Ballantyne James S
Department of Zoology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Comp Biochem Physiol B Biochem Mol Biol. 2004 Nov;139(3):461-7. doi: 10.1016/j.cbpc.2004.09.015.
The contributions of Peter Hochachka to the development of comparative and adaptational biochemistry are substantial. In particular, he and his academic offspring made major contributions to the understanding of the metabolism of molluscs and fishes. These two large taxonomic groups each have marine, freshwater and terrestrial/semiterrestrial representatives, and their mitochondrial metabolism has been shaped by these environmental conditions. In particular, the importance of amino acids and lipids as energy sources has interesting correlations with the environment and the osmotic strategy used. In marine molluscs, amino acids are important aerobic energy sources, and are used as osmolytes and participate in anaerobic metabolism. In marine elasmobranchs, amino acids and ketone bodies, but not lipids per se, are important energy sources in extrahepatic tissues. Marine and freshwater teleost fish by contrast use lipids as an extrahepatic energy source with minimal use of ketone bodies. Furthermore, ketone bodies are important in the metabolism of freshwater and terrestrial but not marine molluscs. The bases for these different metabolic plans may lie in the solute systems used by the different groups (e.g. amino acids in marine molluscs and urea in marine elasmobranchs). The various metabolic options used by fishes and molluscs indicate the plasticity of metabolic design in an environmental context.
彼得·霍查克对比较生物化学和适应性生物化学发展的贡献颇为重大。尤其值得一提的是，他及其学术后辈对软体动物和鱼类的新陈代谢研究做出了重要贡献。这两个大型分类群体各自都有海洋、淡水以及陆地/半陆地的代表物种，并且它们的线粒体代谢受到这些环境条件的影响。特别要指出的是，氨基酸和脂质作为能量来源的重要性与环境以及所采用的渗透策略存在着有趣的关联。在海洋软体动物中，氨基酸是重要的有氧能量来源，还被用作渗透质并参与无氧代谢。在海洋软骨鱼类中，氨基酸和酮体而非脂质本身是肝外组织的重要能量来源。相比之下，海洋和淡水硬骨鱼类则将脂质用作肝外能量来源，对酮体的利用极少。此外，酮体在淡水和陆地软体动物的新陈代谢中很重要，但在海洋软体动物中并非如此。这些不同代谢模式的基础可能在于不同群体所使用的溶质系统（例如海洋软体动物中的氨基酸和海洋软骨鱼类中的尿素）。鱼类和软体动物所采用的各种代谢方式表明了在环境背景下代谢设计的可塑性。
