The p47 pfsub-1 gene product localizes to dense granules within the apical domain of free P. falciparum merozoites. Top, air-dried smears of naturally released merozoites were fixed with acetone and then probed with anti-PfSUB-1m antibodies. Bound antibody was detected with a Texas Red conjugated anti-mouse IgG. The preparations were finally incubated briefly with an FITC-conjugated monoclonal antibody (2F10) reactive with MSP-1 and examined by confocal microscopy. The plate consists of an overlaid z series of 12 images recorded at 400-nm intervals, projected as a single image, with Texas Red fluorescence and FITC fluorescence shown overlaid. Bottom, thin sections of resin embedded merozoites (A) or mature schizonts (B and C) were probed with the anti-PfSUB-1m antiserum, and then bound antibodies were detected using a gold-labeled anti-mouse IgG antibody. Dense granules (D), rhoptries (R), and micronemes (Mi) are indicated, as is the cytoplasm of the infected erythrocyte (E). Bar, 0.5 mm.

Blackman MJ, Fujioka H, Stafford WH, Sajid M, Clough B, Fleck SL, Aikawa M, Grainger M, Hackett F. A subtilisin-like protein in secretory organelles of Plasmodium falciparum merozoites. J Biol Chem. 1998 273:23398-409.