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Commitment of the malaria parasite Plasmodium falciparum to sexual and asexual development

Published online by Cambridge University Press:  06 April 2009

M. C. Bruce
Affiliation:
Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland
P. Alano
Affiliation:
Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland
S. Duthie
Affiliation:
Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland
R. Carter
Affiliation:
Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland

Summary

Blood-stage malaria parasites in the vertebrate host can develop either into the asexual, multiplying forms, called schizonts, or into gametocytes, the sexual stages of the parasite. In the present work we studied the differentiation into asexual parasites or gametocytes of the progeny of single, isolated schizonts of the clone 3D7A of Plasinodium falciparum, using monoclonal antibodies specific for the sexual or asexual stages of the parasite. We observed that schizonts obtained from a continuous culture undergoing serial cycles of growth and dilution with fresh red blood cells produced either only gametocytes or only asexual parasites, showing a high degree of commitment to one or the other developmental pathway.

The relative proportion of schizonts which produced gametocytes was very low at low parasite densities in culture, while at high parasite densities a much greater proportion of schizonts produced gametocytes. Nevertheless, at both low and high parasite densities individual schizonts were almost always fully committed to producing only gametocytes or only asexual parasites.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1990

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