• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.473-479
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• 2021

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.313-320
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• 2018

Rice is the staple food of more than 50% of the world population. Cultivated rice has the AA genome (diploid, 2n = 24) and small genome size of only 430 megabase (haploid genome). As the sequencing of rice genome was completed by the International Rice Genome Sequencing Project (IRGSP), many researchers in the world have been working to explore the gene function on rice genome. Insertional mutagenesis has been a powerful strategy for assessing gene function. In maize, well characterized transposable elements have traditionally been used to clone genes for which only phenotypic information is available. In rice endogenous mobile elements such as MITE and Tos have been used to generate gene-tagged populations. To date T-DNA and maize transposable element systems have been utilized as main insertional mutagens in rice. The Ac/Ds system offers the advantage of generating new mutants by secondary transposition from a single tagged gene. To enhance the efficiency of gene detection, advanced gene-tagging systems (i.e. activation, gene or enhancer trap) have been employed for functional genomic studies in rice. Internationally, there have been many projects to develop large scales of insertional mutagenized populations and databases of insertion sites has been established. Ultimate goals of these projects are to supply genetic materials and informations essential for functional analysis of rice genes and for breeding using agronomically important genes. In this report, we summarize the current status of Ac/Ds-mediated gene tagging systems that has been conducted by collaborative works in Korea.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.39-45
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• 2021

To establish the environmentally friendly biological control of two-spotted spider mites (TSSM), Tetranychus urticae, in exported strawberry greenhouses, the TSSM density reduction efficiency of chemical and biological control measures was compared in commercial, exported strawberry greenhouses. In the biological control greenhouse, only Phytoseiulus persimilis, a natural enemy of TSSM, was released, and the chemical control greenhouse was only sprayed with commercial chemical pesticides. The density of each developmental stage of TSSM was higher in the chemical control greenhouse than in the biological control greenhouse. The management costs were lower for the biological control greenhouse than the chemical control greenhouse. These results suggest that it is possible to effectively control TSSM using P. pesrsimilis in exported strawberry greenhouses.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.364-371
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• 2020

The Korea Centers for Disease Control and Prevention is conducting surveillance of climate change vectors across all regions in Korea to counteract the spread of these vectors. As a part of this surveillance project, wild rodents were captured using traps to investigate the spread of chigger mites, the vector of Tsutsugamushi disease, across Jeonbuk, Jinan region, and to conduct studies on pathogens. Twenty samplers were used to sample chigger mites weekly from September to November in four different locations. Six hundred and eleven chigger mites of eight varying types were captured. The largest number of captured chigger mites was N. tamiyai, with 434 samples (71.0%). With the addition of 66 wild rodents captured from traps, 3,050 chigger mites were sampled, which yielded a Chigger index of 46.2. The monthly Chigger index was highest in November with a value of 206.1. the result of the test conducted in the presence of pathogens showed two positive results, each from May and September, out of all 85 pools. This result was aligned with the increased frequency in tsutsugamushi disease cases in spring and fall seasons.

• BMB Reports
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• v.54 no.3
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• pp.182-187
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• 2021

Leukotriene B4 (LTB4) is a lipid mediator of inflammation that is generated from arachidonic acid via the 5-lipoxygenase pathway. Previous studies have reported that the receptors of LTB4, BLT1, and BLT2 play mediatory roles in the allergic airway inflammation induced by ovalbumin (OVA). However, considering that house dust mites (HDMs) are the most prevalent allergen and well-known risk factor for asthmatic allergies, we are interested in elucidating the contributory roles of BLT1/2 in HDM-induced allergic airway inflammation. Our aim in this study was to investigate whether BLT1/2 play any roles in HDM-induced allergic airway inflammation. In this study, we observed that the levels of ligands for BLT1/2 [LTB4 and 12(S)-HETE (12(S)-hydroxyeicosatetraenoic acid)] were significantly increased in bronchoalveolar lavage fluid (BALF) after HDM challenge. Blockade of BLT1 or BLT2 as well as of 5-lipoxygenase (5-LO) or 12-lipoxygenase (12-LO) markedly suppressed the production of TH2 cytokines (IL-4, IL-5, and IL-13) and alleviated lung inflammation and mucus secretion in an HDM-induced eosinophilic airway-inflammation mouse model. Together, these results indicate that the 5-/12-LO-BLT1/2 cascade plays a role in HDM-induced airway inflammation by mediating the production of TH2 cytokines. Our findings suggest that BLT1/2 may be a potential therapeutic target for patients with HDM-induced allergic asthma.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.399-405
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• 2020

The susceptibility and control efficacy evaluated for 10 kinds of commercialized acaricides, to obtain basic data for the chemical control strategy of Two-spotted spider mite (Tetranychus urticae) in Hooker chives. The susceptibility evaluation of T. urticae female adults, Abamectin EC, Pyflubumide SC, Cyenopyrafen SC, and Acequinocyl SC showed 100% mortality, and Pyflubumide SC, Acequinocyl SC, and Etoxazole SC showed zero hatching rate, i.e. 100% mortality of eggs. As a result of evaluating the field test for Abamectin EC, Pyflubumide SC, Cyenopyrafen SC, Cyflumetofen SC, and Acequinocyl SC, which had excellent mortality in the laboratory conditions, all treatment plots showed more than 90.3% control efficiency on after 7 days.

• Molecules and Cells
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• v.44 no.8
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• pp.580-590
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• 2021

Patients with severe asthma have unmet clinical needs for effective and safe therapies. One possibility may be mesenchymal stem cell (MSC) therapy, which can improve asthma in murine models. However, it remains unclear how MSCs exert their beneficial effects in asthma. Here, we examined the effect of human umbilical cord blood-derived MSCs (hUC-MSC) on two mouse models of severe asthma, namely, Alternaria alternata-induced and house dust mite (HDM)/diesel exhaust particle (DEP)-induced asthma. hUC-MSC treatment attenuated lung type 2 (Th2 and type 2 innate lymphoid cell) inflammation in both models. However, these effects were only observed with particular treatment routes and timings. In vitro co-culture showed that hUC-MSC directly downregulated the interleukin (IL)-5 and IL-13 production of differentiated mouse Th2 cells and peripheral blood mononuclear cells from asthma patients. Thus, these results showed that hUC-MSC treatment can ameliorate asthma by suppressing the asthmogenic cytokine production of effector cells. However, the successful clinical application of MSCs in the future is likely to require careful optimization of the route, dosage, and timing.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.64.1-64.9
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• 2022

Background: Fluralaner is a novel drug belonging to the isoxazoline class that acts on external parasites of domestic animals. It is used systemically via drinking water, especially against red poultry mite in layer chickens. Fluralaner is frequently used in layers infected with D. gallinae. However, no study to date has investigated the effects of feed intake and water hardness. Objectives: This study aimed to investigate the effects of variable water hardness and feed intake on the pharmacokinetic profile of fluralaner. Methods: Layer chickens were divided into four groups (n = 8): fed + purified water (Group 1), feed restricted + purified water (Group 2), feed restricted + hard water (Group 3), and feed restricted + soft water (Group 4). After administering a single dose of the drug with drinking water, the blood samples were collected for 21 days. Fluralaner concentrations in plasma samples were determined by liquid chromatography/tandem mass spectrometry. The maximum plasma concentration (C_max), time to reach maximum plasma concentration (t_max), area under the concentration-time curve values (AUC_0-21d), half-life (t_1/2), and other pharmacokinetic parameters were calculated. Results: Although the highest maximum plasma concentration (C_max) was determined in Group 1 (fed + purified water), no statistically significant difference was found in the C_max, t_max, t_1/2, MRT_{0-inf_obs}, Vz/F_obs, and Cl/F_{_obs} parameters between the experimental groups. Conclusions: It was concluded that the feed intake or water hardness did not change the pharmacokinetic profile of fluralaner in layer chickens. Therefore, fluralaner could be used before or after feeding with the varying water hardness in poultry industry.

• Analytical Science and Technology
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• v.22 no.6
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• pp.458-463
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• 2009

A new quantitative analytical method has been established for the rapid determination of flumethrin in honey products using high performance liquid chromatography (HPLC). Sample was dissolved and extracted in the mixture of water and acetonitrile (1:2). The extracts were purified with silica cartridge eluted by the mixture of hexane and dichloromethane (55:45) and analyzed at 266 nm using HPLC. The percentage recovery of flumethrin spiked in sample was found to be 90.2-97.8% and the limit of detection is 0.003 mg/kg. We validated the method for the linearity, the precision and the reproducibility. We investigated the residues of flumethrin in honey products retailed in market using the established method. Flumethrin was not detected at all among 130 samples of honey.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.193-205
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• 2023

Botanical insecticides derived from plant extracts exhibit repellent, antifeedant and enzyme-inhibiting activities against insect pests. Among such pests, phytophagous mites are major threats to horticultural crops. Botanical extracts derived from neem, chrysanthemum, and shrubby sophora are employed as field acaricides. These botanical extracts have low toxicities against natural enemies of the insect pests and, thus, are valuable in pest management. This review focuses on the potential for botanical extracts in the controls of mites, with comparisons of the spectrum of activity, the lethal dose and times and their mode of action. This information will enable better formulation of botanical extracts in integrated mite control.