FLUORESCENCE OF EUGLENA-GRACILIS PHOTORECEPTOR PIGMENT AN IN-VIVO MICROSPECTROFLUOROMETRIC STUDY

By means of a tunable dye-laser microspectrofluorometer, some of the spectroscopic properties of the photoreceptor pigment of the green flagellate E.gracilis were examined. The in vivo fluorescence excitation spectrum was determined and the fluorescence quantum yield measured. Flavins are indeed present in the paraflagellar body of E. gracilis and their fluorescence quantum yield is much lower than that of a free flavin. An estimate of the order of magnitude of the rate constants for primary molecular reactions is tentatively given.