Complementary chromatic adaptation in a filamentous blue-green alga.
Fluorescent and red light environments generate greatly different patterns of pigmentation and morphology in Fremyella diplosiphon. Most strikingly, red-illuminated cultures contain no measurable C-phycoerythrin and have a mean filament length about 10 times shorter than fluorescent-illuminated cultures. C-phycoerythrin behaves as a photoinducible constituent of this alga. Spectrophotometric and immunochemical procedures were devised so that C-phycoerythrin metabolism could be studied quantitatively with [(14)C]-phenylalanine pulse-chased cultures. Transfer of red-illuminated cultures to fluorescent light initiates C-phycoerythrin production by essentially de novo synthesis. C-phycoerythrin is not degraded to any significant extent in cultures continuously illuminated with fluorescent light. Transfer of fluorescent-illuminated cultures to red light causes an abrupt cessation of C-phycoerythrin synthesis. The C-phycoerythrin content of cultures adapting to red light decreases and subsequently becomes constant. Loss of C-phycoerythrin is not brought about by metabolic degradation, but rather by a decrease in mean filament length which is effected by transcellular breakage. In this experimental system, light influences intracellular C-phycoerythrin levels by regulating the rate of synthesis of the chromoprotein.
D000222:Adaptation, Physiological; D000941:Antigens / Q000032:analysis; D002247:Carbon Isotopes; D000458:Cyanobacteria / Q000378:metabolism*; D005453:Fluorescence; D008027:Light; D010649:Phenylalanine / Q000378:metabolism; D010775:Photic Stimulation; D010860:Pigments, Biological / Q000378:metabolism*; D010940:Plant Proteins / Q000096:biosynthesis*; D013053:Spectrophotometry
D000941:Antigens; D002247:Carbon Isotopes; D010860:Pigments, Biological; D010940:Plant Proteins; D010649:Phenylalanine