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Title: EVIDENCE FOR 1,8-DIHYDROXYNAPHTHALENE MELANIN IN THREE HALOPHILIC BLACK YEASTS GROWN UNDER SALINE AND NON-SALINE CONDITIONS

Author
item KOGEJ, TINA - UNIVERSITY OF LJUBLJANA
item Wheeler, Michael - Mike
item RIZNER, TEA - UNIVERSITY OF LJUBLJANA
item GUNDE-CIMERMAN, NINA - UNIVERSITY OF LJUBLJANA

Submitted to: Federation of European Microbiological Societies Microbiology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2004
Publication Date: 2/13/2004
Citation: Kogej, T., Wheeler, M.H., Rizner, T.L., Gunde-Cimerman, N. 2004. Evidence for 1,8-dihydroxynaphthalene melanin in three halophilic black yeasts grown under saline and non-saline conditions. FEMS Microbiology Letters. 232:203-209.

Interpretive Summary: The fungi used in this investigation, called Hortaea werneckii, Phaeotheca triangularis, and Trimmatostroma salinum, are known to live in lakes containing large amounts of salt. These fungi were found to produce a black substance, known as melanin, that is believed to help them survive in bodies of water containing salt. The kind of melanin in these three fungi was identified and found to be identical to that in a number of other fungi, including several that infect plants and animals.

Technical Abstract: 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, g-glutaminyl-3,4-dihydroxybenzene, or catechol. Tricyclazole-treated cultures of the fungi were reddish brown in colour 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.