Novel apparatus to measure hyperthermal heavy ion damage to DNA: strand breaks, base loss, and fragmentation.
We have developed a novel apparatus that allows us to irradiate nonvolatile organic films of high mass (1-100 microg range) spread out over a large surface area (42 cm(2)) with low energy (kT-100 eV) heavy ions and to quantitatively analyze the film substance via standard biochemical techniques afterwards. Here we discuss the details of the apparatus and method and show that it allows us to measure substantial damage to double stranded DNA molecules (plasmids) and its fundamental subunits induced by heavy ions with unprecedented low energies, i.e., 2.5 eV/amu; these energies correspond to track end energies of stopping ions or secondary ions created along primary ion tracks. We find that hyperthermal Ar(+) ions interacting with plasmid DNA will lead to the formation of single and double strand breaks, as well as fragmentation of nucleosides, which also involve chemical modifications and site specific rupture along the N1-C1 glycosidic bond, resulting in base release. In cells, such localized clustered damage will enhance the severity of DNA strand lesions, thus making them harder to repair.
Sellami
L
L
Ion Reaction Laboratory, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada.
Lacombe
S
S
Hunting
D
D
Wagner
R J
RJ
Huels
M A
MA
D020137:Base Pair Mismatch / Q000528:radiation effects; D017076:Computer-Aided Design; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000528:radiation effects*; D053960:DNA Breaks; D004249:DNA Damage; D053938:DNA Fragmentation / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020450:Heavy Ions; D010315:Particle Accelerators / Q000295:instrumentation*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004247:DNA