STRUCTURE-ACTIVITY-RELATIONSHIPS AND INTERACTIONS AMONG TRICHOTHECENEMYCOTOXINS AS ASSESSED BY YEAST BIOASSAY

A yeast (Kluyveromyces marxianus) bioassay was used to establish the r elative toxicity of 16 trichothecenes and some of their interactions. Removal of an isovaleryl group, one or two acetyl groups, or two acety l plus an isovaleryl groups from T-2 toxin (T2) to form diacetoxyscirp enol, HT-2 toxin (HT2), T2-triol and T-2 tetraol (T2-4ol) decreased to xicity 7, 36, 276 and 558-fold, respectively, A combination of T2 and HT2, T2 and T2-4ol, deoxynivalenol (DON) and nivalenol (NIV), or DON a nd T2 exhibited synergistic (T2 and HT2 or DON and NIV) or antagonisti c (DON and T2) responses.