Comet Assay: A Strong Tool for Evaluating DNA Damage and Comprehensive Guidelines for Plant Cells

Heavy metals affect plant system in various toxic ways including morphophysiological alterations and genotoxic damages inside a plant cell. The extent of DNA damage under any genotoxic agents can be effectively measured in single cells applying comet assay approach. Comet assay primarily measures DNA strand breakage in single cells and its use has increased in different areas: clinical applications, human monitoring, radiation biology and genetic ecotoxicology. This paper is a review of the detailed protocol and precautions to be taken while performing comet assay and may have been slightly modified from other original protocols according to the plant, organ, cell type, etc. In conclusion, the study reviewed in this paper demonstrate that the comet assay application in plants provides a reliable, sensitive and rapid system for the study of environmental genotoxicity caused by heavy metals.

Avian genetic ecotoxicology: DNA of the canary in a coalmine

Genotoxic chemicals, through damage and alteration of the genetic material of wild organisms, pose significant threats to the persistence of wild animal populations. Their damaging effects can ultimately impair the health of the ecosystem and its provision of services to human society. Bird species are good candidates for the role of sentinels of the effects of genotox-ins, thanks to (i) the diversity of their ecological niches, (ii) their ubiquity across environments, (iii) their conspicuousness, abundance and approachability, together with (iv) their well-known life histories and the availability of historical data series. Avian diversity increases the likelihood that adequate model species be available for monitoring genotoxicants and assessing their impact. This paper reviews the methods utilized by genetic ecotoxicological studies of wild birds, highlighting their benefits and shortcomings. It also summarizes the genetic ecotoxicological studies so far conducted. In spite of a paucity of studies, several classes of genotoxicants have already been investigated across a variety of species and environments, thus supporting the versatility of birds as monitors of genotoxic contamination. Future technical advancements and applications are suggested, with particular reference to the analysis of mutational events, gene expression and methylation patterns. Finally, I argue that the development of avian genetic ecotoxicology will contribute to the understanding of natural variation in the underlying machinery for coping with DNA damage and oxidative stress, both of which are increasingly recognized as proximate factors in the evolution of life history adaptations.