NIKKOMYCIN-RESISTANT MUTANTS OF MUCOR-ROUXII - PHYSIOLOGICAL AND BIOCHEMICAL-PROPERTIES

We isolated three nikkomycin-resistant mutants of the dimorphic fungus M. rouxii which were physiologically characterized regarding their re sponse to yeast-phase inducing conditions and their sensitivity to bac ilysin. Mutant strains G21 and G23, showed a qualitatively normal, tho ugh delayed, dimorphic transition and partial cross-resistance to baci lysin. Mutant strain G27 showed an altered dimorphism, producing a hig h proportion (50%) of hyphal cells, and a wild-type sensitivity to bac ilysin. Cell-free extracts from this mutant exhibited an activity of b oth basal and protease-activated chitin synthetase which was overexpre ssed as compared with the parental strain and mutants G21 and G23. Res ults are discussed in terms of the different genetic background of the mutants.