Evaluation of DNA Damage in Common Carp (Cyprinus carpioL.) by Comet Assay for Determination of Possible Pollution in Lake Mogan (Ankara)

Abstract

Contamination of the aquatic environment with various concentrations of pollutants results in unexpected threats to humans and wildlife. The consequences of exposure and metabolism of pollutants/xenobiotics, especially carcinogens and mutagens, can be suitably assessed by investigating severe events, such as DNA damage; for example, DNA adducts and DNA strand breaks. One of the commonly used techniques to detect DNA damage in aquatic organisms is single-cell gel electrophoresis (comet assay). This study was carried out using Cyprinus carpio in order to identify the possible pollution in Lake Mogan, near Ankara, Turkey, where the city's sewer system and pesticides used in agriculture are believed to be the common causes of pollution. From the comet assay, the tail length (μm), tail intensity (%), and tail moment values of fish caught from Lake Mogan were found to be 31.10 ± 10.39, 7.77 ± 4.51, 1.50 ± 1.48, respectively, whereas for clean reference sites they were found to be 22.80 ± 1.08, 3.47 ± 1.59, 0.40 ± 0.51, respectively. The values are statistically different from each other (p < 0.0001, p < 0.0001, and p < 0.0013, respectively). These results indicate that Lake Mogan may be polluted with substances that have genotoxic effects and constitute an early warning for the lake system. Further detailed research is needed to establish the source of the pollution and the chemicals responsible.

Heavy Metal Accumulation and the Genotoxicity in Barbel (Barbus barbus) as Indicators of the Danube River Pollution

“…were both significantly higher ( P = 0) than in fish from the reference site (0.31 and 12.80, resp.). Tail moment in carp ( Cyprinus carpio ) from the Lake Mogan, which is under pollution stress of agricultural activities, was 1.50 ± 1.48 [ 24 ], which is a similar result to the one obtained in the present study (1.28 ± 1.41).…”

“…However, the main disadvantage of this parameter is that two cells with different tail lengths may have the same degree of tail intensity and may produce the same result. A major advantage when using the tail moment as an index of the DNA damage is that both the amount of the damaged DNA and the distance of the genetic material migration in the tail are represented by a single number [ 24 ]. Which parameter of DNA migration will be applied often depends on the personal preferences of the investigator.…”

Scenario of Genotoxicity in Fishes and Its Impact on Fish Industry

“…Marcon et al (2010) found that a high content of certain metals in the water could be one of the factors that might cause genetic damages in fish. The comet assay has been successfully used to investigate effects of genotoxic pollutants on the integrity of DNA (Çok et al, 2011;Ferraro et al, 2004;Scalon et al, 2010). Micronucleus test was the only genotoxicity test applied thus far on barbel specimens from the natural population in the Danube River (Boettcher et al, 2010).…”

Comparison of comet assay parameters for estimation of genotoxicity by sum of ranking differences

“…Three measures of DNA migration are commonly used: tail length, OTM, and % of the DNA in tail (tail intensity) [30][31][32]. Although OTM appeared to be the most statistically significant measurement [33], the inter-laboratory comparison of results seems to be difficult for this parameter [34].…”