• Journal of Animal Reproduction and Biotechnology
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• v.34 no.4
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• pp.318-321
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• 2019

Recent studies showed that tight junctions (TJs) integrity and assembly are required for blastocyst development in mouse and pig models. However, the biological functions of TJs associated with embryo implantation and maintenance of pregnancy were not investigated yet. To examine whether disrupted TJs affect further embryo development, we employed RNAi approach and inhibitor treatment. The embryos were injected with Cxadr (Coxsackievirus and adenovirus receptor) siRNA for knock down (KD) and treated with Adam10 (A Disintegrin and Metalloproteinase specific inhibitor 10; GI254023X; SI). We compared blastocyst development and paracellular sealing assay using FITC dextran uptake between control and KD or SI embryos. Finally, we transferred control and Cxadr KD or Adam 10 SI treated blastocyst to uteri of recipients. Cxadr KD and Adam 10 SI showed lower blastocyst development and more permeable to FITC-dextran. Moreover, we observed that half of KD and inhibited embryos failed to maintain pregnancies after the second trimester. Our findings suggested that TJs integrity is required for the maintenance of pregnancy and can be used as a selective marker for the successful application of assisted reproduction technologies.

• Biomolecules & Therapeutics
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• v.3 no.3
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• pp.210-216
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• 1995

Partially purified water-soluble extract mixture from Ricini and Coptidis (named as RIC) showed to be a potent inhibitor of human immunodeficiency virus-1 (HIV-1) replication. RIC was evaluated for in vitro anti-HIV activity using SupTl and H9 cells infected by a recombinant virus (pSVCAT) containing chloramphenicol acetyltransferase (CAT) gene substituted for nef gene in the HIV-1 genome. RIC inhibited syncytiaformation of SupTl cells with a half maximal effective concentration, $IC_{50}$/, of 2.5 $\mu\textrm{g}$/mι and showed marked inhibition of CAT activity in the infected H9 cells and also suppressed reverse transcriptase (RT) activity in the supernatant of the infected H9 culture. However, RIC did not inhibit the activity of reverse transcriptase directly when it was mixed with the enzyme or with viral particles. Berberine, one of components of RIC, also showed similar anti-HIV activity as RIC did. The data suggest that there are active ingredients which mediate anti-HIV activity in RIC.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1516-1524
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• 2014

Flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) can utilize a variety of external electron acceptors and also has stricter substrate specificity than any other glucose oxidoreductases, which makes it the ideal diagnostic enzyme in the field of glucose biosensors. A gene coding for a hypothetical protein, similar to glucose oxidase and derived from Aspergillus terreus NIH2624, was overexpressed in Pichia pastoris GS115 under the control of an AOX1 promoter with a level of 260,000 U/l in the culture supernatant after fed-batch cultivation for 84 h. After a three-step purification protocol that included isopropanol precipitation, affinity chromatography, and a second isopropanol precipitation, recombinant FAD-GDH was purified with a recovery of 65%. This is the first time that isopropanol precipitation has been used to concentrate a fermentation supernatant and exchange buffers after affinity chromatography purification. The purified FAD-GDH exhibited a broad and diffuse band between 83 and 150 kDa. The recombinant FAD-GDH was stable across a wide pH range (3.5 to 9.0) with maximum activity at pH 7.5 and $55^{\circ}C$. In addition, it displayed very high thermal stability, with a half-life of 82 min at $60^{\circ}C$. These characteristics indicate that FAD-GDH will be useful in the field of glucose biosensors.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.93-103
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• 2023

Persistence and degradation patterns of acequinocyl and its metabolite, hydroxyl-acequinocyl (acequinocyl-OH) and fenpyroximate in butterburs (Petasites japonicus Max.) were investigated after pesticide application. Butterburs, one of the minor crops in South Korea, was planted in two plots (plot A for double and plot B for single application) in a greenhouse. Butterburs samples were also planted in a separate plot without pesticide treatment, as the control. A commercial pesticide containing acequinocyl and fenpyroximate was applied to the foliage of butterburs at hourly intervals after dilution. Recoveries of acequinocyl and acequinocyl-OH were 78.6-84.7% and 83.7-95.5%, respectively; the relative standard deviation of the two compounds were less than 5%. The method limit of quantification was 0.01 mg/kg. The total (Ʃ) acequinocyl residues in butterburs reduced by 96.0% at 14 days and 75.9% at 7 days, in plot A and B, respectively, after final pesticide applications. The biological half-life (DT₅₀) of Ʃ acequinocyl and fenpyroximate, calculated using the dissipation rate, was 3.0 days and 4.0 days, respectively. These data were used to set up maximum residue and safe standard levels when the pesticides are applied to control pests during butterbur cultivation. Risk assessment results showed that the maximum % acceptable daily intake was 7.74% for Ʃ acequinocyl and 0.16% for Ʃ fenpyroximate. The theoretical maximum daily intake of Ʃ acequinocyl and fenpyroximate was 26.3% and 35.8%, respectively. In conclusion, the concentrations of Ʃ acequinocyl and fenpyroximate in butterburs pose no significant health risks to Koreans.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.120-127
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• 2015

BACKGROUND: Supervised residue trials were conducted to establish pre-harvest residue limit(PHRL), a criterion to ensure the safety of the pesticide residue in the crop harvest, of amisulbrom for winter-grown cabbage in two fields. Following to application of amisulbrom on the crop, time-course study was carried out to obtain the amisulbrom dissipation of statistical significance which enabled to calculate the predicted values of PHRL. METHOD AND RESULTS: During cultivation under greenhouse condition, samples of winter-grown cabbage were collected at 0, 1, 3, 5, 7 and 10 days after amisulbrom application, and subjected to residue analysis. Analytical method was validated by recoveries ranging 93.7~100.0% as well as limit of quantitation(LOQ) of 0.04 mg/kg. Amisulbrom residues in winter-grown cabbage gradually decreased as time elapsed. The dissipation rate of the residue would be affected by intrinsic degradation along with dilution by the cabbage growth. The decay pattern was well fitted by the simple first-order kinetics. CONCLUSION: Biological half-lives of amisulbrom in winter-grown cabbage ranged 3.7~4.1 days in two field conditions. Based on the regression of amisulbrom dissipation, PHRLs of amisulbrom in winter-grown cabbage were recommended as 8.86~9.47 and 4.21~4.35 mg/kg for 10 and 5 days before harvest, respectively.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.155-161
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• 2013

The residue patterns of clothianidin and thiacloprid, insecticides registered in the ginseng, were investigated to predict pre-harvest residues limits (PHRL). Pesticides were treated under Korea GAP (Good Agricultural Practices) with the recommended dose (single dose) and twice of recommended dose (double dose). Samples were collected 11 times over 42 days (each 0, 2, 5, 8, 12, 16, 20, 24, 28, 33, 42 days after treatment). Residues of clothinidin and thiacloprid were analyzed by UPLC/TQD. Biological half-life of clothinidin in single dose and double dose were 14.6 days and 10.2 days and that of thiacloprid were also 9.7 days and 11.2 days, respectively. The PHRL of ginseng on 10 days before harvest was 0.3 mg/kg in clothianidin and 0.18 mg/kg in thiacloprid.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.53-57
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• 1997

The rate of hydrolysis of insecticidal 1-(6-chloro-3-pyridylmethyl) -2-nitro-iminoimidazolidine (common name; imidacloprid) have been investigated in 15%(v/v) aqueous dioxane at $45^{\circ}C$. From the kinetics and non-kinetics data such as pH-effect, solvent effect(m=0.04, n=0.30 IT m<${\Delta}H^{\neq}=16.14kcal{\cdot}mol^{-1}\;&\;{\Delta}S^{\neq}=-0.03e.u.$), rate equation ($k_{obs.}=4.56{\times}10^{-3}[OH^-]$) and analysis of hydrolysis product, 1-(6-chloro-3-pyridylmethyl-2)-imidazolidinon, the hydrolysis mechanism of imidacloprid is proposed that the specific base catalyzed hydrolysis($K_{OH^-}$) through nucleophilic addition-elimination ($Ad_N-E$) mechanism proceed via intermediate, 1-(6-chloro-3- pyridylmethyl)-2-hydroxy-2-imidazolidinylisonitraminate (I) and ${\beta}$-3-(6-chloro-3-pyridylmethyl)aminoethyl-1-nitrourea(III). And the half-life(t1/2) of hydrolytic degradation at pH 8.0 and $45^{\circ}C$ was about 4.5 months.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.71-75
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• 1997

Important physicochemical properties of captafol [N-(1,1,2,2-tetrachloro-ethylthio)cyclohex-4-ene-1,2-dicarboximide], water solubility, vapor pressure, hydrolysis and octanol/water partition coefficient(Kow) were measured based on the standard EPA and OECD methods. Water solubility of the chemical was 2.24 ppm at $25^{\circ}C$. Half-life by hydrolysis at $25^{\circ}C$ in the buffer solution of pH 3.0, pH 7.0, and pH 8.0 was 77.8 hr, 6.54 hr and 0.72 hr, respectively, demonstrating instability in alkaline solution. The half-life in acid condition was not significantly different by temperature change, however, that in neutral or alkaline solution became shorter at $40^{\circ}C$. Hydrolysis study with a reference compound, diazinon, proved that the experimental method of the present study is reliable. Vapor pressure of captafol, $8.27{\times}10^{-9}$ torr at $20^{\circ}C$, was calculated from the equation, log P=6.94-(4401.6/T) plotted on the experiment results under different temperature conditions, 40, 50, and $60^{\circ}C$. pressure of captafol, the contamination of captafol would not happen easily in environment by vaporization. High Kow value of 1,523 was observed and this might result in bioconcentration through food chain when captafol was exposed. However, affecting human health through aquatic bioaccumulation is not likely to occur due to its rapid hydrolysis in the environment.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.644-654
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• 2016

Supervised residue trials for mandipropamid in Korean cabbage(Brassica campestris L.) were conducted to establish its pre-harvest residue limit (PHRL), a criterion to ensure the safety of the terminal pesticide residue during cabbage production. Tissues of Korean cabbage were collected at 0, 1, 3, 5, 7, and 10 days after mandipropamid application and subjected to residue analysis. The analytical method was validated by recoveries ranging from 88.2-92.2% at two levels (0.4 and $2.0mg{\cdot}kg^{-1}$), and a limit of quantitation (LOQ) of $0.04mg{\cdot}kg^{-1}$. Mandipropamid residues in Korean cabbage gradually decreased over time. The dissipation rate of the residue would be affected by intrinsic degradation of the compound along with dilution resulting from the fast growth of Korean cabbage. The decay pattern was well fitted by simple first-order kinetics. Biological half-lives of mandipropamid in Korean cabbage ranged from 3.9-4.0 days in two field conditions. Calculated by the regression curve of mandipropamid dissipation, the PHRLs of mandipropamid in Korean cabbage were recommended as 11.07-12.19 and $5.76-6.05mg{\cdot}kg^{-1}$ for 10 and 5 days prior to harvest, respectively.

• Applied Biological Chemistry
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• v.24 no.1
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• pp.1-6
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• 1981

Studios on the effects of rice straw amendments, soil autoclaving and repeated application related to disappearance of diazinon (diethyl 2-isopropyl -4-methyl -6-pyrimidinyl phosphorothionate) in submerged soils and paddy water were conducted under the laboratory conditions. Degradation of diazinon was slightly accelerated by the amendment of rice straw. The amended soil had 2.4 days shorter half life for diazinon than unamended soil. By autoclaving soils, diazinon degradation was greatly inhibited. The autoclaved soil had about 20 days longer half life for diazinon than the non-autoclaved soil. After repeated application of diazinon granules to the submerged soils, rapid degradation of the insecticide occured in flooded soils and paddy water. The development of diazinon degrading factors in flooded soils and paddy water after repeated application was roughly proportional to the increase of the frequency of diazinon application. By autoclaving soils and paddy water which received repeated application of diazinon, no rapid biodegradation of the insecticide occurred during the 30 days incubation period.