• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.60.2-61
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• 2000

No Abstract, See Full Text

• Applied Biological Chemistry
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• v.47 no.3
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• pp.366-369
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• 2004

Myristica fragrans Houtt were extracted in 80% aq. MeOH and solvent fractionated sing $CHCl_3$, EtOAc, n-BuOH and water, successively. The n-BuOH fraction gave three phenylpropanoids through application of silica gel column chromatographies. The chemical structures of the phenylpropanoids were determined by the interpretation of several spectral data, including NMR and MS as meso-dihydroguaiaretic acid (1), nectandrin B (2) and syringin methyl ether (3). Compound 1, which was first isolated from this plant by authors, showed inhibitory activities with $60.0{\pm}2.1%\;(100\;{\mu}g/ml),\;42.6{\pm}0.9%\;(140\;{\mu}g/ml)\;and\;12.2{\pm}0.2%\;(200\;{\mu}g/ml)$ on ACAT(acyl-CoA:Cholesterol Acyltransferase), chitin synthase III and HMG-CoA reductase (3-hydroxy-3-methylglutaryl coenzyme A reductase), respectively. Compound 3 showed inhibitory activities with $27.2{\pm}0.9%\;(100\;{\mu}g/ml),\;45.5{\pm}0.8%\;(200\;{\mu}g/ml)$ on ACAT and chitin synthase III.

• Mycobiology
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• v.42 no.4
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• pp.422-426
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• 2014

Depending on the acquisition of developmental competence, the expression of genes for ${\beta}$-1,3-glucan synthase and chitin synthase was affected in different ways by Aspergillus nidulans LAMMER kinase. LAMMER kinase deletion, ${\Delta}lkhA$, led to decrease in ${\beta}$-1,3-glucan, but increase in chitin content. The ${\Delta}lkhA$ strain was also resistant to nikkomycin Z.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.10a
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• pp.39-45
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• 2000

It hab been proposed that CHS3-mediated chitin synthesis during the vegitative cell cycle is regulated by CHS4. To investigate direct protein-protein interaction between their coding products, we used yeast two hybrid system and found that a domain of Chs3p was responsible for interaction with Chs4p. This domain, termed MIRC3-4 (maximum interacting region of chs3p with chs4p), spans from 647 to 700 residues. It is well conserved among CHS3 homologs of various fungi such as Candida albicans, Emericella nidulans, Neurospora crassa, Magnaporthe grisea, Ustilago maydis, Glomus versiforme, Exophiala dermatitidis, Rhizopus microsporus. A series of mutaion in the MIRC3-4 resulted in no appearance of chitin ring at the early G 1 phase but did not affect chitin synthesis in the cell wall after cytokinesis. Absence of chitin ring could be caused either by delocalization of Chs3p to the septum or by improper interaction with Chs4p. To discriminate those two, not mutually exclusive, alternatives, mutants cells were immunostained with Chs3p-specific antibody. Some exhibited localization of chs3p to the septum, while others failed. These results indicate that simultaneous localization and activation Chs3p by Chs4p is required for chitin ring synthesis.

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.29-33
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• 2010

KGD1 gene was cloned by functional complementation of defects in $\beta$-1,3-glucan synthase activity of the previously isolated Saccharomyces cerevisiae mutant LP0353, which displays a number of cell wall defects at restrictive temperature. We performed the gene disruption experiment to characterize the function of KGD1 gene, which encodes $\beta$-ketoglutarate dehydrogenase, in cell wall biosynthesis. The disruption of KGD1 showed the decreased growth rate, the increase of chitin synthases activity, alterations in cell wall composition, and increase of susceptibility to cell wall inhibitors such as Calcofluor white and Nikkomycin Z. These results suggested that KGD1 might be involved in cell wall biogenesis, especially the biosynthesis of $\beta$-1,6-glucan and chitin in S. cerevisaie.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.613-617
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• 1998

The Chsl, Chs2, and Chs3 activities of a pathogenic fungus, Candida albicans, perform the same biochemical reactions, but exert different functions. Therefore, the determination of each enzyme activity is important. The three chitin synthases differ in their optimal pH and the effect of divalent cations as either stimulatory or inhibitory factors. The CAChsl, CAChs2, and CAChs3 activities are optimal at pH 7.5, 6.5, and 8.5, respectively. $Co^{2+} stimulates CAChsl and CAChs3, but inhibits CAChs2. $Ni^{2＋}$ inhibits CAChsl and CAChs2 with little effect on CAChs3. $Mg^{2＋}$ stimulates CAChs2 and CAChs3, but hardly affects CAChsl. These characteristics are similar to those of the Saccharomyces cerevisiae enzymes except in degree. The sensitivity against $Ni^{2＋}$ of CAChsl is higher than that of CAChs2, whereas the reverse is true in S. cerevisiae. Metal dependence of chitin synthases in C. albicans is less marked than that in S. cerevisiae, except for CAChs2. The activities of CAChsl and CAChs3 from EDTA-treated membranes were increased 1.5 fold, while that of CAChs2 was stimulated 7 fold in the presence of divalent cations. These results could provide new criteria for screening systems of antifungal agents.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.303.2-303
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• 1998

No Abstract, See Full Text

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2303-2309
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• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.439-445
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• 2012

The chitinase producing Lysobacter enzymogenes C-3 has previously been shown to suppress plant pathogens in vitro and in the field, but little is known of the regulation of chitinase production, or its role in antimicrobial activity and biocontrol. In this study, we isolated and characterized chitinase-defective mutants by screening the transposon mutants of L. enzymogenes C-3. These mutations disrupted genes involved in diverse functions: glucose-galactose transpoter (gluP), disulfide bond formation protein B (dsbB), Clp protease (clp), and polyamine synthase (speD). The chitinase production of the SpeD mutant was restored by the addition of exogenous spermidine or spermine to the bacterial cultures. The speD and clp mutants lost in vitro antifungal activities against plant fungal pathogens. However, the gluP and dsbB mutants showed similar antifungal activities to that of the wild-type. The growth of the mutants in nutrient rich conditions containing chitin was similar with that of the wild-type. However, growth of the speD and gluP mutants was defective in chitin minimal medium, but was observed no growth retardation in the clp and dsbB mutant on chitin minimal medium. In this study, we identified the four genes might be involved and play different role in the production of extracellular chitinase and antifungal activity in L. enzymogenes C-3.

• Mycobiology
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• v.48 no.4
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• pp.321-325
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• 2020

A Colletotrichum species was isolated from leaves of Cymbidium exhibiting symptoms of anthracnose. In this study, the isolates obtained were identified based on recent taxonomic approaches for the genus Colletotrichum. The identity of the causal pathogen was confirmed using morphological data and phylogenetic analysis of combined multi-gene dataset (internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, chitin synthase-1, actin, histone3, beta-tubulin, and calmodulin). Pathogenicity testing revealed that the isolates were pathogenic to Cymbidium. Based on these results, the fungal pathogen occurring on Cymbidium orchids was identified as Colletotrichum cymbidiicola, which is a newly recorded species in Korea.