title: Effect of intense, ultrashort laser pulses on DNA plasmids in their native state: strand breakages induced by in situ electrons and radicals.
abstract: Single strand breaks are induced in DNA plasmids, pBR322 and pUC19, in aqueous media exposed to strong fields generated using ultrashort laser pulses (820 nm wavelength, 45 fs pulse duration, 1 kHz repetition rate) at intensities of 1-12  TW cm(-2). The strong fields generate, in situ, electrons and radicals that induce transformation of supercoiled DNA into relaxed DNA, the extent of which is quantified. Introduction of electron and radical scavengers inhibits DNA damage; results indicate that OH radicals are the primary (but not sole) cause of DNA damage.
authors.affiliation: UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098, India.
authors.forename: J S
authors.initials: JS
authors.lastname: D'Souza
authors.forename: J A
authors.initials: JA
authors.lastname: Dharmadhikari
authors.forename: A K
authors.initials: AK
authors.lastname: Dharmadhikari
authors.forename: B J
authors.initials: BJ
authors.lastname: Rao
authors.forename: D
authors.initials: D
authors.lastname: Mathur
mesh_terms: D004247:DNA / Q000528:radiation effects*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D004583:Electrons / Q000009:adverse effects; D016166:Free Radical Scavengers / Q000737:chemistry; D005609:Free Radicals / Q000009:adverse effects; D017665:Hydroxyl Radical / Q000009:adverse effects*; D007259:Infrared Rays; D007834:Lasers; D010957:Plasmids / Q000528:radiation effects*; D011675:Pulse Radiolysis / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D016166:Free Radical Scavengers; D005609:Free Radicals; D014867:Water; D017665:Hydroxyl Radical; D004247:DNA