Carotenoid Pigments of the Dematiaceous FungusWangiella Dermatitidis

Abstract

The synthesis of carotenoid pigments by Wangiella dermatitidis was demonstrated with both wild-type (wt) and melanin-deficient (Mel~) strains. The carotenoids synthesized included torulene and torularhodin and their syntheses were shown to require photoinduction. Illuminated incubation of a Mel~ strain provided carotenoid-pigmented cells which were more resistant to ultraviolet irradiation than dark-incubated, nonpigmented cells. Both the wt and Mel strains were capable of photoreactivation following exposure to ultraviolet light. These data describe the first observation of carotenoid synthesis by one ofthe dematiaceous yeasts and suggest that these pigments may have some role in photoprotection. Carotenoids are polyisoprenoid compounds responsible for the pigmentation of a number of fungi, including the red yeasts of the form-genus Rhodotorula (Goodwin, 1972; Simpson et al, 1964) and their perfect forms as the basidiomycetous teliomorphs of the genus Rhodosporidium (Kockova-Kratochvilova and Bystricky, 1974). The fungal form-family Dematiaceae is characterized by the production of dark pigments associated with the cell wall (Ainsworth, 1971), but carotenoid production has been demonstrated in only two dematiaceous molds, Epicoccum nigrum Link ex Fr. (Gribanovski-Sassu and Foppen, 1969) and Alternaria alternata (Fries) Keissler (Haggblom and Unestam, 1979), and in none of the black yeasts. The human pathogen, Wangiella dermatitidis (Kano) McGinnis (McGinnis, 1977'a, b) is a polymorphic, dematiaceous fungus which grows in vitro primarily as a yeast, but may also produce hyphal or multicellular morphologies (Szaniszlo et al, 1981). Like other dematiaceous fungi, this organism produces a darklypigmented cell wall. Melanin synthesis within the cell wall is responsible for the dark pigmentation (Geis and Szaniszlo, unpublished observation). The purpose of this communication is to report the isolation and identification of carotenoid pigments from yeast cells of W. dermatitidis and to demonstrate the potential role of these pigments in photoprotection.