PLASMODIUM BERGHEI - PRODUCTION IN VITRO OF FREE FATTY ACIDS

Rat blood cells parasitized by Plasmodium berghei produce large quantities of free fatty acid (FFA) when incubated in vitro as compared with unparasitized mature and immature rat blood cells similarly incubated. This FFA production is inhibited by chloroquine and is largely independent of a glucose supply. The chloroquine inhibition may involve inhibition of parasite lipolytic activities since P. berghei freed from the host cell was found to possess appreciable phospholipase A enzyme activity and chloroquine was shown to inhibit the lipolytic activity of purified phospholipase A enzyme. This production of FFA by intraerythrocytic P. berghei appears to reflect a proportionate increase of the various cellular FFA present prior to incubation rather than a selective production of a particular acid. Palmitic acid accounted for about 45-50% and stearic acid about 35% of the total cellular FFA recovered both before and after incubation. This distribution is very similar to the relative fatty acid composition of the FFA isolated from unparasitized rat red blood cells. These observations suggest that the FFA production largely reflects hydrolysis of host cell lipids in contrast to de novo fatty acid synthesis or hydrolysis of the parasite's own lipids. Such hydrolysis could supply the parasite with fatty acids required for phospholipid synthesis and hence membrane synthesis and also could partially explain the increased fragility of parasitized cells. © 1969.