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DY: Fachverband Dynamik und Statistische Physik

DY 42: Fluid Physics of Life (joint session DY/BP)

DY 42.7: Vortrag

Mittwoch, 18. März 2020, 17:00–17:15, ZEU 160

Topological defects in growing bacterial colonies — Anh LP Thai, Arkajyoti Ghoshal, and •Anupam Sengupta — Physics of Living Matter Group, University of Luxembourg, Luxembourg

Bacterial populations are known to mediate vital processes in ecology, medicine and industry. Morphology, a key biophysical trait, has been long studied for its biological relevance in uptake, motility and selection. Yet, only recently we have started to uncover the role of morphology in biophysical interactions between cells or with their micro-environment [1]. Here, I will present recent results that elucidate how non-motile bacteria harness morphology to regulate transport processes over colony scales. We examine the geometric and mechanical properties of growing colonies, with a particular focus on the emergence of topological defects. Our results indicate that the number of topological defects depends on the cell physiology and colony dimensions, which in turn regulate the active dynamics of the colony. We compare our experimental results with MD simulations and continuous modelling [2, 3], and demonstrate that an expanding colony of non-motile cells self-organizes into domains of aligned cells. Topological defects mediate the interactions between domains, ultimately yielding an active nematodynamic system. Topology mediated mechanics can potentially lead to physiological functions due to the active hydrodynamics at scales that are orders of magnitude larger than single cells. [1] A. Sengupta, Microbial Active Matter: A Topological Perspective (under rev.); [2] You, Pearce, Sengupta, Giomi, Phys. Rev. X. 8 (2018); [3] You, Pearce, Sengupta, Giomi, Phys. Rev. Lett. 123 (2019).