanisms of Cell-Size Regulation in Bacteria

by Anatoly Kolomeisky

Rice University

at Physics Colloquium

Mon, 05 Apr 2021, 16:10
Zoom

Abstract

How bacteria are able to maintain their sizes and shapes so precisely remains an open fundamental question. It is believed that cells have narrow distributions of sizes and shapes as a consequence of a homeostasis, a set of physiological conditions that allow bacteria to function at the most optimal conditions. Several phenomenological approaches to explain these observations have been presented, but the microscopic origins of the cell-size regulation are still not understood. Current explanations rely heavily on the assumption of thresholds, but experimental observations did not find any mechanisms that would support thresholds. Here, we propose a new idea to explain these striking observations. It is based on the stochastic approach to investigate the molecular mechanisms of maintaining the cell sizes in bacteria. We argue that the cell-size regulation is a result of coupling of at least two stochastic processes, cell growth and division, which eliminates the need for introducing the thresholds. Dynamic properties of the system are explicitly evaluated, and it is shown that the model is consistent with the experimentally supported adder principle of the cell-size regulation. In addition, theoretical predictions agree with experimental observations on several bacteria. Theoretical analysis clarifies some important features of bacterial cell growth.

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Created on 30-03-2021 by Kats, Yevgeny (katsye)
Updaded on 30-03-2021 by Kats, Yevgeny (katsye)