Nováková Eva, Vyšín Luděk, Burian Tomáš, Juha Libor, Davídková Marie, Múčka Viliam, Čuba Václav, Grisham Michael E, Heinbuch Scott, Rocca Jorge J
Department of Radiation and Chemical Physics, Institute of Physics CAS, Na Slovance 2, Prague 8, 182 21, Czech Republic.
Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, Prague 1, 115 19, Czech Republic.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Apr;91(4):042718. doi: 10.1103/PhysRevE.91.042718. Epub 2015 Apr 29.
Ionizing radiation induces a variety of DNA damages including single-strand breaks (SSBs), double-strand breaks (DSBs), abasic sites, modified sugars, and bases. Most theoretical and experimental studies have been focused on DNA strand scissions, in particular production of DNA double-strand breaks. DSBs have been proven to be a key damage at a molecular level responsible for the formation of chromosomal aberrations, leading often to cell death. We have studied the nature of DNA damage induced directly by the pulsed 46.9-nm (26.5 eV) radiation provided by an extreme ultraviolet (XUV) capillary-discharge Ne-like Ar laser (CDL). Doses up to 45 kGy were delivered with a repetition rate of 3 Hz. We studied the dependence of the yield of SSBs and DSBs of a simple model of DNA molecule (pBR322) on the CDL pulse fluence. Agarose gel electrophoresis method was used for determination of both SSB and DSB yields. The action cross sections of the single- and double-strand breaks of pBR322 plasmid DNA in solid state were determined. We observed an increase in the efficiency of strand-break induction in the supercoiled DNA as a function of laser pulse fluence. Results are compared to those acquired at synchrotron radiation facilities and other sources of extreme-ultraviolet and soft x-ray radiation.
电离辐射会引发多种DNA损伤，包括单链断裂（SSB）、双链断裂（DSB）、无碱基位点、修饰的糖和碱基。大多数理论和实验研究都集中在DNA链断裂上，特别是DNA双链断裂的产生。双链断裂已被证明是分子水平上导致染色体畸变形成的关键损伤，常常导致细胞死亡。我们研究了由极紫外（XUV）毛细管放电类氖氩激光（CDL）提供的46.9纳米（26.5电子伏特）脉冲辐射直接诱导的DNA损伤的性质。剂量高达45千戈瑞，重复频率为3赫兹。我们研究了简单DNA分子模型（pBR322）的单链断裂和双链断裂产率对CDL脉冲注量的依赖性。琼脂糖凝胶电泳法用于测定单链断裂和双链断裂的产率。测定了固态pBR322质粒DNA单链和双链断裂的作用截面。我们观察到超螺旋DNA中链断裂诱导效率随激光脉冲注量的增加而增加。将结果与在同步辐射设施以及其他极紫外和软X射线辐射源获得的结果进行了比较。
