HISTOCHEMICAL AND ULTRASTRUCTURAL IDENTIFICATION OF BIPHASIC GRANULESIN THE ALBUMIN SECRETORY-CELLS OF ARION-SUBFUSCUS (GASTROPODA, PULMONATA)

Two types of globules, differing in size, structure, and nature, are d emonstrated within each secretory cell of the albumen gland of Arion s ubfuscus. Large secretory globules, with a homogeneous granular conten t, are rich in proteins and carbohydrates, with the protein-reacting g roups probably partially masked by intimate junction with the polysacc harides. Smaller secretory globules lie inside the large ones and are more electron-lucent and foam-like in substructure, containing mostly glycosaminoglycans but also proteins. Lectin-sugar specificities show that the carbohydrates synthesized by the gland are mainly galactogen, but other neutral polysaccharides, such as glycogen, are also present in the secretory vesicles. The reactions of each type of globule to t he lectins are also very different.