| Abstract: | New results on sensitization of fluorescence of Profiuvine, Acridine Orange and Ethidium Bromide complexes wilh double stranded poly A-poly U upon ultraviolet irradiation are presented. Together with older results on dye DNA complex, they are interpreted to show that base to base transfer plays essentially no role compared to direct base to dye transfer. A lower limit of base to base transfer time (which is at the same time a higher limit for life time of fluorescence) in DNA (2. 10?11 sec.) and poly A-poly U (2. 10?13 sec.) is obtained which cast some doubt upon the validity of calculations of optical properties using the exciton (strong coupling) approximation. |
