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781.
Wei Sun Linjie Tian Hui Qi Dan Jiang Ying Wang Song Li Junhai Xiao Xiaohong Yang 《中国化学》2013,(9):1144-1152
A series of tri-substituted chiral pyrrolidin-2-one derivatives have been designed and synthesized as CC chemokine receptor 4 (CCR4) antagonists. The structure of CCR4 was built by homology modeling. Asymmetric synthesis was applied to synthesize the R,R configuration chiral pyrrolidin-2-one scaffold. The stereoisomeric con- figurations of the compounds were identified by 2D I H-~H COSY spectroscopy and 1D NOESY spectroscopy. This method was more economical and convenient than traditional X-ray single crystal diffraction. In addition, the inter- actions between these compounds and the N-terminal extracellular tail of CCR4 were studied using capillary zone electrophoresis. The CCR4 chemotaxis inhibition effect was tested in CCR4-transfected HEK293 cells. Several compounds showed potent activities as CCR4 antagonists. Among these compounds, lc is the most active one. Its apparent binding constant of CZE experiment result is (1.569±0.11)× 10s L·mol ^-1, and its percentage inhibition of the HEK293/CCR4 cells migration with the concentration of I gmol·L ^-1 in DMSO is 59%. And compound If has slightly higher affinity to N-terminal of CCR4 according to its apparent binding constant than lb because of the in- troduced ester linkage. Further studies on the mechanism of these compounds are in progress. 相似文献
782.
A novel fluorescent nanoprobe for glutathione S‐transferase (GST) has been developed by incorporating 3,4‐dinitrobenzamide (a specific substrate of GST) onto CdTe/ZnTe quantum dots. The probe itself displays a low background signal due to the strong quenching effect of the electron‐withdrawing unit of 3,4‐dinitrobenzamide on the quantum dots. However, GST can efficiently catalyze the nucleophilic substitution of reduced glutathione on the p‐nitro group of the nanoprobe, leading to a large fluorescence enhancement. Most notably, this enhancement shows high selectivity and sensitivity towards GST instead of the other biological substances. With this nanoprobe, a simple fluorescence imaging method for intracellular GST has been established, and its applicability has been successfully demonstrated for imaging GST in different living cells, which reveals that A549 cells express GST about 3 times higher than NIH‐3T3 and Hela cells. 相似文献
783.
Yang Sun Zhipeng Ran Hongyan Tang Yong Li Wenshuang Song Qingguang Ren Wuli Yang Jilie Kong 《中国化学》2013,31(6):787-793
Mesoporous silica nanoparticles (MSN) were coated by pH‐responsive polymer chitosan‐poly (methacrylic acid) (CS‐PMAA). This nano drug delivery system showed good application prospects and the polymer‐coated microspheres were promising site‐specific anticancer drug delivery carriers in biomedical field. A continuous detection of pH‐responsive drug delivery system in cells in situ, utilizing MSN/CS‐PMAA composite microspheres, was proposed. Two kinds of different cell lines, tumor cell line (Hela) and normal somatic cells (293T), were used to investigate the behaviours of the drug loaded system in the cells. Conclusions could be drawn from the fluorescent images obtained by confocal laser scanning microscopy (CLSM), modified drug‐loaded microspheres (MSN/CS‐PMAA) were ingested into cells more easily, the uptake of DOX@FITC‐MSN/CS‐PMAA by HeLa/293T cells were performed at pH 7.4/pH 6.8, DOX was released during the ingestion process, fluorescence intensity decreased with time because of efflux transport and photo‐bleaching. Fluoresence detection by flow cytometry was performed as comparison. The continuous fluorescent observation in situ could be widely used in the pH‐responsive releasing process of drug delivery system in the cells. 相似文献
784.
合成了1种含四氯合钴配阴离子的4-氯苄基吡啶季铵盐[4-ClBzPy]2[CoCl4];利用元素分析仪、X射线单晶衍射仪以及紫外光谱仪和红外光谱仪等分析了其组成、晶体结构及光谱学性质;利用电导仪测定了[4-ClBzPy]2[CoCl4]的电导,并检测了其对金黄色葡萄球菌和大肠杆菌的抗菌活性.结果表明,合成的[4-ClBzPy]2[CoCl4]季铵盐为单斜晶系,P2(1)/c空间群,晶胞参数为a=0.769 5(13)nm,b=1.895 1(3)nm,c=0.946 3(15)nm,β=93.183(2)°,V=1.378 0(4)nm3,Z=2,Dc=1.470g/cm3,GOOF=1.007,R1=0.041 8,wR2=0.100 2.与此同时,季铵盐[4-ClBzPy]2[CoCl4]对金黄色葡萄球菌和大肠杆菌均具有较好的抗菌活性. 相似文献
785.
采用电感耦合等离子体原子发射光谱法(ICP-AES)法测定钛合金中W,Nb,Ta元素的含量。样品采用盐酸、氢氟酸和硝酸溶解,并对仪器工作参数和试验条件进行了优化试验,确定了仪器最佳工作条件,考察了钛合金基体和共存元素对待测元素的影响,确定了各待测元素谱线为W207.911nm,Nb309.418nm,Ta240.063nm。选定的待测元素分析线不受合金基体和共存元素的干扰,通过基体匹配消除基体的影响。加标回收率在98%104%之间,测定结果的相对标准偏差为0.3%~2.4%(n=8),方法的检出限为0.003-0.013μg/mL。进行了标准物质对照试验,试验结果与标准值相符。 相似文献
786.
787.
Ik Hyun Kwon Hye Ryoung Park Young Youp Song 《Russian Journal of Electrochemistry》2013,49(3):221-227
LiNi1 ? y Ti y O2 (0.000 ≤ y ≤ 0.100) and LiNi0.990M0.010O2 (M = Zn, Al, and Ti) were synthesized by the combustion method. The effects of Zn, Al and Ti substitution for Ni of LiNiO2 on the electrochemical properties of LiNiO2 were investigated. LiNi0.995Ti0.005O2 has the largest first discharge capacity (188.1 mA h/g) among the Ti-substituted samples. LiNi0.990Ti0.010O2 has a relatively large first discharge capacity (185.5 mA h/g) and a relatively good cycling performance. Among LiNi0.990M0.010O2 (M = Ni, Zn, Al, and Ti), LiNiO2 has the largest discharge capacities at a rate of 0.1 C from n = 1(189.3 mA h/g) to n = 10. LiNi0.990Al0.010O2 has the lowest discharge capacities from n = 1 to n = 10, but it has the best cycling performance. LiNi0.990Zn0.010O2 showed poor crystallinity, LiNi0.990Ti0.010O2 showed high cation mixing, and LiNi0.990Al0.010O2 had good crystallinity and showed low cation mixing. Fewer occurrence of phase transitions and the least change of the ?dx/|dV| vs. voltage curve at the second cycle from the curve at the first cycle of LiNi0.990Al0.010O2 suggest that Al substitution stabilizes the structure and leads to a good cycling performance. 相似文献
788.
Arbia Khemiri Bertrand Naudin Xavier Franck Philippe Chan Tchi Song Thierry Jouenne Pascal Cosette 《Analytical and bioanalytical chemistry》2013,405(30):9835-9842
In prokaryote organisms, N-glycosylation of proteins is often correlated to cell–cell recognition and extracellular events. Those glycoproteins are potential targets for infection control. To date, many surface-glycosylated proteins from bacterial pathogens have been described. However, N-linked Pseudomonas surface-associated glycoproteins remain underexplored. We report a combined enrichment and labeling strategy to identify major glycoproteins on the outside of microorganisms. More precisely, bacteria were exposed to a mix of biotinylated lectins able to bind with glycoproteins. The latter were then recovered by avidin beads, digested with trypsin, and submitted to mass spectrometry. The targeted mixture of glycoproteins was additionally deglycosylated in the presence of H2 18O to incorporate 18O during PNGase F treatment and were also analyzed using mass spectrometry. This approach allowed us to identify a few tens of potential N-glycoproteins, among which flagellin FliC was the most abundant. To detect the possible sites of FliC modifications, a de novo sequencing step was also performed to discriminate between spontaneous deamidation and N-glycan loss. This approach led to the proposal of three potential N-glycosylated sites on the primary sequence of FliC: N26, N69, and N439, with two of these three asparagines belonging to an N-X-(S/T) consensus sequence. These observations suggest that flagellin FliC is a heterogeneous protein mixture containing both O- and N-glycoforms. Figure
Analytical scenario developed for bacterial glycoprotein enrichment. This strategy includes three main steps: (1) exposure of Pseudomonas aeruginosa cells to a mixture of biotinylated lectins [wheat germ agglutinin (WGA) and concanavalin A (ConA)]; (2) enrichment of N-glycoproteins by elution with avidin beads; and (3) mass spectrometry (MS) identification and characterization of intact and deglycosylated peptides before and after H2 18O PNGase F enzymatic treatment, respectively 相似文献
789.
Mingqiang Li Shixian Lv Zhaohui Tang Wantong Song Haiyang Yu Hai Sun Huaiyu Liu Xuesi Chen 《Macromolecular bioscience》2013,13(9):1150-1162
Rapid and efficient side‐chain functionalization of polypeptide with neighboring carboxylgroups is achieved via the combination of ring‐opening polymerization and subsequent thiol‐yne click chemistry. The spontaneous formation of polymersomes with uniform size is found to occur in aqueous medium via electrostatic interaction between the anionic polypeptide and cationic doxorubicin hydrochloride (DOX·HCl). The polymersomes are taken up by A549 cells via endocytosis, with a slightly lower cytotoxicity compared with free DOX ·HCl. Moreover, the drug‐loaded polymersomes exhibit the enhanced therapeutic efficacy, increase apoptosis in tumor tissues, and reduce systemic toxicity in nude mice bearing A549 lung cancer xenograft, in comparison with free DOX ·HCl. 相似文献
790.
Hongbin Zhu Shu Liu Xue Li Fengrui Song Zhiqiang Liu Shuying Liu 《Analytical and bioanalytical chemistry》2013,405(23):7437-7445
A novel fingerprinting method, bioactivity fingerprint analysis, based on an ultrafiltration–ultraperformance liquid chromatography–multistage tandem mass spectrometry (UPLC–MS n ) method is proposed for the quality control of herbal medicines from the bioactivity viewpoint concerning the efficacy of herbal medicines. The bioactivity fingerprints reflecting the anti-inflammatory activities of radix Aconiti and radix Aconiti preparata were established. With use of ultrafiltration UPLC–MS n , 11 cyclooxygenase-2 ligands from radix Aconiti preparata and 14 cyclooxygenase-2 ligands from radix Aconiti were found after incubation with cyclooxygenase-2. Twelve of the cyclooxygenase-2 ligands were identified by the ultraperformance UPLC–MS n method. The enrichment factor of each peak in the bioactivity fingerprint was calculated and was demonstrated to be characteristic, which makes bioactivity fingerprint analysis for the quality control of herbal medicines possible from the viewpoint of their bioactivities. Figure
Bioactivity fingerprint analysis is defined as the chromatograms and spectra of the complex system of effective constituents containing information on their pharmacodynamic activities 相似文献