Functional and environmental anaerobiosis in the razor-clam Ensis directus (Mollusca: Bivalvia)

In Ensis directus (Conrad) metabolic changes accompanying muscular activity and experimental anoxia were investigated. Octopine dehydrogenase, strombine dehydrogenase, alanopine dehydrogenase and lactic dehydrogenase were shown to be present in different parts of the body, but the activity of ODH always exceeded that of the other enzymes by far. Muscular activity connected with escape digging or evoked by electrical stimulation resulted in a decrease of stored phosphagen and in an accumulation of octopine. During recovery the normal concentrations of energy-rich phosphates were restored quickly, whereas octopine was removed more slowly. In experimental anoxia only minor quantities of L-and D-alanine, succinate, propionate, and acetate were formed. Quantitatively the most important endproduct was strombine, which rose linearly with the duration of anoxic incubation.