[Cytologic alterations induced in Bacillus thuringiensis (Berliner) by zearalenone]

Zearalenone (F-2 toxin) an estrogenic mycotoxin secreted by some species of Fusarium exhibits an antibacterial activity which can be easily demonstrated in Gram-positive spore forming bacteria, especially in Bacillus sp. Morphologically abnormal cells were produced by Bacillus thuringiensis (Berliner) in response to zearalenone. The most significant ultrastructural alterations obtained with the mycotoxin at 2.5 or 5.0 micrograms/ml, are: increase of number of mesosomes which are hypertrophied, decrease of ribosomes, formation of imperfect cell septa and unknown 'crystalloïd inclusion'. These effects which provoke induction of atypical long cells, resemble those obtained with one other mycotoxin which possesses as zearalenone an unsaturated lactone structure: aflatoxin B1.