scholarly journals Pathways for the reduction of oxidized glutathione in the Plasmodium falciparum-infected erythrocyte: can parasite enzymes replace host red cell glucose-6-phosphate dehydrogenase?

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 827-830 ◽  
Author(s):  
EF Jr Roth ◽  
S Schulman ◽  
J Vanderberg ◽  
J Olson
Keyword(s):  
Plasmodium Falciparum ◽  
Oxidant Stress ◽  
Reduction Rate ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Red Cells ◽  
Host Cells ◽  
Functional Assay ◽  
Red Cell ◽  
Oxidized Glutathione ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Plasmodium falciparum-infected human red cells possess at least two pathways for the generation of reduced nicotinamide adenine dinucleotide phosphate (NADPH): (1) the glucose-6-phosphate dehydrogenase (G6PD) pathway and (2) the glutamate dehydrogenase (GD) pathway using glutamate as a substrate. Uninfected erythrocytes lack the GD pathway. The NADPH generated can be used to reduce oxidized glutathione (GSSG), which accumulates in the presence of an oxidative stress. In red cell G6PD deficiency, this pathway is reduced or absent, and the host cells as well as the parasites within them are vulnerable to oxidant stress. In view of the presence of the GD pathway in parasitized red cells and the recent description of a parasite-derived G6PD enzyme, we have asked whether the pathways for the reduction of GSSG provided by the parasite can substitute for the host G6PD in red cells deficient in G6PD activity. We have devised a functional assay in which the reduction rate of GSSG is monitored in the presence of buffered infected or control red cell lysates and substrates. Infected G6PD-deficient erythrocytes were obtained from in vitro cultures after a single prior growth cycle of the parasites in G6PD deficient cells to eliminate contaminating normal red cells. The results show that only parasitized red cells can reduce GSSG via the GD pathway. In parasitized G6PD Mediterranean red cells (completely G6PD-deficient), there is a detectable GSSG reduction via the G6PD pathway, not found in uninfected lysates from the same individual. In G6PD A- (African type, featuring partial deficiency), a small increment in the G6PD-dependent reduction of GSSG can also be detected. However, when compared to G6PD normal red cells, the activities from the parasite-derived pathways are small and could not be considered substitutes for normal host enzyme activity. It is concluded that while the plasmodium provides additional pathways for the generation of NADPH that may serve its own metabolic needs, the host red cells and hence the parasite itself remain vulnerable to oxidant stress.

scholarly journals Pathways for the reduction of oxidized glutathione in the Plasmodium falciparum-infected erythrocyte: can parasite enzymes replace host red cell glucose-6-phosphate dehydrogenase?

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 827-830
Author(s):  
EF Jr Roth ◽  
S Schulman ◽  
J Vanderberg ◽  
J Olson
Keyword(s):  
Plasmodium Falciparum ◽  
Oxidant Stress ◽  
Reduction Rate ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Red Cells ◽  
Host Cells ◽  
Functional Assay ◽  
Red Cell ◽  
Oxidized Glutathione ◽  
Glucose 6 Phosphate Dehydrogenase

Plasmodium falciparum-infected human red cells possess at least two pathways for the generation of reduced nicotinamide adenine dinucleotide phosphate (NADPH): (1) the glucose-6-phosphate dehydrogenase (G6PD) pathway and (2) the glutamate dehydrogenase (GD) pathway using glutamate as a substrate. Uninfected erythrocytes lack the GD pathway. The NADPH generated can be used to reduce oxidized glutathione (GSSG), which accumulates in the presence of an oxidative stress. In red cell G6PD deficiency, this pathway is reduced or absent, and the host cells as well as the parasites within them are vulnerable to oxidant stress. In view of the presence of the GD pathway in parasitized red cells and the recent description of a parasite-derived G6PD enzyme, we have asked whether the pathways for the reduction of GSSG provided by the parasite can substitute for the host G6PD in red cells deficient in G6PD activity. We have devised a functional assay in which the reduction rate of GSSG is monitored in the presence of buffered infected or control red cell lysates and substrates. Infected G6PD-deficient erythrocytes were obtained from in vitro cultures after a single prior growth cycle of the parasites in G6PD deficient cells to eliminate contaminating normal red cells. The results show that only parasitized red cells can reduce GSSG via the GD pathway. In parasitized G6PD Mediterranean red cells (completely G6PD-deficient), there is a detectable GSSG reduction via the G6PD pathway, not found in uninfected lysates from the same individual. In G6PD A- (African type, featuring partial deficiency), a small increment in the G6PD-dependent reduction of GSSG can also be detected. However, when compared to G6PD normal red cells, the activities from the parasite-derived pathways are small and could not be considered substitutes for normal host enzyme activity. It is concluded that while the plasmodium provides additional pathways for the generation of NADPH that may serve its own metabolic needs, the host red cells and hence the parasite itself remain vulnerable to oxidant stress.

scholarly journals Altered plasma membrane phospholipid organization in Plasmodium falciparum-infected human erythrocytes

Blood ◽  
1987 ◽  
Vol 69 (2) ◽  
pp. 401-407
Author(s):  
RS Schwartz ◽  
JA Olson ◽  
C Raventos-Suarez ◽  
M Yee ◽  
RH Heath ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cell Membrane ◽  
Early Stage ◽  
Red Cells ◽  
Membrane Phospholipid ◽  
Cell Membrane Permeability ◽  
Parasite Development ◽  
Red Cell ◽  
Membrane Phospholipids ◽  
Red Cell Membrane

The intraerythrocytic development of the malaria parasite is accompanied by distinct morphological and biochemical changes in the host cell membrane, yet little is known about development-related alterations in the transbilayer organization of membrane phospholipids in parasitized cells. This question was examined in human red cells infected with Plasmodium falciparum. Normal red cells were infected with strain FCR3 or with clonal derivatives that either produce (K+) or do not produce (K-) knobby protuberances on the infected red cells. Parasitized cells were harvested at various stages of parasite development, and the bilayer orientation of red cell membrane phospholipids was determined chemically using 2,4,6-trinitrobenzene sulphonic acid (TNBS) or enzymatically using bee venom phospholipase A2 (PLA2) and sphingomyelinase C (SMC). We found that parasite development was accompanied by distinct alterations in the red cell membrane transbilayer distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Increases in the exoplasmic membrane leaflet exposure of PE and PS were larger in the late-stage parasitized cells than in the early-stage parasitized cells. Similar results were obtained for PE membrane distribution using either chemical (TNBS) or enzymatic (PLA2 plus SMC) methods, although changes in PS distribution were observed only with TNBS. Uninfected cohort cells derived from mixed populations of infected and uninfected cells exhibited normal patterns of membrane phospholipid organization. The observed alterations in P falciparum-infected red cell membrane phospholipid distribution, which is independent of the presence or absence of knobby protuberances, might be associated with the drastic changes in cell membrane permeability and susceptibility to early hemolysis observed in the late stages of parasite development.

scholarly journals The enzymes of the glycolytic pathway in erythrocytes infected with Plasmodium falciparum malaria parasites

Blood ◽  
1988 ◽  
Vol 72 (6) ◽  
pp. 1922-1925 ◽  
Author(s):  
EF Jr Roth ◽  
MC Calvin ◽  
I Max-Audit ◽  
J Rosa ◽  
R Rosa
Keyword(s):  
Plasmodium Falciparum ◽  
Enzyme Activity ◽  
Adenylate Kinase ◽  
Genetic Basis ◽  
Glucose Consumption ◽  
Fold Increase ◽  
Plasmodium Falciparum Malaria ◽  
Red Cells ◽  
Glycolytic Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Enzymes of the glycolytic pathway as well as some ancillary enzymes were studied in normal red cells parasitized with Plasmodium falciparum in culture at varying parasitemias as well as in isolated parasites. The levels of all enzymes except diphosphoglycerate mutase, glucose-6- phosphate dehydrogenase, and adenylate kinase were elevated. Extreme elevations of hexokinase, aldolase, enolase, pyruvate kinase, and adenosine deaminase concentrations were noted. In most cases, electrophoretically distinct bands of enzyme activity were also seen. These findings partly explain the previously noted 50- to 100-fold increase in glucose consumption of infected red cells and suggest that further knowledge of these parasite enzymes and their genetic basis may aid both in designing new chemotherapy and in understanding the evolution of these parasites.

scholarly journals Neutrophils mediate lipid peroxidation in human red cells

Blood ◽  
1984 ◽  
Vol 64 (5) ◽  
pp. 1079-1084 ◽  
Author(s):  
S Claster ◽  
DT Chiu ◽  
A Quintanilha ◽  
B Lubin
Keyword(s):  
Lipid Peroxidation ◽  
Red Cells ◽  
Red Cell ◽  
Normal Cells ◽  
Sickle Cells ◽  
Induce Lipid Peroxidation ◽  
Activated Neutrophils ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Human Red Cells

Abstract Activated neutrophils (ANs) are known to release reactive oxygen species that may cause oxidative damage to surrounding tissues. We determined if ANs could induce lipid peroxidation (LP) in human red cells and investigated the mechanism involved in this interaction. We studied neonatal glucose-6-phosphate dehydrogenase (G6PD) deficient, and sickle red cells, since each of these are known to be susceptible to oxidant injury. Neutrophils were isolated from whole blood and activated by incubation with opsonized zymosan. Mixtures of such neutrophils and red cells at a ratio of 1:100 were incubated for two hours at 37 degrees C, after which the malonyldialdehyde content in red cells was measured as an index of LP. All red cells underwent LP after AN treatment, and the degree of LP was proportional to the amount of AN in the mixture. Superoxide dismutase and catalase partially inhibited LP. When compared to normal red cells, only sickle cells demonstrated a significant increase in AN-mediated LP. Conversion of hemoglobin to carboxy-hemoglobin increased AN-mediated LP, whereas conversion to met- hemoglobin decreased AN-mediated LP. The protective effect of met- hemoglobin on LP was less in sickle cells than in normal cells. We conclude that AN can induce LP in red cells in vitro and that sickle cells are more susceptible to this process than normal cells. Hemoglobin can serve as an electron trap and protect the cell against peroxidative damage, but this mechanism is impaired in sickle cells. We speculate that the pathogenesis of hemolysis associated with infectious disease may include AN-induced red cell LP.

scholarly journals The effect of X chromosome inactivation on the inhibition of Plasmodium falciparum malaria growth by glucose-6-phosphate-dehydrogenase- deficient red cells

Blood ◽  
1983 ◽  
Vol 62 (4) ◽  
pp. 866-868 ◽  
Author(s):  
EF Jr Roth ◽  
C Raventos Suarez ◽  
A Rinaldi ◽  
RL Nagel
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Plasmodium Falciparum Malaria ◽  
Parasite Growth ◽  
Red Cells ◽  
Normal Cells ◽  
Hemizygous Male ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Cell Glucose

Abstract Previous data on in vitro culture of Plasmodium falciparum malaria demonstrated that red cell glucose-6-phosphate dehydrogenase deficiency (G6PD-) inhibited parasite growth in deficient hemizygous males. This study investigated the effect of heterozygosity for G6PD- on parasite growth. Blood was obtained from 8 female Sardinian G6PD- heterozygotes with G6PD normal cells ranging from 13% to 60%. For comparison, blood from a G6PD- hemizygous male, containing 100% deficient red cells, was mixed in different proportions with compatible normal blood. In both experiments, parasite growth was inhibited by the presence of deficient cells. In both cases, it was found that the inhibition could be explained by a simple dilution of normal cells by G6PD- cells. Thus, the typical female heterozygote is also protected to a significant extent. When considering the “malaria hypothesis” as it relates to G6PD, protection of the female heterozygote as well as the male hemizygote must be taken into account.

scholarly journals Altered plasma membrane phospholipid organization in Plasmodium falciparum-infected human erythrocytes

Blood ◽  
1987 ◽  
Vol 69 (2) ◽  
pp. 401-407 ◽  
Author(s):  
RS Schwartz ◽  
JA Olson ◽  
C Raventos-Suarez ◽  
M Yee ◽  
RH Heath ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cell Membrane ◽  
Early Stage ◽  
Red Cells ◽  
Membrane Phospholipid ◽  
Cell Membrane Permeability ◽  
Parasite Development ◽  
Red Cell ◽  
Membrane Phospholipids ◽  
Red Cell Membrane

Abstract The intraerythrocytic development of the malaria parasite is accompanied by distinct morphological and biochemical changes in the host cell membrane, yet little is known about development-related alterations in the transbilayer organization of membrane phospholipids in parasitized cells. This question was examined in human red cells infected with Plasmodium falciparum. Normal red cells were infected with strain FCR3 or with clonal derivatives that either produce (K+) or do not produce (K-) knobby protuberances on the infected red cells. Parasitized cells were harvested at various stages of parasite development, and the bilayer orientation of red cell membrane phospholipids was determined chemically using 2,4,6-trinitrobenzene sulphonic acid (TNBS) or enzymatically using bee venom phospholipase A2 (PLA2) and sphingomyelinase C (SMC). We found that parasite development was accompanied by distinct alterations in the red cell membrane transbilayer distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Increases in the exoplasmic membrane leaflet exposure of PE and PS were larger in the late-stage parasitized cells than in the early-stage parasitized cells. Similar results were obtained for PE membrane distribution using either chemical (TNBS) or enzymatic (PLA2 plus SMC) methods, although changes in PS distribution were observed only with TNBS. Uninfected cohort cells derived from mixed populations of infected and uninfected cells exhibited normal patterns of membrane phospholipid organization. The observed alterations in P falciparum-infected red cell membrane phospholipid distribution, which is independent of the presence or absence of knobby protuberances, might be associated with the drastic changes in cell membrane permeability and susceptibility to early hemolysis observed in the late stages of parasite development.

A role for microtubules in Plasmodium falciparum merozoite invasion

Parasitology ◽  
1997 ◽  
Vol 114 (1) ◽  
pp. 1-6 ◽  
Author(s):  
P. A. BEJON ◽  
L. H. BANNISTER ◽  
R. E. FOWLER ◽  
R. E. FOOKES ◽  
S. E. WEBB ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Light Microscopy ◽  
No Reduction ◽  
Culture Conditions ◽  
Red Cells ◽  
Red Cell ◽  
Ultrastructural Studies ◽  
Falciparum Merozoite ◽  
Nuclear Particle ◽  
Invasion Inhibition

Colchicine, a drug which poisons the polymerization of microtubules, was assayed for effects on the invasion of Plasmodium falciparum merozoites into red cells in order to investigate if merozoite microtubules have a function in invasion. Culture conditions and concentrations of colchicine were established where the maturation and rupture of schizonts was unaffected by the drug. This was judged first by light microscopy, including morphology and counts of nuclear particle numbers, then by ultrastructural studies which excluded deranged organellogenesis as a cause of merozoite failure, and finally by diachronic cultures in which both recruitment and loss of schizonts could be counted. Specific invasion inhibition was seen when 10 μM–1 mM colchicine was present. Red cells pre-incubated in colchicine and then washed showed no reduction in their extent of invasion, and neither red cell lysis, sphering nor blebbing were apparent. We conclude that intact microtubules are necessary for successful merozoite function.

scholarly journals Glucose-6-phosphate dehydrogenase of malaria parasite Plasmodium falciparum

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1528-1530
Author(s):  
A Yoshida ◽  
EF Jr Roth
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Parasite ◽  
Blot Hybridization ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Minor Component ◽  
Southern Blot Hybridization ◽  
Starch Gel Electrophoresis ◽  
Parasite Plasmodium Falciparum ◽  
A Minor ◽  
Glucose 6 Phosphate Dehydrogenase

Plasmodium falciparum growth is impaired in glucose-6-phosphate dehydrogenase (G6PD)-deficient red blood cells (RBCs), and malaria has been implicated in the spreading of deficient variants in malaria- endemic areas. Recent reports suggest that the malaria parasite can adapt itself to grow in these variant RBCs by producing its own G6PD, but studies on parasite G6PD are very limited. In this report, we define the properties of the parasite G6PD. G6PD was partially purified from infected and uninfected variant RBCs associated with severe G6PD deficiency. G6PD from infected RBCs contained two components separable by starch gel electrophoresis: a major component (approximately 90% activity) with a very slow anodal electrophoretic mobility and a minor component (approximately 10% activity) with the same mobility as the host G6PD. Parasite G6PD exhibited much higher affinity (low Km) to G6P and nicotinamide-adenine dinucleotide phosphate (NADP) than did human G6PD. Southern blot hybridization indicated that the parasite genome contained nucleotide sequences that were hybridizable with the human G6PD cDNA. These data indicate that the parasite is capable of adapting to G6PD-deficient RBCs by producing its own G6PD.

scholarly journals The enzymes of the glycolytic pathway in erythrocytes infected with Plasmodium falciparum malaria parasites

Blood ◽  
1988 ◽  
Vol 72 (6) ◽  
pp. 1922-1925
Author(s):  
EF Jr Roth ◽  
MC Calvin ◽  
I Max-Audit ◽  
J Rosa ◽  
R Rosa
Keyword(s):  
Plasmodium Falciparum ◽  
Enzyme Activity ◽  
Adenylate Kinase ◽  
Genetic Basis ◽  
Glucose Consumption ◽  
Fold Increase ◽  
Plasmodium Falciparum Malaria ◽  
Red Cells ◽  
Glycolytic Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Enzymes of the glycolytic pathway as well as some ancillary enzymes were studied in normal red cells parasitized with Plasmodium falciparum in culture at varying parasitemias as well as in isolated parasites. The levels of all enzymes except diphosphoglycerate mutase, glucose-6- phosphate dehydrogenase, and adenylate kinase were elevated. Extreme elevations of hexokinase, aldolase, enolase, pyruvate kinase, and adenosine deaminase concentrations were noted. In most cases, electrophoretically distinct bands of enzyme activity were also seen. These findings partly explain the previously noted 50- to 100-fold increase in glucose consumption of infected red cells and suggest that further knowledge of these parasite enzymes and their genetic basis may aid both in designing new chemotherapy and in understanding the evolution of these parasites.

Receptors on red cells for Plasmodium falciparum and their interaction with merozoites

1984 ◽  
Vol 307 (1131) ◽  
pp. 189-200 ◽  
Keyword(s):  
Plasmodium Falciparum ◽  
Hydrophobic Interactions ◽  
Membrane Lipid ◽  
Red Cells ◽  
Red Cell ◽  
Naturally Occurring ◽  
Electrostatic And Hydrophobic Interactions ◽  
Wheatgerm Agglutinin ◽  
Human Red Cells

The red cell sialoglycoproteins (glycophorins, The red cell sialoglycoproteins (glycophorins, α(A), δ(B) and β and γ(C)) play a crucial role in the invasion of human red cells by merozoites of Plasmodium falciparum . Red cells deficient in any of the glycophorins, including β (also known as glycoconnectin), resist infection by this parasite to varying degrees. These cells and other naturally occurring well-characterized glycophorin variants provide extremely powerful tools to dissect the role of these molecules in invasion. The binding of merozoites to human red cells appears analogous to the binding of wheatgerm agglutinin to sialoglycoconjugates. In both systems O- and N-linked oligosaccharides may be involved. Membrane lipid has not been implicated as a receptor for merozoites, but may instead non-specifically modify binding, as may electrostatic and hydrophobic interactions. The results of data using monoclonal antibodies and lectins, although possibly helpful in identifying specific determinants, must be interpreted with caution. Overall the data suggest that the red cell receptors for all strains of P. falciparum tested to date are located on the glycophorins. Accordingly these putative receptors have been used to affinity-purify complementary parasite components which may yet prove to be of protective immunological significance in a vaccine.

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