Variations quantitatives des principaux constituants cellulaires d'Entomophthora virulenta lors de la sporogénèse

Abstract

Changes in the relative abundance of cell constituents of Entomophthora virulenta Hall &Dunn were studied during the various differentiation phases leading to the formation of zygospores. The highest total protein (43%) and nucleic acid (5.2% RNA and 0.2% DNA) concentrations were found in the exponential growth phase; these concentrations decreased regularly as the mycelium aged. The amount of lipids was four times larger at the prespore and spore stage (about 25%) than at the exponential mycelial stage. The zygospore contained a very high concentration of chitin (about 17%), three times more than the mycelial concentrations. However, the percentage of polysaccharides without chitin, but including glycogen, was higherin the deceleration phase mycelium (34%) than in the spore (25%). A physiological model of the sexual sporulation of E. virulenta based on these data has been presented.