Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation.
Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation.
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DOI：
10.1038/ngeo2843
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发表时间：
2017-01
影响因子：
18.3
通讯作者：
中科院分区：
文献类型：
--
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渗透性沉积物在大陆架上很常见，是海洋生物地球化学循环的重要贡献者。可渗透沉积物中的有机物以微藻为主，作为真核生物的微藻与细菌、古细菌等原核生物有着不同的厌氧代谢途径。在这里，我们提出了流动反应器实验的分析，表明溶解的无机碳主要是由于厌氧真核代谢活动产生的。在我们的实验中，溶解无机碳的厌氧生产始终伴随着大的溶解H2生产速率，这表明存在发酵。在使用广谱抗菌药物后，溶解的无机碳和H2的产生仍然存在，但在使用甲硝唑治疗后停止。甲硝唑抑制真核生物发酵产氢的铁氧还蛋白/氢化酶途径，提示该途径是产氢和溶解无机碳的来源。代谢组学分析显示，在缺氧开始时，脂质产生大量增加，这与微藻缺氧暗发酵的途径一致。细胞计数显示微藻在沉积物中占主导地位。从研究地点分离的硅藻（Fragilariopsis sp.）和绿藻（Pyramimonas）在黑暗缺氧培养中观察到H2的产生，证实了微藻进行发酵的假设。我们认为微藻暗发酵可能是可渗透沉积物中重要的节能途径。
Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to prokaryotes such as bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H2 production rates, suggesting the presence of fermentation. The production of both dissolved inorganic carbon and H2 persisted following administration of broad spectrum bactericidal antibiotics, but ceased following treatment with metronidazole. Metronidazole inhibits the ferredoxin/hydrogenase pathway of fermentative eukaryotic H2 production, suggesting that pathway as the source of H2 and dissolved inorganic carbon production. Metabolomic analysis showed large increases in lipid production at the onset of anoxia, consistent with documented pathways of anoxic dark fermentation in microalgae. Cell counts revealed a predominance of microalgae in the sediments. H2 production was observed in dark anoxic cultures of diatoms (Fragilariopsis sp.) and a chlorophyte (Pyramimonas) isolated from the study site, substantiating the hypothesis that microalgae undertake fermentation. We conclude that microalgal dark fermentation could be an important energy-conserving pathway in permeable sediments.
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DOI：
10.1038/ismej.2015.257
发表时间：
2016-08
期刊：
The ISME journal
影响因子：
--
作者：
Dyksma S;Bischof K;Fuchs BM;Hoffmann K;Meier D;Meyerdierks A;Pjevac P;Probandt D;Richter M;Stepanauskas R;Mußmann M
通讯作者：
Mußmann M
影响因子：
2.9
作者：
CANFIELD, DE;JORGENSEN, BB;HALL, POJ
通讯作者：
HALL, POJ
影响因子：
3.5
作者：
INUI, H;MIYATAKE, K;KITAOKA, S
通讯作者：
KITAOKA, S
影响因子：
4.8
作者：
Dubini, Alexandra;Mus, Florence;Posewitz, Matthew C.
通讯作者：
Posewitz, Matthew C.
影响因子：
4.5
作者：
Cook, Perran L. M.;Wenzhofer, Frank;Huettel, Markus
通讯作者：
Huettel, Markus