Quelques aspects de la synthèse protéique dans les muscles thoraciques en développement de Schistocerca gregaria (Forsk.)

Polysomes obtained from the postmitochondrial fraction of the thoracic muscles undergo disassociation into monomers when treated with pancreatic RNase. In contrast, the preparations obtained from microsomes on RNase treatment result in the association of monomers into heavier aggregates. A combined treatment with trypsin, however, renders the polysomes sensitive to RNase action. Characteristics of a cell-free amino acid incorporation system have been described and compared with similar systems obtained from other organisms or tissues. GTP seems to reverse the inhibition caused by cycloheximide. Amino acid incorporation capacity of the microsomal and ribosomal fractions prepared from the thoracic muscles at different stages of development was investigated in the presence and absence of added poly U. Both the microsomal and ribosomal preparations respond to the addition of poly U. However, the ribosomes require higher concentrations of this copolymer for attaining full saturation. The significance of the findings reported in this investigation is discussed.