Fluorescence spectrophotometry of pyridine nucleotide in photosynthesizing cells

Abstract

An increase in the blue fluorescence of suspensions of purple bacteria and of a blue alga was observed upon illumination with photosynthetically active infrared or red radiation. The spectrum obtained by subtracting the fluorescence spectrum in the “dark” from that in the “light” was similar to that of reduced pyridine nucleotide. This and other evidence obtained supports the hypothesis that during both algal and bacterial photosynthesis an accelerated reduction of pyridine nucleotide occurs.