Trypanosoma cruzi induces changes in the nucleic acids content of host Hela cells "in vitro".

The nucleic acid content of parasitized, non-parasitized Hela, cells, infected with metacyclic forms of Trypanosoma cruzi, was measured during 7 days of parasitization by means of histochemical techniques. Hela cells were first exposed to the parasite for 12 hrs. and then parasites were removed from the culture medium. Measurements of nuclear RNA + DNA content indicate that the three types of cells behave during 7 days of subsequent culture as three different populations. Similar results were obtained when only nuclear DNA was determined. DNA of parasitized cells increased dramatically compared to control and non-parasitized cells. This increase however was not observed in cells derived from non-parasitized cells, which were infected with trypomastigotes from the first parasitization cycle.

The in vitro cultivation of Taenia pisiformis to sexually mature adults.

Taenia pisiformis was cultivated from a cysticercus to a non-fertile adult in a diphasic medium. This medium was composed of coagulated bovine serum, as a solid phase, and CMRL 1066, modified by the addition of fetal calf serum, yeast extract, glucose and KCl, as a liquid phase. The medium was gassed with 10% O2 and 5% CO2 in N2. Evidence of morphogenesis with proglottid formation occurred after 7-8 days of culture, and genital pores were formed after 22 days. Some worms showed signs of teratological changes with two or three genital pores.