Localization of Acid Phosphatase Activity in Plasmodium berghei and P. gallinaceum: An Electron Microscopic Observation

Abstract

The localization of acid phosphatase activity in the erythrocytic stages of Plasmodium gallinaceum and Plasmodium berghei was studied by electron microscope cytochemistry. Acid phosphatase activity was demonstrated in the food vacuoles and endoplasmic reticulum of both parasites. This study confirmed the food vacuoles as the site of digestion of host cell cytoplasm. Similarly, the enzyme activity was seen in clefts or slitlike structures of the infected host cells. This may indicate that these structures originate from the endoplasmic reticulum of the host cells. Acid phosphatase activity has been demonstrated in various protozoa such as Paramecium (Esteve, 1970), Tetrahymena (Elliott and Clemmons, 1966), Blepharisma (Demkitzer, 1968), and amebae, by means of electron microscopic cytochemistry. These studies have revealed that this enzyme often is associated with organelles related to the digestion of food as well as the endoplasmic reticulum and Golgi complex. There is, however, a lack of bioand cytochemical evaluation of this enzyme in malarial parasites. Therefore, we undertook this investigation to demonstrate the ultrastructural localization of acid phosphatase in the erythrocytic stages of Plasmodium gallinaceum and Plasmodium berghei. Studies such as this may lead to a better understanding of the digestive process of the host cell cytoplasm by the ma-