INDUCTION OF A SOS REPAIR SYSTEM IN LYSOGENIC BACTERIA BY ZEARALENONEAND ITS PREVENTION BY VITAMIN-E

Zearalenone (Zen) is an oestrogenic mycotoxin produced by several Fusa rium species in cereals. It induces modifications of haematological pa rameters in rats with cytotoxicity and inhibition of macromolecular sy nthesis (nucleic acids and protein). Zen and its metabolites have oest rogenic and anabolic activities and interact with human oestrogen rece ptors. Zen and its metabolites showed a positive DNA damaging effect i n recombination tests with Bacillus subtilis. It induces sister chroma tid exchange and chromosomal aberration in CHO cells. Zen was found to be capable of inducing DNA-adduct formation in mouse liver. The genot oxicity of Zen was questionable until the last decade when increasing data tended to show this toxin to be genotoxic in vivo. However the me chanism of its genotoxicity and mutagenicity has not been completely c larified. The present investigations were designed to show whether Zen induces an SOS-DNA repair response in lysogenic bacteria which have a n integrated lambda-bacteriophage in their genome. Zen was found to be genotoxic in the bacterial systems from a concentration of 1.50 mM an d it was also bactericidal (IC50 = 1.45 mM). In addition vitamin E (6. 0-12.0 mM) added 1 h prior to the toxin proved to prevent both the gen otoxic and bactericidal effects of Zen. This vitamin could be active b oth as an antioxidant and as a radical scavenger. The specificity of t his prevention is probably due to the similarity of structure between vitamin E and Zen. (C) 1998 Elsevier Science Ireland Ltd. All rights r eserved.