No oxygen isotope exchange between water and APS–sulfate at surface temperature: Evidence from quantum chemical modeling and triple-oxygen isotope experiments

Kohl, I. E.; Asatryan, Rubik; Bao, Huiming

doi:10.1016/j.gca.2012.07.018

Cited by 19 publications

(26 citation statements)

References 33 publications

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“…100 µL of 13 mM formaldehyde was added, which effectively suppresses the oxidation of sulfite during the subsequent anion-exchange chromatographic step (Lindgren and Cedergren, 1982;Keller-Lehmann et al, 2006). APS is known to hydrolyze rapidly under acidic conditions (Kohl et al, 2012) but rather stable around neutral pH. Based on our tests, without an aid of enzymes, APS was not decomposed in 2 hours at 32°C within the precision of measurement (5%).…”

Section: Intracellular Metabolitesmentioning

confidence: 66%

“…Previously, a negligible equilibrium isotope effect has been presumed between sulfate and APS because of their identical oxidation states (Rees, 1973;Brunner and Bernasconi, 2005). Also, since no sulfur-oxygen bonds are broken during APS formation, a large primary kinetic isotope effect is unlikely (Kohl et al, 2012;Parey et al, 2013). At this point, we cannot specify the mechanism of sulfur isotope fractionation between APS and intracellular sulfate, but possible explanations may include secondary isotope effects due to loosening of the S-O bonds in the transition state, or fractionation associated with the metabolic branch-point between dissimilatory and assimilatory APS reduction.…”

Section: Metabolic Response To Lactate Depletionmentioning

confidence: 97%

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Quantification and isotopic analysis of intracellular sulfur metabolites in the dissimilatory sulfate reduction pathway

Sim

Paris

Adkins

et al. 2017

Geochimica et Cosmochimica Acta

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Please cite this article as: Sim, M.S., Paris, G., Adkins, J.F., Orphan, V.J., Sessions, A.L., Quantification and isotopic analysis of intracellular sulfur metabolites in the dissimilatory sulfate reduction pathway, Geochimica et Cosmochimica Acta (2017), doi: http://dx.doi.org/10. 1016/j.gca.2017.02.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. fractionation between internal and external sulfate is up to 49‰, while at the same time that between external sulfate and sulfide is just a few permil. We interpret this pattern to indicate that enzymatic fractionations remain large but the net fractionation between sulfate and sulfide is muted by the closed-system limitation of intracellular sulfate. This 'reservoir effect' diminishes upon cessation of exponential phase growth, allowing the expression of larger net sulfur isotope fractionations. Thus, the relative rates of sulfate exchange across the membrane versus intracellular sulfate reduction should govern the overall (net) fractionation that is expressed. A strong reservoir effect due to vigorous sulfate reduction might be responsible for the well-established inverse correlation between sulfur isotope fractionation and the cell-specific rate of sulfate reduction, while at the same time intraspecies differences in sulfate uptake and/or exchange rates could account for the significant scatter in this relationship. Our approach, together with ongoing investigations of the kinetic isotope fractionation by key enzymes in the sulfate reduction pathway, should provide an empirical basis for a quantitative model relating the magnitude of microbial isotope fractionation to their environmental and physiological controls.3

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Section: Intracellular Metabolitesmentioning

confidence: 66%

Section: Metabolic Response To Lactate Depletionmentioning

confidence: 97%

Quantification and isotopic analysis of intracellular sulfur metabolites in the dissimilatory sulfate reduction pathway

Sim

Paris

Adkins

et al. 2017

Geochimica et Cosmochimica Acta

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“…fractionation observed during DSR results from reversible enzymatic steps during sulfate reduction, enabling the oxidation of sulfoxy intermediates that rapidly exchange oxygen isotopes with ambient water back to sulfate. Sulfite is considered to be an important intermediate in DSR and is known to rapidly exchange oxygen isotopes with water, unlike the more oxidized sulfoxy anions in DSR, such as APS or cell-internal sulfate (Brunner et al, 2012;Kohl et al, 2012). The value of 15.2& obtained for e EQ SO 2À 3 $H 2 O is much smaller than the estimates for DSR-mediated isotope equilibrium between sulfate and water.…”

Section: Implications Of the Obtained Oxygen Isotope Equilibrium Fracmentioning

confidence: 82%

The oxygen isotope equilibrium fractionation between sulfite species and water

Müller

Brunner

Breuer

et al. 2013

Geochimica et Cosmochimica Acta

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“…Whereas δ 34 S SO4 yields interesting insight on the overall throughput of sulfur through microbial communities, the δ 18 O SO4 better illuminates the internal cell dynamics of sulfur cycling (Mizutani and Rafter 1973;Fritz et al 1989;Brunner et al 2005Brunner et al , 2012Mangalo et al 2007Mangalo et al , 2008Wortmann et al 2007;Antler et al 2013). Oxygen atoms in sulfate molecules equilibrate intracellularly when sulfur is in the intermediate valence state of sulfite (Kohl et al, 2012;Wortmann et al 2007;Brunner et al 2012;Kohl et al 2012). δ 18 O SO4 is useful for tracking the sulfur atom as it transitions among its various valence states during the subsurface sulfur cycle.…”

mentioning

confidence: 99%

Controls on the abiotic exchange between aqueous sulfate and water under laboratory conditions

Rennie

Turchyn

2014

Limnology & Ocean Methods

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The oxygen atoms in sulfate are known to exchange with water at low pH and at high temperature; however, it is unclear what the timescale for exchange is for the pH and temperature conditions commonly experienced in the laboratory. We present a time series of sulfate-oxygen isotope data for solutions with two different sulfate concentrations (28 mM and 11 mM), at a range of low to intermediate pH values (1 to 5), using both hydrochloric and acetic acid. Using water enriched in 18 O, we show that there is negligible exchange of oxygen atoms between sulfate and water over the course of 390 days. We use the external uncertainty in these results to calculate a lower bound estimate on the timescale for oxygen isotope exchange under these conditions. The lower bound of the timescale for oxygen isotope exchange between sulfate and water at laboratory pH is ~2 × 10 5 hours (~25 y), which is broadly in agreement with previous estimates. This result validates the use of δ 18O SO4 as geochemical tool for a variety of solutions that are subjected to low pH at room temperature. AcknowledgmentsWe are grateful to Adina Paytan and two anonymous reviewers for improvements to the manuscript, and to David Hodell for assistance with the oxygen isotope analysis of the water, and James Rolfe for technical assistance with the running of the TC/EA. We are also grateful to Olivier Rouxel for helpful discussions, and Jenny Mills, Xiaole Sun, and Joseph Nicholl for their feedback on early drafts of the manuscript.

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No oxygen isotope exchange between water and APS–sulfate at surface temperature: Evidence from quantum chemical modeling and triple-oxygen isotope experiments

Cited by 19 publications

References 33 publications

Quantification and isotopic analysis of intracellular sulfur metabolites in the dissimilatory sulfate reduction pathway

Quantification and isotopic analysis of intracellular sulfur metabolites in the dissimilatory sulfate reduction pathway

The oxygen isotope equilibrium fractionation between sulfite species and water

Controls on the abiotic exchange between aqueous sulfate and water under laboratory conditions

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