Function of the embryo and the yolk cells in diapause of the silkworm egg ( Bombyx mori)

Abstract

The synthetic activity of separated embryo and yolk cells, and HCl-treated eggs in Bombyx mori, was studied. There was no synthetic activity of the egg before fertilization and of the yolk cells after blastokinesis. It was found that during pre-diapause the yolk-free embryo as well as the dependent one appeared to synthesize DNA, RNA, and protein, whereas the independent yolk cells did not appear to synthesize protein but did appear to synthesize DNA and RNA. During diapause as well as post-diapause, the embryo could also synthesize DNA, RNA, and protein but only RNA synthesis of the yolk cells occurred dependently and independently of the embryo. The yolk cell RNA synthesized during pre-diapause differed in its function from that during diapause and post-diapause. HCl-treatment impeded the embryonic rôle in the protein synthesizing system of the yolk cells. Some implications of mechanism of diapause are discussed.