[Cytochemical study of different stages in the life cycle of Toxoplasma gondii. I. Nucleic acids and proteins in endozoites].

Using the Feulgen technique in addition to the methyl green-pyronin and gallocyanin-chromalum staining, nucleic acids were detected in Toxoplasma gondii of strains SS-119 and RH DNA was revealed in the nuclei of both intracellular and free individuals examined on various days (2--6) after mouse inoculation. A high RNA content in the cytoplasm of endozoites is a most characteristic feature of this stage. However, no definite nucleolus has been demonstrated in the endozoite nucleus. Using the Fast green and Alcian blue techniques, resp., histones were detected in the endozoite nuclei whose locality corresponded to that of Feulgen-positive material. The Acrolein-Schiff method located aldehyde groups of protein in endozoites, the detected stuff being confined mainly to the nuclear and perinuclear areas of the parasite. Tannofilic protein seems to screen the endozoite body, no difference between nuclear and cytoplasmic staining being seen. Tryptophan and tyrosin were not detected in the endozoites of Toxoplasma. The results obtained on Toxoplasma endozoites are compared with the metabolic patterns seen in the host cells of the peritoneal exudate and with previous literature data.