"Cytogenetic biomarkers play a key role in assessing the impact of pollutants in apparently healthy sentinel aquatic organisms such as fishes. Among the cytogenetic end points, the erythrocyte micronucleus assay has gained popularity over other basic cytogenetic assays to assess mutagenic and genotoxic effects of chemicals due to its sensitivity, simplicity, and reliability for detecting cytogenetic DNA damage (Heddle et al. 1983; Al-Sabti and Metcalfe 1995; Cavas and Konen 2007; Bopp et al. 2008; Anbumani and Mohankumar 2012). Pesticides occurring in nature are normally not present individually, but in complex mixtures (Gilliom et al. 2006). "
[Show abstract][Hide abstract] ABSTRACT: Cytogenotoxic effects in the form of micronuclei and deformed nucleus, nuclear buds, binucleated cells, vacuolated nucleus, vacuolated cytoplasm, echinocytes, and enucleus induced by two compounds belonging to two different chemical classes of agrochemicals (monocrotophos and butachlor) at sublethal concentrations (0.625, 1.3, and 2.3 ppm and 0.016, 0.032, and 0.064 ppm) in single and combined chronic exposures were studied under laboratory conditions for a period of 35 days in the economically important Indian fish Catla catla. Statistically significant duration-dependent increases in the frequencies of micronucleus (MN) and other cytological anomalies were observed. Compared to single exposures, a twofold increase in micronuclei frequency was noted at combined exposures indicating the synergistic phenomenon. Binucleated and enucleated cells appeared only in fishes exposed to sublethal concentrations of butachlor. The present study is the first of its kind in exploring a significant positive correlation between micronuclei and other nuclear anomalies suggesting them as new possible biomarkers of genotoxicity after agrochemical exposures. The study highlights the sensitivity of the assay in exploring various predictive biomarkers of genotoxic and cytotoxic events and also elicits the synergistic effects of agrochemicals in apparently healthy fishes. C. catla can be considered as a suitable aquatic biomonitoring sentinel species of contaminated water bodies.
Environmental Science and Pollution Research 11/2014; 22(7). DOI:10.1007/s11356-014-3782-y · 2.76 Impact Factor
"fragments known as micronuclei (MN). These fragments appear in the cytoplasm when the parts of the chromosomes or entire chromosome are not rapidly incorporated in the nuclei of the daughter cells in mitosis because these fragments do not have centromeres; these fragments left behind are incorporated in the secondary nuclei called ''micronuclei'' (Schmid 1975; Heddle et al. 1983). Thus, this test helps to examine the genotoxic effects of contaminants that are present in the aquatic environment (Tucker and Preston 1996). "
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to evaluate the effect of heavy-metal contamination on two fish species (Channa striatus and Heteropneustes fossilis) inhabiting a small freshwater body of northern India. After being captured, each specimen was weighed, measured, and analyzed for heavy metals (chromium [Cr], nickel [Ni], and lead [Pb]). Accumulation of heavy metals was found to be significantly greater (p < 0.05) in different tissues (gill, liver, kidney, and muscle) of fishes captured from the reservoir than from the reference site. Levels of heavy-metal contamination in Shah jamal water was Cr (1.51 mg/l) > Ni (1.22 mg/l) > Pb (0.38 mg/l), which is significantly greater than World Health Organization standards. Bioaccumulation factor was calculated, and it was observed that Pb was most detrimental heavy metal. Condition factor was also influenced. Micronucleus test of fish erythrocytes and comet assay of liver cells confirmed genotoxicity induced by heavy-metal contamination in fishes. Heavy metals (Cr, Ni, and Pb) were increased in both fish species as determined using recommended values of Federal Environmental Protection Agency for edible fishes. This raises a serious concern because these fishes are consumed by the local populations and hence would ultimately affect human health.
Archives of Environmental Contamination and Toxicology 04/2014; DOI:10.1007/s00244-014-0024-8 · 1.96 Impact Factor
"Organization for Economic Cooperation and Development (OECD) guidelines (474), Food and Drug Administration (FDA) guidelines, U.S. Environmental Protection Agency (EPA) guidelines , and guidelines for the testing of chemicals specified by the Collaborative Study Group for the Micronucleus Test (CSGMT) and the Mammalian Mutagenesis Study Group of the Environmental Society of Japan (JEMS.MMS) for the short-term mouse peripheral blood micronucleus test (CSGMT, 1995; U.S. EPA, 1998; FDA, 2000; Heddle et al., 1983; OECD, 1997 "
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to investigate the modulating effects of (-)-epigallocatechin-3-gallate (EGCG), quercetin, and rutin on the genotoxic damage induced by Cr(VI) in polychromatic erythrocytes of CD-1 mice. The animals were divided into the following groups: (i) vehicle only; (ii) flavonoids (10 mg/kg EGCG, 100 mg/kg quercetin, 625 mg/kg rutin, or 100-625 mg/kg quercetin-rutin); (iii) Cr(VI) (20 mg/kg of CrO3); and (iv) flavonoids concomitantly with Cr(VI). All of the treatments were administered intraperitoneally (ip). The genotoxic damage was evaluated based on the number of micronucleated polychromatic erythrocytes (MN-PCE) obtained from the caudal vein 0, 24, 48, and 72 h after treatment. Groups treated with EGCG and quercetin exhibited no significant statistical changes in induction of MN-PCE. However, CrO3 treatment significantly increased MN-PCE induction 24 and 48 h after injection. Treatment with flavonoids prior to CrO3 exposure decreased MN-PCE induction compared with CrO3 only. The magnitudes of the potency of flavonoids were in the following order: rutin (82%) > quercetin (64%) > quercetin-rutin (59%) and EGCG (44%). The group treated with rutin significantly reduced genotoxic damage in mice treated with Cr(VI) (antioxidant effect). However rutin exerted a marginal genotoxic effect when administered alone (pro-oxidant effect). Our findings suggest protective effects of EGCG, quercetin, and rutin against genotoxic damage induced by Cr(VI).
Journal of Toxicology and Environmental Health Part A 03/2014; 77(6):324-36. DOI:10.1080/15287394.2013.865006 · 1.83 Impact Factor
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