• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.176-183
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• 1993

Photolysis experiments were conducted to investigate the stability of a new insecticide, [O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester: KH-502] under the various conditions. In the photolysis experiment, KH-502 was, after being added into the acetone or acetonitrile solution, irradiated under the sunlight or UV lamp $(300{\sim}350nm)$, where acetone or acetonitrile solution was varied with water and $O_2$contents and was treated with humic acid, rosebengal or tryptophan. Results for stability and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. The significant difference in KH-502 decomposition due to photolysis was shown for between KH-502s irradiated at $300{\sim}350$ nm and non-irradiated. KH-502 was photolyzed in the acetone by the sensitizing effect, but was stable in the acetonitrile. 2. The degradation pattern of KH-502 in the photolysis was different as compared to that in the thermal decomposition, and the decomposed products were O,O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester (KH-502 oxo form), O,S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphorothiolate(S-ethyl KH-502), 1-Phenyl-3-trifluoromethyl-5-hydroxy pyrazole (PTMHP) and several unknown compounds. 3. Treatments of acetone or acetonitrile solution with humic acid, rosebengal or tryptophan revealed no-sensitizing effect on the photolysis of KH-502. Dissolved oxygen in the acetone played as a cosensitizer with acetone competitively to enhance the photolysis of KH-502. 4. Treatments of acetone with humic acid or paddy soil water collected from fields decreased the photolysis of KH-502.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.72-79
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• 1997

Adsorption, leaching, and retention of the Flupyrazofos(KH-502), a new active ingredient for insecticide, in the soils under laborarory and field conditions were investigated to provide the basic data for the safety use and to assess a secondary impact of this insecticide on soil and water environments. A significant power function relation was found between the adsorbed KH-502 and time, representing that 45% of the added KH-502 was adsorbed within 30 min. but a quasiequilibrium was reached after 6 to 12 hr with a slower adsorption. Adsorption phenomena followed th first-order kinetics and time required for 50% adsorption was 5.8 hr. The equilibrium adsorption isotherm was explained by the Freundlich equation and was classified as S-type. The amounts of KH-502 leached through the soil column (C) as compared to initial conc. ($C_0$) were very low and these relative concentrations ($C/C_0$) were 0.073 and 0.017 in SL and CL soils, respectively. The residual conc. of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 under the field conditions were estimated to be 20 and 18 days in the SL and CL soils, respectively. The KH-502 cone, transported to the subsurface soils was extremely low. These results demonstrate that KH-502 has a low pollution risk potential to the surrounding environment as far as it is used following the recommended guideline.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.225-234
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• 1992

Thermal decomposition was conducted to investigate the influence of the various factors on stability of a new insecticide, [O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester : KH-502], in view of those informations applicable for industrial exploitation. In the thermal decomposition experiment, KH-502 was, after mixing with Fe, Cu and adjustment of moisture and pH conditions, subjected to three temperatures, 25, 50, and $100^{\circ}C$. Results for stability, and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. Main products of the thermal decomposition when this was conducted in the closed system were identified as following five compounds:O, O, O-Triethylthiophosphoric acid(TEPA), 1-Phenyl-3-trifluoromethyl-5-ethoxypyrazole(PTMEP), 1-Phenyl-2-ethyl-3-trifluoromethyl-5-hydroxypyrazole(PETMHP), O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester(KH-502 oxo form), O, S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phospho rothiolate(S-ethyl KH-502). However, compounds such as oxo form and S-ethyl KH-502 were not identified when the thermal decomposition was proceeded in the open system. 2. KH-502 was stable at 25 and 50$^{\circ}C$, but it was decomposed at 100$^{\circ}C$ following the first-order kinetics at the early stages of decomposition. 3. Rate constants for the thermal decomposition of KH-502 at 100$^{\circ}C$ were in the orders of Cu powder addition 0.344>Cu plate addition 0.21>moisture addition 0.05>closed system=open system=iron addition=pH 5.5 adjustment 0.04>pH 8.5 adjustment 0.027 day$^{-1}$, representing KH-502 was decomposed fast at Cu powder treatment and slow at pH 8.5 adjustment. 4. Half-life for the thermal decomposition of KH-502 at 100$^{\circ}C$ was in the orders of Cu powder addition 2.02

• 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.

• Toxicological Research
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• v.13 no.4
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• pp.317-322
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• 1997

Acute delayed neurotoxicity of KH-502 [O.O-Diethyl O-(1-phenyyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester], an insecticide synthesized newly in Korea, was studied in White Leghorn hens. The doses were determined on the basis of preliminary $LD_{50}$ study. High, middle and low doses were determined to be 1123 mg/kg, 762 mg/kg and 518 mg/kg, respectively. The animals were pretreated with atropine (30 mg/kg) prior to administration of KH-502. The chemical was administrated at the first and 21st day of the study. As positive controls, animals were admlnistrated with triorthocresylphosphate (TOCP 1000 mg/kg and 500 mg/kg). Animals administrated with TOCP or KH-502 were sacrificed by perfusion-fixation at 21st and 42nd day of the study, respectively. The central and peripheral nerve tissues were routinely treated for microscopic observation. As results, eight, three, one, and one chickens died within 2 day after adminiatration with signs of cholinergic acute toxicity in high, middle low and TOCP dose-group (500 mg/kg), respectively. No abnormal clinical signs were observed in the survived chickens administrated with KH-502 in the duration of the study. The chickens in positive control groups showed ataxia and incoordination at the 14th day after administration of TOCP. From necropsy, macroscopic changes were not observed in all groups including positive control groups. Histopathologically, oxonal swelling with myelin loss, focal gliosis, distention around axonal space were observed in the spinal cords of the chickens administrated with TOCP 1000 mg/kg. The lesions were distinct in the dorsal and lateral funiculi of cervical spinal cord, in the lateral and ventral funiculi of thoracic spinal cord and in ventral funiculi of lumbosacral spinal cord. Axonal swelling and mlcrogliosis were infrequently observed in the chickens of other groups including negative control one. However, they were nonspecifically distributed in the spinal cords. In this study, we concluded that the new chemical, KH-502 did not have acute delayed neurotoxicity in White Leghorn hens.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.162-167
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• 2004

In recent years, the diamondback moth (DBM), Plutella xylostella has become one of the most important pests for cruciferous plants in the world. A new type of the thiophosphoryl pyrazole insecticide, called KH502. Its outstanding insecticidal activity could be effective alternative against DBM. We investigated, using the comparative molecular field analysis (CoMPA) method, The structure-activity relationship of various thiophosphorylpyrazole derivatives and structure requirement for insecticidal activity. We found, the key substructures in pyrazole derivatives, the trifluoro-methyl group and the thiophosphoryl group. Both play an important role in insecticidal activity with the binding site. The three dimensional Quantitative Structure Activity Relationship (QSAR) analysis could provide useful information for the structural requirements of pyrazole insecticide as an insecticidal and the design of a new insecticide.

• Agrochemical news magazine
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• v.19 no.2 s.143
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• pp.26-29
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• 1998

• Applied Biological Chemistry
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• v.40 no.1
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• pp.76-79
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• 1997

Several physicochemical properties such as water solubility, vapor pressure, hydrolysis and octanol/water partition coefficient(Kow) of flupyrazofos, the first organophosphorus insecticide developed in Korea, were measured based on EPA and OECD methods. Water solubility was low showing 0.80 ppm at $25^{\circ}C$ and in hydrolysis study, half-life at $25^{\circ}C$ was 266.5 hr(pH 4.0), 180.0 hr(pH 7.0) and 120.9 hr(pH 9.0) demonstrating instability in alkaline solution. At $40^{\circ}C$ hydrolysis rate was $2{\sim}4$ times higher than that at $25^{\circ}C$. The equation log P=0.673-(1565.4/T) was obtained from vapor pressure experiments at three different temperatures (25, 35, $45^{\circ}C$) and $2.81{\times}10^{-5}$ torr was obtained at $25^{\circ}C$. This value is similar to that of diazinon and 1,000 times lower than that of DDVP suggesting it would not give environmental contamination by volatilization. High log Kow(5.24) was observed and this might result in bioconcentration through food chain. However, its possibility is not likely to be high due to its relatively rapid hydrolysis.

• Archives of Pharmacal Research
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• v.21 no.5
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• pp.496-502
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• 1998

The present study was carried out to determine the possible use of cTn-I in the cardiac myofibrillar architecture, as a potential target for in vivo radioimmunodetection of cardiac damage in a brain death pig model. Radioiodiantion of the anti-cTn-I 5F4 McAb was carried out by lactoperoxidase method. the percentage iodine incorporation achieved was 70-75%. The radioiodinated McAbs were purified on Sephadex G-25 column and characterised by Paper chromatography, Phast Gel electrophoresis and electroimmunoblotting. Radioiodinated anticTn-I 5F4 McAbs were employed alongside Pyrophosphate($Tc_{99m}$-PPi$) and $Thallium^{201}$ chloride($TI^{201}$) in 24 landrace pigs (brain-dead=18 & sham-operated=6). The percentage cardiac uptake of the radiolabelled antibody injected dose was significantly higher in the brain dead animals(0.196%) as compared to that of sham-operated animals (0.11%). Specific in vivo localization of radiolabelled McAbs in the infarcted cardiac tissue was confirmed by computer-aided reconstruction of 3-D images of the isolated heart. The preliminary results of the study revealed preferential uptake of radiolabelled antibody at the site of myocyte damage resulting from artificially induced brain death.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.496-502
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• 2015

Polyketide secondary metabolites share common precursor pools, acyl-CoA. Thus, the effects of engineering strategies for heterologous and native secondary metabolite production are often determined by the measurement of pikromycin in Streptomyces venezuelae. It is hard to compare the effectiveness of engineering targets among published data owing to the different pikromycin production media used from one study to the other. To determine the most important nutritional factor and establish optimal culture conditions, medium optimization of pikromycin from Streptomyces venezuelae ATCC 15439 was studied with a statistical method, Plackett-Burman design. Nine variables (glucose, sucrose, peptone, (NH₄)₂SO₄, K₂HPO₄, KH₂PO₄, NaCl, MgSO₄·7H₂O, and CaCO₃) were analyzed for their effects on a response, pikromycin. Glucose, K₂HPO₄, and CaCO₃ were determined to be the most significant factors. The path of the steepest ascent and response surface methodology about the three selected components were performed to study interactions among the three factors, and the fine-tune concentrations for maximized product yields. The significant variables and optimal concentrations were 139 g/1 sucrose, 5.29 g/l K₂HPO₄, and 0.081 g/l CaCO₃, with the maximal pikromycin yield of 35.5 mg/l. Increases of the antibiotics production by 1.45-fold, 1.3-fold, and 1.98-fold, compared with unoptimized medium and two other pikromycin production media SCM and SGGP, respectively, were achieved.