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The adhesion of sea urchin embryonic cells to polysaccharide beads
Dissociated sea urchin embryonic cells were observed to adhere to Sepharose 4B beads when the cells and beads were rotated together in calcium-and-magnesium-free sea water. When placed in Millipore filtered sea water, the cells would not adhere to the beads. It was shown that both calcium and magnesium ions could separately inhibit the adhesion. Galacturonic and glucuronic acid increased the adhesion, while ether haptens had no effect. The cells would adhere to other composition beads, and could be inhibited by the addition of calcium or magnesium ion. It was also shown that the adhesion to Sepharose 4B was pH dependent. Various mechanisms for explaining the adhesion are discussed. Charge-charge, hydrogen bonding, and van der Waals interactions are possibilities. The cell-bead interaction observed here can serve as a model for demonstrating initial cell-cell interaction, leading to specific cell-cell adhesion.