Reduced oxygen levels and increased sulfide concentrations have become a concern for marine animals. This study examines respiratory and energetic adaption to acute (0–96 h) hypoxia (0.5 mg/L dissolved oxygen) with or without sulfide (0.2 mM, 1 mM, 3 mM) in the hypoxia-resistant and sulfide-tolerant ark shell, Anadara broughtonii. The different states of aerobic respiration, energy-balance, and activity of the mitochondrial sulfide oxidation chain (MSOC) under these conditions were evaluated. The results indicated that the anaerobic pathway was activated by hypoxia at 24 h without sulfide, but was activated in the presence of sulfide at only 2 h. Exposure to sulfide resulted in significant accumulation of ATP, probably due to the activated MSOC and lowered metabolism via suppression of Na⁺-K⁺ ATPase activity and protein synthesis. During hypoxia, both enzyme activity and mRNA levels of alternative oxidase (AOX) increased while the key enzymes in MSOC, sulfide: quinone oxidoreductase (SQR) and sulfur dioxygenase (SDO), were not altered. With additional sulfide, the enzyme activity and mRNA levels of AOX, SQR, SDO significantly increased. Classical aerobic respiration was significantly inhibited, and induction of alternative respiration was detected. The corresponding alternative electron transport chain (AETC) accepted the electrons originating from both the tricarboxylic acid cycle and MSOC during the challenge, indicating that the capacity of aerobic respiration and sulfide-oxidation under a reduction state might greatly depend on AETC. The synergistically induced alternative chains (AETC and MSOC) and anaerobic pathway suggested energy-balance between respiration and sulfide-oxidation, which might contribute to the endurance of ark shells to acute sulfide exposure.

氧气含量降低和硫化物浓度增加已成为海洋动物关注的问题。这项研究检查了在耐缺氧和耐硫化的方舟壳中，无论是否含有硫化物（0.2 mM、1 mM、3 mM），对急性（0-96 小时）缺氧（0.5 毫克/升溶解氧）的呼吸和能量适应，阿纳达拉百合。评估了在这些条件下的有氧呼吸、能量平衡和线粒体硫化物氧化链 (MSOC) 的不同状态。结果表明，厌氧途径在没有硫化物的情况下在 24 小时被缺氧激活，但在硫化物存在下仅在 2 小时被激活。暴露于硫化物导致 ATP 显着积累，这可能是由于激活的 MSOC 和通过抑制 Na ⁺降低代谢- K ⁺ATP酶活性和蛋白质合成。在缺氧期间，替代氧化酶 (AOX) 的酶活性和 mRNA 水平均增加，而 MSOC 中的关键酶硫化物：醌氧化还原酶 (SQR) 和硫双加氧酶 (SDO) 未发生改变。添加硫化物后，AOX、SQR、SDO 的酶活性和 mRNA 水平显着增加。经典有氧呼吸受到显着抑制，并检测到替代呼吸的诱导。相应的替代电子传递链（AETC）在挑战过程中接受了来自三羧酸循环和 MSOC 的电子，表明还原状态下的有氧呼吸和硫化物氧化能力可能在很大程度上取决于 AETC。