Fig. 2.

Ultrastructural detection of enolase in Plasmodium ookinetes. (A and B) Two examples of enolase localization (gold particles) using a polyclonal anti-P. falciparum enolase antibody and cultured P. berghei ookinetes. Surface localization is indicated by arrows. (C) Stereological analysis of immunogold-labeled structures. The density (gold particles per mm²) of labeled structures was determined from 20 cryosections. The percentage of individual intracellular compartment density was determined from the sum of gold density normalized for the variation in expression of enolase. Although the majority of enolase localized to the cytoplasm, a significant proportion was located on the surface and in the nucleus, consistent with the enolase distribution in blood forms (20). Gold particles on single- or double-membrane–bound compartments excluding the nucleus (organelles) correspond to negligible background. DV, digestive vacuole; IMC, inner membrane complex; mi, secretory microneme organelle; PM, plasma membrane. (Scale bar: 200 nm.)