Control of Phycoerythrin Synthesis during Chromatic Adaptation

Abstract

Chromatic adaptation is the process by which blue-green algae alter the rates of biliprotein synthesis in response to changes in the color of available light. The control of phycoerythrin synthesis during the early stages of chromatic adaptation in Fremyella diplosiphon was examined using fluorescence spectroscopy and 35S-labeling of polypeptides. Phycoerythrin synthesis begins within 45-90 min after transfer of cells from red to green light, but is blocked by rifamycin. Transfer of cells from green to red light stops phycoerythrin synthesis with a t1/2 [half time] = 45 min, as does the addition of rifamycin in green light. Transfer from green light to darkness slows but does not stop phycoerythrin synthesis. Gel electrophoresis of labeled polypeptides, both soluble and membrane-bound, shows that the synthesis of some polypeptides other than phycoerythrin are also affected by changes in light. Chromatic adaptation apparently involves gene regulation at the transcriptional level.