[Cytochemical research on cysts of the sarcosporidian Sarcocystis bovicanis. II. Oxidation-reduction enzymes].

By the means of light-microscopic cytological enzymatic methods, the presence of several enzymes (NAD.H and NADP.H-tetrazolium reductases, in addition to alcohol, succinate, isocitrate, glucose-6-phosphate, beta-hydroxybutyrate and glutamate dehydrogenases) has been studied in the tissue cysts of S. bovicanis. A mixed character of oxidative metabolism in the cyst stages is suggested, the involvement of gluconeogenesis being proposed. Neither beta-hydroxybutyrate nor alcohol dehydrogenase activity was demonstrated indicating the absence or a very low rate of lipid metabolism, and suggesting that the process of glycolysis may end with malate formation. From the low activity level of succinate dehydrogenases it is concluded that the citric acid cycle plays presumably a secondary role, if at all, in the energy supply of the cyst stages. Also, a low activity of glucose-6-phosphate dehydrogenases is pointed out. Thus, it is proposed that glycolysis may be primary, if not the only, oxidative pathway in the cyst stages.