Rb transport in Leishmania infantum promastigotes under various in vitro culture conditions |
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Authors: | I Suffia H Schmid-Antomarchi J Kubar |
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Institution: | a Groupe de Recherche en Immunopathologie de la Leishmaniose, Laboratoire de Parasitologie, Faculté de Médecine, Avenue de Valombrose, 06107, Nice Cedex 2, France b INSERM U364, Faculté de Médecine, Avenue de Valombrose, 06107, Nice Cedex 2, France |
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Abstract: | The survival of Leishmania, which encounter drastic changes of environment during their life-cycle, requires regulation and control of ionic concentrations within the cell. We analysed the influence of growth stage, ionic composition of the medium, heat and acidic stress on 86Rb+ influx in L. infantum promastigetes. Proliferating promastigotes exibited faster and higher 86Rb+ uptake than stationary cells. Cl? anion did not have any effect, but in the presence of physiological concentration of HCO3?, 86Rb+ uptake was significantly increased. This enhancing effect was only partially inhibited by N,N′-dicyclohexylcarbodiimide (DCCD), a blocker of ion-translocating ATPases. 86Rb+ influx was abolished by N-ethylmaleimide (NEM), indicating a major contribution of plasma membrane transporters. Heat shock and acidic shock notably decreased 86Rb+ influx. Our data provide indirect evidence that an energy-dependent system which brings K+ in, such as K+/H+-ATPase evidenced by Jiang et al. (1994), is active in Leishmania in different environments. Mechanism(s) other than ion-translocating ATPase occur, at least in the presence of HCO3?, and their contribution to K+ pathways varies in different environmental conditions. |
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Keywords: | Author Keywords: Leishmania infantum promastigote 86Rb+ influx K+ pathways K+/H+-ATPase heat shock acidic shock |
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