Abstract
Evidence is presented to show that an epoxide-hydrolyzing enzyme system is present in the uredospores of Puccinia graminis Pers. f. sp. tritici Erikss. and Henn. race 15B and in the teliospores of Gymnosporangium clavariiforme (Pers.) DC. Incubation of the spores results in a partial conversion of cis-9,10-epoxy-octadecanoic acid, which is present in the spore oil as a glyceride, to (+) threo-9,10-dihydroxyoctadecanoic acid.