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161.
162.
Yuguang Jin Yanqing Tian Weiwen Zhang Sei-Hum Jang Alex K.-Y. Jen Deirdre R. Meldrum 《Analytical and bioanalytical chemistry》2010,398(3):1375-1384
The relationship between bacteria and host phagocytic cells is key to the induction of immunity. To visualize and monitor
bacterial infection, we developed a novel bacterial membrane permeable pH sensor for the noninvasive monitoring of bacterial
entry into murine macrophages. The pH sensor was constructed using 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran
(TCF) as an electron-withdrawing group and aniline as an electron-donating group. A piperazine moiety was used as the pH-sensitive
group. Because of the strong electron-donating and -withdrawing units conjugated in the sensing moiety M, the fluorophore
emitted in the red spectral window, away from the autofluorescence regions of the bacteria. Following the engulfment of sensor-labeled
bacteria by macrophages and their subsequent merger with host lysosomes, the resulting low-pH environment enhances the fluorescence
intensity of the pH sensors inside the bacteria. Time-lapse analysis of the fluorescent intensity suggested significant heterogeneity
of bacterial uptake among macrophages. In addition, qRT-PCR analysis of the bacterial 16 S rRNA gene expression within single
macrophage cells suggested that the 16 S rRNA of the bacteria was still intact 120 min after they had been engulfed by macrophages.
A toxicity assay showed that the pH sensor has no cytotoxicity towards either E. coli or murine macrophages. The sensor shows good repeatability, a long lifetime, and a fast response to pH changes, and can be
used for a variety of bacteria. 相似文献
163.
Mi-Young Song Gil-Saeng Jeong Kang-Beom Kwon Sun-O Ka Hyun-Young Jang Jin-Woo Park Youn-Chul Kim Byung-Hyun Park 《Experimental & molecular medicine》2010,42(9):628-638
NF-κB activation has been implicated as a key signaling mechanism for pancreatic β-cell damage. Sulfuretin is one of the main flavonoids produced by Rhus verniciflua, which is reported to inhibit the inflammatory response by suppressing the NF-κB pathway. Therefore, we isolated sulfuretin from Rhus verniciflua and evaluated if sulfuretin could inhibit cytokine- or streptozotocin-induced β-cell damage. Rat insulinoma RINm5F cells and isolated rat islets were treated with IL-1β and IFN-γ to induce cytotoxicity. Incubation of cells and islets with sulfuretin resulted in a significant reduction of cytokine-induced NF-κB activation and its downstream events, iNOS expression, and nitric oxide production. The cytotoxic effects of cytokines were completely abolished when cells or islets were pretreated with sulfuretin. The protective effect of sulfuretin was further demonstrated by normal insulin secretion of cytokine-treated islets in response to glucose. Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by immunohistochemical staining of islets. However, the diabetogenic effects of streptozotocin were completely prevented when mice were pretreated with sulfuretin. The anti-diabetogenic effects of sulfuretin were also mediated by suppression of NF-κB activation. Collectively, these results indicate that sulfuretin may have therapeutic value in preventing β-cell damage. 相似文献
164.
Yeon-Su Chae Seung-Hee Lee Ye-Hwang Cheang Nuribalhae Lee Young-Soo Rim Deok-Jin Jang Bong-Kiun Kaang 《Experimental & molecular medicine》2010,42(1):30-37
The cytoplasmic polyadenylation element (CPE)-binding protein (CPEB) binds to CPE containing mRNAs on their 3'' untranslated regions (3''UTRs). This RNA binding protein comes out many important tasks, especially in learning and memory, by modifying the translational efficiency of target mRNAs via poly (A) tailing. Overexpressed CPEB has been reported to induce the formation of stress granules (SGs), a sort of RNA granule in mammalian cell lines. RNA granule is considered to be a potentially important factor in learning and memory. However, there is no study about RNA granule in Aplysia. To examine whether an Aplysia CPEB, ApCPEB1, forms RNA granules, we overexpressed ApCPEB1-EGFP in Aplysia sensory neurons. Consistent with the localization of mammalian CPEB, overexpressed ApCPEB1 formed granular structures, and was colocalized with RNAs and another RNA binding protein, ApCPEB, showing that ApCPEB1 positive granules are RNA-protein complexes. In addition, ApCPEB1 has a high turnover rate in RNA granules which were mobile structures. Thus, our results indicate that overexpressed ApCPEB1 is incorporated into RNA granule which is a dynamic structure in Aplysia sensory neuron. We propose that ApCPEB1 granule might modulate translation, as other RNA granules do, and furthermore, influence memory. 相似文献
165.
166.
Min Kyong Moon Min Kim Sung Soo Chung Hyun Joo Lee Sung Hee Koh Peter Svovoda Myung Hee Jung Young Min Cho Young Joo Park Sung Hee Choi Hak Chul Jang Kyong Soo Park Hong Kyu Lee 《Experimental & molecular medicine》2010,42(5):345-352
An association between inflammatory processes and the pathogenesis of insulin resistance has been increasingly suggested. The IκB kinase-β (IKK-β)/ nuclear factor-κB (NF-κB) pathway is a molecular mediator of insulin resistance. S-Adenosyl-L-methionine (SAM) has both antioxidative and anti-inflammatory properties. We investigated the effects of SAM on the glucose transport and insulin signaling impaired by the tumor necrosis factor α (TNFα) in 3T3-L1 adipocytes. SAM partially reversed the basal and insulin stimulated glucose transport, which was impaired by TNFα. The TNFα-induced suppression of the tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1) and Akt in 3T3-L1 adipocytes was also reversed by SAM. In addition, SAM significantly attenuated the TNFα-induced degradation of IκB-α and NF-κB activation. Interestingly, SAM directly inhibited the kinase activity of IKK-β in vitro. These results suggest that SAM can alleviate TNFα mediated-insulin resistance by inhibiting the IKK-β/NF-κB pathway and thus can have a beneficial role in the treatment of type 2 diabetes mellitus. 相似文献
167.
Jo E Jhon YH Choi SB Shim JG Kim JH Lee JH Lee IY Jang KR Kim J 《Chemical communications (Cambridge, England)》2010,46(48):9158-9160
A crystal structure of a carbamate of 2-amino-2-methyl-1-propanol (AMP-carbamate) has been elucidated and its structural and electronic properties investigated by density functional theory calculations and natural bond orbital analyses. 相似文献
168.
Jang JS Ham DJ Ramasamy E Lee J Lee JS 《Chemical communications (Cambridge, England)》2010,46(45):8600-8602
Mesoporous tungsten carbides displayed an excellent solar conversion efficiency (7.01%) as a counter electrode for dye sensitized solar cells under 100 mW cm(-2), AM 1.5G illumination, which corresponded to ca. 85% of the efficiency of the conventional platinum electrode. 相似文献
169.
Chang Yeon Lee Dr. Jae Kwon Jang Chul Hoon Kim Dr. Jaehoon Jung Bo Keun Park Dr. Jihee Park Wonyong Choi Prof. Young‐Kyu Han Dr. Taiha Joo Prof. Joon T. Park Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(19):5586-5599
A new artificial photosynthetic triad array, a [60]fullerene–triosmium cluster/zinc–porphyrin/boron–dipyrrin complex ( 1 , Os3C60/ZnP/Bodipy), has been prepared by decarbonylation of Os3(CO)8(CN(CH2)3Si(OEt)3)(μ3‐η2:η2:η2‐C60) ( 6 ) with Me3NO/MeCN and subsequent reaction with the isocyanide ligand CNZnP/Bodipy ( 5 ) containing zinc porphyrin (ZnP) and boron dipyrrin (Bodipy) moieties. Triad 1 has been characterized by various spectroscopic methods (MS, NMR, IR, UV/Vis, photoluminescence, and transient absorption spectroscopy). The electrochemical properties of 1 in chlorobenzene (CB) have been examined by cyclic voltammetry; the general feature of the cyclic voltammogram of 1 is nine reversible one‐electron redox couples, that is, the sum of those of 5 and 6 . DFT has been applied to study the molecular and electronic structures of 1 . On the basis of fluorescence‐lifetime measurements and transient absorption spectroscopic data, 1 undergoes an efficient energy transfer from Bodipy to ZnP and a fast electron transfer from ZnP to C60; the detailed kinetics involved in both events have been elucidated. The SAM of triad 1 ( 1 /ITO; ITO=indium–tin oxide) has been prepared by immersion of an ITO electrode in a CB solution of 1 and diazabicyclo‐octane (2:1 equiv), and characterized by UV/Vis absorption spectroscopy, water contact angle, X‐ray photoelectron spectroscopy, and cyclic voltammetry. The photoelectrochemical properties of 1 /ITO have been investigated by a standard three‐electrode system in the presence of an ascorbic acid sacrificial electron donor. The quantum yield of the photoelectrochemical cell has been estimated to be 29 % based on the number of photons absorbed by the chromophores. Our triad 1 is unique when compared to previously reported photoinduced electron‐transfer arrays, in that C60 is linked by π bonding with little perturbation of the C60 electron delocalization. 相似文献
170.
Sang Eok Jang 《Journal of luminescence》2011,131(12):2788-2791
High efficiency single layer blue phosphorescent organic light-emitting diodes (PHOLEDs) without any charge transport layer were developed. A mixed host of spirobifluorene based phosphine oxide (SPPO13) and 1, 1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) was used as the host in the emitting layer. A high maximum external quantum efficiency of 15.8% and a quantum efficiency of 8.6% at 1000 cd/m2 were achieved in the single-layer blue PHOLEDs without any charge transport layer. The maximum power efficiency and power efficiency at 1000 cd/m2 were 31.4 and 16.9 lm/W, respectively. 相似文献