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A quantitative model of nitrogen fixation in the presence of ammonium

Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing...

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Detalles Bibliográficos
Autores principales: Inomura, Keisuke, Bragg, Jason, Riemann, Lasse, Follows, Michael J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6264846/
https://www.ncbi.nlm.nih.gov/pubmed/30496286
http://dx.doi.org/10.1371/journal.pone.0208282
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author Inomura, Keisuke
Bragg, Jason
Riemann, Lasse
Follows, Michael J.
author_facet Inomura, Keisuke
Bragg, Jason
Riemann, Lasse
Follows, Michael J.
author_sort Inomura, Keisuke
collection PubMed
description Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.
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spelling pubmed-62648462018-12-19 A quantitative model of nitrogen fixation in the presence of ammonium Inomura, Keisuke Bragg, Jason Riemann, Lasse Follows, Michael J. PLoS One Research Article Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models. Public Library of Science 2018-11-29 /pmc/articles/PMC6264846/ /pubmed/30496286 http://dx.doi.org/10.1371/journal.pone.0208282 Text en © 2018 Inomura et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Inomura, Keisuke
Bragg, Jason
Riemann, Lasse
Follows, Michael J.
A quantitative model of nitrogen fixation in the presence of ammonium
title A quantitative model of nitrogen fixation in the presence of ammonium
title_full A quantitative model of nitrogen fixation in the presence of ammonium
title_fullStr A quantitative model of nitrogen fixation in the presence of ammonium
title_full_unstemmed A quantitative model of nitrogen fixation in the presence of ammonium
title_short A quantitative model of nitrogen fixation in the presence of ammonium
title_sort quantitative model of nitrogen fixation in the presence of ammonium
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6264846/
https://www.ncbi.nlm.nih.gov/pubmed/30496286
http://dx.doi.org/10.1371/journal.pone.0208282
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