Non-equilibrium dynamics of bacterial colonies -- growth, active fluctuations, segregation, adhesion, and invasion
Abstract
Colonies of bacteria endowed with a pili-based self-propulsion machinery are ideal models for investigating the structure and dynamics of active many-particle systems. We study Neisseria gonorrhoeae colonies with a molecular-dynamics-based approach. A generic, adaptable simulation method for particle systems with fluctuating bond-like interactions is devised. The simulations are employed to investigate growth of bacterial colonies and the dependence of the colony structure on cell-cell interactions. In colonies, pilus retraction enhances local ordering. For colonies consisting of different types of cells, the simulations show a segregation depending on the pili-mediated interactions among different cells. These results agree with experimental observations. Next, we quantify the power-spectral density of colony-shape fluctuations in silico. Simulations predict a strong violation of the equilibrium fluctuation-response relation. Furthermore, we show that active force generation enables colonies to spread on surfaces and to invade narrow channels. The methodology can serve as a foundation for future studies of active many-particle systems at boundaries with complex shape.
Keywords
Cite
@article{arxiv.2106.06729,
title = {Non-equilibrium dynamics of bacterial colonies -- growth, active fluctuations, segregation, adhesion, and invasion},
author = {Kai Zhou and Marc Hennes and Berenike Maier and Gerhard Gompper and Benedikt Sabass},
journal= {arXiv preprint arXiv:2106.06729},
year = {2022}
}