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In this study, three different sites in the E§en Stream (namely, Site 1 that was used as the control group, Site 2 that had the highest pollution degree, and Site 3), were assayed for genotoxicity induced by nutrient pollution using the Comet assay in the peripheral blood of rainbow trout (Oncorhynchus mykiss). At each site, blood was taken from six samples to investigate the potential damage in fish blood lymphocytes with Comet assay. The results revealed that both DNA tail % and tail moment (pm) significantly increased in Site 2 and Site 3 compared to Site 1. Site 2 had the highest level of water parameters (such as suspended solids, total phosphates, ammonium and nitrate-nitrogen, and chemical oxygen demand) and showed the highest genotoxic damage for both DNA tail % and tail moment. Oxidative DNA damage was also investigated with bacterial enzymes, namely, Endo III and FPG. According to the results, oxidative damage was higher in purines than pyrimidines for the studied sites. These results confirm the usefulness of the Comet assay with fish blood lymphocytes as an in vivo model for eco-genotoxicological studies. [ABSTRACT FROM AUTHOR]

In this study a genotoxic evaluation of titanium dioxide (TiO2, 2.3 nm), zirconium oxide (ZrO2, 6 nm), aluminum oxide (Al2O3, 16.7 nm) nanoparticles (NP) and their ionic forms was conducted using human peripheral blood lymphocytes and cultured human embryonic kidney (HEK293) cells by means of a modified alkaline comet assay with/without the formamidopyrimidine-DNA glycosylase (Fpg) and endonuclease III (Endo III) enzymes. Modifications to the comet assay by using lesion-specific endonucleases, such as Endo III and Fpg, detect DNA bases with oxidative damage. Both human peripheral blood lymphocytes and cultured embryonic kidney cells were incubated with TiO2, ZrO2, or Al2O3NP at concentrations of 1, 10, or 100 μg/ml. Our results showed no significant induction in DNA damage by the comet assay with/without the Endo III and Fpg enzymes at all concentrations of ZrO2and Al2O3. In the case of TiO2NP only the highest concentration of 100 μg/ml significantly induced a genotoxic response. Data thus indicate that both ZrO2and Al2O3NP were not genotoxic in our system and in the case of TiO2the lowest-observed-adverse-effect level (LOAEL) for genotoxicity was 100 μg/ml. Evidence indicates that these metallic NP are considered safe in light of the fact that no genotoxicity was noted with ZrO2and Al2O3and that the highest TiO2concentration is not environmentally relevant. [ABSTRACT FROM AUTHOR]

The genotoxicity of different sweeteners (acesulfame K, aspartame, saccharin and sucralose), has been evaluated in the wing spot and the comet assays, using Drosophila. Results indicate that acesulfame K, saccharin and sucralose were not genotoxic in either of the two assays used. Low but significant increases were obtained in transheterozygous flies treated with aspartame; but, when aspartame results were evaluated in balancer-heterozygous flies, to determine the origin of the mutant clones, negative results were obtained indicating that the observed effects induced by aspartame are mainly due to somatic recombination. Results from aspartame in the comet assay show a genotoxic effect of this sweetener. Thus, in spite of the lack of dose-response, and the low value obtained in the negative concurrent control in the wing spot test with aspartame, the results obtained in the comet assay support a potential genotoxic role of aspartame, at least in Drosophila. [ABSTRACT FROM AUTHOR]

The resveratrol (RSV, 3,4',5-trihydroxy stilbene) is a phytoalexin which is naturally occurring in different plants. The in vivo antigenotoxic effects of RSV against ethyl methane sulfonate (EMS) and potassium dichromate (K2Cr2O7) which causes genotoxicity with different mechanisms was studied in Drosophila melanogaster by using the Drosophila SMART assay and the alkaline Comet assay. For SMART assay the larvae were treated both pre-treat-ments and co-treatments, for Comet assay the larvae were treated simultaneous exposure. The results from the SMART assay showed that in pre-treatments and co-treatments of RSV with EMS and K2Cr2O7 was reduced the genotoxicity in all concentrations excluding only 1 mM concentration in co-treatments of RSV with EMS. Antigenotoxic effects of RSV against EMS and K2Cr2O7 is higher in pre-treatment compared to co-treatment and stronger in especially against genotoxic damage caused by K2Cr2O7. In results of Comet assay RSV showed antigenotoxic effects against genotoxic damage caused by EMS and K2Cr2O7 for tail intensity (%) and tail moment (µm). These results confirm the usefulness of the Comet assay with haemocytes as an in vivo model and support the possibility of antigenotoxicity associated with RSV. This is the first study reporting antigenotoxicity data in somatic cells of Drosophila for RSV. [ABSTRACT FROM AUTHOR]

In this study a genotoxic evaluation of titanium dioxide (TiO2, 2.3 nm), zirconium oxide (ZrO2, 6 nm), aluminum oxide (Al2O3, 16.7 nm) nanoparticles (NP) and their ionic forms was conducted using human peripheral blood lymphocytes and cultured human embryonic kidney (HEK293) cells by means of a modified alkaline comet assay with/without the formamidopyrimidine-DNA glycosylase (Fpg) and endonuclease III (Endo III) enzymes. Modifications to the comet assay by using lesion-specific endonucleases, such as Endo III and Fpg, detect DNA bases with oxidative damage. Both human peripheral blood lymphocytes and cultured embryonic kidney cells were incubated with TiO2, ZrO2, or Al2O3 NP at concentrations of 1, 10, or 100 μg/ml. Our results showed no significant induction in DNA damage by the comet assay with/without the Endo III and Fpg enzymes at all concentrations of ZrO2 and Al2O3. In the case of TiO2 NP only the highest concentration of 100 μg/ml significantly induced a genotoxic response. Data thus indicate that both ZrO2 and Al2O3 NP were not genotoxic in our system and in the case of TiO2 the lowest-observed-adverse-effect level (LOAEL) for genotoxicity was 100 μg/ml. Evidence indicates that these metallic NP are considered safe in light of the fact that no genotoxicity was noted with ZrO2 and Al2O3 and that the highest TiO2 concentration is not environmentally relevant.