BPCPPDYSOE21 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 2: Active Biological Matter I (joint session BP/CPP/DY)
BP 2.2: Vortrag
Montag, 22. März 2021, 09:30–09:50, BPb
Light-regulated cell aggregation in confinement — •Alexandros Fragkopoulos1, Jeremy Vachier1, Johannes Frey1, Flora-Maud Le Menn1, Marco Mazza1,2, Michael Wilczek1, David Zwicker1, and Oliver Bäumchen1,3 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), D-37077 Göttingen, Germany — 2Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom — 3Experimental Physics V, University of Bayreuth, D-95447 Bayreuth, Germany
Photoactive microbes live in complex environments with spatially and temporally fluctuating light conditions. They survive in such habitats by switching their metabolic activity from photosynthesis to aerobic respiration in unfavorable light conditions. We demonstrate that this adaptation in a suspension of soil-dwelling Chlamydomonas reinhardtii cells under confinement leads to a spontaneous separation into regions of high and low cell densities. We show that the inhibition of the photosynthetic machinery is necessary but insufficient to generate the observed aggregation. Microfluidic experiments, simulations, and mean-field theory approaches demonstrate that the emergence of microbial aggregations is governed by the oxygen concentration field inside the microhabitat. In fact, in regions where the energy production is completely arrested by both, the photosynthetic and respiratory systems, the cell speed decreases resulting in an aggregation, which thus takes the form of the underline oxygen field.