Application of comet assay in the study of DNA damage and recovery in rohu (Labeo rohita) fingerlings after an exposure to phorate, an organophosphate pesticide

Abstract

Labeo rohita (rohu) fingerlings were exposed to different concentrations (0.001, 0.002 and 0.01 ppm) of phorate, an organophosphate pesticide; samplings were done at 24, 48, 72 and 96 h. The study was carried out to evaluate tissue specific genotoxic effects produced by phorate, on three different tissue systems and to assess DNA repair response in fish. Results of tissue specific DNA damage experiments showed low baseline damage in blood cells followed by gill and liver cells in control individuals whereas more DNA breaks were found in liver followed by gill and blood cells of treated individuals. Concentrations-dependent DNA damage showed a strong, linear and positive relationship (r(2) = >0.7) in all three tissues. Clear time-related increase in DNA damage was observed for all tissues exposed to all concentrations except in liver cells at 0.01 ppm, where the DNA damage declined significantly after 72 h. For the assessment of DNA repair response, fingerlings were first exposed to 0.01 ppm of phorate for 72 h and then transferred to pesticide free water. Tissue chosen for the repair experiment was liver. Samplings were done at 0, 3, 6, 12 and 24 h after the release of 72 h pesticide treated fishes into pesticide free water. Fishes showed a reduction in DNA breaks from 3 h onwards in pesticide free water and at 24 h returned to control level damage. The results indicate that phorate is a potential genotoxicant, comet assay can be used in DNA damage and repair analysis, response to pollutants in multicellular animals is often tissue specific.

Genotoxic Potential of the Insecticide Imidacloprid in a Non-Target Organism (<i>Oreochromis niloticus</i>-Pisces)

“…In this paper, the authors observed an increase in DNA damage in the erythrocytes of these fish [26]. The same results were observed in studies with the phorate pesticide, a genotoxic organophosphate, in fingerlings of Labeo rohita (Cyprinidae) [27], and Roundup ® herbicide, evaluated in Anguilla anguilla (Anguillidae), also displayed genotoxicity [28]. The results obtained in this study corroborate previous studies with other pesticides and support the claim that the comet assay is a highly sensitive method for the detection of DNA damage induced by environmental pollutants.…”

Assessment of genotoxicity and depuration of anthracene in the juvenile coastal fish Trachinotus carolinus using the comet assay

“…Phorate, an organophosphate pesticide, is genotoxic to Labeo rohita. Specimens contaminated by this pesticide when maintained in water free of pollution also showed the ability to repair DNA damage (MOHANTY et al, 2011). Using the comet assay, Groff et al (2010) detected a reduction in DNA damage to the erythrocytes of Neotropical fish (Arapaima gigas and Colossoma macroporum) 12 hours after exposure to UVR-B (ultraviolet radiation B) and suggest that nucleotide excision repair is involved in DNA repair.…”

Genotoxicity Testing in Pesticide Safety Evaluation

“…Many reviews details the employment of comet assay in the assessment of the genotoxic potential of many compounds, which notably include metals, pesticides, opiates, nitrosamines and anticancer drugs (Collins, 2004). A significant advantage of the comet assay is its applicability to any eukaryotic organism and nucleated cell type (Mohanty et al, 2009a(Mohanty et al, , 2009b(Mohanty et al, , 2011. This assay can be applied both in vitro and in vivo conditions after an exposure to different potent genotoxic and mutagenic agents (.…”

“…A study was carried out by Mohanty et al, (2009aMohanty et al, ( , 2009bMohanty et al, ( and 2011 with an objective to study the genotoxic effects of two pesticides, phorate, an organophosphate and furadan, a carbamate on rohu (Labeo rohita) fingerlings. To evaluate the DNA damage, rohu fingerlings were exposed to control, 0.001, 0.002 and 0.01ppm of phorate control, 0.002, 0.004 and 0.02ppm of furadan for a total time period of 96h.…”