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排序方式: 共有1149条查询结果,搜索用时 31 毫秒
951.
House dust mites (HDM) are critical factors in airway inflammation. They activate respiratory epithelial cells to produce reactive oxygen species (ROS) and activate Toll-like receptor 4 (TLR4). ROS induce the expression of inflammatory cytokines in respiratory epithelial cells. Lycopene is a potent antioxidant nutrient with anti-inflammatory activity. The present study aimed to investigate whether HDM induce intracellular and mitochondrial ROS production, TLR4 activation, and pro-inflammatory cytokine expression (IL-6 and IL-8) in respiratory epithelial A549 cells. Additionally, we examined whether lycopene inhibits HDM-induced alterations in A549 cells. The treatment of A549 cells with HDM activated TLR4, induced the expression of IL-6 and IL-8, and increased intracellular and mitochondrial ROS levels. TAK242, a TLR4 inhibitor, suppressed both HDM-induced ROS production and cytokine expression. Furthermore, lycopene inhibited the HDM-induced TLR4 activation and cytokine expression, along with reducing the intracellular and mitochondrial ROS levels in HDM-treated cells. These results collectively indicated that the HDM induced TLR4 activation and increased intracellular and mitochondrial ROS levels, thus resulting in the induction of cytokine expression in respiratory epithelial cells. The antioxidant lycopene could inhibit HDM-induced cytokine expression, possibly by suppressing TLR4 activation and reducing the intracellular and mitochondrial ROS levels in respiratory epithelial cells. 相似文献
952.
Cocrystals of salicylic acid (derived from reaction between aspirin and coformers) with 4,4′dipyridyl, nicotinamide, isonicotinamide, N,N′‐diacetylpiperazine and piperazine have been examined with intent to improve physicochemical properties of antipyretic agent. All of the resulting cocrystals, salicylic acid/4,4′dipyridyl (2:1), salicylic acid/nicotinamide (1:1), salicylic acid/isonicotinamide (1:1), salicylic acid/piperazine (1:0.5) and salicylic acid/ N,N′‐diacetylpiperazine (2:1) (derived from reaction between aspirin and piperazine) are obtained solution cooling/evaporation experiments. The structural analysis has shown that the well‐known COOH ⋅⋅⋅ N heterosynthon was considered the key element in the cocrystals design strategy. The carboxylic acid ⋅⋅⋅ pyridine hydrogen bond is an often used supramolecular synthon. The results from X‐ray Powder Diffraction, DSC, Raman and single‐crystal X‐ray analysis revealed the formation of cocrystal of salicylic acid with several coformers. 相似文献
953.
Glucose‐induced and fructose‐induced deboronation reaction of 4‐mercaptophenylboronic acid assembled on silver investigated by surface‐enhanced Raman scattering
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Nguyễn Hoàng Ly Anh Thu Ngoc Lam Nguyen Dinh Bao Young‐Je Kwark Sang Woo Joo 《Surface and interface analysis : SIA》2017,49(6):495-502
We examined the deboronation reaction of 4‐mercaptophenylboronic acid (4MPBA) via fructose and glucose on silver surfaces by means of surface‐enhanced Raman scattering (SERS) at the excitation wavelengths of 488, 514, and 633 nm. The SERS spectra on silver nanoparticles clearly exhibited specific spectral signatures of thiophenol (TP) peaks, indicating a deboronation reaction of 4MPBA on the surfaces, whereas no strong TP peaks were observed on gold nanoparticles. The vibrational bands at 417, 999, 1021, and 1574 cm?1 in the Ag SERS spectra could correspond to the in‐plane aromatic ring modes in TP. X‐ray photoelectron spectroscopy also supported the surface reaction on Ag by referring the B1s peaks at ~193 eV. The ratiometric Raman measurements of the band at 1574 cm?1, with respect to that at 1587 cm?1, revealed fructose and glucose quantification in the concentration range of 1–10 mm . We did not identify such changes for mannose, sucrose, and sialic acid. The SERS peaks of 4MPBA on roughened Ag plates also exhibited TP bands to show the time‐dependent spectral change. Our findings indicate that the deboronation of 4MPBA and conjugation with fructose and glucose may be facilitated efficiently on silver surfaces for their quantification. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
954.
We have designed and synthesized new anion receptors 1 and 2, which have amide NH, pyrrole NH and vinyl CH as hydrogen bond donors. These receptors are selective for dimethyl phosphinate and carboxylates. Due to electron withdrawing effect of the cyano group which is trans to the vinyl hydrogen with respect to carbon-carbon double bond, receptor 1 has higher binding constants for phosphinate and carboxylate than those of receptor 2. Modeling studies shows that cyano group polarized all three hydrogens through planar π-electron network. In addition, receptor 1 gave orange colored 1,4-addition product for cyanide. 相似文献
955.
Carboxylated Pillar[5]arene‐Coated Gold Nanoparticles with Chemical Stability and Enzyme‐like Activity
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Dr. Chiyoung Park Eun Sun Jeong Kyung Joo Lee Prof. Dr. Hoi Ri Moon Prof. Dr. Kyoung Taek Kim 《化学:亚洲杂志》2014,9(10):2761-2764
A facile synthesis of gold nanoparticles (AuNPs) covered with a multidentate macrocycle, carboxylated pillar[5]arene ( CP ), via a one‐pot hydrothermal process is reported. The resulting AuNPs are highly stable against salts and pH variations, while their traditional counterparts are not stable at the same conditions. For the stabilization, multiple carboxylate groups of CP might contribute to electrostatic or steric stabilization. In addition, we found that CP ‐coated AuNPs exhibit greater peroxidase‐like activity than citrate‐stabilized AuNPs in the presence of silver cations. The system presented herein would provide a new scheme to fabricate unique sensory systems in combination with enzymes, which can bind to the pocket of CP . 相似文献
956.
Sook-Jeong Lee Sung-Ook Hwang Eun Joo Noh Dong-Uk Kim Miyoung Nam Jong Hyeok Kim Joo Hyun Nam Kwang-Lae Hoe 《Experimental & molecular medicine》2014,46(2):e76
Vorinostat (VOR) has been reported to enhance the cytotoxic effects of doxorubicin (DOX) with fewer side effects because of the lower DOX dosage in breast cancer cells. In this study, we investigated the novel mechanism underlying the synergistic cytotoxic effects of VOR and DOX co-treatment in cervical cancer cells HeLa, CaSki and SiHa cells. Co-treatment with VOR and DOX at marginal doses led to the induction of apoptosis through caspase-3 activation, poly (ADP-ribose) polymerase cleavage and DNA micronuclei. Notably, the synergistic growth inhibition induced by the co-treatment was attributed to the upregulation of the pro-apoptotic protein Bad, as the silencing of Bad expression using small interfering RNA (siRNA) abolished the phenomenon. As siRNA against p53 did not result in an increase in acetylated p53 and the consequent upregulation of Bad, the observed Bad upregulation was mediated by acetylated p53. Moreover, a chromatin immunoprecipitation analysis showed that the co-treatment of HeLa cells with VOR and DOX increased the recruitment of acetylated p53 to the bad promoter, with consequent bad transactivation. Conversely, C33A cervical cancer cells containing mutant p53 co-treated with VOR and DOX did not exhibit Bad upregulation, acetylated p53 induction or consequent synergistic growth inhibition. Together, the synergistic growth inhibition of cervical cancer cell lines induced by co-treatment with VOR and DOX can be attributed to the upregulation of Bad, which is induced by acetylated p53. These results show for the first time that the acetylation of p53, rather than histones, is a mechanism for the synergistic growth inhibition induced by VOR and DOX co-treatments. 相似文献
957.
Quantitative analysis of a ubiquitin‐dependent substrate using capillary electrophoresis with dual laser‐induced fluorescence
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Hyunjung Lee Eunmi Ban Eunice EunKyeong Kim Young Sook Yoo Daekee Lee Eun Joo Song 《Electrophoresis》2014,35(20):2978-2985
Protein degradation by the ubiquitin‐proteasome system (UPS) affects many biological processes. Inhibition of the proteasome has emerged as a potential therapeutic target for cancer treatment. In this study, we developed a method for monitoring the degradation and accumulation of UPS‐dependent substrates in cells using CE with dual LIF. We used a green fluorescent protein (GFP)‐fusion of the ubiquitin substrate ribophorin 1 (GFP‐RPN1) along with red fluorescent protein (RFP) as an internal control to normalize transfection efficiency. Determination of GFP‐RPN1 and RFP in cell lysates were performed in an untreated capillary (75 μm × 50 cm) and 100 mM Tris‐CHES buffer (pH 9.0) containing 10 mM SDS. GFP‐RPN1 and RFP fluorescence were detected at excitation wavelengths of 488 and 635 nm, and emission wavelengths of 520 and 675 nm, respectively, without any interference or crosstalk. The intensity of GFP‐RPN1 fluorescence was normalized to that of RFP. Additionally, the proposed approach was used successfully to detect the degradation of GFP‐RPN1 and evaluate proteasome inhibitors. These results show that the developed method is effective and promising for rapid and quantitative monitoring of UPS‐dependent substrates compared to the current common methods, such as immunoblotting and pulse chase assays. 相似文献
958.
An immunoproteomic approach for characterization of the outer membrane proteins of Salmonella Gallinarum
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Salmonella enterica serovar Gallinarum (SG) is an important pathogen that causes fowl typhoid in chickens. In order to investigate SG outer membrane proteins (OMPs) as potential vaccine candidate proteins, we established a proteomic map and database of antigenic SG‐OMPs. A total of 174 spots were detected by 2DE. Twenty‐two antigen‐reactive spots were identified as nine specific proteins using PMF. OmpA was the most abundant protein among all of the identified OMPs, and it exhibited seven protein species. We conducted Western blot analysis for the SG‐OMPs in order to determine which proteins were cross‐reactive to the serovars Salmonella Enteritidis, Salmonella Typhimurium, and SG. Our results indicated that OmpA was considered to be an antigenic cross‐reactive protein among the three serovars. This study sheds new light on our understanding of cross‐protection among Salmonella serovars. 相似文献
959.
Md. Arifur Rahman Yun Hee Choi Pradeep G. C. Yoon Seok Choi Eun Joo Choi Seung Sik Cho Jin Cheol Yoo 《Applied biochemistry and biotechnology》2014,173(6):1469-1480
An extracellular low molecular weight xylanase (Xyn628) from Streptomyces sp. CS628 was isolated from Korean soil sample, produced in wheat bran medium, purified, and biochemically characterized. Xyn628 was purified 4.8-fold with a 33.78 % yield using Sepharose CL-6B column chromatography. The purified xylanase was ~18.1 kDa estimated by SDS-PAGE and xylan zymography. N-terminal amino acid sequences of Xyn628 were AYIKEVVSRAYM. The enzyme was found to be stable in a broad range of pH (5.0–13.0) and up to 60 °C and have optimal pH and temperature of pH 11.0 and 60 °C, respectively. Xyn628 activities were remarkable affected by various detergents, chelators, modulators, and metal ions. The xylanase produced xylobiose and xylotriose as principal hydrolyzed end products from the xylan. It was found to degrade agro-waste materials like corn cob and wheat bran by Xyn628 (20 U/g) as shown by electron microscopy. As being simple in purification, low molecular weight, alkaline, thermostable, and ability to produce xylooligosaccharides show that Xyn628 has potential applications in bioindustries as a biobleaching agent or/and xylooligosaccharides production with an appropriate utilization of agro-waste. 相似文献
960.
The Design of Dual Emitting Cores for Green Thermally Activated Delayed Fluorescent Materials
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Yong Joo Cho Sang Kyu Jeon Prof. Byung Doo Chin Dr. Eunsun Yu Prof. Jun Yeob Lee 《Angewandte Chemie (International ed. in English)》2015,54(17):5201-5204
Dual emitting cores for thermally activated delayed fluorescent (TADF) emitters were developed. Relative to the corresponding TADF emitter with a single emitting core the TADF emitter with a dual emitting core, 3,3′,5,5′‐tetra(carbazol‐9‐yl)‐[1,1′‐biphenyl]‐2,2′,6,6′‐tetracarbonitrile, showed enhanced light absorption accompanied by a high photoluminescence quantum yield. The quantum and power efficiencies of the TADF devices were enhanced by the dual emitting cores. 相似文献