Correlated Biochemical and ultrastructural changes in nitrogen-starved Euglena Gracilis

Abstract

Growth of Euglena gracilis Z Pringsheim under photoheterotrophic conditions in a nitrogen-deprived medium resulted in progressive loss of chroroplastic material until total bleaching of the cells ocurred. Biochemical analysis and ultrastructural observation of the first stages of the starvation process demonstrated and early lag phase (from 0 to 9 h) in which cells increased in size, followed by a period of cell division, apparently supportde by the mobilization of some chroroplastic proteins such as the photosynthetic CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase