Subject(s)
Education, Medical, Undergraduate , Plagiarism , Teaching/methods , Ethics, Research , HumansABSTRACT
A total of 61 isolates of dematiaceous fungi, including Exophiala jeanselmei, Wangiella dermatitidis, Fonsecaea pedrosoi, Phialophora verrucosa, and a few isolates of related organisms were evaluated for their ability to assimilate 13 carbohydrates and sodium nitrate. Results indicated that patterns of assimilations can facilitate specific identifications when used with microscopic morphologic features. Eleven isolates of W. dermatitidis demonstrated negative results for nitrate assimilation, although most of the other fungi tested had positive reactions. The tests did aid in separating this very complex group of fungi.
Subject(s)
Carbohydrate Metabolism , Exophiala/classification , Mitosporic Fungi/classification , Nitrates/metabolism , Phialophora/classification , Cladosporium/classification , Cladosporium/metabolism , Exophiala/metabolism , Mitosporic Fungi/metabolism , Phialophora/metabolismABSTRACT
Melanin synthesis in the dematiaceous, polymorphic hyphomycete Wangiella dermatitidis, a human pathogen, was investigated by biochemical and physiological techniques. Mutants with a decrease or loss in melanin synthesis were induced and isolated. Melanin precursors were obtained from the mutants, purified, and then identified by comparison with authentic compounds from Verticillium dahliae . Isolation of scytalone , vermelone , flaviolin , and 1,8- dihydroxynaphthalene from the mutants of Wangiella dermatitidis, and cross-feeding of the mutants with those of Verticillium dahliae indicated that melanin synthesis in this organism took place by the pentaketide pathway. Melanin that formed in cell walls of an albino mutant treated with scytalone was identified in appearance to that in cell walls of the wild-type strain. This also suggested that pentaketide synthesis of melanin occurred in the fungus.
