We studied RNA synthesis in Xenopus laevis embryos at the gastrula stage, using both 001 M LiCl concentration, which causes malformations, and lower concentrations to 0.0025 M that allow normal development. A preliminary series of observations on incorporation in treated Xenopus embryos revealed that LiCl concentrations below 0.01 M increase the labelled RNA to 38%. On the contrary, in embryos treated with LiCl concentrations above 0.01 M there is a lower incorporation than in the controls. Therefore...
We have carried out b y the salting-out method, a study on the differences of the protein fractions during the larval and pupal stage of Bombyx mori. We tried to find a relationship between these data and the differences in the ribosomes as studied with the analytical ultracentrifuge and sucrose gradients. The salting-out diagrams of the unfertilized egg and the embryo, show only one peak at 65% ammonium sulphate saturation; when hatched and during the larval stages, the diagrams show 2 peaks at...
An analysis of RNA and protein synthesis has been carried out on Xenopus laevis embryos, cut into two portions, during the early stages of their development. Actinomycin D was employed to inhibit the synthesis. The action of actinomycin on synthesis is stronger during gastrulation than during neurulation. In each stage a correlation between RNA synthesis inhibition and protein synthesis inhibition has been observed. In the ventral fragments of the neurula the ratio between the two inhibitions is...
The action of LiCl on RNA and protein synthesis in Amphibian embryos was studied previously. In this paper the NaSCN effect, which appears in opposition to the LiCl effect, was examined on the same material; this was shown by morphological research as well as by experiments on the protein in solution. Xenopus laevis and Rana esculenta embryos were used and were treated, at late blastula stage, with NaSCN in tap water at increasing concentrations from 1,5 mM to 6.0 mM. After three hours of treatment...
I somiti non si differenziano nell'espianto postnodale del blastoderma di pollo coltivato in vitro col metodo di New. Somiti si differenziano invece se al liquido di allevamento è aggiunto mRNA di miosina 26S estratto da muscoli di embrioni di pollo di 14 giorni. Lo stesso risultato si ottiene se il pezzo postnodale è coltivato in un pool di mRNA di muscolatura. Somiti sono anche indotti se al liquido di allevamento si aggiunge miosina. L'aggiunta di puromicina impedisce l'induzione di somiti per...
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