[Cytochemical study of various stages of the life cycle of Toxoplasma gondii. 3. Phosphatases in the entozoa].

Three methods were used to detect acid phosphatase in toxoplasma endodozoites of strain SS-119 harvested on day 4 after mouse inoculation. The modified lead nitrate method detected the enzymatic activity in host cells only; Gomori metal salt technique revealed the enzyme almost exclusively in the parasite, whereas the Standard Naphthol AS-BI phosphate method suggested the presence of the enzyme simultaneously in the two, though not regularly in the parasites. The enzymatic activity when present was visualized as few coloured granules mainly in the anterior cytoplasmic area on the body and at the periphery, leaving the nuclear zone unstained. Alkaline phosphatase distribution, detected with one method only (Standard Naphtol AS-BI phosphate), appeared less convincing in the parasite than in the host cell. In host cells harbouring endozoites, no increased activity was observed in the immediate closeness of the intracellular parasites.