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Type: Artigo de periódico
Title: Ca2+ Transport In Digitonin-permeabilized Trypanosomatids.
Author: Vercesi, A E
Macedo, D V
Lima, S A
Gadelha, F R
Docampo, R
Abstract: The use of digitonin to permeabilize Leishmania mexicana mexicana, Leishmania agamae, and Crithidia fasciculata plasma membranes enabled us to study Ca2+ transport in situ. The present results show that the mitochondria of these trypanosomatids are able to build up and retain a membrane potential as indicated by a tetraphenylphosphonium-sensitive electrode. Ca2+ uptake caused membrane depolarization compatible with the existence of an electrogenically mediated Ca2+ transport mechanism in these mitochondria. Ca2+ uptake was partially inhibited by ruthenium red, almost totally inhibited by carbonyl cyanide p-trifluoromethoxyphenylhydrazone, and stimulated by inorganic phosphate. Large amounts of Ca2+ were retained by C. fasciculata mitochondria even after addition of thiols and NAD(P)H oxidants such as t-butylhydroperoxide and diamide. In contrast, Ca2+ was not retained in the matrix of Leishmania sp. mitochondria for long periods of time. In addition to the mitochondrial Ca2+ uptake, a vanadate-sensitive Ca2(+)-transporting system was also detectable in these trypanosomatids.
Subject: Animals
Biological Transport
Leishmania Mexicana
Membrane Potentials
Onium Compounds
Organophosphorus Compounds
Rights: fechado
Identifier DOI: 
Date Issue: 1990
Appears in Collections:Unicamp - Artigos e Outros Documentos

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