Abstract
Detection of DNA strand breaks by radiation was carried out using real-time PCR amplification. Gamma irradiation to pBR322 plasmid DNA solutions was done by 137Cs as dose of 0Gy to 150Gy. 1003bp, 505bp and 243bp fragments were amplified by combined primer sets for the plasmid solution including Tris-HCl as a radical scabenger. Higher amplification values such as over 300% to the non-irradiated solution (100%) were observed and could be depending on rate of closed circular shape (CC) and open circular shape (OC) in the original solution of pBR322 used in each experiment. One suitable explanation that the CC is difficult to be amplified by the PCR reaction and structurally changed CC after aberrations ca;used by radicals is possible to be amplified by the real-time PCR. The evident piaks in three amplified fragments were observed at 15 to20 Gy and different values from peak (80Gy) of electrophoresis data concerning sift from CC to OC. The results of the Monte Carlo simulation calculation were not completely fit to the practical PCR data. Therefore, parameters by electrophoresis data should be modified and then we tried to compare with the simulation data using novel break-induced probabilities. We will present that the real-time PCR method predicted that the break-induced probability derived from simulation calculation based on exchanging rate of CC to OC by irradiation on the electrophoresis should be estimated as about 2 times.
