Inhibition of Ergosterol Biosynthesis by Morpholine, Piperidine, and Spiroketalamine Fungicides in Microdochium nivale: Effect on Sterol Composition and Sterol delta 8 DELTA7-Isomerase Activity

We studied the effect of 4-chlorophenoxyacetic acid-raised tomato homogenate on rat erythrocyte antioxidant enzymes, namely glucose-6-phosphate dehydrogenase, catalase, selenium-dependent glutathione peroxidase, and Cu/Zn-superoxide dismutase. Tomatoes were raised with 1, 10, or 20 ppm of 4-chlorophenoxyacetic acid by spraying. Homogenate of tomatoes raised with 1 or 10 ppm of 4-chlorophenoxyacetic acid given in a dose of 1 ml/100 g body weight by gavage did not cause any significant alterations in activities of rat erythrocyte antioxidant enzymes. However, homogenate of tomatoes raised with 20 ppm 4chlorophenoxyacetic acid given in the same dose caused a significant reduction in seleniumdependent glutathione peroxidase (P < 0.05) and an increment in catalase (P < 0.05) activities but did not significantly alter the activities of other enzymes. It is suggested that the alterations in activities of erythrocyte antioxidant enzymes might play a role in toxic effects of phenoxyherbicides.