Death Rate of E. coli during Starvation Is Set by Maintenance Cost and Biomass Recycling

To break down organismal fitness into molecular contributions, costs and benefits of cellular components must be analyzed in all phases of the organism’s life cycle. Here, we establish the required quantitative approach for the death phase of the model bacterium Escherichia coli. We show that in car...

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Bibliographic Details
Published in:	Cell systems 2019-07, Vol.9 (1), p.64-73.e3
Main Authors:	Schink, Severin J., Biselli, Elena, Ammar, Constantin, Gerland, Ulrich
Format:	Article
Language:	eng
Subjects:	bacterial fitness bacterial physiology bacterial survival bacterial systems biology death rate quantitative physiology
Online Access:	Get full text
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Summary:	To break down organismal fitness into molecular contributions, costs and benefits of cellular components must be analyzed in all phases of the organism’s life cycle. Here, we establish the required quantitative approach for the death phase of the model bacterium Escherichia coli. We show that in carbon starvation, an exponential decay of viability emerges as a collective phenomenon, with viable cells recycling nutrients from cell carcasses to maintain viability. The observed collective death rate is determined by the maintenance rate of viable cells and the amount of nutrients recovered from dead cells. Using this relation, we study the cost of a wasteful enzyme during starvation and the benefit of the stress response sigma factor RpoS. While the enzyme increases maintenance and thereby the death rate, RpoS improves biomass recycling, decreasing the death rate. Our approach thus enables quantitative analyses of how cellular components affect the survival of non-growing cells. [Display omitted] •E. coli cells require nutrients to maintain their viability•In starvation, viable cells feed on carcasses of perished cells•An exponential decay of viability emerges as a collective phenomenon•Death rate is determined by two parameters: maintenance rate and biomass recycling yield Schink and Biselli et al. reveal why Escherichia coli cells die exponentially when starved of carbon: viable bacteria recycle nutrients from carcasses of dead bacteria and use them for maintenance. Studying this process permits quantitative insights into how environments and genetic elements affect bacterial survival.
ISSN:	2405-4712 2405-4720