Abstrakt

DNA, a molecule carrying our genome, is constantly exposed to various endogenous and exogenous damaging factors. These factors may lead to the formation of single- or double-strand breaks. Recently, an atomic force microscopy emerged as an attractive tool for determination of the length of DNA fragments deposited at surfaces, allowing quantification of double-strand breaks (DSBs). In spite of this, the length of objects provided via AFM is strictly related to the image spatial resolution, which in consequence leads to underestimation of DSBs quantity. To correct this deficiency, we provide here a novel methodology based on statistics of DNA fragments length. This approach allows for highly accurate determination of the DSBs number. Moreover, we provide the software that enables to automatically calculate the number of DSBs according to the described methodology. Finally, the method is applied for characterization of the DNA plasmid fragmentation by bleomycin - an anticancer chemotherapeutic drug.