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FLUENCE‐RATE DEPENDENCE OF MONOPHOTONIC REACTIONS OF NUCLEIC ACIDS IN VITRO AND IN VIVO
Author(s) -
Lang H.,
Riesenberg D.,
Zimmer Ch.,
Bergter F.
Publication year - 1986
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1986.tb04710.x
Subject(s) - fluence , irradiation , in vivo , nucleic acid , chemistry , in vitro , biophysics , reciprocity (cultural anthropology) , analytical chemistry (journal) , photochemistry , biochemistry , physics , biology , chromatography , nuclear physics , genetics , psychology , social psychology
The Bunsen‐Roscoe law, also known as the reciprocity law ( E = f(F) with F = I t ) has only limited validity for monophotonic reactions of nucleic acids. Especially at low fluence rates, the extent of in vitro and in vivo photoreactions of nucleic acids in the far‐UV and near‐UV range is a function of the fluence and of the fluence rate ( E = f (F;I)). In vitro experiments with poly(dA)poly(dT) clearly show that the far‐UV (254 nm) response, indicated by the changes of the ellipticity at 315 nm, does not obey the Bunsen‐Roscoe law at low fluence rates in the range between 1 W m ‐2 and 20 W m ‐2 . In vivo experiments with Escherichia coli revealed very similar anomalies. Studying the growth delay after irradiation with far‐UV light at 280 nm or near‐UV light at 334 nm, we have confirmed the lack of reciprocity in both spectral ranges. The failure of the Bunsen‐Roscoe law for the 280 nm and 334 nm UV irradiation effect at low fluence rates was in the range O < I < 40 W m ‐2 . In both cases reciprocity occurred at higher fluence rates (40 < I < 100 W m ‐2 ).