UV EFFECTS ON PHOTOSYNTHESIS, PROTEINS AND PIGMENTATION IN THE FLAGELLATE EUGLENA-GRACILIS - BIOCHEMICAL AND SPECTROSCOPIC OBSERVATIONS

Photosynthetic oxygen production, pigmentation and protein composition of the freshwater flagellate, Euglena gracilis, were studied after exposure of the cells to UV radiation. Absorption spectroscopy and fast protein liquid chromatography (FPLC) indicate that the photosynthetic pigments are bleached and their apoproteins destroyed only after extended periods of solar or artificial UV radiation. In contrast, photosynthetic oxygen production is impaired even after short exposure times of a few minutes. Fluorescence spectra show that the energy transfer from the accessory pigments to the reaction centres of photosystem II is impaired by UV radiation, indicating a structural damage within the photosynthetic apparatus.