德国海德堡大学Frank Keppler和Ilka B. Bischofs、Leonard Ernst课题组合作在研究中取得进展。他们的研究揭示了生物体内由活性氧驱动的甲烷(CH4)合成通路。相关论文发表在2022年3月9日出版的《自然》杂志上。

在本研究中，研究人员发现枯草芽孢杆菌和大肠杆菌产生的CH4是由游离铁和活性氧(ROS)引发的，它们由代谢活动产生并由氧化应激增强。ROS诱导的甲基自由基来源于含有硫或氮的甲基有机化合物，是CH4产生的关键中间体。研究进一步展示了来自细菌、古生菌和真核生物领域许多其他模式生物产生CH4的途径，几种生物体存在人类细胞系中。所有这些生物都通过增强CH4形成来响应氧化应激诱导剂。该研究结果表明，所有活细胞可能都具有共同的CH4形成机制，该机制基于ROS、铁和甲基供体之间的相互作用，这为理解CH4的形成和循环开辟了新的视角。

据介绍，CH4是大气中含量最丰富的碳氢化合物，主要来源于生物体，这与有氧和缺氧环境中出现的越来越多的生物有关。一般认为生物来源的CH4是产甲烷古菌对有机物进行缺氧分解产生的。然而，植物、真菌、藻类和蓝细菌也可以在有氧情况下产生CH4。尽管已知产甲烷菌在厌氧能量代谢过程中通过酶促反应产生CH4，但对非产甲烷细胞产生CH4的条件和途径知之甚少。

附：英文原文

Title: Methane formation driven by reactive oxygen species across all living organisms

Author: Ernst, Leonard, Steinfeld, Benedikt, Barayeu, Uladzimir, Klintzsch, Thomas, Kurth, Markus, Grimm, Dirk, Dick, Tobias P., Rebelein, Johannes G., Bischofs, Ilka B., Keppler, Frank

Issue&Volume: 2022-03-09

Abstract: Methane (CH4), the most abundant hydrocarbon in the atmosphere, originates largely from biogenic sources1 linked to an increasing number of organisms occurring in oxic and anoxic environments. Traditionally, biogenic CH4 has been regarded as the final product of anoxic decomposition of organic matter by methanogenic archaea. However, plants2,3, fungi4, algae5 and cyanobacteria6 can produce CH4 in the presence of oxygen. Although methanogens are known to produce CH4 enzymatically during anaerobic energy metabolism7, the requirements and pathways for CH4 production by non-methanogenic cells are poorly understood. Here, we demonstrate that CH4 formation by Bacillus subtilis and Escherichia coli is triggered by free iron and reactive oxygen species (ROS), which are generated by metabolic activity and enhanced by oxidative stress. ROS-induced methyl radicals, which are derived from organic compounds containing sulfur- or nitrogen-bonded methyl groups, are key intermediates that ultimately lead to CH4 production. We further show CH4 production by many other model organisms from the Bacteria, Archaea and Eukarya domains, including in several human cell lines. All these organisms respond to inducers of oxidative stress by enhanced CH4 formation. Our results imply that all living cells probably possess a common mechanism of CH4 formation that is based on interactions among ROS, iron and methyl donors, opening new perspectives for understanding biochemical CH4 formation and cycling. Methane formation by a ROS-mediated process is linked to metabolic activity and is identified as a conserved feature across living systems.

DOI: 10.1038/s41586-022-04511-9

Source: https://www.nature.com/articles/s41586-022-04511-9