• 한국식품영양과학회지
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• 제43권3호
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• pp.349-354
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• 2014

세포내 $Ca^{{+}{+}}$의 증가는 비만세포에서 수용체 활성을 거치지 않고 탈과립을 유도한다. 괴화는 천연 염색 재료로 사용되고 있으며, 또한 항염증 작용과 $Fc{\varepsilon}RI$와 IgE 가교에 의한 항알레르기 효능도 보고되었다. 이번 연구에서 비만세포에서 $Ca^{{+}{+}}$ 유입에 의해 생산되는 알레르기 매개물에 대한 괴화 추출물의 조절 기능을 보고한다. 괴화 추출물은 A23187에 의해 유도되는 IL-4와 TNF-${\alpha}$의 생산과 탈과립을 저해하였다. 또한 괴화 추출물은 DNFB로 유도한 알레르기 피부염의 동물 모델에서 알레르기 반응을 억제하였다. 괴화추출물 50 mg/kg을 경구투여 또는 도말을 한 경우, DNFB를 단독으로 처리한 군보다 IL-4, TNF 그리고 IFN-${\gamma}$와 같은 염증성 사이토카인의 생산량이 감소하였다. 또한 괴화 추출물을 처리한 경우 혈청 내 IgE의 함량이 DNFB를 단독으로 처리한 군보다 감소하였다. 괴화 추출물을 처리한 군에서의 비장과 림프절의 무게도 DNFB를 단독으로 처리한 군보다 감소하였다. 이러한 결과를 토대로 괴화는 비만세포에서 $Fc{\varepsilon}RI$ 자극뿐만 아니라 $Ca^{{+}{+}}$의 유입에 의한 항알레르기 효능이 있다는 것을 보고한다.

• Molecules and Cells
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• 제42권6호
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• pp.460-469
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• 2019

Bacterial ${\alpha}-type$ carbonic anhydrase (${\alpha}-CA$) is a zinc metalloenzyme that catalyzes the reversible and extremely rapid interconversion of carbon dioxide to bicarbonate. In this study, we report the first crystal structure of a hyperthermostable ${\alpha}-CA$ from Persephonella marina EX-H1 (pmCA) in the absence and presence of competitive inhibitor, acetazolamide. The structure reveals a compactly folded pmCA homodimer in which each monomer consists of a 10-stranded ${\beta}-sheet$ in the center. The catalytic zinc ion is coordinated by three highly conserved histidine residues with an exchangeable fourth ligand (a water molecule, a bicarbonate anion, or the sulfonamide group of acetazolamide). Together with an intramolecular disulfide bond, extensive interfacial networks of hydrogen bonds, ionic and hydrophobic interactions stabilize the dimeric structure and are likely responsible for the high thermal stability. We also identified novel binding sites for calcium ions at the crystallographic interface, which serve as molecular glue linking negatively charged and otherwise repulsive surfaces. Furthermore, this large negatively charged patch appears to further increase the thermostability at alkaline pH range via favorable charge-charge interactions between pmCA and solvent molecules. These findings may assist development of novel ${\alpha}-CAs$ with improved thermal and/or alkaline stability for applications such as $CO_2$ capture and sequestration.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.388-396
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• 2023

Entamoeba histolytica is an enteric tissue-invasive protozoan parasite causing amoebic colitis and liver abscesses in humans. Amoebic contact with host cells activates intracellular signaling pathways that lead to host cell death via generation of caspase-3, calpain, Ca²⁺ elevation, and reactive oxygen species (ROS). We previously reported that various NADPH oxidases (NOXs) are responsible for ROS-dependent death of various host cells induced by amoeba. In the present study, we investigated the specific NOX isoform involved in ROS-dependent death of hepatocytes induced by amoebas. Co-incubation of hepatoma HepG2 cells with live amoebic trophozoites resulted in remarkably increased DNA fragmentation compared to cells incubated with medium alone. HepG2 cells that adhered to amoebic trophozoites showed strong dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, suggesting intracellular ROS accumulation within host cells stimulated by amoebic trophozoites. Pretreatment of HepG2 cells with the general NOX inhibitor DPI or NOX2-specific inhibitor GSK 2795039 reduced Entamoeba-induced ROS generation. Similarly, Entamoeba-induced LDH release from HepG2 cells was effectively inhibited by pretreatment with DPI or GSK 2795039. In NOX2-silenced HepG2 cells, Entamoeba-induced LDH release was also significantly inhibited compared with controls. Taken together, the results support an important role of NOX2-derived ROS in hepatocyte death induced by E. histolytica.

• 한국재료학회지
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• 제27권3호
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• pp.155-160
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• 2017

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

• 한국세라믹학회지
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• 제49권2호
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• pp.197-203
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• 2012

In this study, in order to improve densification of $La_{0.8}Ca_{0.2}Cr_{0.9}Co_{0.1}O_{3-\delta}$ (LCCC), which is known for one of the most proper candidate interconnector materials in the solid oxide fuel cells, $CaCrO_4$ was prepared via solid oxide synthesis route and added to the LCCC with different amount and particle sizes. As the amount of the $CaCrO_4$ increased, porosity of the sintered samples increased, and the pore size was proportional to the particle size of the $CaCrO_4$. This supports the fact that the $CaCrO_4$ phase forms liquid during sintering and permeate into the matrix leaving behind large pores. Then the liquid reacts with the matrix through the solid solution. However, when the samples were sintered with a slow ramp up rates, the porosity decreased. This is thought to be caused by the progressive solid solution of $CaCrO_4$ before the temperature reach to the melting temperature and forms a fluent amount of liquids. The sintering behavior of the LCCC with the addition of $CaCrO_4$ was analyzed through the transient liquid phase sintering on the basis of the microstructure observation and phase identification by x-ray diffraction.

• 생명과학회지
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• 제25권3호
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• pp.269-275
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• 2015

생체에서 가장 많은 비율로 분포하고 있는 콜라겐 펩타이드는 동물의 뼈와 해양 생물의 비늘에 많이 함유되어 있다. 콜라겐은 동물 생체의 여러 결합조직에서 구조 단백질로 흔하게 발견된다. 또한, 이들은 생물 의료 자재, 제약, 화장품, 식품 및 가죽 산업에 널리 이용된다. 각종 어류 비늘에서 추출된 펩타이드는 UVB 조사에 의해 유도된 피부의 손상 및 광 노화에 대한 보호 효과가 있었다. 그럼에도 불구하고, UVB 조사에 대한 옥돔 비늘 유래의 펩타이드 특성은 명확히 알려져 있지 않다. 이 연구에서는 옥돔 비늘 추출물에서 분리된 1 kDa 이상(HMP)과 1 kDa 이하(LMP)의 펩타이드를 이용하여 UVB 조사에 의해 유도된 피부 손상과 광 노화에 대한 효과를 연구하였다. 이들 펩타이드는 농도 의존적으로 DPPH 라디칼 소거능을 보였으며 LMP는 HaCaT 인간 피부세포에서 UVB 조사에 의해 유도된 세포 지질 과산화 산물인 8-isoprostane 생성을 억제하였다. 그리고 LMP와 HMP는 B16F10 마우스 흑색종 세포에서 tyrosinase 활성 및 melanin 함량을 감소시켰으며 또한 HaCaT 세포에서 UVB로 유도된 elastase 활성을 감소시켰고 matrix metalloproteinase-1의 활성을 감소시켰다. 이러한 결과는 옥돔 비늘에서 유래된 펩타이드가 미백효과, 항산화제 및 광 노화 억제제로서 유용한 물질이 될 것으로 기대된다.

• Biomolecules & Therapeutics
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• 제19권2호
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• pp.211-217
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• 2011

Panax ginseng CA Meyer, a herb from the Araliaceae, has traditionally been used as a medicinal plant in Asian countries. Ginseng extract fermented by ginsenoside-${\beta}$-glucosidase treatment is enriched in ginsenosides such as Rh2 and Rg3. Here we show that a fermented ginseng extract, BST204, has anti-proliferative and anti-invasive effects on HT-29 human colon cancer cells. Treatment of HT-29 cells with BST204 induced cell cycle arrest at $G_1$ phase without progression to apoptosis. This cell cycle arrest was accompanied by up-regulation of tumor suppressor proteins, p53 and p21$^{WAF1/Cip1}$, down-regulation of the cyclin-dependent kinase/cyclins, Cdk2, cyclin E, and cyclin D1 involved in $G_1$ or $G_1/S$ transition, and decrease in the phosphorylated form of retinoblastoma protein. In addition, BST204 suppressed the migration of HT-29 cells induced by 12-O-tetradecanoylphorbol-13-acetate, which correlated with the inhibition of metalloproteinase-9 activity and extracellular signal-regulated kinase activity. The effects of BST204 on the proliferation and the invasiveness of HT-29 cells were similar to those of Rh2. Taken together, the results suggest that fermentation of ginseng extract with ginsenoside-${\beta}$-glucosidase enhanced the anti-proliferative and the anti-invasive activity against human colon cancer cells and these anti-tumor effects of BST204 might be mediated in part by enriched Rh2.

• Journal of Electrochemical Science and Technology
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• 제11권2호
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• pp.187-194
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• 2020

Two types of sodium cobalt pyrophosphates, triclinic Na_3.12Co_2.44(P₂O₇)₂ and orthorhombic Na₂CoP₂O₇, are compared as high-voltage cathode materials for Na-ion batteries. Na₂CoP₂O₇ shows no electrochemical activity, delivering negligible capacity. In contrast, Na_3.12Co_2.44(P₂O₇)₂ exhibits good electrochemical performance, such as high redox potential at ca. 4.3 V (vs. Na/Na⁺) and stable capacity retention over 50 cycles, although Na_3.12Co_2.44(P₂O₇)₂ delivered approximately 40 mA h g^-1. This is attributed to the fact that Na₂CoP₂O₇ (~3.1 Å) has smaller diffusion channel size than Na_3.12Co_2.44(P₂O₇)₂ (~4.2 Å). Moreover, the electrochemical performance of Na_3.12Co_2.44(P₂O₇)₂ is examined using Na cells and Li cells. The overpotential of Na cells is smaller than that of Li cells. This is due to the fact that Na_3.12Co_2.44(P₂O₇)₂ has a smaller charge transfer resistance and higher diffusivity for Na⁺ ions than Li⁺ ions. This implies that the large channel size of Na_3.12Co_2.44(P₂O₇)₂ is more appropriate for Na⁺ ions than Li⁺ ions. Therefore, Na_3.12Co_2.44(P₂O₇)₂ is considered a promising high-voltage cathode material for Na-ion batteries, if new electrolytes, which are stable above 4.5 V vs. Na/Na⁺, are introduced.

• 동의생리병리학회지
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• 제36권4호
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• pp.125-129
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• 2022

The purpose of study is to evaluate in vitro anti-oxidant and anti-inflammatory effects of Moringa Folium and Eucommiae Cortex 2:1 (g/g) mixtures (MEMix). HaCaT and human normal dermal fibroblast were treated with 0.01-1 mg/mL of MEMix to monitor cytotoxicity. Radical scavenging activities of MEMix were examined by DPPH assay. To explore anti-inflammatory effect, Raw 264.7 cells were pretreated with MEMix for 1h and subsequently exposed to LPS for 18h. NO release and cytotoxicity of Raw 264.7 cells were measured by adding Griess and MTT reagents, respectively. TNF-α, IL-1β, IL-6, and PGE2 productions were examined by ELISA. Immunoblot analysis was conducted to examine COX-2 expression in MEMix pretreated Raw 264.7 cells. Up to 1 mg/mL concentration, treatment of MEMix for 24 h did not affect normal dermal fibroblast viability and significantly reduced cell viability of HaCaT cells with no concentration dependency. MEMix increased DPPH radical scavenging activity with concentration dependency. Radical scavenging activities by 1 mg/mL of MEMix was comparable with 30 µM of trolox. Pretreatment of MEMix did not change the reduction of Raw 264.7 cell viability. Exposure of LPS in Raw 264.7 cells significantly increased NO, TNF-α, IL-1β, IL-6, and PGE2 productions, and MEMix pretreatment attenuated these productions by LPS concentration dependently. However, pretreatment with MEMix did not change COX-2 expression by LPS in Raw 264.7 cells. MEMix showed in vitro anti-oxidant and anti-inflammatory activities. MEMix would be useful candidate agent against inflammation.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.404-416
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• 2020

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO₃) formation. Irregular vaterite-like CaCO₃ minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO₃ around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO₃^2- ions in the CaCO₃ were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.