The May 2018 Editor's Choice article is "Application of the CometChip platform to assess DNA damage in field-collected blood samples from turtles" by Peter Sykora, Ylenia Chiari, Andrew Heaton, Nickolas Moreno, Scott Glaberman, and Robert W. Sobol.
Quick and accurate measurement of DNA damage in environmental studies provides valuable information on the nature and extent of genotoxic insult in a given population or biological system. Ultimately, this information can be used by regulators to protect species against chemical exposures. In the May 2018 issue of Environmental and Molecular Mutagenesis, Peter Sykora and co-workers at the University of South Alabama, demonstrate how a novel, high-throughput CometChip Platform can be successfully applied to measure DNA damage in environmental samples. The CometChip Platform builds on the classical Comet assay and was used to analyze samples from 40 box turtles and red-eared sliders. Authors took advantage of the fact that erythrocytes of non-mammalian vertebrates have a nucleus and thus, can be used for the assessment of DNA damage. As little as 200 microliters of blood was collected per animal, samples were kept on ice, and delivered to the laboratory within two hours. The addition of three known genotoxic compounds to blood samples yielded the expected positive results. In addition, optimal freezing solution, storage times, and the extent to which DNA can be repaired were assessed using the CometChip Platform. Overall, samples stored on ice up to 24 hours did not a show significant increase in the extent of DNA damage. Samples frozen in all freezing solutions significantly reduced the extent of DNA damage seen in samples frozen without such solutions. The extent of DNA repair was measured by taking measurements right after the addition of a DNA-damaging agent and then again after samples were left for 30 min at room temperature. The repair of DNA damage was more efficient in the samples from the box turtle males, following hydrogen peroxide exposure of blood samples, while samples derived from females also had more damage prior to exposure. Overall, box turtle samples had a greater capacity to accumulate and repair DNA damage, while both species had a similar extent of DNA damage prior to the addition of the DNA-damaging agent. Interestingly, DNA repair was more efficient in the samples taken from longer body length, and presumably, older red-eared sliders. This study, therefore, not only demonstrates the feasibility of high-throughput assessment of DNA damage and repair in environmental samples, but it also offers a tool to understand species-, gender-, and age-specific effects on DNA damage and repair. This approach can be applied to all mammalian vertebrates with nucleated erythrocytes and for interdisciplinary investigations, bringing together genetic toxicologists, ecologists, and regulatory scientists aimed at environmental protection. Environ. Mol. Mutagen. 59:322–333, 2018. © 2018 Wiley Periodicals, Inc.