Ispitivanje biosinteze T-2 toksina u čistoj kulturi u različitim laboratorijskim uslovima

Biosinteza T-2 toksina u laboratorijskim uslovima je testirana kod sedam izolata Fusarium spp. Kultivacija je obavljena u pored o na prirodnom čvrstom supstratu (zrnu pšenice) i polusintetičkoj tečnoj podlozi (GPK). Gotovo sva proizvedena količina T-2 toksina je bila ekstracelularnog porekla. Veći prinosi ovog trihotecena su dobijeni kod izolata Fusarium kultivisanih na tečnoj podlozi: 0,8-175,0 mg/L filtra ta u odnosu na 12,5-52,5 mg/kg sintetisanih na zrnu pšenice. Fermentacija na tečnoj podlozi i rotacionoj mučkalici se pokazala kao pogodnija metoda za testiranje toksikogenosti gljivičnih izolata zbog kraće inkubacije, jednostavnije pripreme uzoraka i ekstrakcije T-2 toksina, dobijanja sirovih ekstrakata sa mnogo manje pratećih materija i mogućnosti preciznijeg definisanja faktora koji mogu da utiču na prinos istog trihotecena.Seven isolates of the fungal genus Fusarium, comprising three species: F.culmorum, F.sporotrichioides and F.tricinctum, were tested for T-2 toxin production. Cultivation was carried oout concurrently on a natural substrate (wheat grains) under temperature stress conditions (7 days at 28 °C, 21 days at 15-16 °C), and in a semi-synthetic liquid medium (5% glucose, 0.1 % peptone-1, 0.1 % yeast extract) on a rotary shaker (200 rpm, 5 days at 26 °C). Of the fungal isolates cultivated on wheat grains 85.7% were found to be toxicogenic; the yields of T-2 toxin were rather small (12.5-52.5 mg/kg dry weight). In the liquid medium all Fusarium cultures biosynthesized T-2 toxin; the quantities produced ranged from 0.8 to 175.0 mg/l of the filtrate. At least half of the dispensed sugar was present in the medium when T-2 toxin production started. No correlation was found between the type of mycelial growth, sporulation, biomass quantities and the intensity of T-2 toxin biosynthesis. Most of the produced trichothecene was of extracellular origin. Fermentation in the semi-synthetic liquid medium using a rotary shaker was more suitable for screening the toxicity of the fungal isolates in pure cultures because of a shorter period of incubation, simpler sample preparation and T-2 toxin extraction. In this way factors influencing toxin production could be defined more precisely