scholarly journals Andrographolide effect on both Plasmodium falciparum infected and non infected RBCs membranes

2015 ◽  
Vol 8 (7) ◽  
pp. 507-512 ◽  
Author(s):  
O.I. Zaid ◽  
R. Abd Majid ◽  
M.N. Sabariah ◽  
M.S. Hasidah ◽  
K. Al-Zihiry ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Infected Rbcs

scholarly journals Increased nicotinamide adenine dinucleotide content and synthesis in Plasmodium falciparum-infected human erythrocytes

Blood ◽  
1990 ◽  
Vol 75 (8) ◽  
pp. 1705-1710 ◽  
Author(s):  
CR Zerez ◽  
EF Jr Roth ◽  
S Schulman ◽  
KR Tanaka
Keyword(s):  
Plasmodium Falciparum ◽  
Nicotinic Acid ◽  
Nicotinamide Adenine Dinucleotide ◽  
Biosynthetic Pathway ◽  
Pentose Phosphate ◽  
Nicotinamide Adenine ◽  
Nicotinamide Phosphoribosyltransferase ◽  
Nad Synthesis ◽  
Infected Rbcs ◽  
Nicotinic Acid Phosphoribosyltransferase

Abstract Plasmodium falciparum-infected red blood cells (RBCs) are characterized by increases in the activity of glycolytic enzymes. Because nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP) are cofactors in the reactions of glycolysis and pentose phosphate shunt, we have examined NAD and NADP content in P. falciparum-infected RBCs. Although NADP content was not significantly altered, NAD content was increased approximately 10-fold in infected RBCs (66% parasitemia) compared with uninfected control RBCs. To determine the mechanism for the increase in NAD content, we examined the activity of several NAD biosynthetic enzymes. It is known that normal human RBCs make NAD exclusively from nicotinic acid and lack the capacity to make NAD from nicotinamide. We demonstrate that infected RBCs have readily detectable nicotinamide phosphoribosyltransferase (NPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinamide, and abundant nicotinamide deamidase, the enzyme that converts nicotinamide to nicotinic acid, thereby indicating that infected RBCs can make NAD from nicotinamide. In addition, infected RBCs have a threefold increase in nicotinic acid phosphoribosyltransferase (NAPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinic acid. Thus, the increase in NAD content in P falciparum-infected RBCs appears to be mediated by increases in NAD synthesis from both nicotinic acid and nicotinamide.

scholarly journals The Association of High Prevalence of Trophozoites in Peripheral Blood with Lower Antibody Response toP. falciparumInfected Erythrocytes among Asymptomatic Children in Sudan

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Sara N. Mohamed ◽  
Dina A. Hassan ◽  
Abdelrahim M. El Hussein ◽  
Ihssan M. Osman ◽  
Muntasir E. Ibrahim ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Peripheral Blood ◽  
Surface Antigens ◽  
Igg Antibodies ◽  
Autologous Plasma ◽  
Variant Surface Antigens ◽  
Asymptomatic Children ◽  
Infected Rbcs ◽  
The Mean

Background. The most prominent variant surface antigens (VSAs) ofPlasmodium falciparumare the var gene-encodedPlasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) family, which serves as a parasite-sequestering ligand to endothelial cells. In this study we have examined the antibody reactivity of autologous plasma from symptomatic and asymptomatic malaria infected children against the infected erythrocytes’ surface antigens using flow cytometry.Methods. Ethidium-bromide-labelled erythrocytic mature forms ofP. falciparumparasites obtained from symptomatic and asymptomatic children were sequentially incubated with autologous plasma and fluorescein isothiocyanate-conjugated (FITC) antihuman IgG. Plasma antibody reactivity was detected by flow cytometry.Results. Asymptomatic children had more prevalence of trophozoites in peripheral blood (66%) compared to symptomatic children (16%),p=0.002. The mean percentage of infected RBCs reacting with autologous sera was 89.78 among symptomatic children compared to 79.62 among asymptomatic children (p=0.09). Moreover, the mean fluorescence intensity (MFI) in the asymptomatic was significantly higher compared to symptomatic children (pvalue = 0.040).Conclusion. Variant surface antigens onPlasmodium falciparuminfected RBCs from symptomatic malaria children tend to be better recognized by IgG antibodies. This may suggest a role of some IgG antibodies in severity of malaria.

scholarly journals Resistance to Plasmodium falciparum in sickle cell trait erythrocytes is driven by oxygen-dependent growth inhibition

2018 ◽  
Vol 115 (28) ◽  
pp. 7350-7355 ◽  
Author(s):  
Natasha M. Archer ◽  
Nicole Petersen ◽  
Martha A. Clark ◽  
Caroline O. Buckee ◽  
Lauren M. Childs ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Sickle Cell ◽  
Sickle Cell Trait ◽  
Low Oxygen ◽  
Partial Protection ◽  
Infected Rbcs ◽  
Specific Stage ◽  
Mechanistic Basis ◽  
Dependent Growth

Sickle cell trait (AS) confers partial protection against lethal Plasmodium falciparum malaria. Multiple mechanisms for this have been proposed, with a recent focus on aberrant cytoadherence of parasite-infected red blood cells (RBCs). Here we investigate the mechanistic basis of AS protection through detailed temporal mapping. We find that parasites in AS RBCs maintained at low oxygen concentrations stall at a specific stage in the middle of intracellular growth before DNA replication. We demonstrate that polymerization of sickle hemoglobin (HbS) is responsible for this growth arrest of intraerythrocytic P. falciparum parasites, with normal hemoglobin digestion and growth restored in the presence of carbon monoxide, a gaseous antisickling agent. Modeling of growth inhibition and sequestration revealed that HbS polymerization-induced growth inhibition following cytoadherence is the critical driver of the reduced parasite densities observed in malaria infections of individuals with AS. We conclude that the protective effect of AS derives largely from effective sequestration of infected RBCs into the hypoxic microcirculation.

scholarly journals The Lipid Moiety of Haemozoin (Malaria Pigment) andP. falciparumParasitised Red Blood Cells Bind Synthetic and Native Endothelin-1

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Nicoletta Basilico ◽  
Silvia Parapini ◽  
Francesca Sisto ◽  
Fausta Omodeo-Salè ◽  
Paolo Coghi ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Vascular Endothelium ◽  
Blood Cells ◽  
Vascular Tone ◽  
Amino Acid Peptide ◽  
Lipid Moiety ◽  
Infected Rbcs ◽  
Malaria Pigment ◽  
Dose Dependent

Endothelin1 (ET-1) is a 21-amino acid peptide produced by the vascular endothelium under hypoxia, that acts locally as regulator of vascular tone and inflammation. The role of ET-1 inPlasmodium falciparummalaria is unknown, although tissue hypoxia is frequent as a result of the cytoadherence of parasitized red blood cell (pRBC) to the microvasculature. Here, we show that both synthetic and endothelial-derived ET-1 are removed by parasitized RBC (D10 and W2 strains, chloroquine sensitive, and resistant, resp.) and native haemozoin (HZ, malaria pigment), but not by normal RBC, delipidized HZ, or synthetic beta-haematin (BH). The effect is dose dependent, selective for ET-1, but not for its precursor, big ET-1, and not due to the proteolysis of ET-1. The results indicate that ET-1 binds to the lipids moiety of HZ and membranes of infected RBCs. These findings may help understanding the consequences of parasite sequestration in severe malaria.

scholarly journals Plasmodium falciparum-infected erythrocyte receptor(s) for CD36 and thrombospondin are restricted to knobs on the erythrocyte surface.

1992 ◽  
Vol 40 (9) ◽  
pp. 1419-1422 ◽  
Author(s):  
K Nakamura ◽  
T Hasler ◽  
K Morehead ◽  
R J Howard ◽  
M Aikawa
Keyword(s):  
Endothelial Cells ◽  
Plasmodium Falciparum ◽  
Cerebral Malaria ◽  
Vascular Occlusion ◽  
Cerebral Microvessels ◽  
Erythrocyte Surface ◽  
Infected Rbcs ◽  
First Time

Adherence of Plasmodium falciparum-infected RBCs (PRBC) to endothelial cells causes PRBC sequestration in cerebral microvessels and is considered to be a major contributor to the pathogenesis of cerebral malaria. Both CD36 and thrombospondin (TSP) are glycoproteins that mediate PRBC adherence to endothelial cells in vitro. Because they are both expressed on the surface of endothelial cells, they probably contribute to PRBC sequestration and vascular occlusion in vivo. By applying affinity labeling of receptor binding sites with purified ligands, we showed for the first time that both CD36 and TSP can bind independently to the PRBC surface and that the PRBC receptor(s) for CD36 and TSP are localized specifically to the electron-dense knob protrusions of the PRBC surface. These findings may help in efforts to develop a malaria vaccine to prevent cerebral malaria.

scholarly journals Carrier-Mediated Partitioning of Artemisinin into Plasmodium falciparum-Infected Erythrocytes

2002 ◽  
Vol 46 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Nehal Vyas ◽  
Bonnie A. Avery ◽  
Mitchell A. Avery ◽  
Christy M. Wyandt
Keyword(s):  
Plasmodium Falciparum ◽  
Drug Concentration ◽  
Blood Cells ◽  
Competitive Inhibition ◽  
Temperature Dependent ◽  
Optimum Time ◽  
Rbc Membrane ◽  
Drug Concentrations ◽  
Infected Rbcs ◽  
Time Periods

ABSTRACT The purpose of the present study was to characterize the partitioning of artemisinin into both uninfected and Plasmodium falciparum-infected red blood cells (RBCs). The partitioning of [14C](+)-artemisinin into RBCs was studied at four different hematocrit levels and eight time periods. At the optimum time of 2 h, the partitioning process was investigated with eight different drug concentrations ranging from 0.88 to 3.52 μM at 37 and 4°C. The effect of the presence of unlabeled artemisinin on the partitioning of the same concentration of [14C]artemisinin was studied. About 35 to 40% of the drug was seen to partition into uninfected RBCs at a hematocrit of 33%, irrespective of the incubation period or the drug concentration used. In contrast, infected RBCs showed an increase in partitioning of the drug with time until saturation was achieved at 1 h. While the partitioning of artemisinin into parasitized RBCs at 37°C was found to be significantly higher than that in nonparasitized RBCs, at 4°C both parasitized and nonparasitized RBCs showed identical partitioning of the drug. The partitioning of [14C]artemisinin into parasitized RBCs was completely inhibited in the presence of the same concentration of unlabeled artemisinin. However, no such effect was observed in nonparasitized cells, and no evidence suggesting that binding of the drug in parasitized RBCs is reversible was found. The partitioning of artemisinin into parasitized RBCs was found to be rapid, saturable, temperature dependent, irreversible, and subject to competitive inhibition with unlabeled artemisinin. The results obtained suggest the involvement of carrier mediation in the partitioning of artemisinin across the parasitized RBC membrane. In contrast, simple passive diffusion of artemisinin was seen in nonparasitized RBCs.

scholarly journals Plasmodium falciparum-infected red blood cells depend on a functional glutathione de novo synthesis attributable to an enhanced loss of glutathione

2000 ◽  
Vol 346 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Kai LÜERSEN ◽  
Rolf D. WALTER ◽  
Sylke MÜLLER
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
De Novo ◽  
Specific Inhibitor ◽  
De Novo Synthesis ◽  
Glutamylcysteine Synthetase ◽  
Infected Rbcs ◽  
Erythrocytic Cycle ◽  
Gsh Metabolism

During the erythrocytic cycle, Plasmodium falciparum is highly dependent on an adequate thiol status for its survival. Glutathione reductase as well as de novo synthesis of GSH are responsible for the maintenance of the intracellular GSH level. The first and rate-limiting step of the synthetic pathway is catalysed by γ-glutamylcysteine synthetase (γ-GCS). Using L-buthionine-(S,R)-sulphoximine (BSO), a specific inhibitor of the γ-GCS, we show that the infection with P. falciparum causes drastic changes in the GSH metabolism of red blood cells (RBCs). Infected RBCs lose GSH at a rate 40-fold higher than non-infected RBCs. The de novo synthesis of the tripeptide was found to be essential for parasite survival. GSH depletion by BSO inhibits the development of P. falciparum with an IC50 of 73 μM. The effect of the drug is abolished by supplementation with GSH or GSH monoethyl ester. Our studies demonstrate that the plasmodicidal effect of the inhibitor BSO does not depend on its specificity towards its target enzyme in the parasite, but on the changed physiological needs for the metabolite GSH in the P. falciparum-infected RBCs. Therefore the depletion of GSH is proposed as a chemotherapeutic strategy for malaria, and γ-GCS is proposed as a potential drug target.

scholarly journals Heparan sulphate identified on human erythrocytes: a Plasmodium falciparum receptor

2004 ◽  
Vol 381 (3) ◽  
pp. 593-597 ◽  
Author(s):  
Anna M. VOGT ◽  
Gerhard WINTER ◽  
Mats WAHLGREN ◽  
Dorothe SPILLMANN
Keyword(s):  
Plasmodium Falciparum ◽  
Core Protein ◽  
Heparan Sulphate ◽  
Malarial Parasite ◽  
Human Red Blood Cells ◽  
Parasite Plasmodium ◽  
Parasite Plasmodium Falciparum ◽  
Infected Rbcs ◽  
Malaria Antigen ◽  
Human Rbcs

HS (heparan sulphate) has hitherto not been found on human red blood cells (RBCs, erythrocytes). However, malarial-parasite (Plasmodium falciparum)-infected RBCs adhere to uninfected RBCs via HS-like receptors. In the present paper we demonstrate that human RBCs carry epitopes for an anti-HS antibody. Glycans isolated from RBC membranes reacted to HS-specific degradations and adhered to an HS-binding malaria antigen. Additionally, an HS core protein was identified. This suggests that HS is present on human RBCs.

scholarly journals Stage-Dependent Topographical and Optical Properties of Plasmodium Falciparum-Infected Red Blood Cells

2021 ◽  
Author(s):  
Katharina Preißinger ◽  
Beáta Vértessy ◽  
István Kézsmárki ◽  
Miklós Kellermayer ◽  
Petra Molnár
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Imaging Study ◽  
Close Correlation ◽  
Functional Changes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Infected Rbcs ◽  
Bright Field Microscopy

Abstract Efficient malaria treatment is a major healthcare challenge. Addressing this challenge requires in-depth understanding of malaria parasite maturation during the intraerythrocytic cycle. Exploring the structural and functional changes of the parasite through the intraerythrocytic stages and their impact on red blood cells (RBCs) is a cornerstone of antimalarial drug development. In order to precisely trace such changes, we performed a thorough imaging study of RBCs infected by Plasmodium falciparum, by using atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRF) supplemented with bright field microscopy for stage assignment. This multifaceted imaging approach allows to reveal structure–function relations via correlations of the parasite maturation with morphological and fluorescence properties of the stages. We established diagnostic patterns characteristic to the parasite stages based on the topographical profile of infected RBCs, which show close correlation with their fluorescence (TIRF) map. Furthermore, we found that hemozoin crystals exhibit a strong optical contrast, possibly due to the quenching of fluorescence. The topographical and optical features provide a tool for locating the hemozoin crystals within the RBCs and following their growth.

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