ISOLATION AND CHARACTERIZATION OF A PARTICULATE CELL-AGGREGATION FACTOR FROM SEA URCHIN EMBRYOS*

A particulate factor promoting an aggregation of dissociated embryonic cells was isolated from sea urchin embryos. It was isolated from the supernatant of dissociated embryos with artificial sea water devoid of divalent cations. The factor is a spherical particle in shape and consists of mucopolysaccharide-protein complex rich in acidic groups.