• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.126-129
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• 2003

A relatively high homology between Escherichia coli prolidase and Alteromonas organophosphorous acid anhydrolase suggests that E. coli prolidase may have an activity to d egrade toxic organophosphorous compounds. To confirm this suggestion, we cloned and expressed a prolidase gene (pepQ) of E. coliBL2l. The recombinant E. coli prolidase that consisted of 443 amino acid residues exhibited activity and stereochemical selectivity against organopho sphorous compounds, although its activity was two to three orders of magnitude less than that of the other organophosphorous acid hydrolase isolated from Pseudomonas diminuta.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1339-1342
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• 2010

$^{31}P$ NMR and ESI-MS studies of $Cu^{2+}$ binding to Fenitrothion (FN) were performed by experimentally and theoretically. The calculated $^{31}P$ NMR chemical shifts for FN-$Cu^{2+}$ complexes are in good agreement with experimental chemical shifts in order, and the results present an important information for organophosphorus pesticide metal complexes. ESI-MS and low energy CID MS/MS experiments of FN-$Cu^{2+}$ complexes combined with accurate mass measurements give insight into the metal localization and allow unambiguous identification of fragments and hydrolysis products.

• Toxicological Research
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• v.14 no.2
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• pp.227-235
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• 1998

KH-502 (Flupyrazofos), a new organophosphorus insecticide synthesized by Korea Re-search Institute of Chemical Technology, was found to be effective against diamond-back moth(Plutella xylostella). This study was carried out to determine the acute toxicity of KH-502 in Sprague-Dawley rats and ICR mice. The test article was orally or dermally administered to the animals. Death, tremors, salivation, lacrimation, abnormal gait and corneal opacity were observed. Decrease in body weight gain was observed in all treatment groups. At necropsy, dark red coloration of lung, enlargement of adrenal glands and atrophy of spleen were observed. The oral $LD_{50}$ value was 372 mg/kg in male rats, 605 mg/kg in female rats, 186 mg/kg in male mice, and 115 mg/kg in female mice. And the dermal $LD_{50}$ was 4086 mg/kg in male and 3881 mg/kg in female rats.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1527-1535
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• 2012

Selection of the most informative molecular descriptors from the original data set is a key step for development of quantitative structure activity/property relationship models. Recently, mutual information (MI) has gained increasing attention in feature selection problems. This paper presents an effective mutual information-based feature selection approach, named mutual information maximization by replacing collinear variables (MIMRCV), for nonlinear quantitative structure-property relationship models. The proposed variable selection method was applied to three different QSPR datasets, soil degradation half-life of 47 organophosphorus pesticides, GC-MS retention times of 85 volatile organic compounds, and water-to-micellar cetyltrimethylammonium bromide partition coefficients of 62 organic compounds.The obtained results revealed that using MIMRCV as feature selection method improves the predictive quality of the developed models compared to conventional MI based variable selection algorithms.

• BMB Reports
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• v.31 no.3
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• pp.296-302
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• 1998

A potentiometric flow injection biosensor for the analysis of anti-cholinesterases (anti-ChEs), based on inhibition of enzyme activity, was developed. The sensor system consists of a reactor with acetylcholinesterase (AChE) immobilized on controlled pore glass and a detector with an $H^{+}-selective$ PVC-based membrane electrode. The principle of the analysis is based on the fact that the degree of inhibition of AChE by an anti-ChE is dependent on the concentration of the anti-ChE in contact with AChE. The sensor system was optimized by changing systematically the operating parameters of the sensor to evaluate the effect of the changes on sensor response to ACh. The optimized biosensor was applied to the analysis of paraoxon, an organophosphorus pesticide. Treatment of the inhibited enzyme with pyridine-2-aldoxime fully restored the enzyme activity allowing repeated use of the sensor.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.373-377
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• 2003

Various groups of industrial and agricultural pollutants (heavy metal ions, cyanides, and pesticides) can be detected by enzymes. Since heavy metal ions inhibit urease, cyanides inhibit peroxidase, organophosphorus and carbamate pesticides inhibit butyrylcholinesterase, these enzymes were co-immobilized into a bovine serum albumin gel on the surface of an ion-sensitive field effect transistor to create a bioprobe that is sensitive to the compounds mentioned above. The sensitivity of the present sensor towards KCN corresponded to $1\;\mu\textrm{M}$ with 1 min of incubation time. The detection limits for Hg(II) ions and the pesticide carbofuran were 0.1 and $0.5\;\mu\textrm{M}$, respectively, when a 10 min sensor incubation time in contaminated samples was chosen. The total time for determining the concentrations of all species mentioned did not exceed 20 min.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.959-966
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• 2006

The electron-capture detector (ECD) of gas chromatographs (GC) has been used widely in pesticide analysis. However, as ECD relies on radioactive material, it is troublesome to purchase and maintain. Therefore, potent replacements for ECD were investigated. A Pulsed-discharge detector (PDD) for ECD was tested and the analytical results of PDD (ECD mode), ${\mu}ECD$, and nitrogen-phosphorus detector (NPD) were compared for 107 pesticides including organochroline, organophosphorus, pyrethroids etc. The number of pesticides identified at the lowest limit of detection (LOD) was 36, 29, and 2 for PDD, ${\mu}ECD$, and NPD, respectively. The remaining pesticides showed same response to PDD and ${\mu}ECD$. The GC-PDD analysis of pesticides spiked into representative agricultural products (brown rice, spinach, and mandarin oranges) also showed good and/or equivalent recoveries using $GC-{\mu}ECD$.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.990-992
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• 2006

In a previous study, we obtained polyclonal antibodies against the organophosphorus insecticide fenitrothion and developed an enzyme-linked immunosorbent assay (ELISA) for this pesticide. Using these antibodies and an enzyme tracer, a direct competitive ELISA method specific for fenitrothion using a dipstick format was developed. Dipstick ELISA using antibodies to fenitrothion immobilized on an Immunodyne membrane allowed the quick visual detection of fenitrothion at concentrations above $10\;{\mu}g/L$. The $IC_{50}$ value of dipstick ELISA using reflectance detection was $27\;{\mu}g/L$ with a detection limit of $2\;{\mu}g/L$. The recovery of fenitrothion from spiked lettuce and rice samples using the dipstick ELISA ranged from 87-107%.

• Toxicological Research
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• v.17 no.4
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• pp.287-296
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• 2001

The acute oral LD5O toxicity values of isazofos, pyraclofos, diazinon and methomyl were determined for Japanese quail based on OECD guideline. The $LD_{50}$ of isazofos, pyraclofos and diazinon was 16.26 mg/kg, and 7.11mg/kg body weight In female respectively. And the $LD_{50}$ of each chemical in male was 21.44, 35.64, 8.28 mg/kg body weight respectively. Diazinon was the most susceptible compounds to Japanese quail in both sexes. The $LD_{50}$ of methomyl was 21.24 mg/kg body weights in female, and 28.28 mg/kg body weight in male respectively. Diazinon, isazofos and methomyl were more toxic In the female than male. The symptoms of poisoning were similar in quails administrated with each chemicals. The clinical sign in Japanese quail were ataxia, salivation, diarrhea, ruffled feather and convulsion at dead point. There were severe hemorrhage and catarrhal inflammation from duodenum to ileum In all compounds. In Japanese quail treated with organophosphorus and carbamate compounds, brain acetylcholinesterase was inhibited by 88-96. The recovery was not observed after 5 h in sublethal dose.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.39-46
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• 1997

Mandarin orange fruits were artificially contaminated with an organophosphorus insecticide phenthoate by dipping and the residue level of phenthoate was investigated during the purification steps of dietary fiber or bioflavonoid. The removal rate of phenthoate at 8 and 0.5 ppm levels was 98% in the total dietary fiber, 99% in the insoluble dietary fiber and 99.8% in the soluble dietary fiber preparations. Kuring the preparation of biflavonoid from peels at a 5 ppm pesticide level, the removal rate was 90% in the intermediate extract and 99.9% in the final extract. In conclusion, phenthoate residues in the peels of mandarin orange were mostly removed during the preparation processes of dietary fiber of bioflavonoid and its residue level would not raise any problem in safety aspects of the purified products.