Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/79585
Type: Artigo de periódico
Title: DIGITONIN PERMEABILIZATION DOES NOT AFFECT MITOCHONDRIAL-FUNCTION AND ALLOWS THE DETERMINATION OF THE MITOCHONDRIAL-MEMBRANE POTENTIAL OF TRYPANOSOMA-CRUZI INSITU
Author: VERCESI, AE
BERNARDES, CF
HOFFMANN, ME
GADELHA, FR
DOCAMPO, R
Abstract: Digitonin can be used to permeabilize selectively the plasma membrane of Trypanosoma cruzi epimastigotes without significantly affecting the functional integrity of mitochondria. Addition of digitonin at concentrations close to 64-mu-M caused decrease in the rate of basal respiration of epimastigotes similar to that caused by oligomycin. A further addition of carbonyl cyanide p-trifluorophenylhydrazone (FCCP) brought respiration to the same rate observed prior to the inclusion of digitonin or oligomycin. This suggests that like oligomycin, digitonin is shifting respiration to a nonphosphorylating state probably by depleting the cells from adenine nucleotides due to permeabilization of the plasma membrane. The use of low concentrations of digitonin allowed the quantitative determination of the mitochondrial membrane potential of these cells in situ using safranine O. The response of epimastigotes mitochondrial membrane potential to phosphate, FCCP, valinomycin, nigericin, ADP, and Ca2+ indicates that these mitochondria behave similarly to vertebrate mitochondria regarding the properties of their electrochemical proton gradient. In addition, T. cruzi mitochondria are able to build up and retain a membrane potential of a value comparable to that of mammalian mitochondria. The trypanocidal drug crystal violet, as well as other cationic drugs such as dequalinium, induced a rapid dose-related collapse of the inner mitochondrial membrane potential.
Editor: Amer Soc Biochemistry Molecular Biology Inc
Rights: fechado
Date Issue: 1991
Appears in Collections:Unicamp - Artigos e Outros Documentos

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