Mechanism of photoinactivation of coliphage T7 sensitized by acridine orange

Selected Topics in Photochemistry of Nucleic Acids, Recent Results and Perspectives

“…In DNA apurinic sites are unstable in the presence of alkali and give rise to the appearance of single-strand breaks (Tamm et al, 1953). Freifelder and Uretz (1966) found a dose dependent formation of alkali-labile bonds and correlated them with the photodynamic inactivation of phage T7. Thus is seems possible, that, under proper conditions, strand scissions occur in photodynamically treated DNA samples.…”

Photoinactivation of Latent Herpes Simplex Virus in Rabbit Kidney Cells

“…The inactivation of viruses by the various photosensitizing dyes in the presence of visible light is thought to be the result of the dye binding to the viral nucleic acid and causing the breakdown of guanine residues in a photooxidation reaction (3,(12)(13)(14)18). Extracellular HSV particles have been shown to be photosensitive either when extracellular virus is exposed to neutral red or proflavine (1,17) or when the virus is grown in cells in medium containing the dye (11).…”

“…Experiments with other viruses have indicated that these dyes bind to the viral nucleic acid, resulting in the breakdown of guanine residues (3,(12)(13)(14)18). A number of clinical studies and studies using laboratory animals concerning the therapeutic effects of neutral red and proflavine have been reported (2,4,5,(7)(8)(9)(10)16).…”

Mechanisms of Protection of γ-irradiated Bacteriophage λ by Proflavine

“…All the manipulations with proflavine were performed in the dark with yellow light to prevent any damaging of DNA by visible light (Freifelder, Davidson andGeiduschek 1961, Freifelder andUretz 1966) .…”

“…experiments, the intercalation of proflavine into DNA protects it against y-ray damage (Gregoli, Taverna and Bertinchamps 1970) probably because proflavine is a much better electron acceptor than DNA bases . Intercalated proflavine would successfully compete with DNA bases in the capture of radiation released electrons, which otherwise would transform normal bases into anions, precursors of stable radioproducts .…”