The effect of osmium tetroxide oxidation of single-stranded, circular φX174-DNA on its infectivity in E. coli spheroplasts was investigated. Osmium tetroxide predominantly oxidizes thymine to 5,6-dihydroxy-dihydrothymine in DNA and causes only negligible amounts of strand breakage. Products of the 5,6-dihydroxy-dihydrothymine type represent typical lesions introduced into DNA by ionizing radiation. It was found that osmium tetroxide oxidation inactivated the DNA and that at 37% residual infectivity the φX174-genome contained on average 2.8 ring-saturated thymine residues. No significant differences were observed for spheroplasts from wild type E. coli, E. coli polA, E. coli uvrA, E. coli recA, and E. coli recB.

This content is only available as a PDF.
You do not currently have access to this content.