[Characterization fo mycelial mutants of Mucor rouxii]

The consequences of two different mutations induced with N-methyl-N-nitrosoguanidine (Strain G1) and Trifluoperazine resistance (Strain G5) in Mucor rouxii, were studied. Mutants were stable and exhibited mycelial morphology in aerobiosis. Mutants cells exhibit phenotypic characteristics of slow-growing. The mutants G1 and G5 cultures showed 16.8% and 35.3% of reduction of the growth relative to parental strain. Morphologically mycelia of mutants cell were indistinguishable from wild-type cells, except from reduction in extension and branching of hyphal that has the mutant G5. Calcofluor and FITC-Concanavalin A were used to study the distribution of new cell-wall polymers i.e. Chitin, glucans. The two G1 and G5 strains showed a uniform distribution of fluorescence over the cell surface, indicating that active deposition of new-wall material has occurred. Cellular proteins of mutants and parental strains were labeled with 14C-aminoacid mixture. The proteins pattern revealed that the majority of polypeptides synthesized by parental strain were also synthesized by mutants. It is evident the synthesis preferential of peptides with apparent M(r) > 92K, 60K, 50K, 43K, 38K and 25K. These results indicated that the primary defect of the mutation was not on cellular differentiation. It discuss phenotypic and biochemistry characteristics from mutants.