DNA damage produced by exposure of supercoiled plasmid DNA to high- and low-LET ionizing radiation: Effects of hydroxyl radical quenchers. DNA breakage, neutrons, OH radicals

Technical Report · Mon Aug 01 04:00:00 EDT 1994

DOI:https://doi.org/10.2172/10172487· OSTI ID:10172487

Peak, J G; Ito, T; Peak, M J ^[1]; Robb, F T ^[2]

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1. Argonne National Lab., IL (United States)
2. Univ. of Maryland, Baltimore, MD (United States). Center for Marine Biotechnology

A supercoiled plasmid of 7300 base pairs was isolated and exposed in an aqueous environment to {sup 60}Co {gamma} rays and JANUS 0.85 MeV fission-spectrum neutrons. Dose responses for the production of single-strand breaks (SSBs), double-strand breaks (DSBs) and alkali-labile sites (ALSs) were compared with computations made from the conversion of the supercoil to its relaxed and linear forms. The relative biological effectiveness (RBE) for production of SSBs and DSBs was similar to that previously measured in the cellular environment. The RBE for destruction of genetic transforming activity of M13 viral DNA followed that for DNA damage. This is in contrast to the situation for biological effects such as lethality, mutagenesis, and cellular transformation measured in mammalian cells, where the RBE values are reversed. The role of hydroxyl (OH) radical in DNA damage induction by neutrons was investigated by exposure of plasmid in the presence of known quenchers of this species. Of four quenchers tested, all were able to reduce the yields of both SSBs and DSBs. These findings are consistent with a model for SSB and DSB induction by high linear energy transfer that involves OH radical mediation.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 10172487
• Report Number(s): ANL/BIM/PP--78690; ON: DE94016382
• Country of Publication: United States
• Language: English

Related Subjects

550200
560120
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOCHEMISTRY
BIOLOGICAL RADIATION EFFECTS
DNA
HYDROXYL RADICALS
LET
PLASMIDS
RADIATION EFFECTS ON BIOCHEMICALS, CELLS, AND TISSUE CULTURE
RBE
RESPONSE MODIFYING FACTORS
STRAND BREAKS