Georgakilas A G, Sideris E G, Sakelliou L, Kalfas C A
NCSR Demokritos, Institute of Biology, Athens, Greece.
Biophys Chem. 1999 Aug 9;80(2):103-18. doi: 10.1016/s0301-4622(99)00064-2.
Isolated calf thymus DNA in buffered solutions has been exposed to 0-150 Gy of alpha- and gamma-radiation. The effects of alpha- and gamma-radiation on the thermal stability and electrophoretic mobility of the DNA molecules have been studied by UV spectroscopic 'melting' and Pulsed Field Gel Electrophoresis (PFGE), respectively. The observed thermal denaturation parameters were fitted to the energy propagation descriptive model. The experimental results for the samples exposed to relatively low (low) doses indicate an increased thermal stability and a reduced mobility over that of the controls. The expected overall degradation of the DNA molecules was confirmed for the samples exposed to high doses. Our results are in good agreement with the predictions of the energy propagation model, which now is also tested in the low dose region and for an additional type of ionising radiation (alpha-particles). Our findings are consistent with conformational changes at low doses resulting in a DNA form characterised by localised alterations, which affect the energy flow along the DNA molecule.
缓冲溶液中的小牛胸腺DNA已暴露于0-150 Gy的α射线和γ射线下。分别通过紫外光谱“熔解”和脉冲场凝胶电泳（PFGE）研究了α射线和γ射线对DNA分子热稳定性和电泳迁移率的影响。将观察到的热变性参数拟合到能量传播描述模型中。暴露于相对低（低）剂量的样品的实验结果表明，与对照相比，其热稳定性增加且迁移率降低。对于暴露于高剂量的样品，证实了DNA分子预期的整体降解。我们的结果与能量传播模型的预测高度吻合，该模型现在也在低剂量区域以及另一种电离辐射（α粒子）中进行了测试。我们的发现与低剂量下的构象变化一致，这种变化导致DNA形成局部改变的特征形式，从而影响沿DNA分子的能量流动。
