The formation, in the dark, of phycoerythrin in the preilluminated cells of a blue-green alga, Tolypothrix tenuis, was investigated with special reference to its nitrogen metabolism. On incubating the pre-illuminated algal cells under a darkaerobic condition, and with nitrate as N-source, the formation of phycoerythrin occurs after an induction period of about 5 hours. No time-lag is observed in the nitrate-uptake by the organism. Similar results are obtained with nitrite, ammonia, urea and arginine as N-sources. The above stated formation of phycoerythrin is suppressed by substances such as chloramphenicol and p-fluorophenylalanine, substances known to be potent inhibitors of protein-synthesis. On the basis of these findings, it was inferred that there are two consecutive processes involved in the dark-formation of phycoerythrin in the pre-illuminated cells: (i) uptake and conversion of exogenous nitrogen sources into some intermediary nitrogenous cell substances, and (ii) synthesis of the pigment-protein from these substances.
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Fujita et al. (1960) studied this question.