Comet assay in phytoplankton as biomarker of genotoxic effects of environmental pollution (original) (raw)
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Archives of Environmental Contamination and Toxicology, 2007
Endosulfan, a widely used organochlorine pesticide, is readily bio-accumulative in fishes and can be indirectly harmful to human populations. Limited efforts have been made to study long-term genotoxic effects of endosulfan in different tissues of fish using gentoxicity biomarkers. Therefore, the current investigation was undertaken to detect single-cell DNA strand breaks induced by endosulfan in the fresh water teleost fish Mystus vittatus using the comet assay. The LC50 value of technical grade endosulfan was first determined for the fish species in a semistatic system, and on the basis of the LC50 value, the sublethal and nonlethal concentrations were determined. The DNA damage was measured in gill, kidney, and erythrocytes as the percentage of DNA in comet tails of fish specimens exposed to the sublethal and nonlethal concentrations of endosulfan. In general, significant effects (p < 0.01) from both concentration and time of exposure were observed in exposed fishes. It was found that all the tissues at all concentrations exhibited the highest DNA damage on day 1, after which there was a nonlinear decline in the percentage of tail DNA. The comparison of DNA damage among the tissues at different concentrations could not show the sensitivity of particular tissue to endosulfan. The current study explored the utility of the comet assay for in vivo laboratory studies using fish species to screen the genotoxic potential of chemical agents.
Comet Assay: Quantification of Damaged DNA in Catla catla Exposed to Endosulfan+Chlorpyrifos
Punjab University Journal of Zoology, 2019
In an acute toxicity trail, LC 50 and LC 100 value (96 hr) of endosulfan (END)+chlorpyrifos (CPF) mixture for Catla catla was computed. The genotoxicity of END+CPF mixture in RBCs of fish was also evaluated by comet assay. To check the genotoxicity of END+CPF mixture, blood of fish was sampled after 24-hr of intervals. Some fishes were also kept in clean water known as negative control (NC) and for positive control (PC) cyclophosphamide was injected into fish. The tolerance limits of C. catla against END+CPF was computed as 1.35±0.01μgL-1 (LC 50) and 2.25±0.02μgL-1 (LC 100). Genotoxic results showed that END+CPF mixture caused significant damage to nuclei (22.58±5.37%) and GDI (0.73±0.15%) in RBCs of fish as compare to control. Aduration-specific damage to DNA was observed in RBCs of C. catla.
Ecotoxicity is the science of studying the effects of pesticides and other contaminants that get into the natural environment and affect the non-target wild plants and animals and its impacts on individuals, populations, natural communities and ecosystems. Environmental biomarkers revolve around 3R's – repeatability, reliability and relevance and in many cases repeatability and reliability is not always equal to relevance. Environmental biomarkers should be sensitive enough, easily and rapidly assayed, respond in a dose-dependent manner, valid for the species concerned and evaluated for possible influence by other endogenous and exogenous factors. In the present study molecular biomarker 'DNA integrity' has been studied as dose dependent and time dependent responses of Oreochromis mossambicus to exposure of endosulfan. The fishes were exposed to three different sub-lethal concentrations of endosulfan for different time intervals of 7 days from 14 th day up to 28 days. The DNA isolated from fish fin of control (plain and acetone) and exposed fishes by standard protocol was subjected to spectrophotometric analysis, gel mobility shift analysis. The observed results of these studies performed confirm that endosulfan does produce effect on DNA molecule and alter the DNA stability or integrity. Alteration in DNA gains significance in that any change or mutation in DNA would rather interfere with replication, transcription and translation process thereby produces mutants and code for abnormal proteins with altered functional capacity.
Diagnosis of endosulfan induced DNA damage in rohu (Labeo rohita, Hamilton) using comet assay
Use of different pesticides in the agriculture sector, in order to boost crop yield within a short time period and low labor, has been tremendously increased since the last decade. Pesticide use has elevated crop yield but has produced a number of pronounced problems regarding environmental and health safety. The continuously deteriorating toxicological effects of these pesticides are not only hazardous to humans and land animals but also to economically important aquatic organisms such as fish. One of these extensively used pesticides is an organochlorine insecticide, endosulfan. Experiments conducted in the past have shown the deleterious effects of endosulfan on different aspects of various fish species but its genetic toxicity has not been well studied. The present study was conducted to diagnose the DNA damage induced by endosulfan in peripheral blood erythrocytes of an economically important teleost fish rohu, Labeo rohita (Hamilton, 1822) using comet assay. The fish were exposed to three different sub lethal concentrations (1, 1.5 and 2 µg L -1 ) of endosulfan for 7, 14, 21 and 28 days. Rohu showed different extents of DNA damage at different concentrations and time, in terms of genetic damage index (GDI), percentage of damaged cells (% damaged cell) and cumulative tail length (µm) of the comets. Increase in DNA damage was observed to be concentration and time-dependent. The current study revealed the severe genotoxic effects of endosulfan in rohu, Labeo rohita. Therefore its discriminate use should be avoided as it can contribute to the decline of rohu in natural habitats. Also it should be considered as a hazardous threat for human consumption.
Studies on the genotoxicity of endosulfan in bacterial systems
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 1999
Endosulfan, an organochlorine pesticide, was subjected to the differential sensitivity assay in repair-deficient and Ž . repair-proficient strains of Escherichia coli K12, prophage l induction assay in WP2s l and mutation induction in E. coli K12. The induction of umu gene expression with endosulfan was studied also in Salmonella typhimurium TA1535rpSK1002 cells. The differential sensitivity assay revealed that the recA 13 strain was the most sensitive. Endosulfan induced prophage l in E. coli and umu gene expression in S. typhimurium cells; however, the extent of the effects were low. Endosulfan also induced a dose-dependent increase in forward mutations in E. coli K12 cells from ampicillin sensitivity to ampicillin resistance. Our studies indicate the genotoxic potential of endosulfan and the role of the recA gene in the repair of endosulfan-induced DNA damage. q
DNA damage and mutagenicity induced by endosulfan and its metabolites
Environmental and Molecular Mutagenesis, 2006
Endosulfan is a widely used broad-spectrum organochlorine pesticide, which acts as a contact and stomach poison. Nontarget species, such as cattle, fish, birds, and even humans, are also affected. Studies on the genotoxicity and mutagenicity of endosulfan have been inconsistent and nothing is known about the genotoxicity of its metabolites. In the present study, endosulfan (as a commercial isomeric mixture and as the α- and β-isomers), and metabolites of endosulfan (the sulfate, lactone, ether, hydroxyether, and diol derivatives) were assayed for their ability to induce DNA damage in Chinese hamster ovary (CHO) cells and human lymphocytes using the Comet assay and were assayed for their mutagenicity using the Salmonella reversion assay (Ames test with TA98, TA97a, TA102, TA104, and TA100, with and without S9 activation). The compounds produced statistically significant (P < 0.01), concentration-dependent (0.25–10 μM) increases in DNA damage in both CHO cells and human lymphocytes. Endosulfan lactone caused the most DNA damage in CHO cells, while the isomeric mixture of endosulfan produced the greatest response in lymphocytes. The test compounds also were mutagenic in Salmonella strains at concentrations of 1–20 μg/plate (P < 0.05), with TA98 being the most sensitive strain and the diol and hydroxyether metabolites producing the highest responses. The results indicate that exposure to sublethal doses of endosulfan and its metabolites induces DNA damage and mutation. The contribution of the metabolites to the genotoxicity of the parent compound in Salmonella and mammalian cells, however, is unclear, and the pathways leading to bacterial mutation and mammalian cell DNA damage appear to differ. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc.
Genotoxic effects of endosulfan an orgnaochlorine pesticide on the silkworm Bombyx mori L
2016
The advancement of introduction of environmental chemicals through pesticides regarded as solemn setback, present world is confronted with the indiscriminate use of the several environmental chemicals in agriculture, livestock production, conservation of plants and animals, industrialization and biodiversity. These environmental chemicals are known to affect not only the target organisms and non target organisms endangering the homeostasis mechanism but also causing severe damage to ecosystem because of long lasting residual effects. Toxicity leads to death, irritation, skin sensitization, mutagenicity, tumors etc. The primary step in assessing the toxicity of a chemical substance is to observe the physical and behavioural responses of the poisoned animal. It is in this review, the silkworm Bombyx mori offers as one of the best and convenient laboratory tool because of its important physiological and genetical mechanism simulates the higher eukaryotic system. The methodology develop...
Genotoxicity evaluation of the insecticide endosulfan in the wetland macrophyte Bidens laevis L
Environmental Pollution, 2008
Imidacloprid (IMI) is a neonicotinoid insecticide widely used in agricultural activities all around the world. This compound is transported from croplands to surrounding freshwater ecosystems, producing adverse effects on nontarget organisms. Because of the relevance of aquatic macrophytes in the above-mentioned environments and the lack of studies of potential effects of IMI on them, this work aimed to assess the mitotic process and potential genotoxicity in the aquatic macrophyte Bidens laevis L. Although the analysis of the Mitotic Index (MI) showed that IMI was not cytotoxic, the Cell Proliferation Kinetics (CPK) frequencies evidenced modifications in the kinetics of the mitotic process. Indeed, the anaphases ratio decreased at 10 and 100 μg/L IMI, while at 1000 μg/L an increase of prophases ratio and a decrease of metaphases ratio were observed. Regarding genotoxicity, IMI produced an increase of the abnormal metaphases frequency from 10 μg/L to 1000 μg/L as well as an increase in clastogenic anaphases-telophases frequency at 100 and 1000 μg/L. In addition, aneugenic anaphases-telophases and C-mitosis frequencies also increased at 1000 μg/L, confirming the effects on the mitotic spindle. Considering the genotoxic effects on B. laevis through two different mechanisms (aneugenic and clastogenic) and the wide spread use of IMI in agriculture, these mechanisms of toxicity on macrophytes should be considered among other recognized effects of this insecticide on aquatic biota.