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THE ROLE OF DNA DAMAGE IN PM2 VIRAL INACTIVATION BY METHYLENE BLUE PHOTOSENSITIZATION
Author(s) -
Specht Kathleen G.
Publication year - 1994
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.1751-1097.1994.tb02976.x
Subject(s) - infectivity , dna , dna damage , microbiology and biotechnology , methylene blue , nucleic acid , virus , biology , chemistry , cleavage (geology) , viral envelope , virology , biochemistry , paleontology , photocatalysis , fracture (geology) , catalysis
— This study investigates the importance of DNA damage in viral inactivation by phenothiazines and light. Phenothiazines, including methylene blue (MB), toluidine blue and azure B are of particular interest because of their ability to bind to nucleic acids in vitro. Initial studies employing phages T7, MS2 and PM2 indicated that both DNA and RNA phages as well as enveloped and nonenveloped phages can be inactivated by phenothiazine photosensiti‐zation. PM2, which contains a lipid‐protein bilayer and supercoiled DNA, was used for the mechanistic studies to model blood‐borne viruses. Viral DNA damage was assessed following treatment of phage to known levels of viral inactivation by extracting the DNA and analyzing for both direct and piperidine‐catalyzed strand cleavage by gel electrophoresis. DNA strand cleavage was found to be both sensitizer concentration and light dose dependent. Both viral inactivation and DNA damage were found to be oxygen‐dependent events. In parallel experiments, strand cleavage of isolated PM2 DNA treated with MB and light was also found to be oxygen dependent, in contrast to some previous reports. Transfection studies, which measure the infectivity of the extracted viral DNA, indicated that DNA from MB‐treated phage was just as capable of generating progeny virus as the untreated controls. It was therefore concluded that the observed DNA damage is not correlated with loss of phage infectivity.