Protein synthesis in Sphinx ligustri pupae.

AT the beginning of the pupal stage of Sphinx ligustri, a lysis of larval tissues occurs. In winter, during diapause, the pupa is a bag full of blood containing a suspension of partially broken down larval tissues. In spring, diapause is broken, formation of adult tissues is speeded up and the moth becomes rapidly ready to emerge. Most of the amino-acids used for adult protein synthesis come from larval tissues; the question is whether the larval proteins are hydrolysed to free amino-acids before being used for adult protein synthesis, or whether adult proteins are built up from larger units that might be carried by phagocytes which are known to destroy the larval tissues. In order to approach an answer to this question, we decided to compare the mean specific rates of protein synthesis (rate of synthesis/amount of proteins) from one free amino-acid, namely glycine, in Sphinx ligustri pupæ, either in diapause or at the moment of the development of the adult organs. © 1957 Nature Publishing Group.