A nutrient-permeable channel on the intraerythrocytic malaria parasite

Desai, Sanjay A.; Krogstad, Donald J.; McCleskey, Edwin W.

doi:10.1038/362643a0

Cited by 208 publications

(142 citation statements)

References 26 publications

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“…Having entered the erythrocyte cytosol, the nucleosides are presumed to traverse the parasitophorous vacuole membrane enclosing the intracellular parasite via largediameter, non-selective pores that render this membrane freely permeable to low-molecular-weight solutes (Desai et al ., 1993). This brings them into the parasitophorous vacuole, from where they are taken up by the parasite.…”

Section: Introductionmentioning

confidence: 99%

Transport of nucleosides across the Plasmodium falciparum parasite plasma membrane has characteristics of PfENT1

Downie¹,

Saliba

Howitt³

et al. 2006

Molecular Microbiology

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SummaryLike all parasitic protozoa, the human malaria parasite Plasmodium falciparum lacks the enzymes required for de novo synthesis of purines and it is therefore reliant upon the salvage of these compounds from the external environment. P. falciparum equilibrative nucleoside transporter 1 (PfENT1) is a nucleoside transporter that has been localized to the plasma membrane of the intraerythrocytic form of the parasite. In this study we have characterized the transport of purine and pyrimidine nucleosides across the plasma membrane of 'isolated' trophozoite-stage P. falciparum parasites and compared the transport characteristics of the parasite with those of PfENT1 expressed in Xenopus oocytes. The transport of nucleosides into the parasite: (i) was, in the case of adenosine, inosine and thymidine, very fast, equilibrating within a few seconds; (ii) was of low affinity [ K m (adenosine) = 1.45 ± 0.25 mM; K m (thymidine) = 1.11 ± 0.09 mM]; and (iii) showed 'crosscompetition' for adenosine, inosine and thymidine, but not cytidine. The kinetic characteristics of nucleoside transport in intact parasites matched very closely those of PfENT1 expressed in Xenopus oocytes [ K m (adenosine) = 1.86 ± 0.28 mM; K m (thymidine) = 1.33 ± 0.17 mM]. Furthermore, PfENT1 transported adenosine, inosine and thymidine, with a cross-competition profile the same as that seen for isolated parasites. The data are consistent with PfENT1 serving as a major route for the uptake of nucleosides across the parasite plasma membrane.

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Section: Introductionmentioning

confidence: 99%

Transport of nucleosides across the Plasmodium falciparum parasite plasma membrane has characteristics of PfENT1

Downie¹,

Saliba

Howitt³

et al. 2006

Molecular Microbiology

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“…Estudios previos con esta técnica en eritrocitos infectados con Plasmodium falciparum (24), registran una conductancia a aniones, aunque no queda claro si los registros se obtuvieron de la membrana del eritrocito o de la vacuola parasitófora que contiene Plasmodium. A pesar de esto, existe evidencia que argumenta a favor de cambios en la permeabilidad del eritrocito por modificación de canales iónicos constitutivos de su membrana (25,26) y por expresión de transportadores de origen parasitario (26,27).…”

Section: Discussionunclassified

“…Sin embargo, la expresión de porinas puede ser un mecanismo de entrada de iones y nutrientes a través de la membrana de la vacuola parasitófora como se ha sugerido para otros parásitos (22,24), parte del proceso de salida del parásito (32) o servir en la exclusión de péptidos del parásito limitando así presentación de antígeno.…”

Section: Discussionunclassified

Papel de la vacuola parasitófora de macrófagos de ratón infectados por Leishmania amazonensis en la adquisición de moléculas

et al. 2012

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Introducción. Leishmania son parásitos intracelulares de macrófagos, confinados en compartimentos denominados vacuolas parasitóforas. La permeabilidad de este compartimento depende de su interacción con el tráfico vesicular y transportadores presentes en su membrana. Objetivo. En este trabajo se estudió la permeabilidad de la membrana de la vacuola parasitófora en la línea celular J774.A1 infectada con Leishmania amazonensis, in situ y en compartimentos aislados. Materiales y métodos. El aislamiento de vacuolas parasitóforas se hizo por gradiente de densidad. La permeabilidad de la membrana de estas se valoró por distribución de sondas fluorescentes y electrofisiología. Para establecer indirectamente el transporte de protones se usó naranja de acridina. La presencia de transportadores ABC sensibles a probenecid se estableció con amarillo lucifer y calceína. Por primera vez con la técnica de patch-clamp se registraron corrientes en la membrana de este compartimento aislado. Resultados. La vacuola parasitófora colorea de rojo con naranja de acridina indicando un pH ácido. Concentra amarillo lucifer a través de un transportador sensible a probenecid, pero excluye la sonda calceína. Vacuolas aisladas se marcan de rojo con naranja de acridina y concentran amarillo lucifer a través de un transportador sensible a probenecid. Estas vacuolas excluyeron calceína y presentaron en su membrana una corriente iónica que se activa a diferencias de potencial cercanas a 60 mV, con una conductancia de 46 ± 3 pS. Conclusiones. Se pueden aislar vacuolas parasitóforas con propiedades de permeabilidad que preservan mecanismos de transporte similares a los encontrados in situ. Se registra por primera vez la presencia de una corriente iónica poco selectiva en la membrana de este compartimiento.Palabras clave: Leishmania, membranas intracelulares, permeabilidad, proteínas de transporte de anión, transporte iónico, canales iónicos. Role of the parasitophorous vacuole of murine macrophages infected with Leishmania amazonensis in molecule acquisitionIntroduction. Leishmania are intracellular parasites of macrophages, confined into compartments known as parasitophorous vacuoles. The permeability of this compartment depends on its interaction with the endocytic pathway and transport proteins present on its membrane. Objective. The membrane permeability of the parasitophorous vacuole was studied in J774.A1-macrophage like cells infected with Leishmania amazonensis, in situ and on isolated compartments. Materials and methods. The parasitophorous vacuoles were isolated by density gradients. Fluorescent probe distribution and electrophysiological recordings were used to determine parasitophorous vacuole membrane permeability. Proton transport was evaluated indirectly by acridine orange staining. Probenecid sensitive ABC transporters were detected using the fluorescent probes lucifer yellow and calcein. For the first time ion currents were recorded on the membrane of isolated parasitophorous vacuoles using the patch clamp technique.

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“…Desai and co-wokers [2] suggested approximate 11Å diameter of 'pore', by which some molecules similar size to glucose could pass through, was existed in IRBC plasma membrane. Moreover, in Plasmodium spp.…”

Section: Discussionmentioning

confidence: 99%

Glucose Uptake Activity in Murine Red Blood Cells Infected with Babesia microti and Babesia rodhaini

Ohmori

Adachi

Fukuda

et al. 2004

The Journal of Veterinary Medical Science

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ABSTRACT. The glucose uptake activity in Babesia rodhaini and B. microti -infected red blood cell (IRBC) was investigated in mice using 2-deoxy-D-glucose (2DOG) and L-glucose (L-Glc), a non-metabolizable analogue of D-glucose and non-incorporative glucose to noninfected RBC (NRBC), respectively. The uptake activities of both DOG and L-Glc were higher in IRBCs than those in NRBC. The concentration dependent uptake of 2DOG and L-Glc in both IRBC revealed a linear curve, indicating non-transporter mediated uptake. In addition, B. microti IRBC showed higher 2DOG uptake than B. rodhaini IRBC, whereas no difference was observed in L-Glc uptake. These results indicated that some new glucose uptake system, at least two systems, developed in both IRBC. The new systems were sodium independent, non-competitive to L-Glc, and sensitive to temperature. Babesia rodhaini and B. microti, the major causative protozoa of babesiosis in mice, are classified into the same genus and appear morphologically quite similar each other. However, various differences have been observed between them, particularly on their glucose metabolism. Babesia microti shows high activity of tricarboxylic acid (TCA) cycle enzymes, suggesting to utilize mainly aerobic pathway, whereas B. rodhaini to utilize anaerobic pathway for glucose metabolism [16,17]. Our previous report also demonstrated that mitochondorial function in B. microti was higher than that in B. rodhaini [18].It has been well known that intracellular protozoa Babesia species depend on their substrates of glucose metabolism for the host cell [10,13]. Since mature red blood cell has limited capabilities of these substances synthesis, almost all of them are transported from extracellular fluid. The glucose uptake into infected red blood cell (IRBC) is the most important factor for the glucose metabolism in Babesia protozoa.In this regard, glucose uptake activity was investigated in B. rodhaini and B. microti IRBC using 2-deoxy-D-glucose (2DOG) and L-glucose (L-Glc), those of which are nonmetabolizable analogue of D-glucose and non-incorporative glucose to non-infected red blood cell (NRBC), respectively. Preparation of Babesia IRBCs: Male ICR (6-8 wk old) mice were purchased from SLC Inc. (Shizuoka, Japan). Mice were injected once intraperitoneally with B. rodhaini or B. microti infected whole blood (approximate 1 × 10 4 IRBC/head). Both IRBC were collected from the mice at the high parasitemia stage (approximate 50-60%) by cardiac puncture, and NRBC were collected as a control. Red blood cells (RBC) were diluted in HEPES balanced solution (HBS:145 mM NaCl, 10 mM KCl, 1 mM MgSO 4 , 10 mM HEPES, pH 7.2), and washed (1,200 g, at 4°C, for 5 min) twice and passed through a cellulose column to remove white blood cells [12]. Eluted RBC was washed twice with HBS and diluted to adjust the percent cell volume at 25%. The cell number of adjusted IRBC and NRBC were counted with an hemocytometer. MATERIALS AND METHODS ReagentsGlucose uptake: The uptake of glucose in IRBC and NRBC were measured at 37°C us...

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A nutrient-permeable channel on the intraerythrocytic malaria parasite

Cited by 208 publications

References 26 publications

Transport of nucleosides across the Plasmodium falciparum parasite plasma membrane has characteristics of PfENT1

Transport of nucleosides across the Plasmodium falciparum parasite plasma membrane has characteristics of PfENT1

Papel de la vacuola parasitófora de macrófagos de ratón infectados por Leishmania amazonensis en la adquisición de moléculas

Glucose Uptake Activity in Murine Red Blood Cells Infected with Babesia microti and Babesia rodhaini

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