Photosynthetische Reaktionen in lyophilisierten Zellen der Blaualge Anacystis

Abstract

Intact cells of the bluegreen algae Anacystis nidulans photoreduce p-benzoquinone under O₂-evolution but not ferricyanide. Catalytic amounts of a quinone catalyze the photoreduction of ferricyanide; the more positive its redoxpotential the better is the stimulation. By the simple procedure of lyophilizing Anacystis in 5% sucrose and resuspending in 4·10^—2-m. magnesiumchloride a preparation is obtained which exhibits the same photosynthetic activities as known from isolated chloroplast fragments, i. e. they evolve oxygen and photoreduce ferricyanide, quinones and NADP *; these Hill- reactions are coupled to ATP-formation; they catalyze pseudocyclic and cyclic photophosphorylation. Rates compare favorably with those of isolated chloroplasts except for the NADP-system. A number of known inhibitors like DCMU, KCN, dinitrophenol, salicylaldoxime and ammoniumchloride were checked and found to behave in principal as in photosynthetic chloroplast reactions.