• The Korean Journal of Mycology
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• v.51 no.2
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• pp.147-153
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• 2023

Dark brown leaf molds growing in a vein-limited pattern have been continuously observed on the lower leaf surface of Fatoua villosa in Korea. Fifteen samples deposited in the Korea University herbarium were examined for fungal morphological characterization. Two monoconidial isolates were obtained in 2022, and molecular analysis was performed based on a combined multigene dataset of the internal transcribed spacer (ITS) region and partial actin (actA), translation elongation factor 1-alpha (tef1), and DNA-directed RNA polymerase II second-largest subunit (rpb2). Based on morphological features and molecular phylogenetic analysis, the fungus Pseudocercospora fatouae was identified. To the best of our knowledge, it is the first study reporting the presence of P. fatouae on F. villosa in Korea.

• BMB Reports
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• v.43 no.5
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• pp.375-381
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• 2010

In this study, the cDNA library of Chang-liver cells was immunoscreened using common ADAMs antibody to obtain ADAM related genes. We found one positive clone that was confirmed as a new gene by Blast, which is an uncharacterized helical and coil protein and processes protease activity, and named protease-related protein 1 (ARP1). The submitted GenBank accession number is AY078070. Molecular characterizations of ARP1 were analyzed with appropriate bioinformatics software. To analyse its expression and function, ARP1 was subcloned into glutathione S-transferase fusion plasmid pGEX-2T and expressed by E. coli system. The in vitro expression product of ARP1 was recognized by common ADAMs antibody with western blot. Interestingly, ARP1 cleaves gelatine at pH9.5, which suggests it is an alkaline protease. Semi-quantitative RT-PCR result indicates that ARP1 mRNA is strongly transcribed in the liver and the treated Chang-liver cells.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Journal of Microbiology
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• v.35 no.2
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• pp.117-122
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• 1997

Several dominant 4-CPA-degrading bacteria were isoalted from agricultural soils. Most of the isolates were identified as Burkholderia species by fatty acid methyl ester (FAME) analysis, but they were idstinct in chromosomal patterns obtained by PCR amplification of repetitive extragenic palindromic (REP) sequences. These strains were generally restricted in their substrate utilization capabilities. The 4-CPA degradative enzymes were idnducible by 4-CPA and some isolates appeared to mineralize 4-CPA via formation of 4-chlorophenol and 4-chlorocatechol as intermediates during its biodegradation pathway. Plasmid DNAs were not detected from most of the isoaltes and their 4-CPA genes wer on the chromosomal DAN. The 4-CPA degradation patterns in axenic cultures and natural soils varied depending on the strains and soils. The inoculation of 4-CPA degraders much improved the removal of 4-CPA from the 4-CPA treated soils.

• BMB Reports
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• v.42 no.6
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• pp.367-372
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• 2009

In this study, we showed that WAX9D, a nonspecific lipid-transfer protein found in broccoli, binds palmitate (C16) and stearate (C18) with dissociation constants of 0.56 ${\mu}M$ and 0.52 ${\mu}M$, respectively. WAX9D was fused to thioredoxin protein by genetic manipulation to enhance its solubility. The data revealed strong interaction of Trx-WAX9D with palmitate and stearate. The dissociation constants of Trx-WAX9D for palmitate and stearate were 1.1 ${\mu}M$ and 6.4 ${\mu}M$, respectively. The calculated number of binding sites for palmitate and stearate was 2.5 to 2.7, indicating that Trx-WAX9D can bind three molecules of fatty acids. Additionally, Trx-WAX9D was shown to inhibit the apoptotic effect of palmitate in endothelial cells. Our data using Trx-WAX9D provide insight into the broad spectrum of its biological applications with specific palmitate binding.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.316-321
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• 1992

Catechol 2, 3-dioxygenase (C230) catalyses the oxidative ring cleavage of catechol to 2-hydroxymuconic semialdehyde. This is one of the key reactions in the metabolism of the widespresd pollutant aniline. We have cloned a gene encoding C230 from cells of the aniline degrading bacteria, Pseudomonas acidovorance KCTC2494 strain and expressed in E. coli, A 11.3-kilobase Sau3A partial digested DNA fragment from KCTC2494 was cloned into phagemid vector pBluescript and designated as pLP201. The C230 gene was mapped to a 2.8-kb region, and the derection of transcription was determined. The cloned C230 gene contains its own promoter which can be recognized and employed by E. coli transcriptional apparatus. C230 activities of subclones were identified by enzyme assay and activity staining. The T7 RNA promoter/polymerase system and maxicell analysis showed that a polypeptide with Mw of 35 kDa is the C230 gene product.

• Molecules and Cells
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• v.25 no.3
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• pp.438-445
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• 2008

Leaf senescence is a highly regulated genetic process that constitutes the last stage of plant development and provides adaptive fitness by relocating metabolites from senescing leaves to reproducing seeds. Characterization of various senescence mutants, mostly in Arabidopsis, and genome-wide analyses of gene expression, have identified a wide array of regulatory components, including transcription factors and enzymes as well as signaling molecules mediating growth hormones and environmental stress responses. In this work we demonstrate that a membrane-associated NAC transcription factor, NTL9, mediates osmotic stress signaling in leaf senescence. The NTL9 gene is induced by osmotic stress. Furthermore, activation of the dormant, membrane-associated NTL9 is elevated under the same conditions. A series of senescence-associated genes (SAGs) were upregulated in transgenic plants overexpressing an activated form of NTL9, and some of them were slightly but reproducibly downregulated in a T-DNA insertional NTL9 knockout mutant. These observations indicate that NTL9 mediates osmotic stress responses that affect leaf senescence, providing a genetic link between intrinsic genetic programs and external signals in the control of leaf senescence.

• BMB Reports
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• v.35 no.2
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• pp.220-227
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• 2002

Two aspartate aminoransferase (EC 2.6.1.1) isoenzymes (AAT-1 and AAT-2) from Lupinus albus L. cv Estoril were separated, purified, and characterized. The molecular weight, pI value, optimum pH, optimum temperature, and thermodynamic parameters for thermal inactivation of both isoenzymes were obtained. Studies of the kinetic mechanism, and the kinetics of product inhibition and high substrate concentration inhibition, were performed. The effect of some divalent ions and irreversible inhibitors on both AAT isoenzymes was also studied. Native PAGE showed a higher molecular weight for AAT-2 compared with AAT-1. AAT-1 appears to be more anionic than AAT-2, which was suggested by the anion exchange chromatography. SDS-PAGE showed a similar sub-unit molecular weight for both isoenzymes. The optimum pH (between 8,0 and 9.0) and temperature ($60-65^{\circ}C$) were similar for both isoenzymes. In the temperature range of $45-65^{\circ}C$, AAT-2 has higher thermostability than AAT-1. Both isoenzymes showed a high affinity for keto-acid substrates, as well as a higher affinity to aspartate than glutamate. Manganese ions induced an increase in both AAT isoenzymes activities, but no cooperative effect was detected. Among the inhibitors tested, hydroxylamine affected both isoenzymes activity by an irreversible inhibition mechanism.

• BMB Reports
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• v.35 no.2
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• pp.228-235
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• 2002

Methionine aminopeptidase (MetAP) catalyzes the removal of an amino-terminal methionine from a newly synthesized polypeptide. The enzyme was purified to homogeneity from Bacillus stearothermophilus (KCTC 1752) by a procedure that involves heat precipitation and four sequential chromatographs (including DEAE-Sepharose ion exchange, hydroxylapatite, Ultrogel AcA 54 gel filtration, and Reactive red 120 dye affinity chromatography). The apparent molecular masses of the enzyme were 81,300 Da and 41,000 Da, as determined by gel filtration chromatography and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), respectively. This indicates that the enzyme is comprised of two identical subunits. The MetAP specifically hydrolyzed the N-terminal residue of Met-Ala-Ser that was used as a substrate, and exhibited a strong preference for Met-Ala-Ser over Leu-Gly-Gly, Leu-Ser-Phe, and Leu-Leu-Tyr. The enzyme has an optimal pH at 8.0, an optimal temperature at $80^{\circ}C$, and pI at 4.1. The enzyme was heat-stable, as its activity remained unaltered when incubated at $80^{\circ}C$ for 45 min. The Km and Vmax values of the enzyme were 3.0mM and 1.7 mmol/min/mg, respectively. The B. stearothernmophilus MetAP was completely inactivated by EDTA and required $Co^{2+}$ ion(s) for activation, suggesting the metal dependence of this enzyme.

• Macromolecular Research
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• v.11 no.5
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.