Title |
Large carbon isotope fractionation associated with oxidation of methyl halides by methylotrophic bacteria
|
---|---|
Published in |
Proceedings of the National Academy of Sciences of the United States of America, May 2001
|
DOI | 10.1073/pnas.101129798 |
Pubmed ID | |
Authors |
L. G. Miller, R. M. Kalin, S. E. McCauley, J. T. G. Hamilton, D. B. Harper, D. B. Millet, R. S. Oremland, A. H. Goldstein |
Abstract |
The largest biological fractionations of stable carbon isotopes observed in nature occur during production of methane by methanogenic archaea. These fractionations result in substantial (as much as approximately 70 per thousand) shifts in delta(13)C relative to the initial substrate. We now report that a stable carbon isotopic fractionation of comparable magnitude (up to 70 per thousand) occurs during oxidation of methyl halides by methylotrophic bacteria. We have demonstrated biological fractionation with whole cells of three methylotrophs (strain IMB-1, strain CC495, and strain MB2) and, to a lesser extent, with the purified cobalamin-dependent methyltransferase enzyme obtained from strain CC495. Thus, the genetic similarities recently reported between methylotrophs, and methanogens with respect to their pathways for C(1)-unit metabolism are also reflected in the carbon isotopic fractionations achieved by these organisms. We found that only part of the observed fractionation of carbon isotopes could be accounted for by the activity of the corrinoid methyltransferase enzyme, suggesting fractionation by enzymes further along the degradation pathway. These observations are of potential biogeochemical significance in the application of stable carbon isotope ratios to constrain the tropospheric budgets for the ozone-depleting halocarbons, methyl bromide and methyl chloride. |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
United States | 2 | 3% |
United Kingdom | 1 | 1% |
Uruguay | 1 | 1% |
Unknown | 69 | 95% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Researcher | 23 | 32% |
Student > Ph. D. Student | 16 | 22% |
Student > Master | 7 | 10% |
Professor > Associate Professor | 6 | 8% |
Professor | 5 | 7% |
Other | 8 | 11% |
Unknown | 8 | 11% |
Readers by discipline | Count | As % |
---|---|---|
Earth and Planetary Sciences | 26 | 36% |
Environmental Science | 16 | 22% |
Agricultural and Biological Sciences | 13 | 18% |
Chemistry | 2 | 3% |
Computer Science | 1 | 1% |
Other | 2 | 3% |
Unknown | 13 | 18% |