ISOLATION AND CHARACTERIZATION OF A PRESPORE SPECIFIC STRUCTURE OF THE CELLULAR SLIME MOLD, DICTYOSTELIUM DISCOIDEUM

Abstract

A method was described for isolation of the prespore specific vacuole (PSV) from slugs of the cellular slime mold, D. discoideum. A cellular component, which was fractionated in accordance with immunohistochemical staining using heteroplastic antispore serum, was found to consist of only the PSV. It was thus concluded that the PSV is identical with the cytoplasmic granule which has been shown by the antiserum to be specifically present in the prespore cell, and hence that the PSV is the only structure which contains the prespore specific substance (antigenic mucopolysaccharide). The isolated PSV contained polysaccharide equivalent to 14% of its protein content, and antigenic mucopolysaccharide constitutes about 60% of the total polysaccharide.