Plasmodium falciparum: highly mobile small vesicles in the malaria-infected red blood cell cytoplasm.

A dynamic population of small vesicles within the cytoplasm of live malaria-infected red blood cells has been studied using a laser scanning confocal microscope. Acridine orange was used to follow the movement of vesicles within the infected red blood cell cytoplasm, including the budding of vesicles from the malarial parasite. These highly mobile vesicles are found predominantly in mid- to late ring-stage parasites and are almost entirely absent from young rings and mature trophozoites. Since the known parasite modifications of the red blood cell plasma membrane in mid-ring-to early trophozoite-stage parasites correlates with the appearance of acridine orange-staining vesicles, these vesicles may be an important component in the transport of parasite proteins across the infected red blood cell cytoplasm.