Abstract: | In the polychaete Ophryotrocha labronica the oocyte is supported during vitellogenesis by a single nurse cell, which is cytoplasmically contiguous with the oocyte through an intercellular bridge. Our electrical measurements demonstrate a marked potential difference (22-32 mV) between the oocyte and the nurse cell in mid-vitellogenesis, suggesting an electrophoretically caused migration of nurse cell constituents into the oocyte. Possibly this potential gradient helps to create a developmental prepattern in the oocyte, a role postulated for similar gradients within the oocyte-nurse cell complex of the Cecropia moth. |