Fungal melanin detection by the use of copper sulfide-silver.
Silver-staining procedures were investigated for their effectiveness in identifying cell wall-based fungal melanins in live and fixed plastic embedded samples, particularly 1,8-dihydroxynaphthalene (DHN) based polyketide melanins. We developed a simple and reliable melanin-staining technique based on a silver accumulation method originally published for histological demonstration of heavy metal sulfides in mammalian tissues. Copper is bound to fungal melanin followed by formation of the copper sulfide at melanin sites in fungal cell walls, which then are amplified into vivid black stains using a silver enhancement step. The method demonstrates patterns of melanization in a range of fungal hyphae and is suitable for light and electron microscopy. Albino mutant fungi and normally nonmelanized fungi do not stain with the sulfide-silver technique. Mammalian melanocytes also were labeled by the technique, indicating its universality as a melanin probe.
Butler
M J
MJ
Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 Canada. mjbutler@uwo.ca
Gardiner
R B
RB
Day
A W
AW
D000818:Animals; D002473:Cell Wall / Q000737:chemistry; D003300:Copper; D004295:Dihydroxyphenylalanine / Q000032:analysis; D005658:Fungi / Q000737:chemistry*; D006651:Histocytochemistry; D008543:Melanins / Q000032:analysis* / Q000737:chemistry; D008544:Melanocytes / Q000166:cytology; D051379:Mice; D008809:Mice, Inbred C3H; D008853:Microscopy; D046529:Microscopy, Electron, Transmission; D025282:Mycelium / Q000737:chemistry; D012834:Silver; D013194:Staining and Labeling / Q000379:methods*; D013440:Sulfides
D008543:Melanins; D013440:Sulfides; D012834:Silver; D004295:Dihydroxyphenylalanine; D003300:Copper