INHIBITION OF TETRASPORE ADHESION IN CHAMPIA-PARVULA (RHODOPHYTA)

Tetraspores of the marine red alga Chmapia parvula (C. Agardh) Harvey attached initially to plastic or glass coverslips by extracellular mucilage. Following germination, adhesive rhizoids provided further anchorage. When newly released, floating tetraspores were exposed to cycloheximide, tunicamycin, sodium molybdate or Con A: adhesion was inhibited. These results indicate that proteins, glycoproteins, sulphated polysaccharides, and alpha-D-mannose or alpha-D-glucose respectively are all necessary for adhesion. When the biosynthesis inhibitors or Con A were added to attached tetraspores, they did not detach. This suggests that adhesion is not maintained via synthesis of proteins, glycoproteins or sulphated polysaccharides and that alpha-D-mannosee or alpha-D-glucose maintain adhesion by contacting the substrate and are therefore unavailable to Con A. Newly released, floating tetraspores killed with H2SO4 or sodium azide did not attach; therefore viability is necessary for this process. On the other hand, attached tetraspores did not detach when killed with sodium azide or de-ionized water, but dead sports detached when their mucilage was damaged by H2SO4. The mucilage can be disrupted by enzymes, as tetraspores detached in the presence of the enzymes beta-galactosidase, protease, cellulase, a-amylase, hyaluronidase, sulphatase, and mannosidase.