Isolation of the pellicle ofToxoplasma gondii (Protozoa, Coccidia): Characterization by electron microscopy and protein composition

Abstract

Two methods were compared for the isolation of theToxoplasma gondii pellicle: centrifugation using a discontinuous sucrose gradient and affinity purification by microspheres activated with protein A. Electron microscopy showed that these two means of purification gave similar results, although better yields were obtained with the former than with the latter. Proteins of membrane fractions isolated using sucrose gradient were identified by sodium dodecyl sulfate-polyarylamide gel electrophoresis (SDS-PAGE). Bands in the molecularweight regions of 19, 22, 35, and 79 kDa appeared to be associated with theT. gondii pellicle.