• Journal of Applied Biological Chemistry
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• v.48 no.1
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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.

• Journal of fish pathology
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• v.34 no.2
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• pp.249-253
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• 2021

Anisakiasis is a well-known zoonosis caused by ingestion of raw or thermally undercooked seafood product contaminated with live Anisakis nematode third stage larvae (L3). Several traditional processing techniques have been used to kill or remove the Anisakis larvae worldwide, but thermal processing or deep freezing are the most effective treatments to kill the Anisakis larvae. In this study, we investigated the survival of Anisakis larvae in several condiments (soy bean sauce, wasabi, vinegar, red pepper paste) commonly consumed when eating raw fish in Korea. We also examined several different media (NaCl solution, absolute alcohol, soju) to investigate their larvicidal effect. When directly exposed to various condiments, the most effective larvicidal effect was observed in the mixture of wasabi and soy bean sauce. When exposed to different NaCl solutions, the larvicidal ability became more effective as the concentration increased, but did not show 100% killing effect. In soju, the L3 were killed under less than 4 hr. We observed the larvicidal effects of several condiments in this study, but these results are thought to be carefully interpreted for actual use because all the condiments in this study showed the effect in hours and in general, the L3 are exposed to these condiments only for seconds before ingested in real situation.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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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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• v.40 no.2
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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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• v.37 no.6
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• pp.503-508
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• 1994

Methanol extracts from 45 species of oriental medicinal plants belonging to 17 families were subjected to a screening test for their larvicidal and antifeeding activities against two species of lepidopteran larvae, diamondback moth (Plutella xylostella L.) and tobacco cutworm (Spodoptera litura F.) by a leaf-dipping method. At a concentration of 8,000 ppm, methanol extract of Corydalis turrschaninovii roots only was found to have potent larvicidal activity against S. litura. At 5,000 ppm, strong antifeeding activity against both larvae was observed from the extracts of Clerodendron trichotomum, C. trichotomum var. esculentum, Inura helenium, Arctium lappa, Artemisia messerschmidtiana, Anthriscus sylvestris, Angelica dahurica, and C. turrschaninovii.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.153-158
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• 1996

Methanol extracts from 79 domestic plant species in 41 families and the crude oil of one Japanese plant species were tested for their larvicidal activities against Thecodiplosis japonensis Uchida et Inouye, using filter paperimpregnated and insect-dipping methods. In a test with 10 mgtpaper, strong larvicidal activity (>90% mortality) was obtained from the extracts of roots from three domestic plants belonging to Ranunculaceae (Aconitum pseudo- leave var. eretum, A. carmichaeli and Clematis florida) and the crude oil of sawdust from a Japanese plant, Thujopsis dolabrata var. hondai (Cupressaceae). However, only the crude oil from the Thujopsis sawdust revealed strong larvicidal activity when tested with 5,000 ppm by insect-dipping method. It is concluded that the Thujopsis sawdust-derived materials could be useful as a new control agent against T. japonensis.

• Journal of Applied Biological Chemistry
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• v.48 no.2
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• pp.65-74
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• 2005

Fungicidal, insecticidal, and mosquito larvicidal activities of piperidine alkaloids, pipernonaline and piperoctadecalidine, and isobutylamide alkaloids, pellitorine, guineensine, pipercide, and retrofractaminde A, derived from Piperaceae fruits were studied. Pipernonaline and piperoctadecalidine showed potent fungicidal activities against Puccinia recondita with 91 and 80% control values at 500 ppm. Against Phytophthora infestans, pipernonaline showed strong fungicidal activity with 91 and 80% control values at 1,000 and 500 ppm. $LD_{50}$ values of pipernonaline and piperoctadecalidine against Plutella xylostella were 125 and 95.5 ppm, respectively, and that of piperoctadecalidine against Tetranychus urticae was 246 ppm. Against larvae of Aedes aegypti and Culex pipiens pallens, $LD_{50}$ values of pipernonaline were 0.35 and 0.21 ppm, respectively. Highest larvicidal activities of pipercide and retrofractamide A were found against A. aegypti, A. togoi, and C. pipiens pallens. $LD_{50}$ values of pipercide and retrofractamide A were 0.10 and 0.039 ppm against A. aegypti, 0.26 and 0.01 ppm against A. togoi, and 0.004 and 0.028 ppm against C. pipiens pallens, respectively. Based upon these results and earlier findings, bioactive components derived from Piperaceae fruits may be valuable for development of useful lead product of possibly safer fungicidal, insecticidal, and mosquito larvicidal agents.

• Natural Product Sciences
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• v.9 no.3
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• pp.174-176
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• 2003

Studies on the stem bark extracts of Garcinia cuneifolia have furnished a new xanthone cuneifolin (1) and the triterpene stigmasterol (2). Structures for these compounds were elucidated based on NMR, 2D NMR, MS and GCMS data. Larvicidal activity screening of the crude bark extract using the larvae of Aedes aegypti indicated the larvae to be susceptible to these extracts. $LC_{50}$ values of the bioassays show the extracts to be moderately toxic to the larvae of Aedes aegypti.

• BMB Reports
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• v.37 no.3
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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.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.43-49
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• 2006

Larvicidal activity of 34 plant essential oils were tested against the 4th instar larvae of Culex pipiens pallens. Among them, six oils (basil, fennel, caraway seed, lime, thyme red, and thyme white) showed more than 80% mortality at 100 mg $litre^{-1}$ concentration. GC and GC-MS analyses of the six essential oils and bioassay of their components revealed that anethole (a major component of fennel and basil oil) and (+)-limonene (a major component of caraway seed and lime oil) showed higher larvicidal activities than others. In addition to the above two components, ${\alpha}$-phellandrene, p-cymene, $\gamma$-terpinene, ${\beta}$-pinene, and thymol showed higher larvicidal activity than Bt product.