Plasmodium falciparum: freeze-fracture of the gametocyte pellicular complex.

Freeze-fracturing has been used to study the architecture of the pellicular complex of the gametocytes of Plasmodium falciparum. The gametocyte is surrounded by three membranes and a layer of subpellicular microtubules. During freeze-fracturing, each of the three membranes is split along its hydrophobic interior to yield a total of six fracture faces.

Evaluation of a synthetic oligonucleotide probe for diagnosis of Plasmodium falciparum infections.

A radiolabeled synthetic oligonucleotide was evaluated as a diagnostic probe specific for Plasmodium falciparum using blood samples lysed directly on nitrocellulose filters. The probe technique successfully diagnosed malaria in experimentally infected chimpanzees that had 0.001% parasitemias (50 parasites/microliter) as determined by blood smears, and in 1 chimpanzee whose blood smear was negative, but whose blood was culture-positive for P.

Effect of antibodies to recombinant and synthetic peptides on P. falciparum sporozoites in vitro.

Antibodies were raised in mice immunized with several recombinant and synthetic peptides of the circumsporozoite protein of Plasmodium falciparum. The antibodies were evaluated for protective activity in a human hepatocyte culture system. They exerted their protective effect against the parasite at three points: sporozoite attachment to the hepatocyte surface, entry, and subsequent intracellular development.

Malaria transmitted to humans by mosquitoes infected from cultured Plasmodium falciparum.

Malaria was transmitted to six normal human volunteers by mosquitoes infected from cultured gametocytes of Plasmodium falciparum. This method, which offers advantages over other methods of infecting volunteers, will be useful for evaluating the efficacy of human malaria vaccines.