Abstract
In the yellow and colorless mutant of Chlorella kesseleri, grown with nitrate as the sole nitrogen source, the addition of glucose or the irradiation of blue light inhibited the uptakes of nitrate, amino acids and ammonia in growing cells, while these enhanced the uptakes of nitrate, amino acids and ammonia in starved cells. For the colorless mutant, blue light was shown to activate purified nitrate reductase and also activate glycine oxidase. It is known that Chlorella kesseleri, grown with ammonia as the sole nitrogen source has no nitrate reductase protein.
In this experiment, we observed that ammonia-grown cells showed blue light-induced respiration in similar manner to nitrate-grown cells. These results indicate that in the mutant cells of Chlorella examined, uptake system of nitrogenous compounds such as nitrate, amino acids and ammonia seems to be influenced by two blue light-receptors mediating the effects of ammonia accumulated in the presence of glucose or under blue light.
