Effect of heat and hypoxia stress on mitochondrion and energy metabolism in the gill of hard clam

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology Vol. 266; p. 109556
• Main Authors: Hu, Zhi, Xu, Li, Song, Hao, Feng, Jie, Zhou, Cong, Yang, Mei-Jie, Shi, Pu, Li, Yong-Ren, Guo, Yong-Jun, Li, Hai-Zhou, Zhang, Tao
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2023
• Subjects: Animals; Energy Metabolism; Gills - metabolism; Heat; Hot Temperature; Hypoxia; Hypoxia - metabolism; Mercenaria - metabolism; Mercenaria mercenaria; Mitochondria - metabolism; Mitochondrion; Mitochondrion; Hypoxia; Heat; Energy metabolism; Mercenaria mercenaria
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2023.109556

Aquatic animals suffer from heat and hypoxia stress more frequently due to global climate change and other anthropogenic activities. Heat and hypoxia stress can significantly affect mitochondrial function and energy metabolism. Here, the response and adaptation characteristics of mitochondria and energy metabolism in the gill of the hard clam Mercenaria mercenaria under heat (35 °C), hypoxia (0.2 mg/L), and heat plus hypoxia stress (35 °C, 0.2 mg/L) after 48 h exposure were investigated. Mitochondrial membrane potentials were depolarized under environmental stress. Mitochondrial fusion, fission and mitophagy played a key role in maintain mitochondrion function. The AMPK subunits showed different expression under environmental stress. Acceleration of enzyme activities (phosphofructokinase, pyruvate kinase and lactic dehydrogenase) and accumulation of anaerobic metabolites in glycolysis and TCA cycle implied that the anaerobic metabolism might play a key role in providing energy. Accumulation of amino acids might help to increase tolerance under heat and heat combined hypoxia stress. In addition, urea cycle played a key role in amino acid metabolism to prevent ammonia/nitrogen toxicity. This study improved our understanding of the mitochondrial and energy metabolism responses of marine bivalves exposed to environmental stress. [Display omitted] •Hard clam gill mitochondrial was impaired under heat and hypoxia stress.•Mitochondrial dynamic process helped to maintain mitochondrial function.•Anaerobic metabolism was enhanced for providing energy under stress.•Amino acids were accumulated under heat and combined stress.•Urea cycle might help to prevent ammonia/nitrogen toxicity.