R.A. Cardoso, L.T.A. Pires, T.D. Zucchi, F.D. Zucchi and T.M.A.D. Zucchi
Published February 9, 2010
Genet. Mol. Res. 9 (1): 231-238 (2010)
About the Authors
R.A. Cardoso, L.T.A. Pires, T.D. Zucchi, F.D. Zucchi and T.M.A.D. Zucchi
Corresponding author:
T.M.A.D. Zucchi
E-mail: tzucchi@uol.com.br
ABSTRACT
Some herbicides are suspected of promoting teratogenic, carcinogenic and mutagenic events. Detection of induced mitotic crossing-over has proven to be an indirect way of testing the carcinogenic properties of suspicious substances, because mitotic crossing-over is involved in the multistep process of carcinogenesis. We examined mitotic crossing-over induced by two commercial herbicides (diuron and trifluralin) in diploid strains of Aspergillus nidulans based on the homozygotization index. Low doses (2.5 μg/mL) of diuron were sufficient to increase the mean homozygotization index in 2.1 and 11.3 times for UT448//UT196 and Dp II-I//UT196, respectively, whereas the same dose of trifluralin increased this mean only 1.2 (UT448//UT196) and 3.5 (Dp II-I//UT196) times, respectively. The lower homozygotization index value found for trifluralin could be due to its interference with mitotic crossing-over in eukaryotic cells. We concluded that the diploid Dp II-I//UT196 of A. nidulans is more sensitive to organic compounds than UT448//UT196; these compounds cause recombinational events at a greater frequency in the latter diploid. This system holds promise as an initial test for carcinogenicity of organic compounds, including herbicides.
Key words: Diuron; Trifluralin; Herbicides; Mitotic crossing-over; Aspergillus nidulans; Genotoxic agents.