Cytogenetic study of organic and inorganic toxic substances on Allium cepa, Lactuca sativa, and Hydra attenuata cells

Assessment of genotoxicity (using the micronucleus assay for demonstration of chromosome aberrations and the frequency of double nuclei in cells) and cytotoxicity (here changes in quantitative characteristics of nucleoli were measured as a parameter of cell metabolism) for different organic and inor ganic toxic substances was conducted with three organisms, namely, Allium c epa, Lactuca sativa,and Hydra attenuata. Comparative analyses and discussio n of data along with results obtained on toxicity and mutagenicity were als o performed. Besides correlation between some results, discrepancies were o bserved as well. For instance, the organic compound lindane had a weak toxi city, but the highest indices of genotoxicity, whereas the very toxic mercu ry was one of the least in terms of genotoxicity. The noted difference in v alues of toxicity, mutagenicity, genotoxicity, and cytotoxicity indicates t he importance of using an integrated approach to toxicity testing which com bines several methods to obtain a more objective and realistic estimation o f a chemical toxicity. With this purpose, the trio of methods including the Muta-ChromoPlate test as a modified version of the standard Ames Fluctuati on assay, the micronucleus assay, and the nucleolar biomarker are thus prop osed for the routine monitoring of chemical toxicity. (C) 2000 by John Wile y & Sons, Inc.