CELL-CELL RECOGNITION AND ADHESION DURING EMBRYOGENESIS IN THE SEA URCHIN: DEMONSTRATION OF SPECIES-SPECIFIC ADHESION AMONGARBACIA PUNCTULATA, LYTECHINUS VARIEGATUS, ANDSTRONGYLOCENTROTUS PURPURATUS

The present study investigates species-specific recognition and adhesion between dissociated embryonic cells of hatched blastulae of Arbacia punctulata, Lytechinus variegatus, and Strongylocentrotus purpuratus. The assay used is a modification of one previously developed by McClay and Hausman (1975) and involves collection of labeled single probe cells to unlabeled collecting aggregates. The results indicate that probe cells fixed by glutaraldehyde or formaldehyde or disrupted by sonication do not adhere significantly to their homospecific aggregates. Moreover, fixation of aggregates by glutaraldehyde greatly diminishes binding of labeled probe cells. Thus adhesion, as measured by the present assay, requires both living probe cells and aggregates. In addition, adhesion of probe cells to their homospecific aggregates is found to be significantly greater than adhesion to heterospecific aggregates. The results demonstrate reciprocal species-specific adhesion between Arbacia punctulata versus Lytechinus varie...