cotton whitefly, bemisia tabaci gennadius (homoptera: aleyrodidae) is one of the most seriously damaging insect pests of agricultural products worldwide. it is highly polyphagous, damaging a broad range of food as well as non-food crops through direct feeding, excretion of honeydew and transmission of over 100 plant viruses. in iran, growers usually use insecticides as the main control agent of...

Previous electrophysiological and behavioural studies implicate esterase 6 in the processing of the pheromone cis-vaccenyl acetate and various food odorants that affect aggregation and reproductive behaviours. Here we show esterase 6 has relatively high activity against many of the short-mid chain food esters, but negligible activity against cis-vaccenyl acetate. The crystal structure of estera...

Studies have been carried out to determine the maximal solubilization of cholesteryl oleate and tocopheryl acetate within mixed bile salt-fatty acid micelles and to establish reproducible assays for pancreatic esterase activity using these micellar substrates. At pH 8.5, using 30 mM sodium taurocholate and 10 mM oleic acid, reproducible micellar solutions of the esters could be prepared giving ...

An inducible acetylesterase (EC 3.1.1.6) that hydrolyzes ethyl acetate, an intermediate in the degradation of 2-butanone by Nocardia strain LSU-169, was purified. The polypeptide molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 39,500, and the enzyme molecular weight determined by sucrose density gradient centrifugation was 84,000. The purified enz...

Naphthyl esterase and platelet-activating factor (PAF)-acetylhydrolase activities were detected in the salivary glands of the cat flea, Ctenocephalides felis. Salivary naphthyl esterase activity is disgorged during exploratory probing. Whole extracts of salivary glands contain esterase activity against the short-chain naphthyl esters alpha-naphthyl acetate (approximately 210pmol/min/gland pair;...

During the fermentation of sugars to ethanol relatively high levels of an undesirable coproduct, ethyl acetate, are also produced. With ethanologenic Escherichia coli strain KO11 as the biocatalyst, the level of ethyl acetate in beer containing 4.8% ethanol was 192 mg liter(-1). Although the E. coli genome encodes several proteins with esterase activity, neither wild-type strains nor KO11 conta...

The main objective of this study was to purify and characterize an esterase from Shewanella sp F88. The enzyme was purified 41-fold and an overall yield of 21 %, using a two-step procedure, including ammonium sulfate precipitation and Q-sepharore chromatography. Molecular weight of the enzyme was 62.3 kDa according to SDS-PAGE data. The enzyme showed an optimum activity at pH 6.5 and 58 ˚C. Evo...

The free-living spirochete Spirochaeta aurantia was nearly as susceptible to diacetyl chloramphenicol, the product of chloramphenicol acetyltransferase, as it was to chloramphenicol itself. This unexpected susceptibility to diacetyl chloramphenicol was wholly or partly the consequence of intrinsic carboxylesterase activity, as indicated by high-performance liquid chromatography, thin-layer chro...

Solenopsis invicta and Solenopsis richteri are two closely related invasive ants native to South America. Despite their similarity in biology and behavior, S. invicta is a more successful invasive species. Toxic tolerance has been found to be important to the success of some invasive species. Esterases play a crucial role in toxic tolerance of insects. Hence, we hypothesized that the more invas...

activated the p-nitrophenyl acetateand p-nitrophenyl butyrate-hydrolysing activity of sheep serum at a significantly slower rate than it did the paraoxon-hydrolysing activity. From this and supporting evidence involving theKm for hydrolysis activity of sheep, rabbit and hog sera and of purified paraoxonase towards p-nitrophenyl acetate, it was concluded that a new esterase hydrolysing pnitrophe...