Modifications For Specific Purposes

Enzymatic Detection of Specific Classes of DNA Damage

An enzymatic modification of the alkaline comet assay to allow detection of oxidized bases was first described by Collins et al.[9] These authors suggested the use of lesion-specific DNA glycosylases/endonucleases involved in bacterial DNA repair to convert specific DNA base modifications to strand breaks. The embedded nucleoids are incubated in the presence of the enzyme after the lysis step, so that additional breaks can be introduced at sites of damaged bases. The amount of enzyme-specific lesions can then be calculated by the difference between the breaks found in enzyme-treated and those in buffer-treated slides. Any base modification can be detected with this procedure, as long as the proper repair enzyme is available. Among the DNA repair enzymes used in the comet assay, formamidopyrimidine-DNA glycosylase (FPG) and endonuclease III (ENDO III) have been used for the detection of oxidized purines (8-OH-guanine, 7-methylguanine, 5-OH-cytosine, and 5-OH-uracil) and pyrimidines (thymine glycol, dihydrothymine, dihydroxy-dihydrothymine, and uracil glycol), respectively.

UV endonuclease for recognition of UV-damaged bases (6-4 photoproducts, pyrimidine dimers)[4] and uracil glycosylase (UDG) for detection of misincorporated uracil[10] have also been used.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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