[Investigations on localization and synthesis of egg proteins during early development ofDermestes frischi (Coleoptera)].

1. UV-irradiation, of the entire ectoplasm during intravitelline cleavage stages causes the formation of a pseudoblastoderm. The damaged superficial areas remain free of cleavage nuclei, which contact with their cytoplasm and form a blastodermlike layer inside the yolk-entoplasm. However there is no visible differentiation in the pseudoblastoderm before its death. 2. Disc-electrophoresis was performed on normal developing eggs and on those in pseudoblastoderm stages in order to find out whether the protein pattern of the egg is affected by the loss of cortical regions. Normally with blastoderm formation 2 new protein fractions occur in the electrophoretic pattern. But in the pseudoblastoderm egg they are absent. Three other fractions, which will be removed in the normal blastoderm egg were also not detected in the pattern of the pseudoblastoderm egg. One protein fraction synthetized during intravitelline cleavage and always present in later development could not be observed in pseudoblastoderm stages. 3. Micro-disc-electrophoresis of isolated yolk-entoplasm material was carried out to locate certain protein fractions in the egg system. The same protein fraction, which could be damaged by UV-treatment of the ectoplasm is not detectable in the electrophoretic pattern of the underlying yolk-entoplasm. Therefore this fraction must be situated in superficial regions of the egg confirming reported results of autoradiographic investigations. 4. This leads to the conclusions, that the synthesis of certain protein fractions depends on the functional condition of cortical egg components. Other physiological processes, which are not affected by the loss of the periplasm take place without influence of superficial regions. Beside their role as egg areas in which physiological ooplasmatic factors are located the superficial egg components contain special protein structures.