FIG. 1.

ATP content and adhesion-invasion capacity of T. cruzi metacyclic forms (CL strain) subjected to nutritional stress. (A, B, and C) Parasites were maintained in PBS for the indicated time periods and were then analyzed with regard to the ATP content (A) and the ability to attach to (B) or to enter (C) HeLa cells. Representative results of one out of three experiments are shown. Values represent the means ± standard deviations of the results of triplicate experiments. The numbers of attached or intracellular parasites represented in panels B and C were counted in 250 cells. (D) Giemsa-stained control and starved parasites. (E) The expression levels of the metacyclic-stage-specific surface gp82 molecule in starved parasites were determined by flow cytometry, using the specific MAb 3F6.