Heidelberg 2006 – wissenschaftliches Programm
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ST: Strahlen- und Medizinphysik
ST 12: Biophysikalische Nanoskopie
ST 12.8: Vortrag
Mittwoch, 15. März 2006, 12:00–12:10, D
Radiation induced DNA fragmentation - AFM study. — •Katarzyna Psonka1,2, Gisela Taucher-Scholz2, and Ewa Gudowska-Nowak1,2 — 1Jagiellonian University, Institute of Physics, Cracow, Poland — 2Gesellschaft für Schwerionenforschung, Darmstadt, Germany
Ionizing radiation produces a plethora of lesions in DNA including strand breaks (single or double) and alteration to bases. Double-strand breaks (DSBs) leading to DNA fragmentation are considered to be the most critical lesions resulting in cell killing, cancerogenesis or mutations. We have used Atomic Force Microscopy (AFM) to visualize the DNA fragmentation induced by heavy ions (high LET radiation) and to compare it to the fragmentation pattern obtained after X-rays (low LET radiation). Plasmid DNA was irradiated in vitro with X-rays and 3.9 MeV/u Ni ions within a dose range 0-3000 Gy. Afterwards, the samples were analyzed using AFM, which allowed the detection and length measurement of individual fragments with a nanometer resolution. Recording of the length of the induced fragments allowed to distinguish between molecules broken by a single DSB or by multiple DSBs. The fragment length distributions were derived for different doses and different radiation qualities. Our results show an influence of radiation quality on DSB production. Enhanced induction of short fragments after high LET radiation corresponds to the locally correlated induction of DSB within individual particle tracks.