EFFECTS OF ARTIFICIAL UV-B AND SIMULATED SOLAR RADIATION ON THE FLAGELLATE EUGLENA-GRACILIS - PHYSIOLOGICAL, SPECTROSCOPICAL AND BIOCHEMICAL INVESTIGATIONS

The effects of enhanced artificial UV-B radiation and simulated solar radiation on cell shape, motility, pigmentation, photosynthetic oxygen production, protein pattern and content of the D1 protein have been investigated in the flagellate Euglena gracilis. The experiments showed that a spherical cell shape, vacuolization and the impairment of motility occurred much earlier when the cells were irradiated with enhanced UV-B radiation, while photobleaching of photosynthetic pigments occurred earlier when the cells had been exposed to simulated solar radiation. The inhibition of photosynthetic oxygen production was reversible under simulated solar radiation and irreversible (after 60 h of recovery) after exposure to enhanced UV-B radiation. There was an initial increase in chlorophyll a fluorescence emission after irradiation with enhanced UV-B radiation which did not occur after irradiation with simulated solar radiation. The protein pattern did not change significantly after irradiation but the content of D1 protein decreased after short exposure times to bath radiation sources.