Abstract
The calcium content and transport processes of Plasmodium chabaudi- infected rat erythrocytes were analyzed by atomic absorption spectroscopy and 45Ca2+ flux measurements. Infected erythrocytes, after fractionation on metrizamide gradients according to stage of parasite development, exhibited progressively increasing levels of Ca2+ with schizont and gametocytes containing 10- to 20-fold greater calcium levels than normal cells (0.54 +/- 0.25 nmol/10(8) cells). 45Ca2+ flux experiments showed both increased influx and decreased efflux in infected erythrocytes. Tris/NH4Cl lysis of normal erythrocytes preloaded with 45Ca2+ with the Ca2+ ionophore A23187 released less than 90% of cell calcium after incubation in ethyleneglycol bis(aminoethylether) N,N'-tetraacetic acid containing buffer, whereas lysis of the infected erythrocyte membrane resulted in release of 10- 20% cell Ca2+, with the remaining portion associated with the isolated parasite fraction. This information together with the effects of various metabolic inhibitors indicates the presence of a parasite Ca2+ compartment in P. chabaudi-infected erythrocytes. Dicyclohexylcarbodiimide (DCCD) an inhibitor of proton ATPases of chloroplasts, bacteria, yeast, and mitochondria, and the proton ionophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP), inhibited Ca2+ influx and stimulated efflux from infected cells. These results combined with evidence for a DCCD- and CCCP-sensitive membrane potential in P. chabaudi-infected cells (Mikkelsen et al., accompanying manuscript) suggest that Ca2+ transport of intraerythrocytic parasites is coupled to a proton-motive force across the Plasmodia plasma membrane.
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- Anderson D. R., Davis J. L., Carraway K. L. Calcium-promoted changes of the human erythrocyte membrane. Involvement of spectrin, transglutaminase, and a membrane-bound protease. J Biol Chem. 1977 Oct 10;252(19):6617–6623. [PubMed] [Google Scholar]
- Bygrave F. L. Mitochondria and the control of intracellular calcium. Biol Rev Camb Philos Soc. 1978 Feb;53(1):43–79. doi: 10.1111/j.1469-185x.1978.tb00992.x. [DOI] [PubMed] [Google Scholar]
- Dufour J. P., Boutry M., Goffeau A. Plasma membrane ATPase of yeast. Comparative inhibition studies of the purified and membrane-bound enzymes. J Biol Chem. 1980 Jun 25;255(12):5735–5741. [PubMed] [Google Scholar]
- Dunn M. J. Alterations of red blood cell sodium transport during malarial infection. J Clin Invest. 1969 Apr;48(4):674–684. doi: 10.1172/JCI106025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eugui E. M., Allison A. C. Separation of erythrocytes infected with murine malaria parasites in metrizamide gradients. Parasitology. 1979 Oct;79(2):267–275. doi: 10.1017/s0031182000053348. [DOI] [PubMed] [Google Scholar]
- Kozlov I. A., Skulachev V. P. H+-Adenosine triphosphatase and membrane energy coupling. Biochim Biophys Acta. 1977 Jun 21;463(1):29–89. doi: 10.1016/0304-4173(77)90003-9. [DOI] [PubMed] [Google Scholar]
- Martin W. J., Finerty J., Rosenthal A. Isolation of Plasmodium berghei (malaria) parasites by ammonium chloride lysis of infected erythrocytes. Nat New Biol. 1971 Oct 27;233(43):260–261. doi: 10.1038/newbio233260a0. [DOI] [PubMed] [Google Scholar]
- Mikkelsen R. B., Koch B. Thermosensitivity of the membrane potential of normal and simian virus 40-transformed hamster lymphocytes. Cancer Res. 1981 Jan;41(1):209–215. [PubMed] [Google Scholar]
- Richards W. H., Williams S. G. The removal of leucocytes from malaria infected blood. Ann Trop Med Parasitol. 1973 Jun;67(2):249–250. doi: 10.1080/00034983.1973.11686885. [DOI] [PubMed] [Google Scholar]
- Sarkadi B., Szász I., Gerlóczy A., Gárdos G. Transport parameters and stoichiometry of active calcium ion extrusion in intact human red cells. Biochim Biophys Acta. 1977 Jan 4;464(1):93–107. doi: 10.1016/0005-2736(77)90373-x. [DOI] [PubMed] [Google Scholar]
- Sarkadi B., Szász I., Gárdos G. The use of ionophores of rapid loading of human red cells with radioactive cations for cation-pump studies. J Membr Biol. 1976 May;26(4):357–370. doi: 10.1007/BF01868883. [DOI] [PubMed] [Google Scholar]
- Seeman P. The membrane actions of anesthetics and tranquilizers. Pharmacol Rev. 1972 Dec;24(4):583–655. [PubMed] [Google Scholar]
- Sherman I. W. Biochemistry of Plasmodium (malarial parasites). Microbiol Rev. 1979 Dec;43(4):453–495. doi: 10.1128/mr.43.4.453-495.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shoshan V., Selman B. R. The interaction of N,N'-dicyclohexylcarbodiimide with chloroplast coupling factor 1. J Biol Chem. 1980 Jan 25;255(2):384–389. [PubMed] [Google Scholar]
- Stroobant P., Dame J. B., Scarborough G. A. The Neurospora plasma membrane Ca2+ pump. Fed Proc. 1980 May 15;39(7):2437–2441. [PubMed] [Google Scholar]