Clustered DNA damage on subcellular level: effect of scavengers
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Clustered DNA damages are induced by ionizing radiation, particularly of high linear energy transfer (LET). Compared to isolated DNA damage sites, their biological effects can be more severe. We investigated a clustered DNA damage induced by high LET radiation (C 290 MeV u−1 and Fe 500 MeV u−1) in pBR322 plasmid DNA. The plasmid is dissolved in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers.
KeywordsClustered damage Indirect effects Heavy ion Plasmid in liquid water Scavenger
K. Pachnerová Brabcová and L. Sihver greatly acknowledge the support by the ESA-ESTEC NPI program No. 4000101677/10/NL/PA-NPI 120-2009. This work was performed as a part of accelerator experiments of the Research Project (13J401) at NIRS-HIMAC. We would like to express our thanks to the staff of NIRS-HIMAC for their kind support throughout the experiments for sample irradiation. M. Davidkova and V. Stepan greatly acknowledge the support by the Ministry of Education, Youth and Sports of the Czech Republic, project No. LD12008.
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