• Journal of Life Science
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• v.23 no.10
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• pp.1223-1229
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• 2013

Ursolic acid (UA) a bio-active ingredient found in a variety of fruits and vegetables, and it has potent antioxidant activity. However, the role of UA in mouse embryonic stem (ES) cells is poorly understood. This study investigated the functional role of UA in regulating the development of mouse ES cells under hypoxia. Hypoxia did not exert a significant effect on the undifferentiated state of mouse ES cells. However, it induced reactive oxygen species (ROS) generation and increased the level of lactate dehydrogenase (LDH) production at 48 h of hypoxic exposure. Conversely, oxidative stress induced by hypoxia was significantly inhibited by UA ($30{\mu}M$) pretreatment. Hypoxia significantly decreased cell survival and the level of [$^3H$] thymidine incorporation, both of which recovered following pretreatment of UA. In addition, UA decreased the apoptotic effect of hypoxia by attenuating caspase-3 cleavage or by recovering cellular inhibition of the apoptotic protein (cIAP)-2 and Bcl-2 expression. We further found that UA decreased senescence-associated beta-galactosidase activity. We suggest that UA is a natural antioxidant and one of the functional modulators of hypoxia-induced survival, apoptosis, proliferation, and aging in mouse ES cells.

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.198-205
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• 2004

Cytochrome P4501B1(CYP1B1) is known to be inducible by xenobiotic compounds such as policyclic aromatic hydrocarbon(PAH) and dioxins such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). And these induction of CYP1B1 is also regulated by many categories of chemicals. In order to investigate the effects of several chemicals on CYP1B1 gene expression in Hepa-I and MCF-7 cells, 5' flanking DNA of human CYP1B1 was cloned into pGL3 basic vector containing luciferase gene, and then transfected into these cells. After treatment of chemicals, the luciferase activity was measured. CYP1B1 enzyme metabolize PAHs and estradiol. CYP1B1 metabolize estradiol to 4-hydrozyestradiol that is considered as carcinogenic metabolite. Recent industrialized industrialized society, human has been widely been exposed to widespread environmental contaminants such as PAHs(polycyclic aromatic hydrocarbon) that are originated from the imcomplete combustion of hydrocarbons. PAHs are known to be ligands of the AhR(aryl hydrocarbon receptor). Induction of cytochrome P4501B1(CYP1B1) in cell culture is widely used as a biomarker for PAHs. Therefore we have studied the effect of PAHs in the human breast cancer cells MCF-7 to evaluate bioactivity of PAHs. We have used the United State of America EPA selected 13 different PAHs, PAHs mixtures and extracts from environmental samples to evaluate the bioassay system. We examined effects of PAHs on the CYP1B1-luciferase reporter gene and CYP1B1 mRNA level. Benzo(k)fluoranthene and dibenzo(a, h)anthracene showed strong response to CYP1B1 promoter activity stimulation, and also CYP1B1 mRNAs increase in MCF-7 cells in a concentration-dependent manner. RT-PCR analysis indicated that PAHs significantly up-regulate the level of CYP1B1 mRNA. Some flavonoids such as genistein, daidzein, chrysin, naringenin and morin were also investigeted. These flavonoids decreased B(k)F infuced luciferase activity at low concentration. But, these flavonoids exhibited stimulatory effect at high concentration.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.429-447
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• 1996

Transforming growth factor $-{\beta}$ is one of the polypeptide growth factors that mediate the activity of mesenchymal cells and regulate wound healing process via cell proliferation, migration and extracellular matrix formation. The purposes of this study is to evaluate the effects of transforming growth factor $-{\beta}$ on the protein synthetic activity of human periodontal ligament cells and human gingival fibroblasts. The cells which were prepared were primary cultured gingival fibroblasts and periodontal ligament cells from humans, and the fourth or sixth subpassage were used in the experiments. Cells were seeded and at a confluent state, 0, 0.5, I, 2.5, 5, 10 ng/ml $TGF-{\beta}$ and $2{\mu]Ci/ml\;[^3H]$ proline were added to the cells and cultured for 24 hours. Then, 1 and 5 ng/ml concentrations were selected and added to confluent cells and cultured for 24 and 48 hours. They were labeled with $2{\mu}Ci/ml\;[^3H]$ proline for 24 hours and a collagen assay was done by the Peterkofsky and Diegelman method. The results were presented as the mean disintegration per minute (dpm) per well and S.D. of four determinations, The results were as follows. : The total protein, collagen and noncollagenous protein synthesis in periodontal ligament cells and gingival fibroblasts were increased dose- dependently by transforming growth factor-p to 2.5-5 ng/ml concentration and decreased at 10 ng/ml concentration. The percent of collagen was slightly changed according to the concentration of transforming growth factor-po The effect of transforming growth $factor-{\beta}$ was not specific for collagen synthesis since it increased the total, noncollagenous and collagenous protein, simultaneously. In the comparison of protein synthetic activity between the human periodontal ligament cells and human gingival fibroblasts, the human gingival fibroblasts had higher activities than the human periodontal ligament cells at all times and concentrations of $TGF-{\beta}$. In the comparison of protein synthetic activity between the 24 hour effect and the 48 hour effect of $TGF-{\beta}$, the 48 hour cultured cells' synthetic activity decreased more than the 24 hour cultured cells at human periodontal ligament cells and human gingival fibroblasts. In conclusion, $TGF-{\beta}$ has important roles in the stimulation of protein synthesis in human periodontal ligament cells and human gingival fibroblasts. Thus, it may be useful for clinical application in periodontal regenerative procedures.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.937-941
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• 2005

The antioxidant and anticancer activities of Styela plicata extracts were evaluated. When extracts were prepared with fresh Styela plicata (FR), extraction yield was in the order of methanol > ethanol = acetone > water among treated solvents. However, the extraction order was methanol > water > ethanol > acetate in freeze dried Styela plicata (FD). Radical scavenging activity was the highest in acetone extracts $(37.39\%)$ from FR, while in ethanol extracts $(78.40\%)$ from FD. Reducing power of FR was the greatest in methanol extracts (1.076), and that of FD in ethanol extracts (1.360). The acetone extracts from FD showed significant anticancer activity when revealed with human colon cancer cell line HT-29. These results indicated that extraction yields and properties of extracts from Styela plicata were variable depending on solvent and/or physicochemical state, and appropriate extraction process could provide some valuable bioactive materials from Styela plicata.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.231-236
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• 2015

A 17-year-old girl presented with complaints of headache and decreasing vision of one month's duration, without any history of fever, weight loss, or any evidence of an immuno-compromised state. Her neurological examination was normal, except for papilledema. Laboratory investigations were within normal limits, except for a slightly increased Erythrocyte Sedimentation Rate (ESR). Non-contrast computerized tomography of her head revealed complex mass in left frontal lobe with a concentric, slightly hyperdense, thickened wall, and moderate perilesional edema with mass effect. Differential diagnoses considered in this case were pilocytic astrocytoma, metastasis and abscess. Magnetic resonance imaging (MRI) obtained in 3.0 Tesla (3.0T) scanner revealed a lobulated outline cystic mass in the left frontal lobe with two concentric layers of T2 hypointense wall, with T2 hyperintensity between the concentric ring. Moderate perilesional edema and mass effect were seen. Post gadolinium study showed a markedly enhancing irregular wall with some enhancing nodular solid component. No restricted diffusion was seen in this mass in diffusion weighted imaging (DWI). Magnetic resonance spectroscopy (MRS) showed increased lactate and lipid peaks in the central part of this mass, although some areas at the wall and perilesional T2 hyperintensity showed an increased choline peak without significant decrease in N-acetylaspartate (NAA) level. Arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC) enhanced perfusion study showed decrease in relative cerebral blood volume at this region. These features in MRI were suggestive of brain abscess. The patient underwent craniotomy with excision of a grayish nodular lesion. Abundant acid fast bacilli (AFB) in acid fast staining, and epithelioid cell granulomas, caseation necrosis and Langhans giant cells in histopathology, were conclusive of tubercular abscess. Tubercular brain abscess is a rare manifestation that simulates malignancy and cause diagnostic dilemma. MRI along with MRS and magnetic resonance perfusion studies, are powerful tools to differentiate lesions in such equivocal cases.

• Food Science and Preservation
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• v.13 no.5
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• pp.629-633
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• 2006

Pinus rigida Miller leaf extract (PRLE) showed antimicrobial activity remarkably against food pathogenic and spoilage bacteria at concentrations of $100{\sim}250{\mu}g/mL$. Alcohol-soluble PRLE had higher antimicrobial activity against Staphylococcus aureus and E-coli than any other-soluble PRLE such as butanol, ethyl acetate, ether and water. As PRLE concentration increased alcohol-soluble PRLE increased the remarkable inhibitory zone of microbial growth on the microbial media. PRLE showed good stability against temperature and pH in the range of $40{\sim}150^{\circ}C$ and $4{\sim}11$, respectively. This may indicate that PRLE can be a potential anti-microbial agent for industrial application. In addition, SEM of Listeria monocytogenes suggested that it antimicrobial component would perturb the functions of microbial cell membranes synergistically. In the feeding experiment the formaldehyde content in the serum of formalin-fed and PRLE-treated me decreased remarkably due to the lysis of formaldehyde and the rate of hemoglobin biosynthesis was recovered to the orignal state within a short breeding time.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.459-470
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• 2020

This study investigated the effects of the proteolytic hydrolysates of α-lactalbumin (LA), β-lactoglobulin (LG) and bovine serum albumin (BSA) by alcalase on inflammatory cytokines. The proteolytic hydrolysates were separated into two fraction of peptides, ≤ 10,000 Da and > 10,000 Da, respectively, because various low molecular weight peptides were generated during the hydrolysis reaction time. Among the hydrolysate peptides, BSA (all types), β-LG (> 10,000 Da), and α-LA (> 10,000 Da) showed an inhibitory activity against thymic stromal lymphopoietin (TSLP) mRNA expression in lipopolysaccharide-induced RAW264.7 murine macrophages. α-LA (> 10,000 Da), β-LG (hydrolysates), and BSA (> 10,000 Da) showed an inhibitory activity against tumor necrosis factor (TNF)-α expression. α-LA (all types), β-LG (hydrolysates, > 10,000 Da), and BSA (> 10,000 Da) showed an inhibitory activity against interleukin-6 (IL-6) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against inducible nitric oxide synthase (iNOS) expression. α-LA (> 10,000 Da), β-LG (> 10,000 Da), and BSA (all types) showed an inhibitory activity against cyclooxygenase (COX)-2 expression. The lowest level of TNF-α production was measured with α-LA (> 10,000 Da) and β-LG (> 10,000 Da) for all types, and a similar low level was measured for all types of BSA. The highest level of IL- 6 production was measured with α-LA (≤ 10,000 Da) among α-LA, β-LG, and IL-6. The low level of NO production was similar with α-LA, β-LG, and BSA but not with α-LA (≤ 10,000 Da). These potential peptides from whey protein hydrolysates could be used for food, medicinal, and industrial applications.

• Journal of Life Science
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• v.27 no.12
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• pp.1415-1420
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• 2017

The metallothionein (MT) gene (IbMT3) was selected from an EST library of suspension-cultured sweet potato cells. The MT gene, which is one of abundant ESTs in the library, is involved in stress regulation of cells and tissues. A full-length IbMT3 cDNA was obtained and analysis of its nucleotide sequence revealed that IbMT3 encoded a type 3 MT protein, based on its structural characteristics. The function of type 3 MT in plants is not yet known. Northern blot analysis showed stronger expression of IbMT3 in suspension-cultured cells than in sweet potato plant leaves. Since cell culture is known to impose a state of oxidative stress on cells, sweet potato plants were subjected to oxidative stress to investigate the transcriptional regulation of IbMT3. When the herbicide methyl viologen (MV) was administered for 6, 12, and 24 hr, IbMT3 transcription rapidly increased at 6 hr and then decreased. A cold treatment at $15^{\circ}C$ for 24 and 48 hr resulted in a gradual increase in IbMT3 expression. These findings indicate that IbMT3 expression is regulated in response to environmental and oxidative stress. IbMT3 isoform is expected to have antioxidant effects in sweet potato plants and may play an important role in cellular adaptation to oxidative stress.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.242-248
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• 2007

For an optimal design of automotive electric system, it is important to have a reliable modeling tool to predict the charge-discharge behaviors of the automotive battery. In this work, a two-dimensional modeling was carried out to predict the charge-discharge behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experimental data of the charge-discharge behaviors of a lead-acid battery. The discharge behaviors were measured with three different discharge rates of C/5, C/10, and C/20 at operating temperature of $25^{\circ}C$. The batteries were charged with constant current of 30A until the charging voltage reached to a predetermined value of 14.24 V and then the charging voltage was kept constant. The discharge and charge curves from the measurements and modeling were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, the porosity of the electrodes, and the current density within the electrodes as well as the acid concentration can be predicted as a function of charge and discharge time.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.239-246
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• 1999

A highly sensitive photovoltaic infrared photodiode was fabricated for detecting infrared light in $3{\sim}5\;{\mu}m$ wavelength range on InSb wafer with p-i-n structure grown by MOCVD. Silicon dioxide($SiO_2$) insulating films for the junction interface and surface of photodiode were prepared using RPCVD because InSb has low melting point and evaporation temperature. After formation of In ohmic contacts by thermal evaporation, the electrical properties of the photodiode were characterized in dark state at 77K. A product of zero-bias resistance and area($R_0A$) showed $1.56{\times}10^6\;{\Omega}{\cdot}cm^2$ that satisfied BLIP(background limited infrared photodetector) condition. When the photodiode was tested under infrared light, the normalized detectivity of about $10^{11}\;cm{\cdot}Hz^{1/2}{\cdot}W^{-1}$ was obtained. we successfully fabricated a unit cell with InSb IR array with good quantum efficiency and high detectivity.