Publications by authors named "Carlos E Peres-Sampaio"
In this work we demonstrated that promastigotes of Leishmania amazonensis exhibit an Mg-dependent ecto-ATPase activity, which is stimulated by heat shock. The Mg-dependent ATPase activity of cells grown at 22 and 28 degrees C was 41.0+/-5.
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- The study investigates the capacity of live Trypanosoma cruzi epimastigotes to break down extracellular ATP, revealing low initial hydrolysis rates without divalent metals.
- The addition of MgCl2 significantly enhances ATP hydrolysis, indicating that this process is magnesium-dependent and shows a dose-response relationship, while MnCl2 also stimulates activity but other metals do not.
- An analysis using specific inhibitors confirmed this activity as ecto-ATPase, revealing that infective forms of the parasite are more effective at hydrolyzing ATP compared to the noninfective epimastigotes.
This study describes the possible role of Mg(2+)-dependent ecto-ATPase activity on the Trypanosoma cruzi-host cell interaction. Mg(2+)-dependent ecto-ATPase activity is observed on the cell body and flagellar membranes of the parasite and is about 20 times greater in trypomastigotes, as compared with epimastigotes. Suramin (a competitive antagonist of P2 receptors) and the impermeant agent 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid (DIDS), both inhibitors of ecto-ATPases, strongly inhibited ATPase activity and the adhesion and internalization of both evolutive forms by mouse resident macrophages.
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