ScienceAsia 25 (1999) : 073-075 |doi: 10.2306/scienceasia1513-1874.1999.25.073

Mitochondrial Heter ogeneity in Human Malarial Parasite Plasmodium falciparum

Sudaratana R. Krungkrai^a, Preecha Leangaramgul^b, Sanya Kudan^b, Phisit Prapunwattana^b and Jerapan Krungkrai^b,*

ABSTRACT: Mitochondria of the human malarial parasite Plasmodium falciparum in sexual blood stages (or gametocytes) had been structurally different from those of asexual blood stages of their life cycle in human host. We report here the existence of mitochondrial heterogeneity based on their characteristics of ultrastructural morphology in the asexual and sexual blood stages of P. falciparum from in vitro continuous cultures. Mitochondria in the sexual stage-parasites were more numerous and contained a greater density of cristae than the organelles in the asexual stage-parasites. It was demonstrated that there were apparent variations in size and appearance of the mitochondria between the male and female parasites of the sexual gametocytic stages. Mitochondrial oxygen consumption of the sexual stage-parasites was relatively low, and it was not different from the asexual blood stage-parasites. However, both stages of the parasites’ growth and their oxygen consumption were found to be sensitive to atovaquone, cyanide and 5-fluoroorotate which were inhibitors of mitochondrial electron transport system and pyrimidine biosynthetic pathway, respectively. Therefore, the role of mitochondrial organelles with different morphological properties in the asexual and sexual stages of parasite’s development remains to be elucidated.

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a Department of Biochemistry, Faculty of Science, Rangsit University, Patumthani 12000, Thailand.
b Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand.

* Corresponding author: E-mail: fmedijkk@md2.md.chula.ac.th

Received 11 Feb 1999