title: Proton-induced direct and indirect damage of plasmid DNA.
abstract: Clustered DNA damage induced by 10, 20 and 30 MeV protons in pBR322 plasmid DNA was investigated. Besides determination of strand breaks, additional lesions were detected using base excision repair enzymes. The plasmid was irradiated in dry form, where indirect radiation effects were almost fully suppressed, and in water solution containing only minimal residual radical scavenger. Simultaneous irradiation of the plasmid DNA in the dry form and in the solution demonstrated the contribution of the indirect effect as prevalent. The damage composition slightly differed when comparing the results for liquid and dry samples. The obtained data were also subjected to analysis concerning different methodological approaches, particularly the influence of irradiation geometry, models used for calculation of strand break yields and interpretation of the strand breaks detected with the enzymes. It was shown that these parameters strongly affect the results.
authors.affiliation: Institute of Physics CAS, Na Slovance 1999/2, 182 21, Prague, Czech Republic.
authors.forename: Luděk
authors.initials: L
authors.lastname: Vyšín
authors.forename: Kateřina
authors.initials: K
authors.lastname: Pachnerová Brabcová
authors.forename: Václav
authors.initials: V
authors.lastname: Štěpán
authors.forename: Patrick
authors.initials: P
authors.lastname: Moretto-Capelle
authors.forename: Beatrix
authors.initials: B
authors.lastname: Bugler
authors.forename: Gaelle
authors.initials: G
authors.lastname: Legube
authors.forename: Pierre
authors.initials: P
authors.lastname: Cafarelli
authors.forename: Romain
authors.initials: R
authors.lastname: Casta
authors.forename: Jean Philippe
authors.initials: JP
authors.lastname: Champeaux
authors.forename: Martine
authors.initials: M
authors.lastname: Sence
authors.forename: Martin
authors.initials: M
authors.lastname: Vlk
authors.forename: Richard
authors.initials: R
authors.lastname: Wagner
authors.forename: Jan
authors.initials: J
authors.lastname: Štursa
authors.forename: Václav
authors.initials: V
authors.lastname: Zach
authors.forename: Sebastien
authors.initials: S
authors.lastname: Incerti
authors.forename: Libor
authors.initials: L
authors.lastname: Juha
authors.forename: Marie
authors.initials: M
authors.lastname: Davídková
mesh_terms: D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D045643:DNA Repair Enzymes / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004587:Electrophoresis, Agar Gel; D005720:Gamma Rays / Q000009:adverse effects; D018499:Linear Energy Transfer; D008954:Models, Biological; D010957:Plasmids / Q000378:metabolism / Q000528:radiation effects*; D011522:Protons / Q000009:adverse effects*; D012996:Solutions
chemical_list: D011522:Protons; D012996:Solutions; D045643:DNA Repair Enzymes