• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.1
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• pp.63-68
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• 2002

A cDNA encoding a putative member of cathepsin B of the thiol pretense superfamily was cloned from a cDNA library of the mulberry longicorn beetle, Apriona germari. Sequence analysis of the cDNA encoding the cathepsin B of A. germari (AgCatB) revealed that the 972 bp cDNA has an open reading frame of 324 amino acid residues. The deduced protein sequence of the AgCatB showed high homology with cathepsin B of the insects, Bombyx mori (47.3% amino acid identity), Helicoverpa armigera (46.6%) and Sarcophaga peregrina (45.6%), and the lowest homology with Aedes aegypti (33.2%). The AgCatB contains six disulfate bonds typical for cysteine pretenses. The three amino acid positions Cys-109, His-267, and Asn-287 which are conserved, active sites characteristic for cathepsin B, were also found. Phylogenetic analysis further confirmed that the AgCatB has a close relationship with that of B. mori, H. armigera and S. peregrina.

• 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.

• Korean Journal of Veterinary Service
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• v.43 no.1
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• pp.1-6
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• 2020

Unlike previous studies that reported the infection rates of Dirofilaria immitis in companion dogs, D. immitis genes were tested directly on mosquitoes to see how many mosquitoes actually carry larvae. Mosquito samples were collected from six parks in Incheon from March to August 2018. A total of 18,589 mosquitoes was collected, classified by type and then made 575 sample pools based on 50 mosquitoes. The PCR method was used to detect Dirofilaria immitis genes of sample pools. Dirofilaria immitis genes were detected in 7 of the 575 pools, and these positive mosquito samples were collected in 4 out of the 6 parks. The types of detected mosquitoes were Aedes dorsalis and Ochlerotatus koreanus which have been identified to act as a vector for heart worm propagation in Incheon. Based on these results, it was concluded that D. immitis genes were found in mosquitoes in the neighborhood park.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.303-307
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• 1991

The hemolyic polypeptide in delta-endotoxin from Bacillus thun'ngiensis subsp. darmstadiensis 73ElO-2 was purified by Sephadex G-IOO gel filtration and DEAE-cellulose ion exchange column chromatography. The purity of hemolysin was confirmed by ouchterlony test and SDS-PAGE. The molecular weight of the purified hemolysin was approximately 64 KDa by SDS-PAGE. The purified hemolysin has not mosquitocidal activity against larvae of Aedes agypti, but hemolytic activity on red blood cells of rat. There is no serological relationship between delta-endotoxin from B. thuringiensis subsp. israelensis and the purified hemolysin from the . strain 73ElO-2.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.57-61
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• 2006

Suppressor of cytokine signaling (SOCS) is known to be as a negative feedback regulator in Janus kinase signal transducer and activator of transcription signaling. Highly conserved SOCS box domain was cloned from a Korean malaria vector, Anopheles sinensis. Sequence analysis indicates that it has identity to Anopheles gambiae (96%), Aedes aegypti (94%), Drosophila melanogaster (78%), Mus musculus (72%) and Homo sapiens (72%), respectively. Tissue specificity RT-PCR demonstrated that the expression level of AsSOCS transcript was high at abdomen, midgut, and ovary, whereas developmental expression patterns showed that the level of AsSOCS was high at egg, early pupae, and adult female. On the other hand, RT-PCR analysis after bacterial challenge showed that SOCS mRNA was strongly induced in larvae. In addition, it was also induced by various immune elicitors such as lipoteicoic acid, CpG-DNA, and laminarin. It seems that AsSOCS, repressor of JAK-STAT pathway, is highly conserved in mosquito, and may play an important role in mosquito innate immune response.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.63-67
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• 2006

Suppressor of cytokine signaling (SOCS) is known to playa key role as a negative feedback regulator in JAK/STAT signaling cascade in innate immunity. Our laboratory has recently been interested in elucidating the interactions between Spodoptera exigua (Se) and SeNPV. This context leads us to clone and characterize SeSOCS that may have important functions in response to SeNPV infection. Using the RT-PCR and TA cloning approach, we found a partial fragment (416 bp) of SeSOCS. Blast search and multiple alignment data showed that it has a homology to various insects such as Anopheles gambiae (78%), Aedes aegypti (75%), Drosophila melanogastar (77%), Mus musculus (69%), and Homo sapiens (69%). Temporal induction patterns of SeSOCS were analysed after being immune-challenged with either NPV or laminarin. It showed that the level of SeSOCS mRNA was strongly induced in a biphasic manner in response to SeNPV and laminarin, respectively. It seems that SOCS, a negative regulator of JAK/STAT signaling system is also present in S. exigua and may playa role in innate immunity albeit its precise role should be further elucidated at the molecular and cellular level in the early phase of SeNPV infection in larvae.

• 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.

• BMB Reports
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• v.34 no.2
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• pp.150-155
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• 2001

The mosquito-larvicidal Cry4B protein from Bacillus thuringiensis subsp. israelensds was expressed in Escherichia coli. Upon activation by trypsin, the 130-kDa protoxin was processed into the 65-kDa active toxin containing two polypeptide fragments of ca. 47 and ca. 20 kDa. These two polypeptides are products of internal cleavages on the exposed loop connecting helices 5 and 6 in the seven-helical bundle domain. PCR-based mutagenesis was employed to introduce an additional cleavage site into the loop connecting helices 3 and 4. A series of amino acid changes were introduced into the targeted loop, resulting in seven mutant protoxins. Upon digestion with trypsin, a group of mutants with arginine introduced into the loop (EPRNQ, EPNRNQ, EPRNP, ESRNP and SSRNP) produced polypeptide products similar to those of the wild type (EPNNQ). When the loop, SSRNP, was expanded by an insertion of either asparagine (NSSRNP) or valine (VSSRNP), an additional cleavage was detected with proteolytic products of 47,12 and 6 kDa. This cleavage was confirmed to be at the introduced arginine residue by N-terminal sequencing. The mosquito larvicidal assay against Aedes aegypti demonstrated a relatively unchanged toxicity for the mutants without cleavage and reduced toxicity for those with an additional cleavage.

• BMB Reports
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• v.47 no.10
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• pp.546-551
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• 2014

The insecticidal activity of Bacillus thuringiensis (Bt) Cry toxins involves toxin stabilization, oligomerization, passage across the peritrophic membrane (PM), binding to midgut receptors and pore-formation. The residues Arg-158 and Tyr-170 have been shown to be crucial for the toxicity of Bt Cry4Ba. We characterized the biological function of these residues. In mosquito larvae, the mutants R158A/E/Q (R158) could hardly penetrate the PM due to a significantly reduced ability to alter PM permeability; the mutant Y170A, however, could pass through the PM, but degraded in the space between the PM and the midgut epithelium. Further characterization by oligomerization demonstrated that Arg-158 mutants failed to form correctly sized high-molecular weight oligomers. This is the first report that Arg-158 plays a role in the formation of Cry4Ba oligomers, which are essential for toxin passage across the PM. Tyr-170, meanwhile, is involved in toxin stabilization in the toxic mechanism of Cry4Ba in mosquito larvae.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.4
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• pp.289-296
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• 2018

Purpose: We aimed to study the pattern of liver-injury in children with dengue fever (DF) and validate serum aminotransferase ${\geq}1,000IU/L$ as a marker of severe DF. Methods: Children admitted with DF were included. DF was defined by presence of clinical criteria and positive serological or antigen tests in absence of other etiology. DF severity was graded as dengue without or with warning signs and severe dengue. Liver-injury was defined as alanine aminotransferase (ALT) more than twice the upper limit of normal (boys, 30 IU/L; girls, 21 IU/L). Results: Of 372 children with DF, 144 (38.7%) had liver-injury. Risk of liver-injury and aminotransferase levels increased with DF severity (p<0.001). Recommended ALT and aspartate aminotransferase (AST) cut-off at ${\geq}1,000IU/L$ had sensitivity 4.8% (5/105), specificity 99.3% (265/267) for detection of severe DF. In children with ALT and AST <1,000 IU/L (n=365), the area under receiver operating curves for prediction for severe DF, were 0.651 (95% confidence interval [CI], 0.588-0.714; p<0.001) for ALT and 0.647 (95% CI, 0.582-0.712; p<0.001) for AST. Serum ALT at 376 IU/L and AST at 635 IU/L had sensitivity and specificity comparable to ${\geq}1,000IU/L$ for defining severe DF. Conclusion: Liver-injury is common in DF. The ALT and AST levels increase with DF severity. ALT and AST levels of ${\geq}1,000IU/L$ could be lowered to 376 IU/L and 635 IU/L respectively for defining severe DF.