Laser microspectrofluorometry of photopigments in vivo

A study of the spectral properties of photopigments of microorganisms is of major importance for the understanding of molecular mechanisms whereby these can respond to changes in external illumination conditions. Microspectroscopy in vivo using a tunable dye laser as an excitation source was employed to solve this problem for the case of the unicellular algae Euglena gracilis. This experimental approach made it possible to study fluorescence excitation spectra of photopigments, their average lifetime, and any photochemical reactions which may accompany the absorption of light.