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Brazilian Journal of Microbiology

versão impressa ISSN 1517-8382

Resumo

GOULART, Rosangela de Carvalho  e  MARIN, José Moacir. Reversion by calcium of a yeast-like development to the original filamentous form, of the 10V10 5-fluorocytosine-sensitive mutant of Aspergillus niger. Braz. J. Microbiol. [online]. 2005, vol.36, n.3, pp. 301-306. ISSN 1517-8382.  http://dx.doi.org/10.1590/S1517-83822005000300018.

Some filamentous fungi present the phenomenon of dimorphism, their morphological structure alterations being capable of inducing metabolism changes. The Aspergillus niger strain 10v10, a producer of citric acid, was submitted to the mutagenic action of ultraviolet irradiation which respectively selects mutants sensitive or resistant to the antifungi agent 5 fluorocytosine (5-FC). 5-FC sensitive mutants presented a morphological alteration to a yeast-like form. The effects of pH changes, addition of salts (KH2PO4, NH4NO3, MgSO4 and MgCl2), the presence of osmotic stabilizers, as well as of calcium chloride, on morphological reversal and acid production were studied. Morphological reversal to the filamentous form was observed only in the presence of CaCl2 (500mM) for the mutants strains 1 and 2, while the acid production occurred in both, yeast-like and filamentous forms.

Palavras-chave : Aspergillus niger; 5-fluorocytosine; yeast-like; calcium; acid production; dimorphism.

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