Isolation of Species-Specific and Stage-Specific Adhesion Promoting Component by Disaggregation of Intact Sea Urchin Embryo Cells

The supernatant obtained from dissociation of Strongylocentrotus purpuratus blastula embryos effectively promoted reaggregation of S. purpuratus blastula cells by more than 3-fold over that in the absence of supernatant. The aggregation enhancing effect was completely species-specific and developmental stage-specific. The supernatant enhanced aggregation of glutaraldehyde-fixed cells, suggesting that it acts at the cell surface. Trypsinization of blastula cells did not affect the ability of dissociation supernatant to promote reaggregation, whereas trypsin treatment of dissociation supernatant completely destroyed reaggregation enhancing activity. We feel that the attributes of this system are several: (1) future biochemical work should be informative because liters of active supernatant containing about 1 mg protein/ ml can easily be obtained; (2) all experiments are done in sea water, the natural medium of the cells resulting in experimental manipulations that are not greatly different from the normal living conditions of the cells; (3) the isolated adhesion-promoting component is species-specific and stage-specific and appears to act at the cell surface.