Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 5: Systems biology & gene expression and signaling
BP 5.2: Vortrag
Montag, 1. April 2019, 15:30–15:45, H11
Why E. coli dies exponentially during carbon starvation — •Severin Schink1,2, Elena Biselli2, Constantin Ammar2, Yu-Fang Chang1, Markus Basan2, and Ulrich Gerland1 — 1Harvard Medical School, Department of Systems Biology, 200 Longwood Ave, Boston 02115 MA, USA — 2Technical University of Munich, Physics Department, James-Franck-Str 1, 85748 Garching, Germany
While growth of bacteria is well understood and studied, its counterpart death is not. We use the mathematical simplicity of the decay of viability during carbon starvation, a simple exponential function, to uncover how E. coli survives nutrient limitation. We find that survival crucially depends on cannibalistic biomass recycling, where bacteria survive by metabolizing biomass of perished cells. The interdependence of survival and death leads to a negative feedback loop: increased cell death results in more available nutrients, which in turn reduces cell death. As a result, the state of the cells becomes naturally balanced, so that the death rate remains invariant for several days and viability decreases exponentially. This finding permits quantitative insights into how environments and genetic elements affect bacterial survival, as exemplified by a study of the cost of a wasteful enzyme and the benefit of the stress response sigma factor rpoS.