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Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations

When bacteria are exposed to osmotic stress, some cells recover and grow, while others die or are unculturable. This leads to a viable count growth curve where the cell number decreases before the onset of the exponential growth phase. From such curves, it is impossible to estimate what proportion o...

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Detalles Bibliográficos
Autores principales: George, S. M., Métris, A., Baranyi, J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393428/
https://www.ncbi.nlm.nih.gov/pubmed/25747002
http://dx.doi.org/10.1128/AEM.04018-14
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author George, S. M.
Métris, A.
Baranyi, J.
author_facet George, S. M.
Métris, A.
Baranyi, J.
author_sort George, S. M.
collection PubMed
description When bacteria are exposed to osmotic stress, some cells recover and grow, while others die or are unculturable. This leads to a viable count growth curve where the cell number decreases before the onset of the exponential growth phase. From such curves, it is impossible to estimate what proportion of the initial cells generates the growth because it leads to an ill-conditioned numerical problem. Here, we applied a combination of experimental and statistical methods, based on optical density measurements, to infer both the probability of growth and the maximum specific growth rate of the culture. We quantified the growth potential of a bacterial population as a quantity composed from the probability of growth and the “suitability” of the growing subpopulation to the new environment. We found that, for all three laboratory media studied, the probability of growth decreased while the “work to be done” by the growing subpopulation (defined as the negative logarithm of their suitability parameter) increased with NaCl concentration. The results suggest that the effect of medium on the probability of growth could be described by a simple shift parameter, a differential NaCl concentration that can be accounted for by the change in the medium composition. Finally, we highlighted the need for further understanding of the effect of the osmoprotectant glycine betaine on metabolism.
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spelling pubmed-43934282015-04-30 Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations George, S. M. Métris, A. Baranyi, J. Appl Environ Microbiol Food Microbiology When bacteria are exposed to osmotic stress, some cells recover and grow, while others die or are unculturable. This leads to a viable count growth curve where the cell number decreases before the onset of the exponential growth phase. From such curves, it is impossible to estimate what proportion of the initial cells generates the growth because it leads to an ill-conditioned numerical problem. Here, we applied a combination of experimental and statistical methods, based on optical density measurements, to infer both the probability of growth and the maximum specific growth rate of the culture. We quantified the growth potential of a bacterial population as a quantity composed from the probability of growth and the “suitability” of the growing subpopulation to the new environment. We found that, for all three laboratory media studied, the probability of growth decreased while the “work to be done” by the growing subpopulation (defined as the negative logarithm of their suitability parameter) increased with NaCl concentration. The results suggest that the effect of medium on the probability of growth could be described by a simple shift parameter, a differential NaCl concentration that can be accounted for by the change in the medium composition. Finally, we highlighted the need for further understanding of the effect of the osmoprotectant glycine betaine on metabolism. American Society for Microbiology 2015-04-10 2015-05 /pmc/articles/PMC4393428/ /pubmed/25747002 http://dx.doi.org/10.1128/AEM.04018-14 Text en Copyright © 2015, George et al. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license (http://creativecommons.org/licenses/by/3.0/) .
spellingShingle Food Microbiology
George, S. M.
Métris, A.
Baranyi, J.
Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title_full Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title_fullStr Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title_full_unstemmed Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title_short Integrated Kinetic and Probabilistic Modeling of the Growth Potential of Bacterial Populations
title_sort integrated kinetic and probabilistic modeling of the growth potential of bacterial populations
topic Food Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393428/
https://www.ncbi.nlm.nih.gov/pubmed/25747002
http://dx.doi.org/10.1128/AEM.04018-14
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