Evaluation of genotoxicity of coal fly ash in Allium cepa root cells by combining comet assay with the Allium test

Abstract

Fly ash is a by-product of coal-fired electricity generation plants. Its utilization and disposal is of utmost importance. Using onion (Allium cepa) root tip system, the present study was carried out to evaluate the potential toxic and genotoxic effects of fly ash, collected from a thermal power plant in West Bengal, India. Prior to testing, the collected fly ash sample was mixed with sand in different proportions. Allium bulbs were allowed to germinate directly in fly ash and after five days the germinating roots were processed for the Allium test. Additionally, the Allium test was adapted for detecting DNA damage through comet assay. The results from the Allium test indicate that fly ash at 100% concentration inhibits root growth and mitotic indices; induces binucleated cells as a function of the proportion, but is not toxic at very low concentration. In the comet assay, a statistical increase for DNA strand breaks was found only at higher concentrations. The sample was analyzed by flame atomic absorption spectrometer for Zn, Pb, Cu, Ni, Cd and As, whose presence could partly be responsible for the toxicity of fly ash. The study concludes that the classical Allium test can give a more comprehensive data when done in combination with the comet assay, which is faster, simpler and independent of mitosis. Also when fly ash is used for other purposes in combination with soils, it should be judiciously used at very low concentrations in order to protect the ecosystem health from any potential adverse effects.

Genotoxic effect of distillery effluent on root tip cells of Allium sativum L.

“…Phragmoplast is a plant cell specific structure forms during cytokinesis and serves as a scaffold for cell plate assembly and subsequent formation of a new cell wall separating two daughter cells. It is a complex assembly of microtubules, microfilament and endoplasmic reticulum [27]. Multinucleate cells were common in all the concentrations.…”

Exploring the potential of fungal-bacterial consortium for low-cost biodegradation and detoxification of textile effluent

“…The application of Comet assay is considered to be a rapid, sensitive, inexpensive and simple method for detecting DNA damage on root meristem of individual cells of A. cepa (Chakraborty et al 2009, Phugare et al 2011a). The results of Comet assay demonstrated that the root meristem of A. cepa bulbs showed genetic damage in the presence of textile effl uent as the chromosomal material integrity was disturbed as well as it was oozing out in the form of bulging in nuclear membrane showing comet like structure (Fig.…”

Comparative evaluation of promutagens o-PDA, m-PDA and MH for genotoxic response in root cells of Allium cepa L.

“…The DNA damage studies were carried out using Comet assay, that is, single cell gel electrophoresis (SCGE) according to Singh [17] with slight modification [10,18]. Roots from the same bulbs as has been used for Allium test and anaphase-telophase chromosome aberration assay were used for comet assay following 48 h treatment.…”

“…The Allium test is a well known and convenient method used in laboratories owing to the ease of their storage and germination, and more over can be used as a convenient system for the evaluation of macroscopic (measure of EC 50 ) and microscopic (micronuclei formation, chromosome aberrations) parameters pertaining to genotoxicity [9]. Apart from Allium test, Allium cepa has been used successfully in our laboratory as a biomarker of genotoxicity using comet assay [10]. Comet assay is a simple, sensitive and effective technique used to quantitatively express the extent of genotoxicity of many hazardous agents and has been used widely in genotoxicity monitoring of the environment.…”