真核细胞也能制造甲烷

fadi99

没想到，真核细胞在低氧情况下确实能产生甲烷，那么这样的情况能否产生在其他气体，例如氢，H2S等，看来细菌能做的事情，真核细胞一般都能做，只是我们没有注意。
Cell Physiol Biochem. 2008;21(1-3):251-8. Epub 2008 Jan 16.
Links

Hypoxia-induced generation of methane in mitochondria and eukaryotic cells - an alternative

approach to methanogenesis.

Ghyczy M, Torday C, Kaszaki J, Szabó A, Czóbel M, Boros M.

Cologne, Germany.

Background/Aims: Electrophilic methyl groups bound to positively charged nitrogen moieties may act as electron acceptors, and this mechanism could lead to the generation of methane from choline. The aims were to characterize the methanogenic potential of phosphatidylcholine metabolites, and to define the in vivo relevance of this pathway in hypoxia-induced cellular responses. Methods: The postulated reaction was investigated (1) in model chemical experiments, (2) in rat mitochondrial subfractions and (3) in bovine endothelial cell cultures under hypoxic conditions and in the presence of hydroxyl radical generation. The rate of methane formation was determined by gas chromatography with flame-ionisation detectors. The lucigenin-enhanced chemiluminescence assay was used to determine the reactive oxygen species-scavenging capacity of the choline metabolites. Results: Significant methane generation was demonstrated in all three series of experiments. Phosphatidylcholine metabolites with alcoholic moiety in the molecule (i.e. choline, N,N-dimethylethanolamine and N-methylethanolamine), inhibited oxygen radical production both in vitro and in vivo, and displayed an effectiveness proportional to the amount of methane generated and the number of methyl groups in the compounds. Conclusion: Methane generation occurs in aerobic systems. Phosphatidylcholine metabolites containing both electron donor and acceptor groups may have a function to counteract intracellular oxygen radical production. Copyright [Coffee] 2008 S. Karger AG, Basel.

: FASEB J. 2003 Jun;17(9):1124-6. Epub 2003 Apr 8. Links
Simultaneous generation of methane, carbon dioxide, and carbon monoxide from choline and ascorbic acid: a defensive mechanism against reductive stress?Ghyczy M, Torday C, Boros M.
Phospholipid GmbH, Cologne, Germany.

Indirect evidence suggests that an abnormal increase in reducing power (reductive stress) may be associated with abnormal clinical states. We have recently proposed that under such conditions biomolecules with electrophilic methyl groups (EMGs) bound to positively charged nitrogen or sulfur moieties may act as electron acceptors and that this poising mechanism may entail the generation of methane gas. Here we report for the first time the generation of methane by rat liver mitochondria. We also report the formation of methane from choline in the presence of hydrogen peroxide, catalytic iron, and ascorbic acid. In this system, carbon monoxide and carbon dioxide are formed from the ascorbate molecule in parallel with methane generation. In view of these findings, we try to explain the essential role of biomolecules with EMG moiety. We hypothesize that this concerted reaction may be a defensive response to reductive stress and may provide the protection needed against redox imbalance in living systems