De- And Re-Generation of Chloroplasts in the Cells of Chlorella Protothecoides: V. Degeneration of Chloroplasts Induced by Different Carbon Sources, and Effects of Some Antimetabolites Upon the Process Induced by Glucose

The green cells of Chlorella protothecoides were bleached to different extents when incubated (in the dark) in the nitrogen-free media containing, besides basal mineral nutrients, glucose, fructose, galactose, glycerol or acetate. Glucose and fructose were found to have the strongest bleaching effect. Addition of a nitrogen source (urea) caused a considerable reduction of the bleaching. It was assumed that from the different carbon sources a certain common intermediate(s) causing the bleaching is formed, and that in the presence of the nitrogen source the substance is removed by reacting with it. Using glucose as bleach-inducing agent, the effects of some antimetabolites upon the processes of bleaching, division and growth of green algal cells were investigated, and it was demonstrated that the process of bleaching occurs without being accompanied by growth and division of the algal cells. It was found that during the process of bleaching no net increases in RNA and protein took place.