Keller Lisa M, Colman Daniel R, Boyd Eric S
Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
Nat Commun. 2025 Jan 27;16(1):1063. doi: 10.1038/s41467-025-56418-4.
Aerobic and anaerobic organisms and their functions are spatially or temporally decoupled at scales ranging from individual cells to ecosystems and from minutes to hours. This is due to competition for energy substrates and/or biochemical incompatibility with oxygen (O). Here we report a chemolithotrophic Aquificales bacterium, Hydrogenobacter, isolated from a circumneutral hot spring in Yellowstone National Park (YNP) capable of simultaneous aerobic and anaerobic respiration when provided with hydrogen (H), elemental sulfur (S), and O. Cultivation experiments demonstrated that simultaneous aerobic and anaerobic respiration enhanced growth rates and final cell concentrations when compared to those grown aerobically or anaerobically. Consumption of O measured via gas chromatography and detection of transcripts for proteins involved in S and O reduction in H/S/O-grown cultures confirmed co-occurring aerobic and anaerobic metabolism. This aerobic, S-reducing metabolism is suggested to provide a competitive advantage in environments where O availability is low and variable. Genomic data indicating the prevalence of proteins allowing for this hybrid form of energy metabolism among bacteria and archaea suggest it to be widespread but previously overlooked due to rapid, O-dependent abiotic oxidation of produced sulfide. These observations challenge existing paradigms of strict delineations between aerobic and anaerobic metabolism.
需氧生物和厌氧生物及其功能在从单个细胞到生态系统、从分钟到小时的时间尺度和空间尺度上都是解耦的。这是由于对能量底物的竞争和/或与氧气（O₂）的生化不相容性。在这里，我们报告了一种化能无机营养的 Aquificales 细菌——氢杆菌属（Hydrogenobacter），它是从黄石国家公园（YNP）的一个中性热泉中分离出来的，当提供氢气（H₂）、元素硫（S）和 O₂时，能够同时进行有氧呼吸和无氧呼吸。培养实验表明，与有氧或无氧培养的细菌相比，同时进行有氧呼吸和无氧呼吸可提高生长速率和最终细胞浓度。通过气相色谱法测定 O₂ 的消耗，并检测在 H₂/S/O₂ 培养的细菌中参与 S 和 O₂ 还原的蛋白质的转录本，证实了有氧代谢和无氧代谢同时发生。这种有氧的、还原 S 的代谢方式被认为在 O₂ 可用性较低且变化不定的环境中提供了竞争优势。基因组数据表明，在细菌和古细菌中，允许这种混合能量代谢形式的蛋白质普遍存在，这表明它很普遍，但由于产生的硫化物会快速发生依赖 O₂ 的非生物氧化，以前被忽视了。这些观察结果挑战了有氧代谢和无氧代谢之间严格划分的现有范式。
