Apoptosis in sea bream Sparus aurata eggs

In the present study, the sea-bream Sparus aurata, a pelagic egg spawner, was used as experimental model, in order to establish the occurrence of apoptosis in vertebrates with external reproduction. The same female ovulates floating and nonfloating eggs, but only the former, after fertilization, proceed to embryo development. The eggs were divided into floating and nonfloating and both were analyzed for the presence of several apoptosis markers. The results here reported provide evidence that the nonfloating cells present severe shrinkage and highly express both FAS receptor and FAS ligand on their surface. Furthermore, DNA fragmentation and mitochondria swelling were found, suggesting that the nonfloating eggs were cells programmed to die.