Comparaison, � la lumi�re et � l'obscurit�, des synth�ses sp�cifiques d'ARN chez Euglena gracilis Z en cultures synchrones sur milieu lactate et �tude du Chondriome

Abstract

Synchronization of Euglena gracilis (Z) on lactate medium is shown to be independent of illumination. The existence of a mitochondrial cycle in lightgrown as well as in dark-grown Euglena is demonstrated. When RNA synthesis is studied by pulse labeling with tritiated uracil in synchronously growing cells, a discontinuous RNA synthesis is found. Two peaks of preferential RNA synthesis in dark-grown cells and three peaks in light-grown cells are seen; the significance of the third peak of RNA synthesis in light-grown Euglena is discussed.