Evidence for 1,8-dihydroxynaphthalene melanin in three halophilic black yeasts grown under saline and non-saline conditions

• Published in: FEMS microbiology letters Vol. 232; no. 2; pp. 203 - 209
• Main Authors: Kogej, Tina, Wheeler, Michael H, Lanišnik Rižner, Tea, Gunde-Cimerman, Nina
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier B.V 19.03.2004; Blackwell Publishing Ltd; Blackwell
• Subjects: 1,8-Dihydroxynaphthalene-melanin; Biological and medical sciences; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Culture Media - pharmacology; Fundamental and applied biological sciences. Psychology; Halophilic black yeast; Hortaea werneckii; Melanins - metabolism; Microbiology; Miscellaneous; Mycology; Naphthols - metabolism; Phaeotheca triangularis; Sodium Chloride - pharmacology; Thiazoles - pharmacology; Trimmatostroma salinum; Yeasts - drug effects; Yeasts - growth & development; Yeasts - metabolism; 1,8-Dihydroxynaphthalene-melanin; Trimmatostroma salinum; Phaeotheca triangularis; Hortaea werneckii; Halophilic black yeast; Fungi; Yeast; Halophily; Ascomycetes; Melanin; Thallophyta
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1016/S0378-1097(04)00073-4

The ascomycetous black yeasts Hortaea werneckii, Phaeotheca triangularis, and Trimmatostroma salinum are halophilic fungi that inhabit hypersaline water of solar salterns. They are characterized by slow, meristematic growth and very thick, darkly pigmented cell walls. The dark pigment, generally thought to be melanin, is consistently present in their cell walls when they grow under saline and non-saline conditions. We used the inhibitor tricyclazole to test the fungi in this study for the presence of 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis, since fungal melanins reportedly are derived either from DHN, tyrosine via 3,4-dihydroxyphenylalanine, γ-glutaminyl-3,4-dihydroxybenzene, or catechol. Tricyclazole-treated cultures of the fungi were reddish-brown in color and contained typical intermediates of the DHN-melanin pathway, as demonstrated by high-performance liquid chromatography. This investigation showed that the three fungi synthesized DHN-melanin under saline and non-saline growth conditions.