van Grinsven Sigrid, Sinninghe Damsté Jaap S, Villanueva Laura
Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Utrecht University, 1797 SZ 't Horntje, Texel, The Netherlands.
Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584 CB Utrecht, The Netherlands.
Microorganisms. 2020 Aug 24;8(9):1288. doi: 10.3390/microorganisms8091288.
Marine anaerobic methane oxidation (AOM) is generally assumed to be coupled to sulfate reduction, via a consortium of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). ANME-1 are, however, often found as single cells, or only loosely aggregated with SRB, suggesting they perform a form of AOM independent of sulfate reduction. Oxidized metals and humic substances have been suggested as potential electron acceptors for ANME, but up to now, AOM linked to reduction of these compounds has only been shown for the ANME-2 and ANME-3 clades. Here, the effect of the electron acceptors anthraquinone-disulfonate (AQDS), a humic acids analog, and Fe on anaerobic methane oxidation were assessed by incubation experiments with anoxic Black Sea water containing ANME-1b. Incubation experiments with -methane and AQDS showed a stimulating effect of AQDS on methane oxidation. Fe enhanced the ANME-1b abundance but did not substantially increase methane oxidation. Sodium molybdate, which was added as an inhibitor of sulfate reduction, surprisingly enhanced methane oxidation, possibly related to the dominant abundance of in those incubations. The presented data suggest the potential involvement of ANME-1b in AQDS-enhanced anaerobic methane oxidation, possibly via electron shuttling to AQDS or via interaction with other members of the microbial community.
海洋厌氧甲烷氧化（AOM）通常被认为是通过厌氧甲烷氧化古菌（ANME）和硫酸盐还原细菌（SRB）的共生体与硫酸盐还原相耦合的。然而，ANME-1通常以单细胞形式存在，或者仅与SRB松散聚集，这表明它们进行的是一种独立于硫酸盐还原的AOM形式。氧化态金属和腐殖质被认为是ANME的潜在电子受体，但到目前为止，与这些化合物还原相关的AOM仅在ANME-2和ANME-3进化枝中得到证实。在此，通过用含有ANME-1b的缺氧黑海海水进行培养实验，评估了电子受体蒽醌二磺酸盐（AQDS，一种腐殖酸类似物）和铁对厌氧甲烷氧化的影响。用甲烷和AQDS进行的培养实验表明，AQDS对甲烷氧化有刺激作用。铁提高了ANME-1b的丰度，但没有显著增加甲烷氧化。作为硫酸盐还原抑制剂添加的钼酸钠出人意料地提高了甲烷氧化，这可能与这些培养物中 的优势丰度有关。所呈现的数据表明，ANME-1b可能参与了AQDS增强的厌氧甲烷氧化，可能是通过向AQDS进行电子穿梭或与微生物群落的其他成员相互作用来实现的。
