PROPICONAZOLE AND DIETARY-COMPONENTS AS SPECIFIC INDUCERS OF GLUTATHIONE S-TRANSFERASES IN ORTHOSIA-GOTHICA

Six major glutathione S-transferase (GST) subunits (subunits 1-6), bel onging to two different GST classes (GST1 and GST2), were purified by glutathione-Sepharose affinity chromatography and reverse-phase high-p erformance liquid chromatography (HPLC) from the gut-free soft tissue cytosol of last instar Orthosia gothica fed a bean diet (large white k idney beans) to which propiconazole (250 ppm) had been added for 2 day s. Subunit 2, which belonged to O. gothica GST1, was also present in t he cytosol of the larvae given the bean diet without propiconazole, ap ple leaves (Malus domestica cult.), or willow leaves (Salix caprea). H owever, the amount of subunit 2 relative to the other subunits varied with the diet and pesticide treatment. Subunits 1 and 3-6 all belonged to O. gothica GST2 and all had the same M(r) and pI. Subunits 3 and 6 were not present in the larvae given apple or willow leaves only, and the amount of subunit 3 was significantly higher than the other GST2 subunits in the larvae which had been given propiconazole. The cytosol ic GST activity toward 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nit robenzene, and cumene hydroperoxide did not change with diet and fungi cide treatment. (C) 1995 Academic Press, Inc.