FORMATION OF PHYCOERYTHRIN IN PRE-ILLUMINATED CELLS OF TOLYPOTHRIX TENUIS WITH SPECIAL REFERENCE TO NITROGEN METABOLISM

1. The formation, in the dark, of phycoerythrin in the preilluminatedcells of a blue-green alga, Tolypothrix tenuis, was investigatedwith special reference to its nitrogen metabolism.
2. On incubatingthe pre-illuminated algal cells under a darkaerobiccondition,and with nitrate as N-source, the formation of phycoerythrinoccurs after an induction period of about 5 hours. No time-lagis observed in the nitrate-uptake by the organism. Similar resultsare obtained with nitrite, ammonia, urea and arginine as N-sources.
3. The above stated formation of phycoerythrin is suppressedbysubstances such as chloramphenicol and p-fluorophenylalanine,substances known to be potent inhibitors of protein-synthesis.
4. On the basis of these findings, it was inferred that therearetwo consecutive processes involved in the dark-formationofphycoerythrin in the pre-illuminated cells: (i) uptake andconversionof exogenous nitrogen sources into some intermediarynitrogenouscell substances, and (ii) synthesis of the pigment-proteinfromthese substances.

(Received June 27, 1960; )