UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098, India.
Phys Rev Lett. 2011 Mar 18;106(11):118101. doi: 10.1103/PhysRevLett.106.118101. Epub 2011 Mar 14.
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.
在强场中，单链断裂被诱导发生在 pBR322 和 pUC19 等 DNA 质粒中，该强场是由超短激光脉冲（820nm 波长，45fs 脉冲持续时间，1kHz 重复频率）在 1-12TW/cm2 的强度下产生的。这些强场在原位生成电子和自由基，将超螺旋 DNA 转化为松弛 DNA，其程度可被定量。引入电子和自由基清除剂可抑制 DNA 损伤；结果表明，羟基自由基是 DNA 损伤的主要（但不是唯一）原因。
