In the present work the genetic activity of the fungicide captafol was studied in a heterozygous diploid strain of Aspergillus (Emericella) nidulans. In vitro fungitoxicity tests of captafol on mycelia growth, showed a great increase of the color segregants. Analysis of white and yellow mitotic recombinants suggests that low captafol concentrations increase the mitotic crossing-over frequency while non-disjunction was also occurred at high concentrations. Light and electron microscopic observations of A. nidulans cells showed that captafol induces a number of cytological abnormalities in hyphae as well as in cell structures. A destruction of cytoplasmatic membrane, nucleus membrane and other membranes was observed. At concentrations of the fungicide highly inhibitory to growth (more than 50%), an abnormal nuclear division was observed which did not follow the typical mitotic function which is usually observed in Ascomycetes. On the contrary, the formation of an unequal lobe was present, which leads in an unequal distribution of chromosomal material in the sub-nuclei.
Key words: Aspergillus (Emericella) nidulans, Captafol, Genetic activity, Mitosis
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