phosphorus-radioisotopes and Malaria

There is a high prevalence of the erythrocyte polymorphism ovalocytosis associated with reduced susceptibility to malaria in Papua New Guinea. The major erythrocyte integral membrane protein, Band-3, showed markedly increased phosphorylation in whole cells or isolated ghosts from ovalocytic individuals. The cytoplasmic domain of the ovalocyte Band-3 was found to be approx. 3 kDa larger than the normocytic protein. The N-terminal sequence of the ovalocytic Band-3 was different from the reported sequence for human Band-3, suggesting that the increased size results from an N-terminal extension. Since this is the region of Band-3 which is phosphorylated and interacts with the red cell cytoskeleton, it is likely that this alteration in ovalocytic Band-3 is the underlying cause of the diverse alterations in ovalocytic cells including increased phosphorylation, increased membrane rigidity, decreased agglutinability by blood group antibodies and refractoriness to invasion by malarial parasites.

Topics: Anion Exchange Protein 1, Erythrocyte; Antibodies; Elliptocytosis, Hereditary; Erythrocyte Membrane; Immunity, Innate; Malaria; Melanesia; Membrane Proteins; Peptide Mapping; Phosphates; Phosphopeptides; Phosphorus Radioisotopes; Phosphorylation; Prevalence

A simple procedure was developed for spotting blood samples directly onto nylon membrane filter, without the necessity to treat samples with pronase or proteinase K, followed by hybridizing with 32P-labelled DNA probe, pUNK1-45. This probe detected specifically P. falciparum DNA and did not cross react with DNA from man, P. knowlesi, P. chabaudi or P. cynomolgi. The probe was sensitive to detect a parasitemia of 0.001% in 20 microliters of blood.

Topics: Animals; DNA Probes; Epidemiologic Methods; Humans; Malaria; Nucleic Acid Hybridization; Phosphorus Radioisotopes; Plasmodium falciparum