Cytogenetics Laboratory, Dept. of Botany, University of Calcutta
The Nucleus vol:53 issue:1 pages:45-50
A wide number of chemicals from different sources are released into the environment, some of which upon metabolic activation are converted to mutagenic products. These chemicals might hence possess threat to public health. Genotoxic potential of three promutagens – o-phenylenediamine (o-PDA), m-phenylenediamine (m-PDA) and maleic hydrazide (MH) was evaluated using Allium cepa as the test system. Following treatment the genotoxic endpoints measured in the root tissue were mitotic index, cells with mitotic or chromosome aberration and micronuclei. DNA damage in root cells was evaluated by comet assay. EC50 determined on the basis of root growth for o-PDA, m-PDA, MH were between 7–8 mg/l, 65–70 mg/l and 9–10 mg/l respectively. All the three agents induced genotoxicity significantly, that followed a dose response. While o-PDA and m-PDA did not induce DNA damage significantly, induction of DNA damage by MH was significant and dose dependent. The study identifies the genotoxic potential and re-establishes the fact that Allium cepa could ideally be used for evaluation of chromosome aberration and DNA damage.