The metabolism of the adductor muscle of Saxostrea commercialis

Abstract

An outline of the general biology of Saxostrea commercialis is given as a background to the structure, function and metabolism of the adductor muscle. The anatomy of the muscle is discussed and it is pointed out that neither the nacreous nor the vitreous tissue exhibits true striations. The mode of action of the muscle is next described and its functions are outlined particularly with regard to its importance in the processes of feeding, respiration, excretion and spawning. Experiments on the oxidative metabolism of the muscle are presented. These deal with the level of the endogenous respiration and the action of various factors on this; then the effect of succinic acid is described and the effects of several inhibitors (including narcotics) on the respiration in the presence and absence of succinic acid. Finally the presence of catalase and cytochrome oxidase is shown. Experiments on muscle glycolysis show that although this process is very feeble in both parts of the muscles, the reactions occur equally well under aerobic and anaerobic conditions. Further, it appears that ATP is broken down as a result of muscle activity. It is concluded that breakdown of ATP provides the energy for muscle activity and that ATP is resynthesized through glycolytic processes. A study of the myosin - and soluble - ATP-ases is presented. The general conclusion is made that the adductor muscle shows no essential biochemical difference from muscle from higher animals. Such differences as do exist, are largely quantitative and rarely qualitative.