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Masahito Hayatsu - One of the best experts on this subject based on the ideXlab platform.
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Nucleotide sequence and genetic structure of a novel carbaryl hydrolase gene (cehA) from Rhizobium sp. strain AC100.
Applied and environmental microbiology, 2002Co-Authors: Masayuki Hashimoto, Mitsuru Fukui, Kouichi Hayano, Masahito HayatsuAbstract:Rhizobium sp. strain AC100, which is capable of degrading carbaryl (1-Naphthyl-N-methylcarbamate), was isolated from soil treated with carbaryl. This bacterium hydrolyzed carbaryl to 1-naphthol and methylamine. Carbaryl hydrolase from the strain was purified to homogeneity, and its N-terminal sequence, molecular mass (82 kDa), and enzymatic properties were determined. The purified enzyme hydrolyzed 1-Naphthyl Acetate and 4-nitrophenyl Acetate indicating that the enzyme is an esterase. We then cloned the carbaryl hydrolase gene (cehA) from the plasmid DNA of the strain and determined the nucleotide sequence of the 10-kb region containing cehA. No homologous sequences were found by a database homology search using the nucleotide and deduced amino acid sequences of the cehA gene. Six open reading frames including the cehA gene were found in the 10-kb region, and sequencing analysis shows that the cehA gene is flanked by two copies of insertion sequence-like sequence, suggesting that it makes part of a composite transposon.
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Purification and characterization of carbaryl hydrolase from Blastobacter sp. strain M501
Applied and environmental microbiology, 1993Co-Authors: Masahito Hayatsu, Tadahiro NagataAbstract:A bacterium capable of hydrolyzing carbaryl (1-Naphthyl- N -methylcarbamate) was isolated from a soil enrichment. This bacterium was characterized taxonomically as a Blastobacter sp. and designated strain M501. A carbaryl hydrolase present in this strain was purified to homogeneity by protamine sulfate treatment, ammonium sulfate precipitation, and hydrophobic, anion-exchange, gel filtration, and hydroxylapatite chromatographies. The native enzyme had a molecular mass of 166,000 Da and was composed of two subunits with molecular masses of 84,000 Da. The optimum pH and temperature of the enzyme activity were 9.0 and 45°C, respectively. The enzyme was not stable at temperatures above 40°C. The purified enzyme hydrolyzed seven N -methylcarbamate insecticides and also exhibited activity against 1-Naphthyl Acetate and 4-nitrophenyl Acetate. Images
Paul J. Semtner - One of the best experts on this subject based on the ideXlab platform.
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Diagnostic esterases and insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman (Homoptera: Aphididae)
Pesticide Biochemistry and Physiology, 1992Co-Authors: Yehia A.i. Abdel-aal, E. P. Lampert, R. M. Roe, Paul J. SemtnerAbstract:Abstract Insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman, from different localities in the southeastern United States has been found to exist mainly in aphids with red body coloration. Frequency distribution of esterase activity in individual tobacco aphids collected from a tobacco field and a greenhouse indicated that organophosphate resistance was always linked to high carboxylesterase activity toward 1-Naphthyl Acetate. Two approaches were taken to speed up the detection methodology of the frequency of resistant phenotypes. First, an abbreviated bioassay test, using malathion as a reporter molecule, was developed to rapidly distinguish between OP-resistant and susceptible phenotypes of the tobacco aphid. A time threshold of 50 min following aphid exposure to 50 ppm malathion in a water suspension accurately discriminated between susceptible and resistant phenotypes. Second, assays of aphid carboxylesterases, using the Acetates and propionates of 1-naphthol, 2-naphthol, and 4-nitrophenol, were performed to optimize and better understand the esterase discriminating activity between resistant and susceptible phenotypes. Only activity toward 1-naphtholic esters unambiguously discriminated between susceptible and resistant aphids. In general, resistance to malathion appeared to be esterase-mediated and some electrofocusing-detectable esterase isozymes were associated with resistance.
R. M. Roe - One of the best experts on this subject based on the ideXlab platform.
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Multiple Mechanisms of Pyrethroid Resistance in the German Cockroach, Blattella germanica (L.)
Pesticide Biochemistry and Physiology, 1994Co-Authors: D. D. Anspaugh, Randy L. Rose, P.g. Koehler, Ernest Hodgson, R. M. RoeAbstract:Abstract Pyrethroid-resistant German cockroaches known as the Village Green strain were compared to a susceptible (Orlando Normal) strain in respect to possible mechanisms of insecticide resistance. Male adults of the resistant strain weighed 15% more than susceptible roaches of the same cumulative age from adult eclosion. Based on the topical application of different concentrations of permethrin, the KD 50 for resistant roaches was 20-times greater than that for susceptible insects. Reduced penetration of [ 14 C]permethrin was observed in resistant insects during 24 hr after treatment along with increased in vivo metabolism as compared with susceptible controls. The cytochrome P450 content and monooxygenase activity when measured with methoxyresorufin and benzo[ a ]pyrene was elevated in resistant roaches by as much as 6.9-fold but no difference was found with benzphetamine. The glutathione transferase activity was also increased (1.6-fold with chlorodinitrobenzene) and elevated esterase activity was detected with the substrates, 1-Naphthyl Acetate (1.7-fold) and p -nitrophenyl Acetate (2.1-fold). Using isoelectric focusing, a novel E 2 esterase was identified in resistant cockroaches not found in the susceptible population. E 2 may be partly responsible for the increased esterase activity observed in resistant roaches. Increased esterase activity toward p -nitrophenyl Acetate was used to develop a kinetic, diagnostic assay that could rapidly discriminate resistant from susceptible individuals.
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Diagnostic esterases and insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman (Homoptera: Aphididae)
Pesticide Biochemistry and Physiology, 1992Co-Authors: Yehia A.i. Abdel-aal, E. P. Lampert, R. M. Roe, Paul J. SemtnerAbstract:Abstract Insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman, from different localities in the southeastern United States has been found to exist mainly in aphids with red body coloration. Frequency distribution of esterase activity in individual tobacco aphids collected from a tobacco field and a greenhouse indicated that organophosphate resistance was always linked to high carboxylesterase activity toward 1-Naphthyl Acetate. Two approaches were taken to speed up the detection methodology of the frequency of resistant phenotypes. First, an abbreviated bioassay test, using malathion as a reporter molecule, was developed to rapidly distinguish between OP-resistant and susceptible phenotypes of the tobacco aphid. A time threshold of 50 min following aphid exposure to 50 ppm malathion in a water suspension accurately discriminated between susceptible and resistant phenotypes. Second, assays of aphid carboxylesterases, using the Acetates and propionates of 1-naphthol, 2-naphthol, and 4-nitrophenol, were performed to optimize and better understand the esterase discriminating activity between resistant and susceptible phenotypes. Only activity toward 1-naphtholic esters unambiguously discriminated between susceptible and resistant aphids. In general, resistance to malathion appeared to be esterase-mediated and some electrofocusing-detectable esterase isozymes were associated with resistance.
Yehia A.i. Abdel-aal - One of the best experts on this subject based on the ideXlab platform.
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Organophosphate Resistance in the Tobacco Aphid (Homoptera: Aphididae): Purification and Characterization of a Resistance-Associated Esterase
Journal of Economic Entomology, 1994Co-Authors: Mark A. Wolff, Yehia A.i. Abdel-aal, Doreen K. S. Goh, E. P. Lampert, Michael R. RoeAbstract:A 1-Naphthyl Acetate esterase was identified by isoelectric focusing in organophosphate resistant (red) tobacco aphids, Myzus nicotianae Blackman, which apparently was lacking in susceptible (green) individuals of the same species. This resistance-associated esterase (RAE) was purified from the cytosol of whole body homogenates of adult tobacco aphids by gel permeation chromatography and two successive DEAE-Sephacel ion exchange columns. The enzyme eluted from the second DEAE column in 0.23 to 0.28 M NaCl and was ≍95% pure as determined by high-performance liquid chromatography (HPLC) on a BIO-SIL TSK-125 column. Purified RAE had an apparent molecular weight of 67,300 as determined by gel permeation HPLC and 66,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Wide range isoelectric focusing (pH 3.5-9.5) on polyacrylamide gel plates indicated that the isoelectric point was 4.61. Rabbit antiserum to the green peach aphid, M. persicae (Sulzer), esterase (E4) specifically cross-reacted with the tobacco aphid RAE, and the two esterases had identical molecular weights and isoelectric points as determined by immunoblotting. RAE protein was not detectable in susceptible tobacco aphids.
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Diagnostic esterases and insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman (Homoptera: Aphididae)
Pesticide Biochemistry and Physiology, 1992Co-Authors: Yehia A.i. Abdel-aal, E. P. Lampert, R. M. Roe, Paul J. SemtnerAbstract:Abstract Insecticide resistance in the tobacco aphid, Myzus nicotianae Blackman, from different localities in the southeastern United States has been found to exist mainly in aphids with red body coloration. Frequency distribution of esterase activity in individual tobacco aphids collected from a tobacco field and a greenhouse indicated that organophosphate resistance was always linked to high carboxylesterase activity toward 1-Naphthyl Acetate. Two approaches were taken to speed up the detection methodology of the frequency of resistant phenotypes. First, an abbreviated bioassay test, using malathion as a reporter molecule, was developed to rapidly distinguish between OP-resistant and susceptible phenotypes of the tobacco aphid. A time threshold of 50 min following aphid exposure to 50 ppm malathion in a water suspension accurately discriminated between susceptible and resistant phenotypes. Second, assays of aphid carboxylesterases, using the Acetates and propionates of 1-naphthol, 2-naphthol, and 4-nitrophenol, were performed to optimize and better understand the esterase discriminating activity between resistant and susceptible phenotypes. Only activity toward 1-naphtholic esters unambiguously discriminated between susceptible and resistant aphids. In general, resistance to malathion appeared to be esterase-mediated and some electrofocusing-detectable esterase isozymes were associated with resistance.
Graham D. Moores - One of the best experts on this subject based on the ideXlab platform.
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the interactions between piperonyl butoxide and e4 a resistance associated esterase from the peach potato aphid myzus persicae sulzer hemiptera aphididae
Pest Management Science, 2013Co-Authors: Despina Philippou, Graham D. Moores, Valerio Borzatta, Elisa Capparella, Leni Moroni, Linda M FieldAbstract:BACKGROUND: It has been reported previously that piperonyl butoxide (PBO) can inhibit both P450 and esterase activity. Although the method by which PBO combines with cytochrome P450 has been identified, the way in which it acts as an esterase inhibitor has not been established. This paper characterises the interactions between PBO and the resistance-associated esterase in Myzus persicae, E4. RESULTS: After incubation with PBO/analogues, hydrolysis of 1-Naphthyl Acetate by E4 is increased, but sequestration of azamethiphos is reduced. Rudimentary in silico modelling suggests PBO docks at the lip of the aromatic gorge. CONCLUSIONS: PBO binds with E4 to accelerate small substrates to the active-site triad, while acting as a blockade to larger, insecticidal molecules. Structure–activity studies with analogues of PBO also reveal the essential chemical moieties present in the molecule. © 2012 Society of Chemical Industry
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Esterases and Fenvalerate Resistance in a Field Population ofHelicoverpa punctigera(Lepidoptera: Noctuidae) in Australia
Pesticide Biochemistry and Physiology, 1997Co-Authors: Robin V. Gunning, Graham D. Moores, Alan L. DevonshireAbstract:Abstract A field population of Helicoverpa punctigera, resistant to fenvalerate was detected for first time in Australia on cotton in the Macquarie Valley, New South Wales in March 1994. DEF and profenofos were both partially effective as fenvalerate synergists, but piperonyl butoxide was ineffective. Electrophoretic studies revealed that resistant H. punctigera had increased esterase activity toward 1-Naphthyl Acetate, compared to a susceptible strain. In vitro metabolism and enzyme binding studies provided evidence of esterase-mediated fenvalerate metabolism. The origin of the resistant strain is discussed, as are the implications for insecticide resistance management.
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esterases and esfenvalerate resistance in australianhelicoverpa armigera hubner lepidoptera noctuidae
Pesticide Biochemistry and Physiology, 1996Co-Authors: Robin V. Gunning, Graham D. Moores, Alan L. DevonshireAbstract:Abstract Larvae of pyrethroid-resistant Australian Helicoverpa armigera have enhanced esterase activity which is due to increased production of the enzymes. The most resistant individuals have approximately a 50-fold increase in esterase activity compared to susceptible populations. Resistant H. armigera have additional esterase bands which are not detected in susceptible individuals. Increased esterase hydrolysis of 1-Naphthyl Acetate was correlated to the esfenvalerate resistance factor. Esterase bound readily to esfenvalerate. Homogenates of resistant insects hydrolyzed esfenvalerate and it is also likely that there was significant detoxification by sequestration. The prospect of biochemical assays for pyrethroid resistance and the possible genetic basis of the esterase resistance mechanism are discussed.
