ABSTRACT
The fusarium mycotoxin zearalenone was transformed in cell suspension cultures of Zea mays giving α- and ß-zearalenol and the ß-D-glu cos ides of zearalenone and α- and ß-zearalenol. The structure of zearalenone-4-ß-D-glucopyranoside was determined by liquid - chromatography-mass spectrometry and specific hydrolysis with ß-glucosidase. α- and ß-zearalenol and their glucosides were identified by co chromatography using tic and HPLC and glucosidase - treatment Up to 50% of the mycotoxin added was bound to a non extractable or "bound" residue fraction. After treating this residue by a sequential cell wall fractionation procedure, zearalenone was found to be bound mainly to starch, hemicellulose, and lignin fractions.
ABSTRACT
In order to determine to fungal growth of Fusarium graminearum 480, a method was developed for the extraction and estimation of ergosterol, a sterol specific for fungi. This method includes the direct saponification of bound ergosterol to fungal mycelia followed by n-hexane extraction and quantification using. High performance liquid chromatography (HPLC) with UV-detection. This procedure proved to be superior compared with other methods, since the yield of ergosterol yields was higher (up to 40%). n-Hexane extracts contained minor impurities which interfered with the UV-detection and the retention time of the compound was halved using Si 60 HPLC. The protein and ergosterol contents in F. graminearum cultures increased proportionally over a 3-week incubation period. The fungal formation of the mycotoxin zearalenone started at a level of 50 mg/kg ergosterol and increased rapidly in the stationary phase of growth, which was characterized by decreasing rates of ergosterol formation.
