Estudou-se o potencial recombinogênico da danofloxacina, novo antimicrobiano pertencente ao grupo das 4-fluoroquinolonas e de uso exclusivo em medicina veterinária, no fungo filamentoso Aspergillus nidulans. A linhagem mestra UT196 e o mutante Z1 foram utilizados para formar o diplóide Z1//UT196. Conídios desse diplóide foram inoculados em placas de Petri contendo meio mínimo suplementado com 2,5, 5,0 e 10,0 mig/ml de danofloxacina. As placas foram incubadas por cinco dias a 37 ºC. Segregantes mitóticos foram isolados das colônias tratadas com o antimicrobiano e as análises de seus fenótipos evidenciaram o efeito recombinogênico da danofloxacin na dose de 10,0 mig/ml. Recombinantes para vários intervalos dos cromossomos I e II foram identificados entre os segregantes analisados.

The aim of this work was to demonstrate the recombinogenic effect of danofloxacin, a new 4-fluoroquinolone antimicrobial used only in veterinary medicine, in the filamentous fungi Aspergillus nidulans. The UT196 master strain and the Z1 mutant were used to produce the Z1//UT196 diploid strain. Conidia of this diploid strain were inoculated in Petri dishes containing selective medium supplemented with 2.5, 5.0 or 10.0 mug/ml danofloxacin. The plates were incubated for five days at 37 ºC. Mitotic segregants were isolated from the diploid colonies and phenotypes of the segregants were analyzed. Inoculation of 10.0 mug/ml danofloxacin was shown to be positive in inducing somatic crossing-over in diploid cells of A. nidulans. An increase in the mitotic recombination frequencies was observed in several linkage-intervals of chromosomes I and II from Z1//UT196 diploid strain.