Studies on the synthesis and composition of extracellular mucilage in the unicellular red alga Rhodella.

SO4 has been used to investigate the production of extracellular mucilage by log-phase cells. Uptake of isotope occurs most rapidly in the light, when cells are actively dividing. The mucilage comprises about 50 % carbohydrate, 16% protein and 10 % sulphate. The major sugar is xylose; uronic acid, a small amount of galactose, glucose (trace) and 2 reducing substances are also present. Methylation studies have established the major linkages. Electron-microscope autoradiography shows that the mucilage is packaged in the Golgi bodies, passing to the plasmalemma in large vesicles. Sulphation of the mucilage occurs in the Golgi cisternae.