Alternative nitrogenase activity in the environment and nitrogen cycle implications
| Autor: | Romain Darnajoux, Xinning Zhang, Darcy L. McRose, Jean-Philippe Bellenger, François M. M. Morel, Anne M. L. Kraepiel |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Ethylene Stable isotope ratio 030106 microbiology chemistry.chemical_element Nitrogenase Nitrogen 03 medical and health sciences chemistry.chemical_compound 030104 developmental biology chemistry Acetylene Botany Nitrogen fixation Environmental Chemistry Vanadium nitrogenase Nitrogen cycle Earth-Surface Processes Water Science and Technology |
| Zdroj: | Biogeochemistry. 127:189-198 |
| ISSN: | 1573-515X 0168-2563 |
| DOI: | 10.1007/s10533-016-0188-6 |
| Popis: | Biological nitrogen fixation, the main natural input of fixed nitrogen into the biosphere, is catalyzed by Mo-, V-, or Fe-only nitrogenase metalloenzymes. Although “alternative” V- and Fe-only nitrogenase genes are found in many environments, the contribution of these isoenzymes to N2 fixation is unknown. Here we present a new method (ISARA, isotopic acetylene reduction assay) that distinguishes canonical Mo and alternative nitrogenase activities based on in vivo 13C fractionation of acetylene reduction to ethylene (13eMo = 13.1–14.7 ‰, 13eV = 7.5–8.8 ‰, 13eFe = 5.8–6.5 ‰). ISARA analyses indicate significant contributions of alternative nitrogen fixation in boreal cyanolichens and salt marshes (~10–40 % acetylene reduction, ~20–55 % N2 fixed). These results affect the quantitative interpretation of natural abundance 15N data or traditional acetylene reduction assays. They also invite a reexamination of the conditions under which the different nitrogenase isozymes are active and suggest significant interactions between the cycles of nitrogen and trace metals. |
| Databáze: | OpenAIRE |
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