fractionation of sulfur isotopes by desulfovibrio vulgaris mutants lacking hydrogenases or type i tetraheme cytochrome c3

Clicks: 233
ID: 169534
2013
The sulfur isotope effect produced by sulfate reducing microbes is commonly used to trace biogeochemical cycles of sulfur and carbon in aquatic and sedimentary environments. To test the contribution of intracellular coupling between carbon and sulfur metabolisms to the overall magnitude of the sulfur isotope effect, this study compared sulfur isotope fractionations by mutants of <i>Desulfovibrio vulgaris</i> Hildenborough. We tested mutant strains lacking one or two periplasmic (Hyd, Hyn-1, Hyn-2, and Hys) or cytoplasmic hydrogenases (Ech and CooL), and a mutant lacking type I tetraheme cytochrome (TpI-<sub>c3</sub>). In batch culture, wild-type D. <i>vulgaris</i> and its hydrogenase mutants had comparable growth kinetics and produce the same sulfur isotope effects. This is consistent with the reported redundancy of hydrogenases in D. <i>vulgaris</i>. However, the TpI-<sub>c3</sub> mutant (ΔcycA) exhibited slower growth and sulfate reduction rates in batch culture, and produced more H2 and an approximately 50% larger sulfur isotope effect, compared to the wild type. The magnitude of sulfur isotope fractionation in the CycA deletion strain, thus, increased due to the disrupted coupling of the carbon oxidation and sulfate reduction pathways. In continuous culture, wild-type D. <i>vulgaris</i> and the CycA mutant produced similar sulfur isotope effects, underscoring the influence of environmental conditions on the relative contribution of hydrogen cycling to the electron transport. The large sulfur isotope effects associated with the non-ideal stoichiometry of sulfate reduction in this study imply that simultaneous fermentation and sulfate reduction may be responsible for some of the large naturally-occurring sulfur isotope effects. Overall, mutant strains provide a powerful tool to test the effect of specific redox proteins and pathways on sulfur isotope fractionation.
Reference Key
esim2013frontiersfractionation Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors ;Min Sub eSim;Min Sub eSim;David T Wang;Grant M Zane;Judy D Wall;Tanja eBosak;Shuhei eOno
Journal journal of magnetic resonance (san diego, calif : 1997)
Year 2013
DOI 10.3389/fmicb.2013.00171
URL
Keywords

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

No comments yet. Be the first to comment on this article.