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Assessment of the Effects of Various UV Sources on Inactivation and Photoproduct Induction in Phage T7 Dosimeter

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Author: Fekete, A. · Vink, A.A. · Gaspar, S. · Berces, A. · Modos, K. · Ronto, Gy. · Roza, L.
Institution: Centraal Instituut voor Voedingsonderzoek TNO
Source:Photochemistry and Photobiology, 4, 68, 527-531
Identifier: 234633
Keywords: Nutrition · Pyrimidine dimer · Virus DNA · Bacteriophage T7 · Chemistry · Comparative study · Escherichia coli · Genetics · Radiation exposure · Radiation response · Sunlight · Ultraviolet radiation · Virology · Bacteriophage T7 · DNA, Viral · Dose-Response Relationship, Radiation · Escherichia coli · Pyrimidine Dimers · Sunlight · Ultraviolet Rays


The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7 expressed in HT7 units. The CPD and (6-4)PD were determined by lesion-specific monoclonal antibodies in an immunodot-blot assay. The various lamps induced these lesions at different rates; the relative induction ratios of CPD to (6-4)PD increased with increasing effective wavelength of irradiation source. The amount of total adducts per phage was compared to the BED of phage T7 dosimeter, representing the average number of UV lesions in phage. For UVC (200-280 nm radiation) and unfiltered TL01 the number of total adducts approximates the reading; however, UV sources having longer effective wavelengths produced fewer CPD and (6-4)PD. A possible explanation is that although the most relevant lesions by UVC are the CPD and (6-4)PD, at longer wavelengths other photoproducts can contribute to the lethal damage of phages. The results emphasize the need to study the biological effects of solar radiation because the lesions responsible for the lethal effect may be different from those produced by various UV sources.