• Journal of Applied Biological Chemistry
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• 제48권1호
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• pp.26-28
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• 2005

Evaluation of larvicidal activities of Chamaecyparis obtusa and Thuja orientalis oils against 4th-instar larvae of Aedes aegypti and Culex pipiens pallens revealed larvicidal activities of leaf oils extracted from C. obtusa and T. orientalis were significantly higher than those of stem, fruit, and seed oils. Strong mortality was observed in age class II of C. obtusa and T. orientalis against Ae. aegypti and Cx. pipiens pallens larvae. These results show both leaf part and age class II of C. obtusa and T. orientalis have strong larvicidal activity against Ae. aegypti and Cx. pipiens pallens. Leaf oils of C. obtusa and T. orientalis leaves show promise as natural larvicides against Ae. aegypti and Cx. pipiens pallens.

• International Journal of Industrial Entomology and Biomaterials
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• 제15권1호
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• pp.87-91
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• 2007

A diverse kind of environment-friendly agricultural materials(EFAM) for the control of insect pests is on the market. These EFAMs are a part of essential sources for the accomplishment of successful, sustainable, and environment-friendly agriculture. Thus, accurate information of these EFAMs is one that required for the success of environment-friendly agriculture, but, in reality, still appropriate information is absolutely in shortage. In this study, we, therefore, tested the efficacy of commercial EFAMs against two lepidopteran insect larvae, the diamondback moth Plutella xylostella(Lepidoptera: plutellidae) and the tobacco cutworm Spodoptera litura(Lepidoptera: Noctuidae). After the two insect pests were successfully stabilized in indoor environment the larvicidal activity was tested at $24{\pm}1^{\circ}C$, relative humidity(RH) of $60{\pm}5%$, and a photoperiod of 16L:8D, and mortality was determined 48 hrs after EFAMs are treated. The EFAMs that showed more than 90% of larvicidal activity were each six among 16 against both P. xylostella and S. litura and only three of them showed consistent larvicidal activity against both species, signifying species specificity of EFAMs and importance of selection of proper EFAMs depending on target insect pest.

• BMB Reports
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• 제40권2호
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• pp.163-171
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• 2007

Functional elements of the conserved helix 7 in the poreforming domain of the Bacillus thuringiensis Cry $\delta$- endotoxins have not yet been clearly identified. Here, we initially performed alanine substitutions of four highly conserved aromatic residues, $Trp^{243}$, $Phe^{246}$, $Tyr^{249}$ and $Phe^{264}$, in helix 7 of the Cry4Ba mosquito-larvicidal protein. All mutant toxins were overexpressed in Escherichia coli as 130-kDa protoxins at levels comparable to the wild-type. Bioassays against Stegomyia aegypti mosquito larvae revealed that only W243A, Y249A or F264A mutant toxins displayed a dramatic decrease in toxicity. Further mutagenic analysis showed that replacements with an aromatic residue particularly at $Tyr^{249}$ and $Phe^{264}$ still retained the high-level toxin activity. In addition, a nearly complete loss in larvicidal activity was found for Y249L/F264L or F264A/ Y249A double mutants, confirming the involvement in toxicity of both aromatic residues which face towards the same direction. Furthermore, the Y249L/F264L mutant was found to be structurally stable upon toxin solubilisation and trypsin digestion, albeit a small change in the circular dichroism spectrum. Altogether, the present study provides for the first time an insight into the highly conserved aromaticity of $Tyr^{249}$ and $Phe^{264}$ within helix 7 playing an important role in larvicidal activity of the Cry4Ba toxin.

• Applied Biological Chemistry
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• 제37권6호
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• pp.503-508
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• 1994

17종과 45종 한방 식물체 메탄올 추출물의 배추좀나방과 담배거세미나방 유충에 대한 살충활성 및 섭식저해활성을 잎침지법으로 조사하였다. 살충활성은 8,000 ppm에서 조사하였는바, 현호색 추출물만이 담배거세미나방 유충에 대해 강한 살충활성을 보였다. 섭식저해활성은 5,000 ppm에서 조사한 결과, 누리장나무, 거문누리장나무, 목향, 우방자, 인진, 전호, 백지 및 현호색 추출물이 강한 섭식저해활성을 나타내었다.

• 한국응용곤충학회지
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• 제35권2호
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• pp.153-158
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• 1996

국내산 41종과 79종 식물체 메탄올 추출물 및 일본산 1종 식물체 정유의 솔잎혹파리(Thecodiplosis japonensis Uchida et Inouye) 유충에 대한 살충황성을 여지접촉법과 충제침지법으로 조사한 결과 살추활성은 식물체 종류에 따라 달리 나타났다. 여지접촉법으로 여지당 시료 10mg을 처리하였을 때, 국내산 미나리아재비과의 지범, 부자의 위령선 뿌리 추출물과 일본산 측백나무과의 Thujopsis dolabrata var. hondai 톱밥의 정유가 90%이사의 살충활성을 보였다. 그러나 충제침지법(5,000ppm)을이용한 생물검정에서는 T.dolabrata var. hondai 톱밥의 정유만이 강한 살충활성을 나타내었다. 따라서 T.dolabrata var. Hondai 톱밥의 추출물의 솔잎 혹파리에의한 소나무림의 피해를 줄일 수 있을 것으로 생각된다.

• BMB Reports
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• 제34권5호
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• pp.402-407
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• 2001

Based on the currently proposed toxicity model for the different Bacillus thuringiensis Cry $\delta$-endotoxins, their pore-forming activity involves the insertion of the ${\alpha}4-{\alpha}5$ helical hairpin into the membrane of the target midgut epithelial cell. In this study, a number of polar or charged residues in helix 4 within domain I of the 65-kDa dipteranactive Cry11A toxin, Lys-123, Tyr-125, Asn-128, Ser-130, Gln-135, Arg-136, Gln-139 and Glu-141, were initially substituted with alanine by using PCR-based directed mutagenesis. All mutant toxins were expressed as cytoplasmic inclusions in Escherichia coli upon induction with IPTG. Similar to the wild-type protoxin inclusion, the solubility of each mutant inclusion in the carbonate buffer, pH 9.0, was relatively low When E. coli cells, expressing each of the mutant proteins, were tested for toxicity against Aedes aegypti mosquito-larvae, toxicity was completely abolished for the alanine substitution of arginine at position 136. However, mutations at the other positions still retained a high level of larvicidal activity Interestingly, further analysis of this critical arginine residue by specific mutagenesis showed that conversions of arginine-136 to aspartate, glutamine, or even to the most conserved residue lysine, also abolished the wild-type activity The results of this study revealed an important determinant in toxin function for the positively charged side chain of arginine-136 in helix 4 of the Cry11A toxin.

• 한국응용곤충학회지
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• 제33권4호
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• pp.225-229
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• 1994

배추좀나방과 담배거세미나방 유충에 대한 30종 한방 식물체 메탄올 조추출몰의 살충활성 및 섭식 저해활성을 잎침지법을 이용하여 5,000ppm으로 검정하였다. 황련의 추출물은배추좀나방에 대해 살충작용을 보였다. 길경, 사삼, 세신, 오배자 및 자초의 추출물은 배추좀나방 유충에 대해, 목통 및 속새의 추출물은 담배거세미나방 유충에 대한 강한 섭식저해활성을 보였으나, 오배자와 황련의 추출물은 이들 나비목 유충 모두에 강한 섭식저해활성을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제44권4호
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• pp.494-504
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• 2016

Eucalyptus oils are widely used as spices, perfume industrial materials, food flavorings, and medicines. Several types of Eucalyptus oils also have insecticidal activity and as carminative. This study investigated the chemical composition, insecticidal (larvicidal and repellent) activity of E. urophylla oil against filarial mosquito Culex quinquefasciatus. E. urophylla oil was obtained from fresh leaves by water-steam distillation with oil yield 1.08%. E. urophylla oil in this study had no color (clear), has odor (typical eucalyptus), with specific gravity 0.941; refractive index 1.465; miscibility in 70% ethanol 1 : 3; and optical rotation (-) $5.83^{\circ}$. The major compounds of the oil were ${\alpha}$-pinene (11.73%), 1,8-cineole (49.86%), ${\beta}$-ocimene (6.25%), ${\gamma}$-terpinene (9.11%), and ${\alpha}$-terpinyl acetate (7.63%). The result showed the excellent insecticide activity against C. quinquefasciatus. The oil provided larvicidal activity with $LC_{50}$: 80.21 ppm and $LC_{90}$: 210.18 ppm, and repellent activity with $IC_{50}$: 0.82% and $IC_{90}$: 4.88%. The present study showed the effectiveness of E. urophylla as natural insecticide against C. quinquefasciatus, the mosquito vector of filariasis.

• BMB Reports
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• 제37권3호
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• pp.292-297
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• 2004

The current model for the mechanism of action of the Bacillus thuringiensis Cry $\delta$-endotoxins involves the penetration of the ${\alpha}4-{\alpha}5$ hairpin into the target midgut epithelial cell membranes, followed by pore formation. In this study, PCR-based mutagenesis was employed to identify a critical residue within the ${\alpha}4-{\alpha}5$ loop of the 130-kDa Cry4A mosquito-larvicidal protein. Alanine-substitutions of two charged (Asp-198 and Asp-200) and four polar (Asn-190, Asn-195, Tyr-201 and Tyr-202) residues in the ${\alpha}4-{\alpha}5$ loop were performed. Like the wild-type, all of the mutant toxins were over-expressed as inclusion bodies in Escherichia coli. When E. coli cells expressing each mutant toxin were bioassayed against Aedes aegypti larvae, larvicidal activity was completely abolished for the substitution of only Tyr-202, while replacements at the other positions still retained a high level of toxicity. Further replacement of Tyr-202 with an aromatic side chain, phenylalanine, did not affect the toxicity. These results revealed a crucial role in toxin activity for the conserved aromatic residue at the 202 position within the ${\alpha}4-{\alpha}5$ loop of the Cry4A toxin.

• 농약과학회지
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• 제10권1호
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• pp.43-49
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• 2006

빨간집모기(Culex pipiens pallens) 유충에 대한 34종 식물오일의 살충력을 조사하였다. 80% 이상의 살충효과를 나타낸 오일은 6종(basil, fennel, caraway seed, lime, thyme red, thyme white)이었다. 각 오일의 구성성분을 GC와 GC-MS로 분석하고 각 성분의 살충력을 검정한 결과, basil 및 fennel 오일의 주요성분인 anethole과 caraway seed 오일 및 lime 오일의 주요성분인 (+)-limonene 이 높은 살충력을 나타내었다. 또한 ${\alpha}$-phellandrene, p-cymene, $\gamma$-terpinene, ${\beta}$-pinene, thymol 도 대조약제인 Bt제 보다 높은 살충효과를 나타내었다.