Regulation of cAMP-mediated Photosignaling by a Phytochrome in the Cyanobacterium Anabaena cylindrica¶

Abstract
Changes in cellular adenosine 3′,5′-cyclic monophosphate (cAMP) content induced by monochromatic light of various wavelengths were determined in the cyanobacterium Anabaena cylindrica. Irradiation with monochromatic red light caused a rapid decrease in cAMP content. In contrast, far-red light caused a rapid increase in its content. The effects of red and far-red light were reversible, suggesting the involvement of a prototype phytochrome as the photoreceptor for cAMP-mediated light-responsive signal transduction