• Molecules and Cells
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• 제38권2호
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• pp.180-186
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• 2015

Escherichia coli AcrAB-TolC is a multidrug efflux pump that expels a wide range of toxic substrates. The dynamic nature of the binding or low affinity between the components has impeded elucidation of how the three components assemble in the functional state. Here, we created fusion proteins composed of AcrB, a transmembrane linker, and two copies of AcrA. The fusion protein exhibited acridine pumping activity, suggesting that the protein reflects the functional structure in vivo. To discern the assembling mode with TolC, the AcrBA fusion protein was incubated with TolC or a chimeric protein containing the TolC aperture tip region. Three-dimensional structures of the complex proteins were determined through transmission electron microscopy. The overall structure exemplifies the adaptor bridging model, wherein the funnel-like AcrA hexamer forms an intermeshing cogwheel interaction with the ${\alpha}$-barrel tip region of TolC, and a direct interaction between AcrB and TolC is not allowed. These observations provide a structural blueprint for understanding multidrug resistance in pathogenic Gram-negative bacteria.

• Journal of Gastric Cancer
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• 제3권2호
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• pp.80-83
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• 2003

Purpose: Evidence exists that dysregulation of apoptosis is involved in the pathogenesis of cancer development. Fasassociated death domain (FADD) protein, an adaptor protein of death receptors, is a critical regulatory component of the extrinsic cell- death pathway that exerts its pro-apoptotic effect upon binding with death receptors. Expression of the FADD protein has not been reported in stomach cancer. The aim of this study was to explore the expression status of the FADD protein in stomach cancers. Materials and Methods: In the current study, we analyzed the expression of the FADD protein in 60 advanced stomach cancer by using immunohistochemistry and a tissue microarray approach. Results: Immunopositivity (defined as $\geq\30\%$) was observed for the FADD protein in 23 ($38\%$) of the 60 cancers. Normal gastric mucosal cells showed expression of the FADD protein. Conclusion: Taken together, these results indicate that decreased expression of the FADD protein is a frequent event in stomach cancers and suggest that to avoid apoptosis, stomach cancer cells in vivo may need loss of FADD expression, which might contribute to tumor development.

• 한국통신학회논문지
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• 제40권3호
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• pp.551-558
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• 2015

Wi-Fi 및 핫스팟의 사용이 많아짐에 따라, 최근 비인증 AP는 현대사회에 있어서 중요한 보안문제가 되어가고 있다. 그에 따라 2010년대 초반 비인증 AP를 탐지하는 연구가 꾸준히 이루어지고 있다. 특히나 무선 네트워크 자원을 이용하는 비인증 AP를 탐지하는 다양한 기법들이 제시되었다. 현재 많은 연구들에서 비인증 AP를 찾아내는 방식은 추가된 무선구간으로 인한 지연된 시간(평균이나 표준편차)을 이용하는 방식을 사용되고 있다. 그러나 앞선 대부분의 연구에서 비인증 AP는 노트북에 무선랜카드를 추가하여 구성되는데, 지연된 시간의 원인이 운영체제에 의한 소프트웨어 방식의 네트워크 공유에 있을 수 있음을 고려하지 않고 있다. 이 논문에서는 기존의 시간 측정기반 비인증 AP 탐지 기법들이 고성능 하드웨어를 이용하여 구성된 비인증 AP를 효율적으로 분류해내지 못함을 보이려고 한다.

• Biomolecules & Therapeutics
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• 제22권6호
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• pp.525-531
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• 2014

In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-${\alpha}$ for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription - polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-${\alpha}$ in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-${\alpha}$-induced nuclear factor kappa B (NF-${\kappa}B$) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-${\kappa}B$ activation induced by TNF-${\alpha}$. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha ($I{\kappa}B{\alpha}$) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-${\kappa}B$ signaling pathway in airway epithelial cells.

• 전기전자학회논문지
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• 제22권4호
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• pp.985-991
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• 2018

본 논문에서는 LLC 공진형 하프브릿지 컨버터의 내부손실이 반영된 등가회로를 제안하고, 손실 요소가 포함된 정상상태 특성식을 유도하였다. 그 결과를 이용하여 입출력 전압이득과 입력 임피던스의 주파수 특성을 무손실 모델과 비교하였다. 제안한 모델과 유도식을 검증하기 위해서 최대 전력이 1kW급인 LLC 공진형 하프브릿지 컨버터의 전원장치의 주요 소자를 동일한 조건에서 선정하여 전압이득과 입력 임피던스와 같은 정상상태 특성을 비교하였다. 특히 두 가지 모델에 대한 정상상태 오차를 보다 면밀하게 비교하기 위해서 실제 회로 설계 단계에서 가장 중요하게 고려되는 부하 전류에 대한 스위칭 주파수의 변화를 관찰 하였다. 그 결과 본 논문에서 제안한 모델과 해석 결과로부터 동작 주파수의 오차가 상당 부분 개선되었다는 것을 확인 하였다.

• 한국축산식품학회지
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• 제42권1호
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• pp.84-97
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• 2022

We evaluated the anti-biofilm formation and anti-inflammatory activity of Hovenia monofloral honey (HMH) against Enterococcus faecalis. Co-culture of HMH with E. faecalis attenuated the biofilm formation of E. faecalis on a polystyrene surface. In addition, HMH effectively eradicated the established E. faecalis biofilm. HMH significantly attenuated E. faecalis growth but did not affect the production of extracellular polymeric substances on E. faecalis, indicating that reduction of E. faecalis biofilm is a result of HMH-mediated killing of E. faecalis. Furthermore, we found that HMH can effectively attenuate E. faecalis-induced expression of a proinflammatory interleukin-8 (IL- 8) in HT-29 cells. Interestingly, treatment of HMH significantly attenuated the E. faecalis-mediated expression of Toll-like receptor-2 (TLR-2) and its adaptor molecules, myeloid differentiation primary response 88 (MyD88), in HT-29 cells. In addition, E. faecalis-induced mitogen-activated protein kinases (MAPKs) phosphorylation was significantly attenuated by HMH administration. Furthermore, HMH-mediated antiinflammatory efficacy (0.2 mg/mL of HMHs) had an equal extent of inhibitory efficacy as 5 μM of MyD88 inhibitor to attenuate E. faecalis-mediated IL-8 expression in HT-29 cells. These results suggest that HMH could effectively inhibit E. faecalis-mediated gastrointestinal inflammation through regulating the TLR-2/MyD88/MAPKs signaling pathways. Collectively, our data suggest that HMH could be developed as a potential natural agent to control E. faecalis-mediated biofilm formation and inflammation.

• 대한본초학회지
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• 제28권6호
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• pp.145-153
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• 2013

Objectives : Neuroinflammation is characterized by microglial activation and the expression of major inflammatory mediators. The present study investigated the inhibitory effect of ginsenoside Rg1 ($GRg_1$), a principle active ingredient in Panax ginseng, on pro-inflammatory cytokines and microglial activation induced by systemic lipopolysaccharide (LPS) treatment in the mouse brain tissue. Methods : Varying doses of $GRg_1$ was orally administered (10, 20, and 30 mg/kg) 1 h before the LPS injection (3 mg/kg, intraperitoneally). The mRNA expression of pro-inflammatory cytokines in the brain tissue was measured using the quantitative real-time PCR method at 4 h after the LPS injection, Microglial activation was evaluated using western blotting and immunohistochemistry against ionized calcium binding adaptor molecule 1 (Iba1) in the brain tissue. Cyclooxigenase-2 (COX-2) expressions also observed using western blotting and immunohistochemistry at 4 h after the LPS injection, In addition, double-immunofluorescent labeling of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and COX-2 with microglia and neurons was processed in the brain tissue. Results : $GRg_1$ (30 mg/kg) significantly attenuated the upregulation of TNF-${\alpha}$, interleukin (IL)-$1{\beta}$ and IL-6 mRNA in the brain tissue at 4 h after LPS injection. Morphological activation and Iba1 protein expression of microglia induced by systemic LPS injection were reduced by the $GRg_1$ (30 mg/kg) treatment. Upregulation of COX-2 protein expression in the brain tissue was also attenuated by the $GRg_1$ (30 mg/kg) treatment. Conclusion : The results suggest that $GRg_1$ is effective in the early stage of neuroinflammation which causes neurodegenerative diseases.

• 농업과학연구
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• 제49권1호
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• pp.11-18
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• 2022

A disrupted immune system during pregnancy is involved in pregnancy complications, such as spontaneous abortion, preeclampsia, and recurrent pregnancy loss. This study examined the role of toll-like receptor (TLR) 4 and ASC (apoptosis-associated speck-like protein containing a CARD [c-terminal caspase recruitment domain]) in pregnancy complications using a lipopolysaccharide (LPS)-induced miscarriage mice model. Incidences of miscarriage and embryonic resorption were examined at 9.5 days of pregnancy in wild-type (WT), ASC knockout (KO), and TLR4 KO mice after injecting them with LPS. The fetuses and placenta were obtained after sacrifice at 15.5 days of pregnancy. A significantly lower frequency of fetus absorption was found in TLR4 KO mice, whereas corresponding absorption outcomes were strongly induced in the WT and ASC KO mice upon an LPS injection. As expected, TLR4 KO mice were resistant to LPS-induced abortion. A histological analysis of the miscarried placenta showed increasing levels of the eosin staining of spongiotrophoblast cells without any obvious difference between WT and ASC KO mice. These results suggest that TLR4 KO mice are resistant to LPS, which affects pregnancy persistence, whereas WT and ASC KO mice show high miscarriage rates due to LPS. Moreover, the ASC adaptor is not directly involved in LPS-induced miscarriages, and the NLRP3 inflammasome can be activated by other proteins in the absence of ASC.

• The Korean Journal of Physiology and Pharmacology
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• 제27권3호
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• pp.197-208
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• 2023

Dysregulation of certain long non-coding RNAs may facilitate tumor initiation and progression. However, numerous carcinogenesis-related long noncoding RNAs have not been characterized. The goal of this study was to elucidate the role of LINC00562 in gastric cancer (GC). The expression of LINC00562 was analyzed using real-time quantitative PCR and Western blotting. The proliferative capacity of GC cells was determined using Cell Counting Kit-8 and colony-formation assays. The migration of GC cells were evaluated using wound-healing assays. The apoptosis of GC cells was assessed by measuring the expression levels of apoptosis-related proteins (Bax and Bcl-2). Xenograft models in nude mice were constructed for in vivo functional analysis of LINC00562. The binding relationship between miR-4636 and LINC00562 or adaptor protein complex 1 sigma 3 (AP1S3), obtained from public databases, was confirmed using dual-luciferase and RNA-binding protein immunoprecipitation experiments. LINC00562 was expressed in GC cells at high levels. Knockdown of LINC00562 repressed GC cell growth and migration, promoted apoptosis in vitro, and inhibited tumor growth in nude mouse models. LINC00562 directly targeted miR-4636, and miR-4636 depletion restored the GC cell behavior inhibited by LINC00562 absence. AP1S3, an oncogene, binds to miR-4636. MiR-4636 downregulation increased AP1S3 level, restoring GC cell malignant behaviors inhibited by AP1S3 downregulation. Thus, LINC00562 exerts carcinogenic effects on GC development by targeting miR-4636-mediated AP1S3 signaling.

• Clinical and Experimental Vaccine Research
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• 제12권4호
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• pp.328-336
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• 2023

Purpose: Human peripheral blood mononuclear cell (PBMC)-based in vitro systems can be of great value in the development and assessment of vaccines but require the right medium for optimal performance of the different cell types present. Here, we compare three commonly used media for their capacity to support innate and adaptive immune responses evoked in PBMCs by Toll-like receptor (TLR) ligands and whole inactivated virus (WIV) influenza vaccine. Materials and Methods: Human PBMCs were cultured for different periods of time in Roswell Park Memorial Institute (RPMI), Dulbecco's minimal essential medium (DMEM), or Iscove's modified DMEM (IMDM) supplemented with 10% fetal calf serum. The viability of the cells was monitored and their responses to TLR ligands and WIV were assessed. Results: With increasing days of incubation, the viability of PBMCs cultured in RPMI or IMDM was slightly higher than that of cells cultured in DMEM. Upon exposure of the PBMCs to TLR ligands and WIV, RPMI was superior to the other two media in terms of supporting the expression of genes related to innate immunity, such as the TLR adaptor protein gene MyD88 (myeloid differentiation factor 88), the interferon (IFN)-stimulated genes MxA (myxovirus resistance protein 1) and ISG56 (interferon-stimulated gene 56), and the leukocyte recruitment chemokine gene MCP1 (monocyte chemoattractant protein-1). RPMI also performed best with regard to the activation of antigen-presenting cells. As for adaptive immunity, when stimulated with WIV, PBMCs cultured in RPMI or IMDM contained higher numbers of IFNγ-producing T cells and secreted more immunoglobulin G than PBMCs cultured in DMEM. Conclusion: Taken together, among the different media assessed, RPMI was identified as the optimal medium for a human PBMC-based in vitro vaccine evaluation system.