• BMB Reports
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• v.32 no.5
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• pp.486-491
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• 1999

An engineered cDNA from Phanerochaete chrysosporium encoding both the mature and propeptide-sequence regions of lignin peroxidase H2 (Lip H2) was overexpressed in Escherichia coli BL21 (DE3) to evaluate its catalytic characteristics and potential application as a pollution scavenger. All expressed proteins were aggregated in an inactive inclusion body, which might be due to inherent disulfide bonds. Active enzyme was obtained by refolding with glutathione-mediated oxidation in refolding solution containing $Ca^{2+}$, heme, and urea. Propeptide-sequence region was not processed as evidenced by N-terminal sequence analysis. Recombinant Lip H2 (rLip H2) had the same physical properties of the native protein but differed in the $K_{cat}$. Catalytic efficiency ($k_{cat}/K_m$) of rLip H2 was slightly higher than that of the native enzyme. In order to express an active protein, fusion systems with thioredoxin or Dsb A, which have disulfide isomerase activity, were used. The fused proteins expressed by the Dsb A fusion vector were aggregated, whereas half of the thioredoxin fusion proteins were recovered as a soluble form but still catalytically inactive. These results suggest that Lip H2 may not be expressed as an active enzyme in Escherichia coli although the activity can be recovered by in vitro refolding.

• BMB Reports
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• v.39 no.1
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• pp.84-90
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• 2006

During our search for macrophage stimulating compounds from medicinal plants, we isolated biopolymers from Acanthopanax sessiliflorus. Isolated fraction AS-5 showed maximum potential, and stimulated lysosonal enzymatic activity by 230% at $300\;{\mu}g/ml$. The nitric oxide (NO) producing ability of AS-5 $100\;{\mu}g/ml$ was $58\;{\mu}M$ when treated with interferon-$\gamma$ and lipopolysaccharide $20\;{\mu}g/ml$. The lymphocyte proliferating effects of isolated biopolymer fractions were also investigated. Highest lymphoproliferative activity (a 2.8-fold enhancement compared to saline treated group was exhibited by AS-3 at $200\;{\mu}g/ml$ followed by AS-5 and AS-6. The AS-3 fraction stimulated only T-lymphocytes and had little or no effect on B-lymphocyte proliferation. Partially methylated alditol acetates were prepared to elucidate the glycosyl linkage-compositions of the AS-3 and AS-5 biopolymers, and were analyzed by GC-MS. The AS-3 and AS-5 biopolymer fractions were found to contain 2,3,4-tri-O-methyl-D-glucitol, 2,3,4-tri-O-methyl-D-galacitol 3,4,6-tri-O-methyl-galacitol, 2-O-methyl-arabinitol and 2,4,6-tri-O-methyl-D-glucitol, 2,3,6-tri-O-methyl-D-galacitol linkages, respectively.

• BMB Reports
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• v.39 no.4
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• pp.426-431
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• 2006

Embryonic stem cells (ESCs), representing a population of undifferentiated pluripotent cells with both self-renewal and multilineage differentiation characteristics, are capable of spontaneous differentiation into cardiomyocytes. The present study sought to define the kinetic characterization of lactate dehydrogenase (LDH) and creatine kinase (CK) of ESC- and neonatal-derived cardiomyocytes. Spontaneously differentiated cardiomyocytes from embryoid bodies (EBs) derived from mouse ESC line (Royan B1) and neonatal cardiomyocytes were dispersed in a buffer solution. Enzymes were extracted by sonication and centrifugation for kinetic evaluation of LDH and CK with spectrophotometric methods. While a comparison between the kinetic properties of the LDH and CK of both groups revealed not only different Michaelis constants and optimum temperatures for LDH but also different Michaelis constants and optimum pH for CK, the pH profile of LDH and optimum temperature of CK were similar. In defining some kinetic properties of cardiac metabolic enzymes of ESC-derived cardiomyocytes, our results are expected to further facilitate the use of ESCs as an experimental model.

• BMB Reports
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• v.45 no.11
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• pp.653-658
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• 2012

After the outbreak of the swine-origin influenza A H1N1 virus in April 2009, World Health Organization declared this novel H1N1 virus as the first pandemic influenza virus (2009 pH1N1) of the $21^{st}$ century. To elucidate the characteristics of 2009 pH1N1, the growth properties of A/Korea/01/09 (K/09) was analyzed in cells. Interestingly, the maximal titer of K/09 was higher than that of a seasonal H1N1 virus isolated in Korea 2008 (S/08) though the RNP complex of K/09 was less competent than that of S/08. In addition, the NS1 protein of K/09 was determined as a weak interferon antagonist as compared to that of S/08. Thus, in order to confine genetic determinants of K/09, activities of two major surface glycoproteins were analyzed. Interestingly, K/09 possesses highly reactive NA proteins and weak HA cell-binding avidity. These findings suggest that the surface glycoproteins might be a key factor in the features of 2009 pH1N1.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.746-752
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• 2014

Photo electrode is an important component of DSSC, so this paper did some research on it. Through the method of adding PEG additive into $TiO_2$ paste, the electrical characteristics and efficiencies of DSSCs with photo electrode surface area were studied. In the case of not adding PEG in $TiO_2$ paste, $26{\mu}m$ thickness $TiO_2$ photo electrode shows 5.081% efficiency. The highest short circuit current density was $10.476mA/cm2^$. The structure of porous $TiO_2$ film can be controlled through changing the PEG additive amount in $TiO_2$ paste and the molecular weight of PEG. When the additive amount of PEG 20,000 in $TiO_2$ paste reaches 5%, the peak efficiency with $26{\mu}m$ thickness $TiO_2$ photo electrode was 5.387% and its highest current density were $11.084mA/cm^2$.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.311-316
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• 2012

Fusarium root disease can be a serious problem in forest and conservation nurseries in the western United States. Fusarium inoculum is commonly found in most container and bareroot nurseries on healthy and diseased seedlings, in nursery soils, and on conifer seeds. Fusarium spp. within the F. oxysporum species complex have been recognized as pathogens for more than a century, but attempts to distinguish virulence by correlating morphological characteristics with results of pathogenicity tests were unsuccessful. Recent molecular characterization and pathogenicity tests, however, revealed that selected isolates of F. oxysporum are benign on Douglas-fir (Pseudotsuga menziesii) seedlings. Other morphologically indistinguishable isolates, which can be virulent, were identified as F. commune, a recently described species. In a replicated greenhouse study, inoculating Douglas-fir seedlings with one isolate of F. oxysporum prevented expression of disease caused by a virulent isolate of F. commune. Moreover, seedling survival and growth was unaffected by the presence of the F. oxysporum isolate, and this isolate yielded better biological control than a commercial formulation of Bacillus subtilis. These results demonstrate that an isolate of nonpathogenic F. oxysporum can effectively reduce Fusarium root disease of Douglas-fir caused by F. commune under nursery settings, and this biological control approach has potential for further development.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.568-574
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• 1998

Two types of chitosanases produced from Aspergillus fumigatus KH-94 were purified by ion exchange and gel permeation chromatography. Molecular weights of the enzymes are 22.5 kDa (chitosanase I) and 108 kDa (chitosanase II). pI, optimum pH, and temperature of chitosanase I are 7.3, 5.5, and 70-$80^{\circ}C$, respectively, and those of chitosanase II are 4.8, 4.5~5.5, and 50~$60^{\circ}C$, respectively. Activities of both chitosanases were increased by $Mn^{2+}$ but inhibited by $Cu^{2+}$ and $Hg^{2+}$ . Chitosanase I has endo-splitting activity that hydrolyzes chitopentaose, chitohexaose, and chitosan to chitobiose, chitotriose, and chitotetraose, whereas chitosanase II has exo-splitting activity that hydrolyzes chitobiose and chitosan to glucosamine. Chitosanase II was found to have transglycosylation activity also in the reaction of 2% more chitooligosaccharides as a substrate and at the initial reaction. The higher degree of deacetylation, the stronger activities of chitosanase Iand II toward chitosans. Both chitosanases could hydrolyze chitosan and glycol chitosan but not chitin, cellulose, and carboxymethyl cellulose. To produce higher degree of polymerization of chitooligosaccharides, chitosanase I was used and yielded 80% of recovery.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.10-16
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• 2009

Polymerase chain reactin (PCR) could be a simple way to screen new microbial strains producing useful secondary metabolites if their biosynthetic genes are known and candidate strains to be screened are available. In this study, we have screened two myxobacterial strains, KYC3047 and KYC3076, carrying genes appeared to be biosynthetic genes of soraphen A, a potent antifungal substance, out of 50 cellulose degrading myxobacteria using PCR. The two strains were identified as Sorangium cellulosum based on morphological, physiological, and molecular biological characteristics. Both of the strains produced substances having strong antifungal activities as expected against Candida albicans, a causative agent of candidiasis, and Colletotrichum acutatum, a causative agent of anthracnose on pepper.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1016-1023
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• 2008

Lichens are predominant and important components of flora in the terrestrial ecosystem of Antarctica. However, relatively few researches on the phylogenetic position of Antarctic lichen-forming fungi have been accomplished. In this study, partial sequences of nuclear large subunit rDNAs from 50 Antarctic specimens were obtained and the phylogeny was reconstructed. Antarctic lichen species were distributed in 4 orders, including the monophyletic order Agyrales, paraphyletic orders Pertusariales and Teloschistales, and polyphyletic order Lecanorales. Species diversity was highest in the order Lecanorales, followed by Teloschistales and Pertusariales. Based on the phylogeny and sequence similarity analyses, it is proposed that the taxonomy of Stereocaulon alpinum, Physcia caesia, Usnea aurantiacoatra, and Cladonia species should be revised by careful examination of their phenotypic and molecular characteristics. Six species known to be endemic to Antarctica, Catillaria corymbosa, Himantormia lugubris, Leptogium puberulum, Pertusaria pertusa, Rhizoplaca aspidophora, and Umbilicaria antarctica, formed unique lineages, implying independent origins in the Antarctic area.

• Environmental Engineering Research
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• v.11 no.5
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• pp.266-276
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• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.