נגישות
menu      
חיפוש מתקדם
Ishaaya, I., Department of Entomology, ARO, The Volcani Center, Bet Dagan 50-250, Israel
Degheele, D., Faculty of Agricultural Sciences, State University of Ghent, Coupure Links 653, B-9000 Ghent, Belgium
Optimal assay conditions for gut diflubenzuron (DFB) hydrolase(s) of the Egyptian cotton leaf worm Spodoptera littoralis larvae are 0.9 mg protein of the postmitochondrial supernatant fraction incubated for 2 hr at 37°C with 0.5 nmol [14C]DFB (uniformally labeled on the aniline ring) in 0.4 ml of 0.05 M glycine-NaOH buffer (pH 9.0). The radiolabeled metabolites are separated and quantitatively evaluated using a TLC procedure. DFB hydrolase activity is a major factor for DFB detoxification in S. littoralis larvae. This conclusion is based on the ability of the larval gut enzyme to hydrolyze DFB to 4-chloroaniline (4-CA) and 4-chlorophenylurea (4-CPU), 4-CA being a major metabolite with a level of about 10% and 4-CPU a minor one with a level of about 1% of the total recovery. A relatively high level of radiolabeled polar metabolites is observed at the origin of the TLC plate; these metabolites are considered to be conjugated materials. DFB hydrolysis is totally inhibited in vitro at a concentration of 10-5 M of profenofos or DEF, which are both considered typical esterase inhibitors. Over 90% inhibition of DFB hydrolase activity in vivo is obtained when larvae are fed with castor bean leaves treated with 2.4 × 10-4% profenofos. Addition of sublethal concentrations of profenofos to dietary DFB resulted in a considerably higher toxicity of the latter. © 1988.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Properties and toxicological significance of diflubenzuron hydrolase activity in Spodoptera littoralis larvae
32
Ishaaya, I., Department of Entomology, ARO, The Volcani Center, Bet Dagan 50-250, Israel
Degheele, D., Faculty of Agricultural Sciences, State University of Ghent, Coupure Links 653, B-9000 Ghent, Belgium
Properties and toxicological significance of diflubenzuron hydrolase activity in Spodoptera littoralis larvae
Optimal assay conditions for gut diflubenzuron (DFB) hydrolase(s) of the Egyptian cotton leaf worm Spodoptera littoralis larvae are 0.9 mg protein of the postmitochondrial supernatant fraction incubated for 2 hr at 37°C with 0.5 nmol [14C]DFB (uniformally labeled on the aniline ring) in 0.4 ml of 0.05 M glycine-NaOH buffer (pH 9.0). The radiolabeled metabolites are separated and quantitatively evaluated using a TLC procedure. DFB hydrolase activity is a major factor for DFB detoxification in S. littoralis larvae. This conclusion is based on the ability of the larval gut enzyme to hydrolyze DFB to 4-chloroaniline (4-CA) and 4-chlorophenylurea (4-CPU), 4-CA being a major metabolite with a level of about 10% and 4-CPU a minor one with a level of about 1% of the total recovery. A relatively high level of radiolabeled polar metabolites is observed at the origin of the TLC plate; these metabolites are considered to be conjugated materials. DFB hydrolysis is totally inhibited in vitro at a concentration of 10-5 M of profenofos or DEF, which are both considered typical esterase inhibitors. Over 90% inhibition of DFB hydrolase activity in vivo is obtained when larvae are fed with castor bean leaves treated with 2.4 × 10-4% profenofos. Addition of sublethal concentrations of profenofos to dietary DFB resulted in a considerably higher toxicity of the latter. © 1988.
Scientific Publication
You may also be interested in