Effect of environmental factors on Fonsecaea pedrosoi morphogenesis with emphasis on sclerotic cells induced by propranolol

The influence of growth conditions, as well as of propranolol on Fonsecaea pedrosoi morphogenesis was established using the chemically defined media of Czapeck-Dox (CD) and Butterfield (BF). Mycelial growth of F. pedrosoi in both media was obtained at room temperature (25 °C) for 14 days, without shaking, whereas conidia formed at 37 °C, for 4 days, in shaken cultures and could be isolated free from the mycelium by filtration in gauze. At low pH (2.5–3.0), there appeared sclerotic cells attached to normal hyphae. When propranolol was added to the CD medium moniliform hyphae were observed, whereas this drug in the BF medium induced formation of sclerotic cells. Ultrastructural examination revealed that the propranolol-induced sclerotic cells were very similar to those observed in infected tissues.