Organophosphorus hydrolase (OPH, also known as phosphotriesterase) is a bacterial enzyme that is capable of degrading a wide range of neurotoxic organophosphate nerve agents. Directed evolution has been used to generate one variant (22A11) with up to 25-fold improved hydrolysis of methyl parathion. Surprisingly, this variant also degraded all other substrates (paraoxon, parathion and coumaphos)...

The role of glutathione S-transferase (GST, EC 2.5.1.18) in the degradation of and resistance to some insecticides of diamondback moth (DBM) larvae has been confirmed through the purification and characterization of its four isozymes from this notorious insect pest of cruciferous vegetables. Two immuno-related isozymes, GST-3 and GST-4, exhibit apparent substrate preference for 1,2-dichloro-4ni...

Two mixed bacterial cultures isolated by soil enrichment were capable of utilizing methyl parathion (O,O-dimethyl O-p-nitrophenylphosphorothioate) and parathion (O,O-diethyl O-p-nitrophenylphosphorothioate) as a sole source of carbon. Four isolates from these mixed cultures lost their ability to utilize the pesticides independently in transfers subsequent to the initial isolation. One member of...

Fenitrothion: An organophosphorus insecticide, fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate; CAS No. 122-14-5), which is a yellow-brown liquid with an unpleasant odor at room temperature, was introduced in 1959 by both Sumitomo Chemical Company and Bayer Leverkusen, and later by American Cyanamid Company (Hayes, 1982; Hayes and Laws, 1990; Worthing and Walker, 1987). Organophos...

Wetland ecosystems have reduced ambient levels of various organic and metallic compounds, although their effectiveness on agricultural pesticides is not well documented. Five stations within each of two 10 x 50 m constructed wetlands (two vegetated, two nonvegetated) were selected to measure the fate and effects of methyl parathion (MeP). Following a simulated storm event (0.64 cm of rainfall),...

A consistent correlation between elevated esterase activity and methyl parathion resistance among Nebraska western corn rootworm, Diabrotica virgifera virgifera LeConte, populations has previously been documented. Characterization of general esterase activity using naphtholic esters as model substrates indicated that differences between resistant and susceptible strains could be maximized by op...

BACKGROUND Although Pichia pastoris has been successfully used to produce various recombinant heterologous proteins, the efficiency varies. In this study, we used methyl parathion hydrolase (MPH) from Ochrobactrum sp. M231 as an example to study the effect of protein amino acid sequence on secretion from P. pastoris. RESULTS The results indicated that the protein N-terminal sequence, the endo...

A miniaturized analytical system for separating and detecting toxic organophosphate nerve agent compounds, based on the coupling of a micromachined capillary electrophoresis chip with a thick-film amperometric detector, is described. Factors influencing the on-chip separation and detection processes have been optimized. Using a MES buffer (20 mM, pH 5.0) running buffer, a 72-mm-long separation ...

The contaminated soil caused by an organophosphorus pesticide production enterprise was evaluated, in order to provide constructive suggestions for the future remediation work. This study follows basic technical route of sampling with method distribution, and combined relevant national laws regulations actual situation site evaluate analyze, finally find out whether characteristic pollutants ex...