Comet assay in genetic ecotoxicology: A review

Abstract

The Comet assay, also called the single cell gel electrophoresis (SCGE) assay or microgel electrophoresis (MGE) assay, primarily measures DNA strand breakage in single cells. Since the protocol was published by Singh et al. [1988], its use has increased in different topic areas: clinical applications, human monitoring, radiation biology, genetic toxicology, and genetic ecotoxicology. This study is a review of the investigations that have involved the alkaline version of the Comet assay in genetic ecotoxicology. It focuses mainly on the type of organisms (plants, worms, molluscs, fish, amphibians, and mammalians) but also on the type of cells that have been used for ecotoxicological studies. In the 23 papers published since 1993 and presented here, the original test procedure may have been slightly modified according to the cell type. In vitro and in vivo experiments as well as in situ studies have been carried out in various environments (water, soil, and air). Although the Comet assay is able to detect genotoxic effects of chemical and physical agents, only chemical substances and environmental complex mixtures will be considered in this review. Environ. Mol. Mutagen. 34:246–255, 1999 © 1999 Wiley‐Liss, Inc.

Biomarkers responses of the earthworm Eisenia fetida to acetochlor exposure in OECD soil

“…Comet assay was proved to be a sensitive and useful tool for measuring DNA damage and repair of different chemical pollutants in a variety of organisms, from plants to mammals (Singh et al, 1988;Cotelle and Ferard, 1999;Reinecke and Reinecke, 2004). Its application to earthworm is very valuable for monitoring and detection of genotoxicity of different chemical pollutants in terrestrial ecosystem (Verschaeve and Gilles, 1995;Salagovic et al, 1996;Cotelle and Ferard, 1999).…”

“…Its application to earthworm is very valuable for monitoring and detection of genotoxicity of different chemical pollutants in terrestrial ecosystem (Verschaeve and Gilles, 1995;Salagovic et al, 1996;Cotelle and Ferard, 1999). This technique has shown clear dose responses even at relatively low levels of naturally occurring genotoxicants (Fairbairn et al, 1995;Zang et al, 2000).…”

Assessment of DNA Damage in Leukocytes of Patients With Coronary Artery Disease by Comet Assay

“…28) Olive tail moment is the product of tail length and the fraction of total DNA in tail. 29) Damage frequency is the frequency distribution of the number of nucleoids with tails. 30) Damage index, in which each cell was assigned to one of 4 classes (from no damage = 0 to maximum damage = 4) according to tail size and shape.…”

Miniaturizing the comet assay with 3D vertical comets

“…Tail length is described here as the length between the most distant tail pixel and the center of the comet head. Calculation of the comet moment was carried out with the following formula: comet moment ϭ i n I zi(tailpixels) ⅐ z i i n I zi (4) where I z and I z(tailpixels) are the cumulative intensities at distance z for all comet and tail pixels, respectively. To calculate the comet inertia, the factor z i in the formula for the comet moment was replaced by its square.…”

“…Since its introduction two decades ago (1), many advances have greatly increased the flexibility and usability of this technique in radiation biology, clinical applications, and environmental toxicology (2)(3)(4)(5)(6). The assay is suitable for virtually any type of organism and cell (4) and allows the evaluation of DNA integrity at the resolution of a single cell.…”