The effect of inhibitors of macromolecular biosynthesis on the in vitro infectivity and morphology of Trypanosoma cruzi trypomastigotes.

The effect of inhibitors of RNA, protein, and glycoprotein biosynthesis has been studied on the development of in vitro infectivity and the transformation to spheromastigotes occurring when recently isolated trypomastigotes of Trypanosoma cruzi are incubated extracellularly. Puromycin (1 microgram/ml) blocks the development of parasite adhesion and penetration of Vero cells, as well as the transformation. Actinomycin D (8 ng/ml) and tunicamycin (30 ng/ml) inhibit completely the development of infectivity, without blocking adhesion and transformation. The last two parameters are inhibited by higher actinomycin D concentrations, but are unaffected by tunicamycin. The results obtained suggest that a parasite glycoprotein is involved in the penetration step of T. cruzi trypomastigotes into fibroblastic cells, and that adhesion, penetration, and transformation to spheromastigotes are three different processes, each one of them requiring de novo synthesis of distinct proteins.