Aging a little:On the optimality of limited senescence in Escherichia coli

Blitvic, Natasha and Fernandez, Vicente (2020) Aging a little:On the optimality of limited senescence in Escherichia coli. Journal of Theoretical Biology, 502. ISSN 0022-5193

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Abstract

Recent studies have shown that even in the absence of extrinsic stress, the morphologically symmetrically dividing model bacteria Escherichia coli do not generate offspring with equal reproductive fitness. Instead, daughter cells exhibit asymmetric division times that converge to two distinct growth states. This represents a limited senescence / rejuvenation process derived from asymmetric division that is stable for hundreds of generations. It remains unclear why the bacteria do not continue the senescence beyond this asymptote. Although there are inherent fitness benefits for heterogeneity in population growth rates, the two growth equilibria are surprisingly similar, differing by a few percent. In this work we derive an explicit model for the growth of a bacterial population with two growth equilibria, based on a generalized Fibonacci recurrence, in order to quantify the fitness benefit of a limited senescence process and examine costs associated with asymmetry that could generate the observed behavior. We find that with simple saturating effects of asymmetric partitioning of subcellular components, two distinct but similar growth states may be optimal while providing evolutionarily significant fitness advantages.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Theoretical Biology
Additional Information:
This is the author’s version of a work that was accepted for publication in Journal of Theoretical Biology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Theoretical Biology, 502, 2020 DOI: 10.1016/j.jtbi.2020.110331
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2700
Subjects:
ID Code:
141761
Deposited By:
Deposited On:
24 Feb 2020 09:10
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Nov 2020 15:20