Abstract
In non-photosynthetic, yellow or colorless mutant cells of Chlorella kessleri, grown with nitrate as sole nitrogen source, 6-deoxy-D-glucose enhanced the uptake of the glycine, while it did not influence the uptake of nitrate in both growing and resting cells. On the other hand, the addition of glucose inhibited the uptake of nitrate in growing cells. Addition of methionine sulphoximine, a potent inhibitor of glutamine synthetase, to cells incubated with glucose, resulted in intracellular ammonia-accumulation and the uptake of nitrate was also extremely inhibited by extra cellular ammonia. Thus the utilization of exogenous nitrogen compounds such as ammonia, amino acids and nitrate is controlled by ammonia accumulated in inner cells. The role of glucose, ammonia and blue light in the uptake of nitrogenous compounds is discussed.
