• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
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• pp.86-86
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• 2002

• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
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• pp.55-55
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• 2002

• 한국균학회지
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• 제43권3호
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• pp.158-164
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• 2015

2010년부터 2015년까지 전국 8도에 있는 벼 포장에서 수확기에 총 509개의 이삭시료가 채집되었다. 시료당 105개의 벼 종실이 potato dextrose agar (PDA) 배지에 처리되었고 6,658개의 Fusarium 균주가 분리되었다. $EF-1{\alpha}$ 유전자의 염기서열을 기초로, 분리된 Fusarium 중 67균주를 Fusarium armeniacum으로 동정하였고, 형태적, 배양적 특성을 확인하였다. F. armeniacum은 분생포자 크기, 균총 색, 및 $EF-1{\alpha}$ 염기서열에서 균주간에 상당한 차이가 있었다. 액체크로마토크래피-질량분석기를 사용하여 potato sucrose agar (PSA) 배지에서 T-2와 HT-2 독소생성능력을 결정하였던 바 F. armeniacum 24균주 중 21균주가 T-2와 HT-2 독소를 모두 생성하였으며, 독소생성 수준은 균주간에 다양하였다. 이러한 결과는 한국산 F. armeniacum 균주들이 형태적, 배양적, 유전적 및 독소학적 성질에서 다양성을 갖는다는 것을 보여준다.

• 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.

• 한국발생생물학회지:발생과생식
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• 제16권1호
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• pp.69-75
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• 2012

Hatching occurred in the time dependent manners and strictly controlled. Although, the hatching processes are under the control of muti-embryotrophic factors and the expressed G proteins of cell generate integrated activation, the knowledge which GPCRs are expressed during hatching stage embryos are very limited. In the present study, which G proteins are involved was examined during blastocyst development to the hatching stage. The early-, expanded-, and lobe-stage blastocysts were treated with various $G_{\alpha}$ activators and H series inhibitors, and examined developmental patterns. Pertusis toxin (PTX) improved the hatching rate of the early-stage blastocyst and lobe-formed embryos. Cholera toxin (CTX) suppressed the hatching of the early-stage blastocyst and expanded embryos. The effects of toxins on hatching and embryo development were changed by the H7 and H8. These results mean that PTX mediated GPCRs activation is signaling generator in the nick or pore formation in the ZP. In addition, PTX mediated GPCR activation induces the locomotion of trophectoderm for the escaping. CTX mediate GPCRs activation is the cause of suppression of hatching processes. Based on these data, it is suggested that various GPCRs are expressed in the periimplantation stage embryos and the integration of the multiple signals decoding of various signals in a spatial and temporal manner regulate the hatching process.

• BMB Reports
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• 제34권4호
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• pp.293-298
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• 2001

Tryptic activation of the 130-kDa Bacillus thuringiensis Cry4B $\delta$-endotoxin produced protease-resistant products of ca. 47 kDa and ca. 21 kDa. The 21-kDa fragment was identified as the N-terminal five-helix bundle (${\alpha}1-{\alpha}5$,) which is a potential candidate for membrane insertion and pore formation. In this study, we constructed the recombinant clone over-expressing this putative pore-forming (PPF) fragment as inclusion bodies in Escherichia coli. The partially purified inclusions were composed of a 23-kDa protein, which cross-reacted with Cry4B antibodies, and whose N-terminus was identical to that of the 130-kDa protein. Dissimilar to protoxin inclusions, the PPF inclusions were only soluble when the carbonate buffer, pH 9.0, was supplemented with 6 M urea. After renaturation via a stepwise dialysis, the refolded PPF protein appeared to exist as an oligomer and was structurally stable upon trypsin treatment. Unlike the 130kDa protoxin, the refolded protein was able to release entrapped glucose from liposomes, and showed comparable activity to the full-length activated toxin, although it lacks larvicidal activity These results, therefore, support the notion that the PPF fragment that consists of ${\alpha}1-{\alpha}5$ of the activated Cry4B toxin is involved in membrane pore-formation.

• Genomics & Informatics
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• 제21권1호
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• pp.7.1-7.11
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• 2023

The gram-positive bacterium Listeria monocytogenes is an important foodborne intracellular pathogen that is widespread in the environment. The functions of hypothetical proteins (HP) from various pathogenic bacteria have been successfully annotated using a variety of bioinformatics strategies. In this study, a HP Imo0888 (NP_464414.1) from the Listeria monocytogenes EGD-e strain was annotated using several bioinformatics tools. Various techniques, including CELLO, PSORTb, and SOSUIGramN, identified the candidate protein as cytoplasmic. Domain and motif analysis revealed that the target protein is a PemK/MazF-like toxin protein of the type II toxin-antitoxin system (TAS) which was consistent with BLASTp analysis. Through secondary structure analysis, we found the random coil to be the most frequent. The Alpha Fold 2 Protein Structure Prediction Database was used to determine the three-dimensional (3D) structure of the HP using the template structure of a type II TAS PemK/MazF family toxin protein (DB ID_AFDB: A0A4B9HQB9) with 99.1% sequence identity. Various quality evaluation tools, such as PROCHECK, ERRAT, Verify 3D, and QMEAN were used to validate the 3D structure. Following the YASARA energy minimization method, the target protein's 3D structure became more stable. The active site of the developed 3D structure was determined by the CASTp server. Most pathogens that harbor TAS create a crucial risk to human health. Our aim to annotate the HP Imo088 found in Listeria could offer a chance to understand bacterial pathogenicity and identify a number of potential targets for drug development.

• 한국동물위생학회지
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• 제34권1호
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• pp.31-35
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• 2011

This is a case report that 24 heads of cattle suddenly died without clinical signs in a Hanwoo farm. The cause of death was Clostridium perfringens enterotoxemia resulted from them with feeding leftover food. The clinical signs were observed just before the death; increase of heart rate, shallow and rapid respiration, amyostasia, spasm and so forth. In autopsy, blood coagulation disorder, a little abdominal inflation, hepatomegaly and different size of red spots, congestion hemorrhage and undercurrent of bloody exudation were observed in the entire parts of small and large intestines. C. perfringens were isolated from the substantive organs, and a unique fragment of 405bp C. perfringens was amplified by PCR. Therefore, this case was diagnosed as enterotoxemia caused by ${\alpha}$-toxin of C. perfringens A type.

• 대한의생명과학회지
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• 제23권3호
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• pp.175-184
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• 2017

Cholera toxin (CT) is an ADP-ribosylating bacterial exotoxin that has been used as an adjuvant in animal studies of oral immunization. The mechanisms of mucosal immunogenicity and adjuvanticity of CT remain to be established. In this study, we investigated the role of indoleamine 2,3-dioxygenase (IDO), which participates in the induction of immune tolerance, in CT-mediated breakdown of oral tolerance. When IDO-deficient ($IDO^{-/-}$) mice and their littermates were given oral ovalbumin, significant changes in antibody responses, footpad swelling and $CD4^+$ T cell proliferation were not observed in $IDO^{-/-}$ mice. Feeding of CT decreased IDO expression in mesenteric lymph nodes (MLN) and Peyer's patch (PP). CT-induced downregulation of IDO expression was reversed by inhibitors of nuclear factor-kappa B (NF-${\kappa}B$), pyrrolidine dithiocarbamate and p50 small interfering RNA. IDO expression was downregulated by the NF-${\kappa}B$ inducers lipopolysaccharide and tumor necrosis factor-${\alpha}$. CT dampened IDO activity and mRNA expression in dendritic cells from MLN and PP. These data indicate that CT disrupts oral tolerance by activating NF-${\kappa}B$, which in turn downregulates IDO expression. This study betters the understanding of the molecular mechanism underlying CT-mediated abrogation of oral tolerance.

• BMB Reports
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• 제40권1호
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• pp.58-64
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• 2007

Similar to the other known structures of Bacillus thuringiensis Cry $\delta$-endotoxins, the crystal structure of the 65-kDa activated Cry4Ba toxin comprises three domains which are, from the N- to C-terminus, a bundle of $\alpha$-helices, a three-$\beta$-sheet domain, and a $\beta$-sandwich. To investigate the properties of the C-terminal domain III in isolation from the rest of the toxin, the cloned Cry4Ba-domain III was over-expressed as a 21-kDa soluble protein in Escherichia coli, which cross-reacted with anti-Cry4Ba domain III monoclonal antibody. A highly-purified domain III was obtained in a monomeric form by ion-exchange and size-exclusion FPLC. Circular dichroism spectroscopy indicated that the isolated domain III fragment distinctly exists as a $\beta$-sheet structure, corresponding to the domain III structure embodied in the Cry4Ba crystal structure. In vitro binding analysis via immuno-histochemical assay revealed that the Cry4Ba-domain III protein was able to bind to the apical microvilli of the susceptible Stegomyia aegypti larval midguts, albeit at lower-binding activity when compared with the full-length active toxin. These results demonstrate for the first time that the C-terminal domain III of the Cry4Ba mosquito-larvicidal protein, which can be isolated as a native folded monomer, conceivably participates in toxin-receptor recognition.