Selenium-Independent Glutathione Peroxidase in Malaria Parasites
Inherited and/or acquired alterations of red blood cell metabolism, like glucose-6-phosphate dehydrogenase- or vitamin E deficiency, which influence peroxide metabolism, inhibit the regular intracellular development of the malaria parasite. Many antimalarials are peroxides (e.g., t-butyle-hydroperoxide/t-BHP, qinghaosu/QHS) or radical generators (e.g., primaquine, isouramil). Reactive oxygen species are thought to belong to the main mediators in the unspecific immune reactions against intracellular protozoan parasites (reviewed by Clark et al. 1986; Roth et al. 1986). It is still unknown as to whether the parasite, the host erythrocyte, or both are responsible for the increased susceptibility to oxidative damage and whether the parasite participates in the redox cycle capacity of the host cell. The susceptibility of the normal red blood cell, the parasitized erythrocyte or the parasite to oxidative damage depends on the individual antioxidant capacity. The relation of Oxidative Stress Versus Antioxidant Capacity (OSVAC) is very decisive for either the survival or non-survival of malaria parasites or infected erythrocytes. An increase in the oxidant stress and/or a decrease in the antioxidant capacity (e g, inhibition of the redox cycle enzymes, vitamin E or vitamin C deficiency) disturbs the critical OSVAC balance within the infected cell and might thus lead to a more or less selective destruction of the parasite or the host RBC. Because the parasitized red blood cell is a multicompartment system, it is very difficult to distinguish between the metabolic activities of host and guest cells. In the course of its intracellular multiplication, the parasite degrades up to 75% of host's cell stroma and as such the metabolic capacity of the residual erythrocytes becomes more and more labile. The aim of these investigations was to determine whether malaria parasites depend on the host cell's redox cycle and whether OSVAC of host and guest cells are of different qualities.
KeywordsRedox Cycle Cumene Hydroperoxide Percoll Density Gradient Intracellular Protozoan Parasite Percoll Density Gradient Centrifugation
Unable to display preview. Download preview PDF.
- Ager AL, Levander OA, May R, Morris VC (1986) Effect of vitamin E on the anti-malaria action of Qinghaosu. Fed Proc 46: 1163Google Scholar
- Heidrich H-G, Rüssmann L, Bayer B, Jung A (1979) Free-flow electrophoresis for the separation of malaria-infected and uninfected mouse erythrocytes and for the isolation of free parasites (P. vinckei): a new and rapid technique for the liberation of malaria parasites from their host cells. Z Parasitenkd 58: 151–159PubMedCrossRefGoogle Scholar
- Levander OA, Ager AL, May R (1986) Effect of selenium (Se) deficiency on the anti-malaria action of Quinghaosu in mice. Fed Proc 45: 415Google Scholar
- Roth E Jr, Raventos-Suarez C, Gilber H, Stump D, Thnowitz H, Rowin KS, Nagel RL (1984) Oxidative stress and falciparum malaria: a critical review of the evidence. In: Eaton JW, Brewer GJ (eds) Malaria and the red cell. Alan R Riss, New York, pp 13–22Google Scholar