Author/Editor		Lanišnik-Rižner, Tea; Žakelj-Mavrič, Marija
Title		17beta-hidroksisteroidna dehidrogenaza pri ekstremofilnih črnih kvasovkah
Type		članek
Source		In: Bole-Hribovšek V, Ocepek M, Klun N, editors. Zbornik s programom 2. kongres slovenskih mikrobiologov z mednarodno udeležbo; 1998 sep 27-30; Portorož. Ljubljana: Slovensko mikrobiološko društvo,
Publication year		1998
Volume		str. 91-5
Language		slo
Abstract		17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity was found in all representatives of different fungal classes. To elucidate its role in the fungal metabolism 17 beta-HSD from the filametous fungus Cochliobolus lunatus (17 beta-HSDcl) was purified and cloned. The cDNA and corresponding protein sequence was determined. High homology was found to enzymes that are involved in the biosynthesis of fungal pigment melanin, suggesting that 17 beta-HSDcl might be primarily involved in melanin biosynthesis. To check this possibility, three black yeasts, Hortaea werneckii, Trimmatostroma sp. and Phaetheca triangularis, were tested for the enzyme activity using androstenedione, testosterone, estrone and estradiol as substrates. Since existence of melanin was reported to be correlated with environmental stress conditions, yeast strains isolated from salterns were chosen and grown at presence of NaCI. In all cases 17 beta-HSD activity was detected favouring reduction of androstenedione and estrone, similar to 17 beta-HSDcl. To determine further possible similarities between 17 beta-HSD from black yeasts and 17 beta-HSDcl Western and Northern blot analyses were performed using polyclonal antibodies against 17 beta-HSDcl and a 530 bp fragment of 17 beta-HSD cDNA from the same fungus.
Descriptors		17-HYDROXYSTEROID DEHYDROGENASES ASCOMYCETES YEASTS MELANINS