Cytoplasmic pH (pHi) regulation was studied in Trypanosoma cruzi epimastigotes using fluorescent probes. Steady-state pHi was maintained even in the absence of extracellular Na+ or K+, but was significantly decreased in the absence of Cl-. Acid-loaded epimastigotes regained normal pHi by a process that was ATP-dependent and sensitive to N-ethylmaleimide, dicyclohexylcarbodi-imide and diethylstilboestrol, suggesting involvement of a H+-pumping ATPase. Recovery from an acid load was independent of extracellular Na+ or K+ and insensitive to omeprazole, vanadate and low concentrations of bafilomycin A1. Using the fluorescent probe bisoxonol to measure the membrane potential of intact cells, acid loading of epimastigotes was shown to result in a dicyclohexylcarbodi-imide-sensitive hyperpolarization, which suggests electrogenic pumping of protons across the plasma membrane. Addition of glucose, but not of 6-deoxyglucose, produced a transient cellular acidification of possible metabolic origin, and increased the rate of recovery from an acid load. Taken together, these results are consistent with an important role of a H+-ATPase in the regulation of pHi homoeostasis in T. cruzi.
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Research Article|
August 15 1996
The role of a H+-ATPase in the regulation of cytoplasmic pH in Trypanosoma cruzi epimastigotes
Nicole VANDERHEYDEN;
Nicole VANDERHEYDEN
1Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Ave., Urbana, IL 61801, U.S.A.
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Gustavo BENAIM;
Gustavo BENAIM
*
1Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Ave., Urbana, IL 61801, U.S.A.
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Roberto DOCAMPO
Roberto DOCAMPO
†
1Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Ave., Urbana, IL 61801, U.S.A.
†To whom correspondence should be addressed.
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Publisher: Portland Press Ltd
Received:
December 08 1995
Revision Received:
April 11 1996
Accepted:
April 22 1996
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1996
1996
Biochem J (1996) 318 (1): 103–109.
Article history
Received:
December 08 1995
Revision Received:
April 11 1996
Accepted:
April 22 1996
Connected Content
A correction has been published:
The role of a H+-ATPase in the regulation of cytoplasmic pH in Trypanosoma cruzi epimastigotes
Citation
Nicole VANDERHEYDEN, Gustavo BENAIM, Roberto DOCAMPO; The role of a H+-ATPase in the regulation of cytoplasmic pH in Trypanosoma cruzi epimastigotes. Biochem J 15 August 1996; 318 (1): 103–109. doi: https://doi.org/10.1042/bj3180103
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