Enzyme cytochemical observations on the tissue stages of the life cycle of Eimeria acervulina and Eimeria necatrix

Cytochemical studies concerning the presence and distribution of various enzymes in the tissue stages of the life cycle of Eimeria acervulina and E. necatrix have been undertaken.Acid and alkaline phosphatases as well as ATPase (pH 7·2) were found to be present in all the stages of the life cycles examined, the latter enzyme being very strong in the plastic granules of the macrogametocytes and in the inner membrane of the oocyst wall. The reaction for all three enzymes was observed in the cytoplasm but not the nucleus. Non-specific esterase and glucose-6-phosphatase were also found in all stages examined, the latter occurring in greater amounts in stages where deposition of glycogen (amylopectin) was pronounced. Succinic dehydrogenase occurred only in the second generation schizonts and merozoites of E. necatrix and in the formed oocysts of both species. No reaction for β-glucuronidase or leucine naphthylamidase was apparent in any stage, although a slight reaction for leucine naphthlyamidase was seen in the second generation merozoites of E. necatrix lying free in the intestinal lumen.The presence and distribution of these enzymes and their possible function were discussed.