Determination of genotoxic effects of copper sulphate and cobalt chloride in Allium cepa root cells by chromosome aberration and comet assays (original) (raw)
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Plants are direct recipients of agro – toxics and therefore important materials for assessing environmental chemicals for genotoxicity. The meristematic mitotic cells of Allium cepa is an efficient cytogenetic material for chromosome aberration assay on environmental pollutants. Onion root tips were grown on moistened filter paper in petri dish at room temperature. Germinated root tips were then exposed to three concentrations of each pesticide for 24 h. About 1 – 2 mm length of root tip was cut, fixed in cornoy’s fixative, hydrolyzed in warm 1 N HCL, stained with acetocarmine and squashed on glass slide. About 3000 cells were scored and classified into interphase and normal or aberrant division stage. Cytotoxicity was determined by comparing the mitotic index (MI) of treated cells with that of the negative control. The MI of cells treated with Dichlorophen and Dichlorovos at one or more concentration was half or less than that of control are said to be cytotoxic. Genotoxicity was m...
Cytogenotoxicity evaluation of two industrial effluents using Allium cepa assay
The cytogenotoxic effects of the industrial effluents from paint (0, 7.2, 18, 36 and 72%) and textile (0, 1.6, 4, 8 and 16%) manufacturing were evaluated using root tip cells of Allium cepa. In this study, root length and chromosomal aberration assays were used to determine the 96 h effective concentration (96 h EC 50 ), root growth inhibition, mitotic index and chromosome aberration rate. Based on the 96 h EC 50 , textile effluent was 4.5 times more toxic than the paint effluent. Analysis of Variance (ANOVA) showed that there was significant difference (P < 0.05) in the mean root length of A.
2007
The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. This test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of Allium cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. In this study we evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from twenty-one treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in Allium cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.
THE CYTO-AND GENOTOXIC EFFECTS INDUCED BY SULPHATES IN Allium cepa L
The scope of this paper is to assess the cyto-and genotoxic effects of sulphate on Allium cepa mitosis for root meristem. Three different concentrations of sodium sulphate (i.e. 0,1%; 1% and 5%) have been used, in which the onion bulbs were immersed for different periods of time such as 6, 24 and 72 hours. In the end of the experiment the harvested root tips were prepared according to Feulgen's squash technique and using Schiff reagent. The cytotoxic effects of sulphate were investigated by calculating the mitotic index and also through the analysis of chromosomes alterations during the mitosis. The phase ratio of cells undergoing mitosis in all the phases is estimated for all variants. For microscopy investigations it was used a Novex Holland B microscope with digital camera included. The cytological analysis realized on Allium cepa revealed a strong decrease in the mitotic index due to sulphate treatments which is more intense with the time of exposure. Moreover this phenomenon is associated with the appearance of different chromosomal complement alterations including the appearance of highly condensed chromatin. The mitotic index and genotoxic observations over the chromosomes can also be correlated with phase ratio of cells undergoing mitosis.
Caryologia, 2008
Cytogenetic effects of phenoxy herbicide viz. quizalofop-P-ethyl (QPE, ethyl (R)-2-[4-[(6-chloro-2quinoxalinyl)oxy]phenoxy] propionate) were evaluated in the root meristem cells of Allium cepa. In the Allium root growth test, the effective concentration (EC 50) value was determined as approximately 1.5 ppm. Cytological experiments were carried out using QPE concentrations of 0.75 (EC 50 /2), 1.5 (EC 50) and 3 ppm (EC 50 x2) at 24, 48, 72, and 96 h, with a control for each combination. Mitotic index decreased with increasing the herbicide concentration at each exposure time. In anaphase-telophase cells, the total percentages of stickiness, bridges, vagrant chromosomes, c-anaphase, multipolarity, and fragments according to total cells with chromosome aberrations were calculated as 38.57, 28.42, 16.67, 14.10, 1.60, and 0.64%, respectively. The total chromosome aberrations increased with an increasing the QPE concentration. Micronucleated cells were observed at interphase. The frequency of the micronucleus was markedly higher at 3 ppm compared to other test concentrations.
Effect of Chemical Mutagens on Chromosomal behavior of Allium cepa L
Annals of Plant Sciences, 2018
Effect of chemical mutagens was studied in mitotic cells of Allium cepa L. For this purpose root tips were treated with saturated solution of peradichloro benzene, 0.2% EMS and 0.2 % freshly prepared colchicines for 4hours to 9hours.The studies revealed a wide range of chromosomal abnormalities such as stickiness, laggards, chromosomal bridge, unequal separation, nuclear budding, multinuclear cells etc.The parentage of chromosomal abnormalities in different mitotic stages were calculated on mitotic index, frequency of phases and percentage of abnormalities in mitosis. The chromosomal abnormalities increase with increase duration of treatment. The results showed that in colchicines and EMS more than 50% abnormalities ware observed after 8 hrs of treatment, while in PDB it takes 6 hours treatment. Minimum MI was recorded as 65% in controlled cells. In colchicines and EMS treated cells 0.9.5%, 20% MI ware observed after 8hrs of treatment. Whereas in PDB maximum 23% MI was recorded in c...
Cytogenetic effects of different herbicides viz. Atrazine, Avenoxan, Diuron and Quizalofop-P-ethyl (QPE), were evaluated in the root tip meristem cells of Allium cepa. In the Allium root growth test, the effective concentration (EC 50) value was determined as approximately 0.5 ppm in the case of Atrazine and Avenoxan and 1.0 ppm in the case of Diuron and QPE herbicides with a control for each combination. Mitotic index decreased with increasing herbicide concentration at each exposure time. In anaphase-telophase cells, the total percentages of different chromosomal aberrations like stickiness, bridges, break(s), ring chromosomes, vagrant chromosomes, c-mitosis, delayed anaphase, laggard(s) and micronuclei at high concentration (1 ppm) were calculated as 31.85% (Atrazine), 29.94% (Avenoxan), 36.66% (Diuron) and 41.04% (QPE). The total number of chromosome aberrations increased as herbicide concentration increased. Micro-nucleated cells were observed at different stages of the cell cycle. The frequency of the micronucleus was markedly higher at 1 ppm than at other test concentrations.
Copper-Induced Genotoxic Effects in Root Meristems of Triticum Aestivum L. CV. Beti
Copper is one the most abundant heavy metals in agricultural soils and its excess in soil comes from the largely use of this heavy metal in industry and agriculture (as fungicide). Mitotic index, rate and categories of ana-telophase chromosome aberrations, as well as the frequency and types of metaphase disturbances were scored in root tip meristems of Triticum aestivum L. cv. Beti after seed exposure to copper, provided as copper acetate and copper citrate, at four concentrations (10, 25, 50, and 100 µM) containing 0.64, 1.59, 3.18, 6.35 µg ml -1 Cu 2+ , and 1. 91, 4.77, 9.53, 19.06 µg ml -1 Cu 2+ , respectively. Except the mitostimulant effect of 25 μM concentration, all the other concentrations of copper acetate and copper citrate showed mitodepressive action. The copper genotoxicity is expressed in the increased level (1.5 -5-fold higher than in control) of the rate of chromosome aberrations in mitotic ana-telophases of copper-treated variants. Chromosome bridges, laggards and complex aberrations are the most numerous, although multipolarity, fragments and micronuclei are present, but with lower frequency and not in all copper-treated variants. Concerning the rate of metaphase disturbances, copper acetate augmented 2 -3 times the rate of abnormalities in all variants, whereas only variant treated with 25 μM copper citrate exceeded the control in a substantial manner. Metaphases with chromosomes expulsed from equatorial plate are numerically preponderant, followed by C-metaphases. These observations constitute a signal about the risks of the widespread and increasing presence of some heavy metals into environment. The results reported here could be considered in a future evaluation of copper effects on other organisms, even on human health, due to large use of copper compounds, inclusively as fungicides.