DNA damage produced by exposure of supercoiled plasmid DNA to high- and low-LET ionizing radiation: effects of hydroxyl radical quenchers.
Int J Radiat Biol
; 67(1): 1-6, 1995 Jan.
Article
en En
| MEDLINE
| ID: mdl-7852813
Production of DNA damage by exposure to ionizing radiation was measured in two in vitro systems. A supercoiled plasmid of 7.3 kbp was isolated and exposed in an aqueous environment to 60Co gamma rays and JANUS 0.85 MeV fission-spectrum neutrons. Dose responses for the production of single-strand breaks (ssbs) and double-strand breaks (dsbs) were computed from the conversion of the supercoil to its relaxed and linear forms. The relative effectiveness (neutrons:gamma-rays) for destruction of genetic transforming activity of M13 viral DNA was 0.23, close to that for ssb production, in contrast with the situation for biological effects such as lethality, mutagenesis and cellular transformation measured in mammalian cells, where RBEs are > 1. The role of hydroxyl (OH) radicals 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 radiation that involves OH radical medication.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plásmidos
/
Daño del ADN
/
ADN Superhelicoidal
/
ADN Viral
/
Depuradores de Radicales Libres
/
Radical Hidroxilo
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Int J Radiat Biol
Asunto de la revista:
RADIOLOGIA
Año:
1995
Tipo del documento:
Article
Pais de publicación:
Reino Unido