PARASITIC APICOMPLEXANS HARBOR A CHLOROPHYLL A-D1 COMPLEX, THE POTENTIAL TARGET FOR THERAPEUTIC TRIAZINES

Ultrastructural evidence is presented for the presence of plastid-like organelles in Toxoplasma gondii, Sarcocystis muris, Babesia ovis, and Plasmodium falciparum. In addition, it was shown that merozoites of T . gondii contain protochlorophyllidae a and traces of chlorophyll a bo und to the photosynthetic reaction centers I PS I and PS II. A psbA ge ne was isolated from merozoites of S. muris by the polymerase chain re action (PCR). Partial sequencing of the PCR product revealed that the herbicide-binding region is highly conserved. Therefore, it is likely that the sensitivity of apicomplexans to the herbicide toltrazuril dep ends on the interaction of the herbicide with the D1 protein of the ph otosynthetic reaction center of the parasite's organelles.