Les effets de l'énucléation sur la synthèse des protéines chez Acetabularia mediterranea

Abstract

The evolution of proteic nitrogen, wet weight and the length of nucleated and anuleated fragments of the green unicellular alga, Acetabularia mediterranea, has been followed up for about a month after the sectioning of the alga. The results show that the synthesis of proteins in the anucleated fragment occurs at the same rate as in the nucleated half of the alga for the 15 days that follow the sectioning of the alga, and that it ceases immediately. Thus the nucleus does not seem indispensable to the synthesis of proteins. The rate of two fractions of cytoplasmic particles obtained by differential centrifugation, the “chloroplasts” and the “little granules”, has been followed up for more than a month after the enucleation. Contrary to expectations, the microsomial fraction is not affected at first by enucleation; the quantity of protein decreases first in the chloroplats. This result suggests that ribonucleic acid is not the factor that limits protein synthesis in the enucleated fragments, but that it is the lack of nucleotidic co-enzymes that inhibits the elaboration and utilisation of the amylaceous reserves of the cellule.