RESISTANCE TO ETHIDIUM-BROMIDE IN ASPERGILLUS-NIDULANS

A mutant of Aspergillus nidulans resistant to ethidium bromide was isolated and the semi-dominant gene responsible for this resistance was allocated on linkage group II at 17.42±3.05 units of recombination from the wA3 gene. The gene also confers cross-resistance to acriflavin, malachite green and crystal violet. It was also shown that riboflavin is antagonistic to the toxic effect of ethidium bromide, at certain concentrations. The mechanisms which could be responsible for the toxic effect of this drug are discussed and compared with those of acriflavin. The use of the Etb1 gene in genetical analysis through the parasexual cycle is suggested. © 1978 Birkhäuser Verlag.