• Molecules and Cells
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• v.41 no.4
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• pp.301-310
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• 2018

LysR-type transcriptional regulators (LTTRs) contain an N-terminal DNA binding domain (DBD) and a C-terminal regulatory domain (RD). Typically, LTTRs function as homotetramers. VV2_1132 was identified in Vibrio vulnificus as an LTTR that is a homologue of HypT (also known as YjiE or QseD) in Escherichia coli. In this study, we determined the crystal structure of full-length VV2_1132 at a resolution of $2.2{\AA}$, thereby revealing a novel combination of the domains in the tetrameric assembly. Only one DBD dimer in the tetramer can bind to DNA, because the DNA binding motifs of the other DBD dimer are completely buried in the tetrameric assembly. Structural and functional analyses of VV2_1132 suggest that it might not perform the same role as E. coli HypT, indicating that further study is required to elucidate the function of this gene in V. vulnificus. The unique structure of VV2_1132 extends our knowledge of LTTR function and mechanisms of action.

• Journal of fish pathology
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• v.20 no.3
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• pp.307-313
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• 2007

In this study, a QCM biosensor was made to detect Edwardsiella tarda (E. tarda) using a specific antibody. A 9 MHz AT-cut piezoelectric wafer layered with two gold electrodes of 5mm diameter had a reproducibility of 0.1 Hz in frequency response and was used as the transducer of the QCM biosensor. Self assembled layer (SAM) was conformed on a quartz crystal by treating with 3-mer-captopropionic acid (MPA) and activated with N-ethyl-N'-(3-dimethyl-aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The resulting NHS group was further converted to hydrazide by the reaction with hydrazine. Aldehyde group was introduced into the carbohydrate moiety of anti-E. tarda antibody by the reaction with periodic acid and was used to immobilise the antibody through the reaction with hydrazide group on the electrode surface. A baseline was established in the presence of phosphate-buffered saline (PBS) and a resonant frequency (F1) was measured. Sample was added to the sensor surface and second resonant frequency (F2) was measured after unbound substances were washed out with PBS several times. Finally, the frequency shift (ΔF) representing the mass change was calculated by subtracting F2 from F1. After adding the oxidized anti-E. tarda antibody to the electrode surface containing hydrazide group, frequency shift of 288.811.4 Hz (mean S.E) was observed, thus proving that considerable amount of antibody was immobilized. In the immunoassay test, the frequency shift of 1877.75 Hz, 580.67 Hz, 221.39 Hz, 7.671.83 Hz (mean S.E) were observed at doses of 1000, 500, 100, 50 g of bacterial cells, respectively. It was also demonstrated that the prepared sensor chip was stable enough to withstand repeated surface regeneration with 0.2 M Tris-glycine and 1 % DMSO, pH 2.3 more than ten times.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.139-148
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• 2010

A virus causing stunt, yellowing, severe mosaic, malformation symptoms on leaves and uneven development and malformation on fruits of zucchini was prevalent around Goseong, Gyeongsangnam-do, Korea. A survey conducted (2004) in the Goseong area revealed about 20% virus infection rate. The disease causative identified as Cucumber mosaic virus (CMV-Z1) was further characterized. The isolate induces mosaic symptoms on Cucumis sativus, while severe mosaic, stunt and malformation on C. pepo. Thin section analyses have shown that virus inclusions are formed in the cuticle layers as well as epidermal, parenchyma and collenchymas cells in virus-infected Nicotiana tabacum. CMV-Z1 isolate induced specific cytoplasmic inclusion bodies such as irregular clumps (IC), crystal (Cr) and irregular chloroplasts (ICh). IC was made up of virus particles interspersed with a darkly stained amorphous material and found both in the cytoplasm and vacuoles, whereas ICh and Cr were rarely found in the vacuoles. The genome of CMV-Z1 RNA-1 consists of 3359 nucleotide (nt) encoding 1a protein of 993 amino acids (aa). The CMV-Z1 RNA-2 was 3050 nt in length containing 2a (857 aa) and 2b (110 aa), while RNA-3 encoding 3a movement protein (279 aa) and coat protein (218 aa) was 2215 nt in length. Phylogenetic analyses of nucleotide sequences of CMV-Z1 isolate appeared it is more closely related to subgroup IA than to subgroup IB or II.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.35.1-35.1
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• 2011

New photovoltaic (PV) materials and manufacturing approaches are needed for meeting the demand for lower-cost solar cells. The prototypal thin-film photovoltaic absorbers (CdTe and $Cu(In,Ga)Se_2$) can achieve solar conversion efficiencies of up to 20% and are now commercially available, but the presence of toxic (Cd,Se) and expensive elemental components (In, Te) is a real issue as the demand for photovoltaics rapidly increases. To overcome these limitations, there has been substantial interest in developing viable alternative materials, such as $Cu_2ZnSnS_4$ (CZTS) is an emerging solar absorber that is structurally similar to CIGS, but contains only earth abundant, non-toxic elements and has a near optimal direct band gap energy of 1.4~1.6 ev and a large absorption coefficient of ${\sim}10^4\;cm^{-1}$. The CZTS absorber layers are grown and investigated by various fabrication methods, such as thermal evaporation, e-beam evaporation with a post sulfurization, sputtering, non-vacuum sol-gel, pulsed laser, spray-pyrolysis method and electrodeposition technique. In the present work, we report an alternative method for large area deposition of CZTS thin films that is potentially high throughput and inexpensive when used to produce monolithically integrated solar panel modules. Specifically, we have developed an aqueous chemical approach based on chemical bath deposition (CBD) with a subsequent sulfurization heat treatment. Samples produced by our method were analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, absorbance and photoluminescence. The results show that this inexpensive and relatively benign process produces thin films of CZTS exhibiting uniform composition, kesterite crystal structure, and good optical properties. A preliminary solar cell device was fabricated to demonstrate rectifying and photovoltaic behavior.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.33.1-33.1
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• 2011

Strontium doped lanthanum manganite (LSM) with perovskite structure for SOFC cathode material shows high electrical conductivity and good chemical stability, whereas the electrical conductivity at intermediate temperature below $800^{\circ}C$ is not sufficient due to low oxygen ion conductivity. The approach to improve electrical conductivity is to make more oxygen vacancies by substituting alkaline earths (such as Ca, Sr and Ba) for La and/or a transition metal (such as Fe, Co and Cu) for Mn. Among various cathode materials, $LaSrMnCuO_3$ has recently been suggested as the potential cathode materials for solid oxide fuel cells (SOFCs). As for the Cu doping at the B-site, it has been reported that the valence change of Mn ions is occurred by substituting Cu ions and it leads to formation of oxygen vacancies. The electrical conductivity is also affected by doping element at the A-site and the co-doping effect between A-site and B-site should be described. In this study, the $La_{1-x}Sr_xMn_{0.8}Cu_{0.2}O_{3{\pm}{\delta}}$ ($0{\leq}x{\leq}0.4$) systems were synthesized by a combined EDTA-citrate complexing process. The crystal structure, morphology, thermal expansion and electrical conductivity with different Sr contents were studied and their co-doping effects were also investigated.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.308-313
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• 2001

The purpose of this study is to validate the potential etiologic factors for temporomandibular disorder(TMD). TMJ arthroscopic examination was performed in upper joint compartment of 32 joints from 20 patients with mandibular fractures. Synovial fluid was collected from the upper joint space during pumping manipulation with normal saline. Cytologic smearing and histomorphologic exam of synovial fluid were performed in 15 joints. Prostaglandin $E_2(PGE_2)$ concentration was measured in 11 joints. Leukotriene $B_4(LTB_4)$ concentration was measured in 8 joints. There were several arthroscopic variables such as ecchymosis, fibrillation, and adhesion. Histomorphologic exam showed a variety of findings such as bloody smears, cellular cluster, degenerated cells and cartilage, undifferentiated crystal. Mean $PGE_2$ concentrations were 316.5 pg/ml. Mean LTB4 concentrations were 45.9pg/ml. This study demonstrated a variety of findings on inflammatory and degenerative changes of TMJ. Because acute trauma such as mandibular fracture is a major etiologic factor in cartilage degradation and biochemical and intraarticular pathology, clinicians must identify and address TMJ signs and symptoms during follow-up periods in the long term.

• Natural Product Sciences
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• v.3 no.2
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• pp.81-88
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• 1997

NAD(P)H:quinone reductase (QR) is one of the protective phase II enzymes against toxicity that accomplishes the capacity of detoxification by modulating the effects of mutagens and carcinogens. The detoxification mechanism is that quinone reductase promotes the 2-electron reduction of quinones to hydroquinones which are less reactive. This study is to search new inducers of quinone reductase from natural products, which can be used as cancer chemopreventive agents. Plant extracts were evaluated by using quinone reductase generating system With Hepa 1c1c7 murine hepatoma cell lines for enzyme inducing properties and crystal violet staining method for the measurement of cytotoxicity provoked. We have tested approximately 106 kinds of natural products after partition into n-hexane, ethyl acetate and aqueous layers from 100% methanol extracts of natural products. The ethyl acetate fractions of Vitex rotundifolia $(fruits,\;2FC:\;12.7\;{\mu}g/ml)$, Cnidium officinale $(aerial\;parts,\;2FC:\;10.5\;{\mu}g/ml)$, Chrysanthemum sinese $(flowers,\;2FC:\;17.4{\mu}g/ml)$ and the hexane fractions of Angelica gigas $(roots,\;2FC:\;13.2\;{\mu}g/ml)$, Smilax china $(roots,\;2FC:\;l1.9\;{\mu}g/ml)$, Sophora flavescens $(roots,\;2FC:\;16.3\;{\mu}g/ml)$ revealed the significant induction of quinone reductase in a murine hepatic Hepa 1c1c7 cell culture system.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.116.1-116.1
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• 2011

Materials with a combination of high electrical conductivity and optical transparency are important components of many electronic and optoelectronic devices such as liquid crystal displays, solar cells, and light emitting diodes. In this study, to fabricate a low-resistance and high optical transparent electrode film for organic photovoltaic, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll imprinted (TRI) poly-carbonate (PC) patterned films, the manufacture of high-conductivity and low-resistance Ag paste which was filled into patterned PC film using a doctor blade process and then coated with a thin film layer of conductive polymer by a spin coating process. As a result of these imprinting processes the PC films obtained a line width of $10{\pm}0.5{\mu}m$, a channel length of $500{\pm}2{\mu}m$, and a pattern depth of $7.34{\pm}0.5{\mu}m$. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of $9.65{\Omega}$/sq, optical transparency values were 83.69 % at a wavelength of 550 nm.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.710-715
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• 2005

A novel recombinant baculovirus, Bactrus, was constructed by the insertion of the Bacillus thuringiensis cry1Ac gene between two polyhedrin genes of Autographa californica nucleopolyhedrovirus (AcNPV) under the control of the polyhedrin gene promoter. Polyhedra produced by Bactrus in insect cells were incorporated with 130 kDa of polyhedrin-Cry1Ac-polyhedrin fusion protein, and 30 kDa of intact polyhedrin, resulting from a homologous recombination between two polyhedrin genes, was also expressed. The insecticidal activity of Bactrus against Spodoptera exigua larvae was similar to that of AcNPV, but it showed significantly higher toxicity towards Plutella xylostella larvae in comparison with that of AcNPV. The expression level of fusion protein and the insecticidal activity of recombinant polyhedra produced by the Bactrus against P. xylostella larvae were decreased after serial passages. In conclusion, the Bactrus had improved insecticidal activity and returned to wild-type AcNPV after several passages.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.439-447
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• 2018

The aromatic compound p-hydroxybenzoate (PHBA) is an important material with multiple applications, including as a building block of liquid crystal polymers in chemical industries. The cytochrome P450 (CYP) enzymes are beneficial monooxygenases for the synthesis of chemicals, and CYP53A15 from fungus Cochliobolus lunatus is capable of executing the hydroxylation from benzoate to PHBA. Here, we constructed a system for the bioconversion of benzoate to PHBA in Escherichia coli cells coexpressing CYP53A15 and human NADPH-P450 oxidoreductase (CPR) genes as a redox partner. For suitable coexpression of CYP53A15 and CPR, we originally constructed five plasmids in which we replaced the N-terminal transmembrane region of CYP53A15 with a portion of the N-terminus of various mammalian P450s. PHBA productivity was the greatest when CYP53A15 expression was induced at $20^{\circ}C$ in $2{\times}YT$ medium in host E. coli strain ${\Delta}gcvR$ transformed with an N-terminal transmembrane region of rabbit CYP2C3. By optimizing each reaction condition (reaction temperature, substrate concentration, reaction time, and E. coli cell concentration), we achieved 90% whole-cell conversion of benzoate. Our data demonstrate that the described novel E. coli bioconversion system is a more efficient tool for PHBA production from benzoate than the previously described yeast system.