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Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria
Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen—protium and deuterium—that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the ma...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4969296/ https://www.ncbi.nlm.nih.gov/pubmed/27531993 http://dx.doi.org/10.3389/fmicb.2016.01166 |
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author | Osburn, Magdalena R. Dawson, Katherine S. Fogel, Marilyn L. Sessions, Alex L. |
author_facet | Osburn, Magdalena R. Dawson, Katherine S. Fogel, Marilyn L. Sessions, Alex L. |
author_sort | Osburn, Magdalena R. |
collection | PubMed |
description | Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen—protium and deuterium—that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ(2)H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ(2)H suggest much potential as an environmental recorder of metabolism. |
format | Online Article Text |
id | pubmed-4969296 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-49692962016-08-16 Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria Osburn, Magdalena R. Dawson, Katherine S. Fogel, Marilyn L. Sessions, Alex L. Front Microbiol Microbiology Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen—protium and deuterium—that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ(2)H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ(2)H suggest much potential as an environmental recorder of metabolism. Frontiers Media S.A. 2016-08-02 /pmc/articles/PMC4969296/ /pubmed/27531993 http://dx.doi.org/10.3389/fmicb.2016.01166 Text en Copyright © 2016 Osburn, Dawson, Fogel and Sessions. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Microbiology Osburn, Magdalena R. Dawson, Katherine S. Fogel, Marilyn L. Sessions, Alex L. Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title | Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title_full | Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title_fullStr | Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title_full_unstemmed | Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title_short | Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria |
title_sort | fractionation of hydrogen isotopes by sulfate- and nitrate-reducing bacteria |
topic | Microbiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4969296/ https://www.ncbi.nlm.nih.gov/pubmed/27531993 http://dx.doi.org/10.3389/fmicb.2016.01166 |
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