• Korean journal of applied entomology
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• v.32 no.4
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• pp.373-381
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• 1993

Resistance evolution to organophosphate-based pesticides in apple and pear inhabiting arthropods of western North America extends to many classes of pest and some beneficial species. Resistance management programs to minimize resistance in pests while exploiting it in natural enemies have met with mixed success. Among beneficials, resistances have been exploited mostly among predators of pest mites. Evolution of resistant mites, leafminers, leafhopper, aphids, leafrollers and some internal fruit feeders have led to development of new monitoring methods and means to delay or avoid resistance. But it is resistance to azinphosmethyl in codling moth (Cydia pomonella) that is changing the pest control system and moving it from chemical to biologically-based means. Newly merging IPM system will depend more on use of biological, cultural, behavior and genetic controls. But more selective pesticides also will be needed to augment pheromones, resistant host plants and genetically altered organisms. These more biologically-based tactics will be prone to resistance evolution in pests as well, if used too unilaterally and/or too extensively.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.54-63
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• 2015

Streptomyces spp. isolated from turfgrass rhizosphere and tested for their response to large-patch control fungicides. The tested fungicides were actually used in golf course or turfgrass cultivation to prevent large-patch disease. Tolerance to 3 triazole group of the strains was the highest to the PR fungicide, and following the SR fungicide, whereas the isolated strains were no tolerance to HR fungicide. Tolerances to three kind of Strobilurin group were similar for the all of the tested Streptomyces spp.. Growth and sporulation of the all strain was normal in CB and AP fungicide treatments. However no spore formulated in double concentration. Strains, tolerance to acetanilide fungicides, appeared that KT fungicide tolerance was higher than MK fungicide. The selected strains showed strong tolerance against AT fungicide but have no tolerance to ATR fungicides. In conclusion, the bacterial strains showed tolerance against 1 carbamate, 1 organophosphate and 1 cyanopyrrole group, while have no tolerance against two mixture formulations (1 Quinone + Strobilurin and 1 Imidazole + Triazole).

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.171-178
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• 2007

Esterase isozymes were extracted from final instar larvae of M. saltuarius treated with selective diets and inhibitors. Twenty esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, or ${\alpha}$-naphthyl butyrate). Interestingly, the isozymes of Est7(${\alpha}$-naphthyl acetate and ${\alpha}$-naphthyl butyrate) and Est6(${\beta}$-naphthyl acetate) were specifically activated in final instar larvae fed with the bark of Pinus koraiensis. However, we could not find any band from substrate ${\beta}$-naphthyl stearate. The esterase activities of Est3, Est6, and Est7 were inhibited by organophosphate and carbamate insecticides. In addition, The esterase activities of Est4, Est6, and Est7 were also inhibited by eserine. However, inhibition of esterase activities in methoprene, bornyl acetate, linal, cineol, and citral was not observed. However, It is necessary to reconfirm these results in vivo.

• Journal of The Korean Society of Clinical Toxicology
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• v.15 no.1
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• pp.56-59
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• 2017

Pneumatosis cystoides intestinalis and portomesenteric venous gas are uncommon radiological findings, but are found commonly in cases of bowel ischemia, or as a result of various non-ischemic conditions. A 72-year-old man visited an emergency center with altered mental status 2 hours after ingestion of an unknown pesticide. On physical examination, he showed the characteristic hydrocarbon or garlic-like odor, miotic pupils with no response to light, rhinorrhea, shallow respiration, bronchorrhea, and sweating over his face, chest and abdomen. Laboratory results revealed decreased serum cholinesterase, as well as elevated amylase and lipase level. We made the clinical diagnosis of organophosphate poisoning in this patient based on the clinical features, duration of symptoms and signs, and level of serum cholinesterase. Activated charcoal, fluid, and antidotes were administered after gastric lavage. A computerized tomography scan of the abdomen with intravenous contrast showed acute pancreatitis, poor enhancement of the small bowel, pneumatosis cystoides intestinalis, portomesenteric venous gas and ascites. Emergent laparotomy could not be performed because of his poor physical condition and refusal of treatment by his family. The possible mechanisms were believed to be direct intestinal mucosal damage by pancreatic enzymes and secondary mucosal disruption due to bowel ischemia caused by shock and the use of inotropics. Physicians should be warned about the possibility of pneumatosis cystoides intestinalis and portomesenteric venous gas as a complication of pancreatitis following anticholinesterase poisoning.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.113-120
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• 2009

Twenty-seven fenitrothion-degrading bacteria were isolated from different soils, and their genetic and phenotypic characteristics were investigated. Analysis of the 16S rDNA sequence showed that the isolates were related to members of the genera Burkholderia, Pseudomonas, Sphingomonas, Cupriavidus, Corynebacterium, and Arthrobacter. Among the 27 isolates, 12 different chromosomal DNA fingerprinting patterns were obtained by polymerase chain reaction(PCR) amplification of repetitive extra genic palindromic(REP) sequences. The isolates were able to utilize fenitrothion as a sole source of carbon and energy, producing 3-methyl-4-nitrophenol as the intermediate metabolite during the complete degradation of fenitrothion. Twenty-two of 27 isolates were able to degrade parathion, methyl-parathion, and p-nitrophenol but only strain BS2 could degrade EPN(O-ethyl-O-p-nitrophenyl phenylphosphorothioate) as a sole source of carbon and energy for growth. Eighteen of the 27 isolates had plasmids. When analyzed with PCR amplification and dot-blotting hybridization using various specific primers targeted to the organophosphorus pesticide hydrolase genes of the previously reported isolates, none of the isolates showed positive signals, suggesting that the corresponding genes of our isolates had no significant sequence homology with those of the previously isolated organophosphate pesticide-degrading bacteria.

• Korean Journal of Veterinary Research
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• v.48 no.2
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• pp.131-137
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• 2008

Pesticides are extensively used for the control of crop pests in agriculture and forestry. Organophosphate (OP) and carbamate pesticides are especially effective for the control of a variety of harmful insects. However, these cholinesterase inhibitors are also dangerous to non-target organisms (wildlife and other animals) because of their high acute toxicity. Most poisonings by pesticides occur as a result of misuse or accidental exposure, but intentional killing of unwanted animals also occurs. At the request of a local autonomous entity, we investigated wild bird poisonings by pesticides from 2003 to 2007. The 207 suspicious samples of pesticide poisoning based on the necropsy were analyzed by GC/NPD, GC/FPD, or GC/MSD. We looked for trends in the identification of pesticides in wild birds thought to have died from poisoning. Pesticides were determined in 59% of the total samples analyzed. Phosphamidon and monochrotophos were the most common pesticides identified, which amounted to 77% of the subtotal. Other OP and carbamate pesticides were also found in various concentrations from dead wild birds. The determined rates of pesticides were as high as 86% and 76% in 2003 and 2006, respectively, during an outbreak of avian influenza in Korea.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.941-952
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• 2023

The metabolites of agrichemicals, such as organophosphorus pesticides, are known to be more hazardous than their parent pesticides. 3,5,6-trichloro-2-pyridinol (TCP) is a major degradation product of chlorpyrifos, one of the organophosphate insecticides widely used in agriculture. In vivo or in vitro exposure to chlorpyrifos has been known to interfere with male reproductive functions, leading to reduced fertility in mammals. Therefore, this study was performed to examine the changes in the fertilization competence of boar spermatozoa exposed to TCP. Sperm samples were subjected to varying concentrations of TCP (10, 50, 100, 200 µM) and different periods of incubation. Sperm motility, motion kinematics, viability, acrosome integrity, intracellular reactive oxygen species (ROS) production, and gene expression levels (ODf2, ZPBP2, AKAP3 and AKAP4) were evaluated after exposure of the sperm to TCP. A significant dose-dependent reduction in motility was observed in sperm samples incubated with TCP compared to the controls after both incubation periods. Sperm viability was significantly decreased in samples incubated with 50, 100, and 200 µM TCP in both incubation periods. A significantly lower percentage of normal acrosomes and gene expression levels were observed in sperm samples exposed to 50, 100, and 200 µM TCP after both incubation periods, compared to the controls. There was a significant increase in the ROS production in spermatozoa incubated with 100 - 200 µM TCP after both incubation periods. Consequently, the direct exposure of boar spermatozoa to TCP interferes with sperm functions and leads to decreased fertilization. In order to identify and address the various causes of reproductive decline, the impact of chemical metabolites needs to be discussed in depth.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.453-461
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• 2009

Killifish (Oryzias latipes) were exposed to an organophosphate pesticide, pirimiphos-methyl, in a flow-through system to determine the bioconcentration factor (BCF) following GLP (Good Laboratory Practice). This study was conducted at two different concentrations (1 and $10\;{\mu}$g/L) of $^{14}C$-labeled pirimiphos-methyl for 28 days uptake and 14 days depuration according to the OECD 305 test guideline. The $BCF_{ss}$ for total radioactive residues in whole fish were 1,251 and 1,277 for low and high concentrations, respectively. The $BCF_k$ based on the uptake and depuration rate constants were 1,200 for both low and high concentrations. During the depuration phase, the accumulated test substance was rapidly depurated from fish. Greater than 95% of the residue at steady-state was depurated after 2 days. Although the measured BCF values were high, pirimiphos-methyl could be evaluated as a low risk from bioaccumulation by aquatic organisms due to the short depuration period and low amount of bound residue (1.5%). We suggest that in evaluating bioaccumulation, not only the BCF should be considered, but also depuration time and bound residue in aquatic organisms give an indication of the potential environmental risks.

• Journal of The Korean Society of Clinical Toxicology
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• v.13 no.2
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• pp.55-61
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• 2015

Purpose: Many studies have examined the mechanisms of impaired glucose homeostasis after organophosphate (OP) exposure, however no study has evaluated the clinical utility of blood glucose measurements in patients with OP poisoning. The current study was conducted to evaluate the initial glucose level at presentation and the glycemic variables during the first 3 days after admission as a predictor of mortality. Methods: This retrospective observational case series included 228 patients with a history of OP poisoning. Among other clinical data, information on the initial glucose level at presentation and mean glucose level, delta glucose level, and the presence of a hypoglycemic event during the first 3 days of admission, was collected. Results: Survivors had lower initial glucose levels at presentation and glucose variability during the first 3 days of admission compared to non-survivors. The frequency of hypoglycemic events was higher in non-survivors. In multivariate analysis, the initial glucose level (> 233 mg/dl) was an independent predictor of mortality, along with age. Conclusion: The initial glucose level at presentation can be helpful in prediction of mortality in cases of OP intoxication at bedside. The physician should pay attention to patients with a glucose level >233 mg/dl at presentation after ingestion of OP.

• Environmental Analysis Health and Toxicology
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• v.13 no.1_2
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• pp.33-41
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• 1998

Chlorpyrifos, o,o diethyl-o-(3,5,6-trichloro-2-pyridyl) phosphorothioate, is a broad spectrum organophosphate insecticide. The use of chlorpyrifos has been increased more and more as pesticide. But the effects of chlorpyrifos on the immune alterations has not been yet observed. Therefore, we investigated the effects of chlorpyrifos on the immune alterations in CICA male mice. Chlorpyrifos was administered to mice by a single intraperitoneal injection for the purpose of observing acute effects. On the one hand to get the information on immunopathologic alterations we observed hematological values, counted total circulating leukocytes and assessed the ratio of lymphocytes and neutrophils from the peripheral blood, measured the ratio of organ/body weight and counted splenic cellularity in CBA male mice which treated chlorpyrifos intraperitoneally. But we could not find any significant immunopathologic alterations statistically by a single intraperitoneal injection. Also, the exposure of chlorpyrifos caused no significant change in the number of PFC/10$^6$ spleen cells at any three given doses. On the other hand a singte intraperitoneal injection of chlorpyrifos decreased the lymphocyte proliferation response slightly to ConA or LPS stimulation at a dose of 6 mg/kg b.w. Administrations of chlorpyrifos reduced mixed leukocyte response(MLR). MLR was decreased moderately at doses of 3mg/kg b.w. and 6mg/kg b.w. Therefore, all these findings suggest that chlorpyrifos may alter the immune functions acutely. especially by the changes of T lymphocyte activity.