Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 5, 2012
Previous Article Next Article

Gene-TEQ—a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents

Author affiliations

Abstract

Existing methods for the comparison of genotoxic effects in the comet assay bear considerable disadvantages such as the problem to link information about concentration dependence and severity of effects. Moreover, given the lack of standardized protocols and the use of various standards, it may be extremely difficult to compare different studies. In order to provide a method for standardized comparative assessment of genotoxic effects, the concept of genotoxicity equivalents (Gene-TEQ) was developed. As potential reference compounds for genotoxic effects, three directly acting (N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), methyl-methanesulfonate, and N-methyl-N-nitrosourea) and three indirectly acting (cyclophosphamide, dimethylnitrosamine, and 4-nitroquinoline-oxide) genotoxic substances were compared with respect to their cytotoxic (neutral red) and genotoxic (comet assay) concentration–response profiles in the permanent fish cell line RTL-W1. For further comparison, two sediment extracts from the upper Danube River were investigated as environmental samples. Based on the results of cytotoxicity and genotoxicity testing, MNNG was selected as the reference compound. At several exposure levels and durations, genotoxic effects of both the other pure substances and the environmental samples were calculated as percentages of the maximum MNNG effect and related to the absolute MNNG effect (EC values). Thus, genotoxicity equivalent factors (Gene-TEQs) relative to MNNG could be calculated. Gene-TEQs can easily be applied to pure substances, mixtures and field samples to provide information about their toxicity relative to the reference compound. Furthermore, the Gene-TEQ concept allows a direct comparison of environmental samples from different laboratories.

Graphical abstract: Gene-TEQ—a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents

Back to tab navigation

Article information


Submitted
23 Nov 2011
Accepted
22 Feb 2012
First published
28 Feb 2012

J. Environ. Monit., 2012,14, 1325-1334
Article type
Paper

Gene-TEQ—a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents

C. Faßbender, T. Braunbeck and S. H. Keiter, J. Environ. Monit., 2012, 14, 1325
DOI: 10.1039/C2EM10947F

Search articles by author

Spotlight

Advertisements