Electron microscopic examination of common red cell ghosts: cytoplasmic contamination.

Red blood cell ghost preparations are often cited as providing unequivocal or convincing evidence for the active transport of solutes from a solution of low concentration across a membrane to a solution of higher concentration. Electron microscopic examination of the more widely used ghost preparations show that a considerable quantity of cytoplasmic macromolecules (including hemoglobin) remain within the treated red blood cells. That is, many of the ghost preparations are not hollow membrane perparations. It is concluded that the problem of active solute transport in red blood cell ghost preparations should be reexamined. Furthermore, experiments with ghost preparations purporting to demonstrate active transport should include electron photomicrographs of the preparation utilized.