• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.379-385
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• 2014

The purpose of this study was to compare the ability of an engineered Escherichia coli to degrade chlorpyrifos (Cp) using an organophosphorus hydrolase enzyme, encoded in both Flavobacterium sp. ATCC 27551 or Pseudomonas diminuta, by employing the Lpp-OmpA chimera and the N-terminal domain of the ice nucleation protein as anchoring motifs. Tracing of the expression location of the recombinant protein using SDS-PAGE showed the presentation of OPH by both anchors on the outer membrane. This is the first report on the presentation of OPH on the cell surface by Lpp-OmpA under the control of the T7 promoter. The results showed cell growth in the presence of Cp as the sole source of energy, without growth inhibition, and with higher whole-cell activity for both cells harboring plasmids pENVO and pELMO, at approximately 10,342.85 and 10,857.14 U/mg, respectively. Noticeably, the protein displayed by pELMO was lower than the protein displayed by pENVO. It can be concluded that Lpp-OmpA can display less protein, but more functional OPH protein. These results highlight the high potential, of both engineered bacteria, for use in the bioremediation of pesticide-contaminated sources in the environment.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.946-951
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• 2008

The opd gene, encoding organophosphorus hydrolase (OPH) from Flavobacterium sp. capable of degrading a wide range of organophosphate pesticides, was surface- and intracellular-expressed in Synechococcus PCC7942, a prime example of photoautotrophic cyanobacteria. OPH was displayed on the cyanobacterial cell surface using the truncated ice nucleation protein as an anchoring motif. A minor fraction of OPH was displayed onto the outermost surface of cyanobacterial cells, as verified by immunostaining visualized under confocal laser scanning microscopy and OPH activity analysis; however, a substantial fraction of OPH was buried in the cell wall, as demonstrated by proteinase K and lysozyme treatments. The cyanobacterial outer membrane acts as a substrate (paraoxon) diffusion barrier affecting whole-cell biodegradation efficiency. After freeze-thaw treatment, permeabilized whole cells with intracellular-expressed OPH exhibited 14-fold higher bioconversion efficiency ($V_{max}/K_m$) than that of cells with surface-expressed OPH. As cyanobacteria have simple growth requirements and are inexpensive to maintain, expression of OPH in cyanobacteria may lead to the development of a low-cost and low-maintenance biocatalyst that is useful for detoxification of organophosphate pesticides.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.513-522
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• 2019

Catalysts based on organic compounds, transition metal and metal-organic frameworks (MOFs) have been applied to degrade or remove organophosphorus toxic compounds (OPs). During the last 20 years, various MOFs were designed and synthesized to suit application purposes. MOFs with $Zr_6$ based metal node and organic linker were widely used as catalysts due to their tunability for the pore size, porosity, surface area, Lewis acidic sites, and thermal stability. In this review, effect on catalytic efficiency between MOFs properties according to the structure, stability, particle size, number of connected-ligand, organic functional group, and so on will be discussed.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.30-35
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• 2001

Diamondback moth (Plutella xylostella L.) recently became a single worst insect which is not controlled effectively by organophosphorus and carbamate insecticides in Kangwon alpine croplands. The objective of this study was to determine if diamondback moth has developed a resistance to organophosphorus and carbamate insecticides. Resistance of diamondback moth, collected at Keichon, Jangpyong Taebaek, Chunchon, and Hongchon, was determined by the concentration required to kill fifty percent of population, $LC_{50}$. Their response of resistance varied to insecticides and locations: Taebaek populations were 35 and 70 times more resistant to chlorpyrifos and fenitrothion, respectively, than susceptible(S) population. Hongchon populations were 94 and 254 times more resistant to chlorpyrifos and fenitrothion, respectively, than S population. In addition, Chunchon populations were 37 and 19 times more resistant to profenofos and benfuracarb, respectively, than S population. However, the field populations did not differ in resistance to diazinon, phenthoate, flupyrazofos, carbofuran, and furathiocarb. This study show that field populations of diamondback moth found in Kangwon alpine vegetable croplands have developed a resistance and/or multiple resistance to some insecticides, implying that farmers are losing organophosphorus and carbamate insecticide options for selective control in vegetable crops.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.277-285
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• 2012

BACKGROUND: For safety evaluation of imported agri-food in Korea, the multiresidue analysis method was establised for unregistered organophosphorus pesticides, aspon, chlorthion, chlorthiophos, crotoxyphos, demeton-O, demeton-S, demeton-S-methyl, dioxathion, heptenophos, iodofenphos, leptophos, methyl-trithion, propetamphos and sulfotep. METHODS AND RESULTS: The used method for multiresidue analysis in brown rice and orange used as representative samples of imported agri-food was the official method of Korean Food and Drug Administration. The results of validation test of 13 organophosphorus pesticides except crotoxyphos for multiresidue analysis method are compared to the criteria such as specificity, linearity, accuracy, precision and limit of quantification. CONCLUSION: The used method for multiresidue analysis of unregistered 13 organophosphorus pesticides except crotoxyphos in Korea can surely be used as an official method for routine analysis of imported agri-food.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.436-440
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• 2000

Recently, we reported an improved technology for the degradation of organophosphate nerve agents using whole cells of genetically engineered Escherichia coli that anchored and displayed the enzyme organophosphorus hydrolase on the cell surface. In this paper we report the immobilization of these cells on highly porous sintered glass beads and the subsequent application of the immobilized cell in a continuous-flow packed bed bioreactor for the biodetoxification of a widely used insecticide, coumaphos.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.423-427
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• 2005

The bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex-272) and sodium diethyl- dithiocarbamate (NaDDC) ligands were used to extract of metal ions ($Cd^{2+},\;Co^{2+},\;Cu^{2+},\;Pb^{2+},\;Zn^{2+}$) in supercritical $CO_2$. Experiments showed a strong synergistic effect and better extraction efficiency if the two ligands were used together. In-situ UV-visible observation indicates that NaDDC in the water/supercritical $CO_2$ started to decompose slowly. The synergistic effect seems to come from the deprotonation of the organophosphorus ligand by amines from the decomposed NaDDC. The enhancing role of amines was confirmed using the mixture of Cyanex-272 and diethylamine(DEA) in the metal extraction.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.78-79
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• 2003

Organophosphorus (OP) pesticides have largely replaced the use of organochlorine pesticides and have been widely used in agriculture and houses in recent years because of their rapid breakdown in water and their low environmental persistence. As a result, consumers are directly or indirectly exposed to organophosphorus pesticides through several food groups including meat, dairy products, fruits, vegetables, dried foods, and most processed food in which a significant amount of pesticide residues have been found.(omitted)

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.599-603
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• 2002

A selective enzyme-linked immunosorbent assay (ELISA) for the insecticide isofenphos was developed. Three different analogues (haptens) of isofenphos were synthesized and were coupled to carrier proteins through the pesticide thiophosphate group t o use as immunogens or coating antigens. Rabbits were immunized with one of the haptens coupled to BSA for production of polyclonal antibodies and the sera were screened against each of the other two haptens coupled to ovalbumin (OVA). Using the sera of highest specificity, an antigen-coated ELISA was developed, which showed an I50 of 96 ng/mL with the detection limit of 2 ng/mL. The antibodies showed negligible cross-reactivity with other organophosphorus pesticides and the phenol metabolite of isofenphos, which makes the developed assay suitable for the selective detection of isofenphos. An antibody-coated ELISA was also developed, which showed an I50 of 580 ng/mL with a detection limit of 70 ng/mL.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1399-1426
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• 2002

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative detection of the organophosphorus insecticide bromophos. Three bromophos analogues (haptens) were synthesized and were coupled to carrier proteins to use as immunogens or coating antigens. Rabbits were immunized with either one of two haptens coupled to bovine serum albumin (BSA) for production of polyclonal antibodies, and the sera were screened against one of the haptens coupled to ovalbumin (OVA). Using the serum with highest specificity and an enzyme tracer, an antibody-coated ELISA was developed, which showed an $IC_{50}$ of 40 ng/mL with a detection limit of 7 ng/mL. The antibodies in this assay showed negligible cross-reactivity with other organophosphorus pesticides except with the insecticides chlorpyrifos and fenitrothion.