Adaptational and Phenotypic Differences in Capacity for Intracellular pH Regulation in Molluscan Cardiac Myocytes

海洋双壳类软体动物，如牡蛎、蛤蜊和贻贝，通常生活在氧气供应随时间变化很大的栖息地。例如，生活在潮间带的物种可能在退潮时经历每天的空气暴露循环。大多数物种关闭它们的外壳以避免干燥。然而，这导致内部氧气的严重消耗，因为生物体有效地与呼吸环境隔绝。令人惊讶的是，这些物种中的许多在没有氧气的情况下存活了很长一段时间，这是因为它们的细胞在没有氧气的情况下能够产生能量。无氧发电的一个主要缺点是代谢酸会作为废物积累起来。本研究将探讨这些动物的细胞如何处理缺氧期间产生的代谢性酸。将进行实验，看看来自潮间带高水平物种（经常缺氧）的细胞是否比来自潮间带低水平物种（不经常缺氧）的细胞具有更高的处理这些代谢酸的能力。进一步的研究将调查当动物遭受慢性氧应激时，细胞应对酸负荷的能力是否会增强。这些研究将提供有关这些动物适应其栖息地的独特机制的信息，并对适用于高等生物的一般机制产生见解。//

Marine bivalve molluscs such as oysters, clams and mussels often are found in habitats where oxygen availability may vary dramatically with time. For instance, species which live in the intertidal zone may go through daily cycles of air exposure at low tides. Most species close their shells to avoid desiccation. However, this results in a severe depletion of internal oxygen since the organism is effectively sealed from the respiratory environment. Surprisingly, many of these species survive without oxygen for extended periods due to the ability of their cells to produce energy in the absence of oxygen. One major drawback in making energy without oxygen is that metabolic acids accumulate as waste products. This study will investigate how the cells of these animals deal with the metabolic acids produced during period of hypoxia. Experiments will be conducted to see if cells from high intertidal species (frequent exposure to oxygen deprivation) show a higher capacity for dealing with these metabolic acids than cells from low intertidal species (infrequent exposure to oxygen deprivation). Additional studies will investigate whether the capacity for cells to cope with acid loads is enhanced when animals are subjected to chronic oxygen stress. These studies will provide information on the unique mechanisms by which these animals are adapted to their habitats and also yield insights into general mechanisms applicable to higher organisms.//