[Autoradiographic studies on synthesis and incorporation pattern of egg proteins during blastoderm development in the early embryogenesis ofDermestes frischi (Coleoptera)].

1. 3H-amino acid incorporation into newly synthetized egg proteins was investigated by means of autoradiography in order to analyze the synthesis rate of different developmental stages. Furthermore the incorporation pattern of the egg system was studied to find out whether physiological and morphological processes during early embryogenesis are connected with a certain protein synthesis. The tritium-labelled amino acids were injected into the yolk system of the egg, since the yolk proteins serve as amino acid sources for embryogenesis. 2. There is a permanent transfer of radioactivity from the yolk system into the cortical egg regions during intravitelline cleavage and blastoderm development. Therefore the radioactivity is continuously accumulating in these areas. Typical morphological processes like the formation of cell membranes and the secondary periplasm are characterized by local region specific incorporation of radioactivity. The physiological activities of blastoderm nuclei and vitellophages seem to be linked directly with high incorporation of the3H-amino acids. 3. A certain protein synthesis rate already takes place shortly after egg deposition. During intravitelline cleavage its value rises only slowly. But with migration of the cleavage nuclei into the periplasm the synthesis rate begins to increase rapidly to more than 100% of its original amount. In the first blastoderm stages the permanent increase of the synthesis is less than before and reaches its maximum in the late blastoderm. Near the end of blastoderm development the protein synthesis rate is slightly reduced. 4. Characteristic developmental processes can be determined by significant increases of the protein synthesis before they become morphologically detectable. Immediately before the formation of cell membranes and the secondary periplasm a higher synthesis rate was identified.