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Search Results: 1 - 10 of 27554 matches for " Jong-Kook Lee "
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A Study on the Seismic Isolation Systems of Bridges with Lead Rubber Bearings  [PDF]
Woo-Suk Kim, Dong-Joon Ahn, Jong-Kook Lee
Open Journal of Civil Engineering (OJCE) , 2014, DOI: 10.4236/ojce.2014.44031
Abstract: This study consists of the development and presentation of example of seismic isolation system analysis and design for a continuous, 3-span, cast-in-place concrete box girder bridge. It is expected that example is developed for all Lead-Rubber Bearing (LRB) seismic isolation system on piers and abutments which placed in between super-structure and sub-structure. Design forces, displacements, and drifts are given distinctive consideration in accordance with Caltrans Seismic Design Criteria (2004). Most of all, total displacement\"\" on design for all LRBs case is reduced comparing with combined lead-rubber and elastomeric bearing system\"\" . Therefore, this represents substantial reduction in cost because of reduction of expansion joint. This presents a summary of analysis and design of seismic isolation system by energy mitigation with LRB on bridges.
Selective Algicidal Action of Peptides against Harmful Algal Bloom Species
Seong-Cheol Park, Jong-Kook Lee, Si Wouk Kim, Yoonkyung Park
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026733
Abstract: Recently, harmful algal bloom (HAB), also termed “red tide”, has been recognized as a serious problem in marine environments according to climate changes worldwide. Many novel materials or methods to prevent HAB have not yet been employed except for clay dispersion, in which can the resulting sedimentation on the seafloor can also cause alteration in marine ecology or secondary environmental pollution. In the current study, we investigated that antimicrobial peptide have a potential in controlling HAB without cytotoxicity to harmless marine organisms. Here, antimicrobial peptides are proposed as new algicidal compounds in combating HAB cells. HPA3 and HPA3NT3 peptides which exert potent antimicrobial activity via pore forming action in plasma membrane showed that HPA3NT3 reduced the motility of algal cells, disrupted their plasma membrane, and induced the efflux of intracellular components. Against raphidoflagellate such as Heterosigma akashiwo, Chattonella sp., and C. marina, it displayed a rapid lysing action in cell membranes at 1~4 μM within 2 min. Comparatively, its lysing effects occurred at 8 μM within 1 h in dinoflagellate such as Cochlodium polykrikoides, Prorocentrum micans, and P. minimum. Moreover, its lysing action induced the lysis of chloroplasts and loss of chlorophyll a. In the contrary, this peptide was not effective against Skeletonema costatum, harmless algal cell, even at 256 μM, moreover, it killed only H. akashiwo or C. marina in co-cultivation with S. costatum, indicating to its selective algicidal activity between harmful and harmless algal cells. The peptide was non-hemolytic against red blood cells of Sebastes schlegeli, the black rockfish, at 120 μM. HAB cells were quickly and selectively lysed following treatment of antimicrobial peptides without cytotoxicity to harmless marine organisms. Thus, the antibiotic peptides examined in our study appear to have much potential in effectively controlling HAB with minimal impact on marine ecology.
Isolation and Purification of a Novel Deca-Antifungal Peptide from Potato (Solanum tuberosum L. cv. Jopung) Against Candida albicans
Jong-Kook Lee,Ramamourthy Gopal,Chang Ho Seo,Hyeonsook Cheong,Yoonkyung Park
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13044021
Abstract: In a previous study, an antifungal protein, AFP-J, was purified from tubers of the potato ( Solanum tuberosum cv. L Jopung) and by gel filtration and HPLC. In this study, the functional peptide was characterized by partial acid digestion using HCl and HPLC. We obtained three peaks from the AFP-J, the first and third peaks were not active in the tested fungal strain. However, the second peak, which was named Potide-J, was active (MIC; 6.25 μg/mL) against Candida albicans. The amino acid sequences were analyzed by automated Edman degradation, and the amino acid sequence of Potide-J was determined to be Ala-Val-Cys-Glu-Asn-Asp-Leu-Asn-Cys-Cys. Mass spectrometry showed that its molecular mass was 1083.1 Da. Finally, we confirmed that a disulfide bond was present between Cys 3 and Cys 9 or Cys 10. Using this structure, Potide-J was synthesized via solid-phase methods. In these experiments, only the linear sequence was shown to display strong activity against Candida albicans. These results suggest that Potide-J may be an excellent candidate compound for the development of commercially applicable antibiotic agents.
Ground beetle (Coleoptera: Carabidae) assemblage in the urban landscape, Korea
Jong-Kook Jung,Seung-Tae Kim,Sue-Yeon Lee,Chang-Kyu Park
Journal of Ecology and Field Biology , 2012,
Abstract: This study was conducted with the intention of clarifying the effects of land-use types on a species of ground beetle’s richness,abundance, and composition; the study focused on urban landscapes. We also selected the potential bioindicatorsclassifying land-use types; eleven sites were selected from an urban landscape in Korea. Overall, land-use types in urbanlandscapes did not appear to cause significant decrease in species richness or the abundance of total ground beetle assemblage.According to habitat preferences, several land-use types and distances from the forest significantly affectedthe species richness and abundance, while the open-habitat species were not affected by these variables. Land-use typeswere classified into two major groups, forest and non-forest areas, based on ground beetle assemblage; several indicators,such as Dolichus halensis halensis and subfamily Carabinae species, were of particular consideration. In conclusion, environmentalchange by anthropogenic disturbance can cause different effects on ground beetle assemblages, and forestspecialists can be negatively affected.
A Study on Water Repellent Effectiveness of Natural Oil-Applied Soil as a Building Material  [PDF]
Jong-Kook Lee, Jee-Eun Lee, Seong-Cheol Park, Hee-Dong Cho, Hye-Woong Yoo, Young-Sang Kim, Seong-Ryong Ryu, Woo-Suk Kim, Dong-Joon Ahn
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.51014
Abstract: This study was performed to investigate the water repellent effectiveness of natural oil-applied soil when it is used as a building material. Natural oil types such as olive oil, bean oil, perilla oil and linseed oil, which are being used for producing water repellent timber, are selected for the experiments. It is expected that perilla oil and in seed oil, which are drying oil types will have better water repellent effectiveness than the other types. For the evaluation of water repellence of natural oil-applied soil, a contact angle test was performed. A contact angle of water drop on various surface conditions were tested, and large differences were seen between the natural oil-applied soil and untreated soil. As a result, it is showed that all natural oil types have water repellent effectiveness. However, linseed oil, which is a drying oil type, shows an outstanding water repellent effectiveness value, while perila oil, which is also a drying oil type, shows the lowest value. Additionally, results show that there is no link between water repellent effectiveness and the number of applications of natural oil. Nevertheless, existing commercial water repellents show better performance than natural oil, and it is anticipated that the results of this study will provide essential information for further research to enhance the water repellent effectiveness of soil as a building material.
Novel Antibacterial Activity of β2-Microglobulin in Human Amniotic Fluid
Jin-Young Kim, Seong-Cheol Park, Jong-Kook Lee, Sang Joon Choi, Kyung-Soo Hahm, Yoonkyung Park
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0047642
Abstract: An antibacterial protein (about 12 kDa) was isolated from human amniotic fluid through dialysis, ultrafiltration and C18 reversed-phase HPLC steps. Automated Edman degradation showed that the N-terminal sequence of the antibacterial protein was NH2-Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr?-Ser-Arg-His-Pro-Ala-Glu-Asn-Gly-.The N-terminal sequence of the antibacterial protein was found to be identical to that of β2-microglobulin, a component of MHC class I molecules, which are present on all nucleated cells. Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) revealed that the molecular mass of the antibacterial protein was 11,631 Da. This antibacterial protein, β2M, possessed potent antibacterial activity against pathogenic bacteria. Specially, antibacterial activity was observed in potassium buffer, and potassium ion was found to be critical for the antibacterial activity. Interestingly, the antibacterial action of β2M was associated with dissipation of the transmembrane potential, but the protein did not cause damage to the membrane that would result in SYTOX green uptake. In addition, stimulation of WISH amniotic epithelial cells with the bacterial endotoxin lipopolysaccharide (LPS) induced dose-dependent upregulation of β2M mRNA expression. These results suggest that β2M contributes to a self-defense response when amniotic cells are exposed to pathogens.
Axon Guidance of Sympathetic Neurons to Cardiomyocytes by Glial Cell Line-Derived Neurotrophic Factor (GDNF)
Keiko Miwa, Jong-Kook Lee, Yoshiko Takagishi, Tobias Opthof, Xianming Fu, Masumi Hirabayashi, Kazuhiko Watabe, Yasuhiko Jimbo, Itsuo Kodama, Issei Komuro
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065202
Abstract: Molecular signaling of cardiac autonomic innervation is an unresolved issue. Here, we show that glial cell line-derived neurotrophic factor (GDNF) promotes cardiac sympathetic innervation in vitro and in vivo. In vitro, ventricular myocytes (VMs) and sympathetic neurons (SNs) isolated from neonatal rat ventricles and superior cervical ganglia were cultured at a close distance. Then, morphological and functional coupling between SNs and VMs was assessed in response to GDNF (10 ng/ml) or nerve growth factor (50 ng/ml). As a result, fractions of neurofilament-M-positive axons and synapsin-I-positive area over the surface of VMs were markedly increased with GDNF by 9-fold and 25-fold, respectively, compared to control without neurotrophic factors. Pre- and post-synaptic stimulation of β1-adrenergic receptors (BAR) with nicotine and noradrenaline, respectively, resulted in an increase of the spontaneous beating rate of VMs co-cultured with SNs in the presence of GDNF. GDNF overexpressing VMs by adenovirus vector (AdGDNF-VMs) attracted more axons from SNs compared with mock-transfected VMs. In vivo, axon outgrowth toward the denervated myocardium in adult rat hearts after cryoinjury was also enhanced significantly by adenovirus-mediated GDNF overexpression. GDNF acts as a potent chemoattractant for sympathetic innervation of ventricular myocytes, and is a promising molecular target for regulation of cardiac function in diseased hearts.
Tumor Suppressive Function of mir-205 in Breast Cancer Is Linked to HMGB3 Regulation
Ola A. Elgamal, Jong-Kook Park, Yuriy Gusev, Ana Clara P. Azevedo-Pouly, Jinmai Jiang, Avtar Roopra, Thomas D. Schmittgen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076402
Abstract: Identifying targets of dysregulated microRNAs (miRNAs) will enhance our understanding of how altered miRNA expression contributes to the malignant phenotype of breast cancer. The expression of miR-205 was reduced in four breast cancer cell lines compared to the normal-like epithelial cell line MCF10A and in tumor and metastatic tissues compared to adjacent benign breast tissue. Two predicted binding sites for miR-205 were identified in the 3’ untranslated region of the high mobility group box 3 gene, HMGB3. Both dual-luciferase reporter assay and Western blotting confirmed that miR-205 binds to and regulates HMGB3. To further explore miR-205 targeting of HMGB3, WST-1 proliferation and in vitro invasion assays were performed in MDA-MB-231 and BT549 cells transiently transfected with precursor miR-205 oligonucleotide or HMGB3 small interfering RNA (siRNA). Both treatments reduced the proliferation and invasion of the cancer cells. The mRNA and protein levels of HMGB3 were higher in the tumor compared to adjacent benign specimens and there was an indirect correlation between the expression of HMGB3 mRNA and patient survival. Treatment of breast cancer cells with 5-Aza/TSA derepressed miR-205 and reduced HMGB3 mRNA while knockdown of the transcriptional repressor NRSF/REST, reduced miR-205 and increased HMGB3. In conclusion, regulation of HMGB3 by miR-205 reduced both proliferation and invasion of breast cancer cells. Our findings suggest that modulating miR-205 and/or targeting HMGB3 are potential therapies for advanced breast cancer.
Two Gnaphosid Spiders (Araneae: Gnaphosidae) New to Korean Spider Fauna  [PDF]
Sue Yeon Lee, Seung Tae Kim, Joon-Ho Lee, Jung Sun Yoo, Jong Kook Jung, Jae Won Lim
Open Journal of Animal Sciences (OJAS) , 2014, DOI: 10.4236/ojas.2014.43018
Abstract: Drassyllus yaginumai Kamura, 1987 and Zelotes tortuosus Kamura, 1987 belonging to Gnaphosidae were captured by pitfall trap in maize and soybean fields during the survey of arthropod fauna of agricultural ecosystem in Korea. Present work describes these 2 species with illustrations of taxonomic characters.
Effect of Repetitive Lysine-Tryptophan Motifs on the Eukaryotic Membrane
Ramamourthy Gopal,Jong Kook Lee,Jun Ho Lee,Young Gwon Kim,Gwang Chae Oh,Chang Ho Seo,Yoonkyung Park
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14012190
Abstract: In a previous study, we synthesized a series of peptides containing simple sequence repeats, (KW) n–NH 2 ( n = 2,3,4 and 5) and determined their antimicrobial and hemolytic activities, as well as their mechanism of antimicrobial action. However, (KW) 5 showed undesirable cytotoxicity against RBC cells. In order to identify the mechanisms behind the hemolytic and cytotoxic activities of (KW) 5, we measured the ability of these peptides to induce aggregation of liposomes. In addition, their binding and permeation activities were assessed by Trp fluorescence, calcein leakage and circular dichrorism using artificial phospholipids that mimic eukaryotic liposomes, including phosphatidylcholine (PC), PC/sphingomyelin (SM) (2:1, w/ w) and PC/cholesterol (CH) (2:1, w/ w). Experiments confirmed that only (KW) 5 induced aggregation of all liposomes; it formed much larger aggregates with PC:CH (2:1, w/ w) than with PC or PC:SM (2:1, w/ w). Longer peptide (KW) 5, but not (KW) 3 or (KW) 4, strongly bound and partially inserted into PC:CH compared to PC or PC:SM (2:1, w/ w). Calcein release experiments showed that (KW) 5 induced calcein leakage from the eukaryotic membrane. Greater calcein leakage was induced by (KW) 5 from PC:CH than from PC:SM (2:1, w/ w) or PC, whereas (KW) 4 did not induce calcein leakage from any of the liposomes. Circular dichroism measurements indicated that (KW) 5 showed higher conformational transition compared to (KW) 4 due to peptide-liposome interactions. Taken together, our results suggest that (KW) 5 reasonably mediates the aggregation and permeabilization of eukaryotic membranes, which could in turn explain why (KW) 5 displays efficient hemolytic activity.
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