Chemical damage, modified base

The ReProComet assay (repair-proficient comet assay) was developed to detect chemically induced DNA damage in sperm cells. In order to overcome the intrinsic DNA repair deficiency of the sperm cells this modified comet assay is based on the addition of a protein extract from HeLa cells to agarose-embedded sperm on microscopic slides previously exposed to mutagenic compounds. A clear-cut dose-dependent effect was measured after addition of the cell extract representing a proof of concept of a novel in vitro mutagenicity test on sperm [18]. Transferability to other laboratories remains to be addressed. 

DNA primary damage DNA adducts (alkyl and bulky adducts) are nucleotide bases covalently modified by reactive electrophilic chemical intermediates or free radicals. 

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