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Titolo:
Functional state of the plasma membrane Ca2+ pump in Plasmodium falciparum-infected human red blood cells
Autore:
Tiffert, T; Staines, HM; Ellory, JC; Lew, VL;
Indirizzi:
Univ Cambridge, Physiol Lab, Cambridge CB2 3EG, England Univ Cambridge Cambridge England CB2 3EG Lab, Cambridge CB2 3EG, England Univ Oxford, Univ Lab Physiol, Oxford OX1 3PT, England Univ Oxford Oxford England OX1 3PT Lab Physiol, Oxford OX1 3PT, England
Titolo Testata:
JOURNAL OF PHYSIOLOGY-LONDON
fascicolo: 1, volume: 525, anno: 2000,
pagine: 125 - 134
SICI:
0022-3751(20000515)525:1<125:FSOTPM>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN-ERYTHROCYTES; CALCIUM-PUMP; INTRACELLULAR CALCIUM; CONTINUOUS CULTURE; MALARIA PARASITES; K+ TRANSPORT; PERMEABILITY; INHIBITION; POTASSIUM; CHANNEL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Tiffert, T Univ Cambridge, Physiol Lab, Downing St, Cambridge CB2 3EG, England Univ Cambridge Downing St Cambridge England CB2 3EG G, England
Citazione:
T. Tiffert et al., "Functional state of the plasma membrane Ca2+ pump in Plasmodium falciparum-infected human red blood cells", J PHYSL LON, 525(1), 2000, pp. 125-134

Abstract

1. The active Ca2+ transport properties of malaria-infected, intact red blood cells are unknown. We report here the first direct measurements of Ca2pump activity in human red cells infected with Plasmodium falciparum, at the mature, late trophozoite stage.2. Ca2+ pump activity was measured by the Co2+-exposure method adapted foruse in low-K+ media, optimal for parasitised cells. This required a preliminary study in normal, uninfected red cells of the effects of cell volume, membrane potential and external Na+/K+ concentrations on Ca2+ pump performance.3. Pump-mediated Ca2+ extrusion in normal red cells was only slightly lower in low-K+ media relative to high-K+ media despite the large differences in membrane potential predicted by the Lew-Bookchin red cell model. The effect was prevented by clotrimazole, an inhibitor of the Ca2+-sensitive K+ (K-Ca) channel, suggesting that it was due to minor cell dehydration.4. The Ca2+-saturated Ca2+ extrusion rate through the Ca2+ pump (V-max) ofparasitised red cells was marginally inhibited (2-27%) relative to that ofboth uninfected red cells from the malaria-infected culture (cohorts), anduninfected red cells from the same donor kept under identical conditions (co-culture). Thus, Ca2+ pump function is largely conserved in parasitised cells up to the mature, late trophozoite stage.5. A high load in parasitised red cells is taken up by A high proportion of the ionaphore-induced Ca2+ load in parasitised red cells is taken up by cytoplasmic Ca2+ buffers within the parasite. Following pump-mediated Ca2+ removal from the host, there remained a large residual Ca2+ pool within the parasite which slowly leaked to the host cell, from which it was pumped out.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 11:34:09