• Korean Journal of Agricultural Science
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• v.34 no.2
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• pp.171-179
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• 2007

The new insecticidal active molecules from the based on the holographic quantitative structure-activity relationships (HQSAR) between a series of $1-(R_1)-2-(n-octyl)-3-(R_2)$, $3-(R_3)-pseudothiourea$ derivatives and their insecticidal activities against Diamond-back moth (Plutella Xylostella Linnaeus) were designed and discussed quantitatively. The most active molecule from the based graphical analyses of atomic contribution maps with the optimized HQSAR C-1 model ($q^2=0.764$ & $r^2{ncv}=0.942$) was 1-(n-butyl)-2-(t-butyl)-3,3-diisopropylpseudothiourea (P1: $pI_{50}=5.30$, $IC_{50}=1.397ppm$). Therefore, it is suggested that the new designed molecule would increased the activity as much as 23.5 times as compared to X=n-octyl substituent 17($pI_{50}=4.00$, $IC_{50}=32.86ppm$) which was the highest active molecule in training set compounds.

• 보존과학연구
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• s.31
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• pp.89-102
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• 2010

This study evaluated the activity of biocidal compounds isolated from natural products and confirmed applicable possibility as conservative agents for orgainic cultural heritages damaged by biological degradation. we used methanol extracts of 11 Korean trees and 17 medicinal plants as natural resources. Among these extracts, Phellodendron amurense was investigated on antifungal activity against Coniophora puteana, Lentinus lepideus, Tyromyces palustris and Aspergillus niger. Asarum sieboldii was investigated on insecticidal activity against adult of Lasioderma serricorne. First, the extract of Phellodendron amurense was partitioned into hexane, dichloromethan and ethylacetate fraction. Among them, the ethylacetate fraction had the most significant antifungal activity. In addition, Asarum sieboldii essential oil showed an effective antifungal and insecticidal activity. As a result, the extract of Phellodendron amurense and Asarum sieboldii essential oil could be useful for conservation of organic cultural heritage against biological deterioration by wood rot fungi and Lasioderma serricorne.

• 보존과학연구
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• s.29
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• pp.125-136
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• 2008

To investigate bioactive materials for development of natural conservative agent on organic cultural heritage, methanol extracts from 17 medicinal plants were screened for antifungal and insecticidal activity against 6 wood rot fungi and adult of Lasioderma serricorne. Antifungal activity of extracts was tested by using paper disc soaking method against wood-rot fungi. Among these extracts, the most significant antimicrobial activity was observed from the extract of Coptis japonica at 5 mg/disc against all wood rot fungi tested. The insecticidal activity of extracts was examined by topical application against L. serricorne adults. The extracts from Asarum sieboldii gave 83.3 % mortality at $25{\mu}g/adult$ for 24hr. From these result, the methanol extract from C. japonica and A. sieboldii described could be useful for conservation of organic cultural heritage against biological deterioration by wood rot fungi and L. serricorne.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.249-253
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• 1997

The acaricidal and ovicidal activity against red spider mite (Tetranychus urticae) was examined for a series of S-aryl arenethiosulfonates and compared with sulfonate acaricide, ovex and senile. Substituted diphenyl disulfides were obtained from substituted thiophenols, chloronitrobenzene and aniline derivatives. The S-aryl arenesulfonothioates were synthesised from the oxidation of disulfides. Three kind of para substituted compounds were found to have good ovicidal effect but acaricidal activity against adult mite was negligible in all S-aryl arenethiosulfonates.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.201-202
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• 2021

We confirmed the convenient bioassay method for the black cutworm, Agrotis ipsilon in semi-field conditions. And we surveyed the susceptibility to commercial pesticides of A. ipsilon, which feeds Chinese cabbage through this bioassay process. As a result of the test, six soil mixing insecticides and eight soil drenching insecticides showed more than 90% insecticidal activity.

• Journal of Environmental Science International
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• v.27 no.9
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• pp.771-780
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• 2018

To develope a microbial weed control agent, HCN-producing bacteria were isolated, and their characteristics were investigated. A selected strain of WA15 was identified as Pseudomonas koreensis by morphological, cultural, biochemical and 16S rRNA gene analyses. The conditions for HCN production was investigated by a One-Variable-at-a-Time (OVT) method. The optimal HCN production conditions were tryptone 1%, glycine 0.06%, NaCl 1%, and an initial pH and temperature of 5.0 and $30^{\circ}C$, respectively. The major component for HCN production was glycine. Under optimal conditions, HCN production was about 3 times higher than that of the basal medium. The WA15 strain had physiological activities, such as indoleacetic acid that was associated with the elongation of plant roots and siderophore and ammonification inhibiting fungal growth, and produced hydrolytic enzymes, such as cellulase, pectinase and lipase. The strain was able to inhibit the growth of phytopathogenic fungi, such as Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum, by the synergistic action of volatile HCN and diffusible antimicrobial compounds. A microscopic observation of R. solani that was teated with the WA15 strain showed morphological abnormalities of fungal mycelia, which could explain the role of the antimicrobial metabolites that were produced by the WA15 strain. The volatile HCN produced by the WA15 strain was also found to have insecticidal activity against termites. Our results indicate that Pseudomonas koreensis WA15 can be applied as a microbial agent for weed control and also as a termite repellent. Furthermore, it could be applied as a microbial termiticidal agent to replace synthetic insecticides.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.281-285
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• 1994

This study was conducted to establish a nce insect pest control system, ~ es.ys tematic application of insecticides using carbohran and buproiezin, in Korea. The effects oi various dates of application and rates of buprofezin (25% WP) after carbofuran (3G) soil incorpombon in late May on the pop~~lation densities of the brown planthoppa (BPH) immigrating in July were investigated Appropriate application tune of buprofezin for the BPH that had evaded insecticidal effect of 5011 incorporated carbofuran was late July-early August. Application rate of buprofezln at 7.0g a.i/lOa was enough to suppress the BPH density. Buprofezin treatment after carbofumn soil incorporation could also suppress the whlte backed planthopper population but did not affect the densities oi the paddy rice spiders. Considering the charactenstics of occurring patterns of the nce insect pests in Korea. buprofezin treatment m late July or early August after carbofuran soil incorporation in late May can be a useful application system of ir~sectic~deins controlling early season Insect pests and migmtoly planthoppers on rice.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.250-254
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• 2007

Bacillus thringiensis strain 108 was isolated from soil and had nematicidal activity against second stage juvenile of plant root-knot nematode, Meloidogyne incognita. The strain 108, a rod shape, spore forming and Gram positive bacterium, produced lecithinase, catalase, and ${\delta}$-endotoxin. The strain 108 belongs to H serotype 3, Bacillus thuringiensis var. kurstaki. A nematicidal substance of the strain 108 was partially purified on Sephadex G-25 gel filtration, activated carbon adsorption, silica gel adsorption, and Sephadex G-10 gel filtration. $LC_{90}$ of the partially purified substance against M incognita was $1.2\;{\mu}g/ml$. The nematicidal substance was stable by heat treatment at $100^{\circ}C$ for 1hr, but was perfectly lost nematicidal activity after autoclave ($110^{\circ}C$, 30 min).

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.417-428
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• 2007

Most oriental medicinal plants in domestic markets have been imported, but these medicines are being easily exposed to many insect pests because of the poorness of storage facilities. This study was carried out to identify stored products insect pests occurring in 158 storage medicinal plants belonging to 134 genera of 67 families. No insect pests were not observed in 44 medicinal plants including Artemisia argyi Levl. et Vant., Cassia sieboldii Presl., and Juniperus chinensis L. Most commonly observed stored products insect pests in the surveyed medicinal plants were the order of as follows; Ahasverus advena(Waltl) 12.3%, Lasioderma serricorne F. 11.5%, Oryzaephilus surinamensis L. 10.3%, Tribolium castaneum (Herbst) 9.4%, Stegobium paniceum L. 8.4%, and Plodia interpunctella(Hbner) 7.9%. And these insects also are likely to prefer more root or rhizome part than the other ones. Based on these basic survey results, natural products researchers can obtain an important information in finding an insecticidal or fumigant compounds contained in the medicinal plants which any insect pests do not attack.

• Journal of Life Science
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• v.32 no.1
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• pp.1-10
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• 2022

Natural products have gained increasing attention due to their advantage of long-term safety and low toxicity for a very long time. Torreya nucifera is widespread in southern Korea and Jeju Island and its seeds are commonly used as edible food. Oriental ingredients have often been reported for their insecticidal, antioxidant and antibacterial properties, but there have not yet been any studies on their antidiabetic effect. In this study, we investigated several biological activities of T. nucifera pericarp (TNP) and seeds (TNS) extracts and proceeded to characterize the antidiabetic compounds of TNS. The initial results suggested that TNS extract at 15 and 10 ㎍/ml concentration has inhibitory effects on α-glucosidase and protein tyrosine phosphatase 1B, that is 14.5 and 4.35 times higher than TNP, respectively. Thus, the stronger antidiabetic TNS was selected for the subsequent experiments to characterize its active compounds. Ultrafiltration was used to determine the apparent molecular weight of the active compounds, showing 300 kDa or more. Finally the mixture was then partially purified using Diaion HP-20 column chromatography by eluting with 50~100% methanol. Therefore we concluded that the active compounds of TNS have potential as therapeutic agents in functional food or supplemental treatment to improve diabetic diseases.