• Journal of Korean Society for Atmospheric Environment
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• 제18권E1호
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• pp.29-36
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• 2002

The selective catalytic reduction (SCR) reaction of promoter catalysts was investigated in this study. A pure anatase type of TiO$_2$ was used as support. Activation measurement of prepared catalysts was practiced on a fixed reactor packing by the glass bead after filling up catalysts in 1/4 inch stainless tube. The reaction temperature was measured by K-type thermocouple and catalyst was heated by electric furnace. The standard compositions of the simulated flue gas mixture in this study were as follows: NO 1,780ppm, NH$_3$1,780ppm, $O_2$1% and $N_2$ as balance gas. In this study, gas analyzer was used to measure the outgassing gas. Catalyst bed was handled for 1hr at 45$0^{\circ}C$, and the reactivity of the various catalyst was determined in a wide temperature range. Conversion of NH$_3$/NO ratio and of $O_2$ concentration was practiced at 1,1.5 and 2, respectively. The respective space velocity were as follows . 10,000, 15,000 and 17,000 hr-1. It was found that the maximum conversion temperature range was in a 5$0^{\circ}C$. It was also found toi be very sensitive at space velocity, $O_2$ concentration, and NH$_3$/NO ratio. We also noticed that the maximum conversion temperature of (W, Mo, Sn) -V$_2$O$_{5}$/TiO$_2$ catalysts was broad. Specially WO$_3$-V$_2$O$_{5}$TiO$_2$2 catalyst appeared nearly 100% conversion at not only above 30$0^{\circ}C$ ut also below 25$0^{\circ}C$. At over 30$0^{\circ}C$, NH$_3$ oxidation decreased with decrease of surface excess oxygen. In addition, WO$_3$-V$_2$O$_{5}$TiO$_2$ catalyst did not appear to affect space velocity, $O_2$ concentration, and NH$_3$/NO ratio.ratio.

• 한국정보시스템학회지:정보시스템연구
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• 제26권2호
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• pp.85-104
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• 2017

Purpose The purpose of this study is to improve the efficiency of the activities of loosely connected network organization through the platform(Ba) of knowledge sharing. Loosely connected network organizations have been tried to promote new work and complement the scarce resources through collaborations. NPO(Non-Profit Organization) is essential to establish cooperation networks in order to achieve the public interest on the basis of scarce resources. This study interpreted the Ba on the 'Change-On' program and analyzed the social networks of regional organizations through the activation of the Ba. The 'Change-On' program is conducted for several years to promote the efficiency of the NPO network by Daum Generation Foundation. Design/methodology/approach This study made a design to organize the Ba concept of Nonaka & Konno and presented a case of the Ba activated based on the NPO network of regional order. According to the social network analysis of regional cooperation within the network of participating organizations was extended, it was found that the principal plays a significant role as a central hub made. Findings According to the empirical analysis, this study illustrated that various types of network were formed among NPOs based on the 'Change-On'. Furthermore, the networks surrounding NPOs are extended to the other people connected to them. This means that the network of NPOs had been diversified via the facilitation of the Ba. This study throws new highlights on the new role for the Ba as a network promoter in addition to the partner as a technology-provider in the NPO ecosystem. Moreover, the network analysis between before-and-after can be used for the evaluation of the effectiveness of the various Ba programs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권6호
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• pp.636-642
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• 2007

Background: CpG DNA plays an important role in immune cell function. This study examined whether the temporal control of toll-like receptor (TLR)9 by CpG DNA can regulate the expression of matrix metalloproteinase-9(MMP-9). Methods and materials: Macrophages were cultured in the presence of 10% FBS. For the various MMP genes analysis, RT-PCR and real-time PCR were performed. In addition, zymography assay performed for the MMP activity. The phosphorylation assay did for the ERK1/2 and NF${\kappa}B$ activation, and luciferase promoter assay was for the NF${\kappa}B$ activity. Results: CpG DNA induced the mRNA expression of MMP-2, MMP-9, and MMP-13, but not of MMP-7, MMP-8, and MMP-12, in a time-dependent manner. Especially, the mRNA expression of MMP-9 was strongly induced by CpG DNA using real-time RT-PCR. The TLR9 inhibitor, chloroquine, suppressed CpG DNA-induced MMP-9 expression and its activity. Moreover, CpG DNA induced the phosphorylation of ERK and the inhibition of ERK by U0126 suppressed CpG DNA-induced MMP-9 expression and its activity. CpG DNA stimulated $I{\kappa}B-{\alpha}$ degradation and luciferase activity. In addition, pretreatment of SN-50, the inhibitor of NF${\kappa}B$, strongly blocked the CpG DNA-induced MMP-9 expression and activity. Conclusion: These observations suggest that CpG DNA may play important roles in the activation of macrophages by regulating the production of MMP-9 via the sequential TLR9-ERK-NF${\kappa}B$ signaling pathway.

• BMB Reports
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• 제50권9호
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• pp.472-477
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• 2017

The transcription repressor Bach2 has been proposed as a regulator of T cell quiescence, but the underlying mechanism is not fully understood. Given the importance of interleukin-2 in T cell activation, we investigated whether Bach2 is a component of the network of factors that regulates interleukin-2 expression. In primary and transformed $CD4^+$ T cells, Bach2 overexpression counteracted T cell receptor/CD28- or PMA/ionomycin-driven induction of interleukin-2 expression, and silencing of Bach2 had the opposite effect. Luciferase and chromatin immunoprecipitation assays revealed that Bach2 binds to multiple Maf-recognition element-like sites on the interleukin-2 proximal promoter in a manner competitive with AP-1, and thereby represses AP-1-driven induction of interleukin-2 transcription. Thus, this study demonstrates that Bach2 is a direct repressor of the interleukin-2 gene in $CD4^+$ T cells during the immediate early phase of AP-driven activation, thereby playing an important role in the maintenance of immune quiescence in the steady state.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.168-168
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• 2017

Drought conditions during cultivation reduce agricultural production yield less than a theoretical maximum yield under normal condition. Plant specific NAC transcription factors in rice are known to play an essential roles in stress resistance transcriptional regulation. In this study, we report the rice (Oryza sativa L japonica) NAM, AFTF and CUC transcription factor OsNAC17, which is predominantly induced by abiotic stress in leaf, was contribute to the drought tolerance mediated reactive oxygen species (ROS) in transgenic rice plants. Constitutive (PGD1) promoter was introduced to overexpress OsNAC17 and produced the transgenic PDG1:OsNAC17. Overexpression of OsNAC17 throughout the whole plant improved drought resistance phenotype at the vegetative stage. Morphological characteristics such as grain yield, grain filling rate, and total grain weight improved by 22~64% over wild type plants under drought conditions during the reproductive stage. The improved drought tolerance in transgenic rice was involved in reducing stomatal density up to 15% than in wild type plants and in increasing reactive oxygen species-scavenging enzyme. DEG profiling experiment identified 119 up-regulated genes by more than twofold (P<0.01). These genes included UDP-glycosyltransferase family protein, similar to 2-alkenal reductase (NADPH-dependent oxireductase), similar to retinol dehydrogenase 12, Lipoxygenase, and NB-ARC domain containing protein related in cell death. Furthermore, OsNAC17 was act as a transcriptional activator, which has an activation domain in C-terminal region. These result demonstrate that the overexpression of OsNAC17 improve drought tolerance by regulating ROS scavenging enzymes and by reducing stomatal density

• BMB Reports
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• 제46권6호
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• pp.322-327
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• 2013

The ATP-binding cassette transporters ABCG5 and ABCG8 form heterodimers that limit absorption of dietary sterols in the intestine and promote cholesterol elimination from the body through hepatobiliary secretion. To identify cis-regulatory elements of the two genes, we have cloned and analyzed twenty-three evolutionary conserved region (ECR) fragments using the CMV-luciferase reporter system in HepG2 cells. Two ECRs were found to be responsive to the Liver-X-Receptor (LXR). Through elaborate deletion studies, regions containing putative LXREs were identified and the binding of $LXR{\alpha}$ was demonstrated by EMSA and ChIP assay. When the LXREs were inserted upstream of the intergenic promoter, synergistic activation by $LXR{\alpha}/RXR{\alpha}$ in combination with GATA4, $HNF4{\alpha}$, and LRH-1, which had been shown to bind to the intergenic region, was observed. In conclusion, we have identified two LXREs in ABCG5/ABCG8 genes for the first time and propose that these LXREs, especially in the ECR20, play major roles in regulating these genes.

• Molecules and Cells
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• 제42권12호
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• pp.850-857
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• 2019

The Gram-negative opportunistic pathogen, Pseudomonas aeruginosa, has multiple multidrug efflux pumps. MexT, a LysR-type transcriptional regulator, functions as a transcriptional activator of the MexEF-OprN efflux system. MexT consists of an N-terminal DNA-binding domain and a C-terminal regulatory domain (RD). Little is known regarding MexT ligands and its mechanism of activation. We elucidated the crystal structure of the MexT RD at 2.0 Å resolution. The structure comprised two protomer chains in a dimeric arrangement. MexT possessed an arginine-rich region and a hydrophobic patch lined by a variable loop, both of which are putative ligand-binding sites. The three-dimensional structure of MexT provided clues to the interacting ligand structure. A DNase I footprinting assay of full-length MexT identified two MexT-binding sequence in the mexEF-oprN promoter. Our findings enhance the understanding of the regulation of MexT-dependent activation of efflux pumps.

• 한국해양바이오학회지
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• 제2권2호
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• pp.81-85
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• 2007

글루코코르티코이드의 다양한 생리학적 과정은 이 호르몬에 의해 활성화된 수용체가 표적 유전자의 전사를 촉진 혹은 억제시킴으로써 일어나게 된다. 본 논문은 렌티바이러스 리포터 시스템을 이용하여 글루코코르티코이드 호르몬에 의한 GR 활성을 핵내에서 GRE에 의해 유도된 리포터 단백질인 mRFP 또는 루시퍼라아제의 발현을 통해 정성, 정량화 하였다. 그 결과 GR이 endogenous 하게 발현되는 HeLa 세포에서 코티졸을 처리하였을 때 활성화된 GR에 의해 GRE-inducible한 RFP와 루시퍼라아제의 발현이 각각 공초점 형광 현미경과 IVIS-200을 이용하여 형광 또는 BLI을 통해 증가함을 확인하였다. 이러한 결과를 통해 렌티바이러스 리포터 시스템을 이용한 연구는 세포 내에서 뿐 만 아니라 향후 생체내에서의 GR signaling을 모니터링하는데 유용하게 사용되어질 수 있을 것이다.

• Archives of Pharmacal Research
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• 제28권3호
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• pp.351-357
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• 2005

Endosulfan is one of the organochlorine pesticides, which are well-known endocrine disruptors (EDs), and it acts as an estrogen agonist. Estrogen is a group of hormones that play an important role in mammary gland function and are implicated in mammary carcinogenesis. In the present study, we studied the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in mouse mammary gland development using a mouse mammary gland organ culture (MMOC) system. Although endosulfan-treated mammary glands did not form NLALs, more alveolar buds were formed in this group than in the negative control (vehicle-treated) group. In addition, telomerase reverse transcriptase (TERT) mRNA expression levels were increased in endosulfan-treated mammary glands in a dose-dependent manner. Telomerase can be activated by estrogen, therefore, we examined the effects of endosulfan on telomerase activity, and found that the telomerase activity in estrogen receptor-positive MCF-7 cells was up-regulated by endosulfan treatment. Moreover, this activation was accompanied by the up­regulation of the TERT mRNA expression. Also, transient expression assays using CAT reporter plasm ids containing various fragments of the TERT promoter showed that this imperfect palindromic estrogen-responsive element is almost certainly responsible for the transcriptional activation by endosulfan. These results may help elucidate the endocrine disrupting mechanism of endosulfan.

• International Journal of Oral Biology
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• 제38권3호
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• pp.121-126
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• 2013

Tumor necrosis factor alpha ($TNF{\alpha}$) is a multifunctional inflammatory cytokine that regulates various cellular and biological processes. Increased levels of $TNF{\alpha}$ have been implicated in a number of human diseases including diabetes and arthritis. Sympathetic nervous system stimulation via the beta2-adrenergic receptor (${\beta}2AR$) in osteoblasts suppresses osteogenic activity. We previously reported that $TNF{\alpha}$ upregulates ${\beta}2AR$ expression in murine osteoblastic cells and that this modulation is associated with $TNF{\alpha}$ inhibition of osteoblast differentiation. In our present study, we explored whether $TNF{\alpha}$ induces ${\beta}2AR$ expression in human osteoblasts and then identified the downstream signaling pathway. Our results indicated that ${\beta}2AR$ expression was increased in Saos-2 and C2C12 cells by $TNF{\alpha}$ treatment, and that this increase was blocked by the inhibition of NF-${\kappa}B$ activation. Chromatin immunoprecipitation and luciferase reporter assay results indicated that NF-${\kappa}B$ directly binds to its cognate elements on the ${\beta}2AR$ promoter and thereby stimulates ${\beta}2AR$ expression. These findings suggest that the activation of $TNF{\alpha}$ signaling in osteoblastic cells leads to an upregulation of ${\beta}2AR$ and also that $TNF{\alpha}$ induces ${\beta}2AR$ expression in an NF-${\kappa}B$-dependent manner.