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181.
Zhuo Li Yang Zhang Fang-Hong Tong Ting-Ting Jiang Hui-Ping Zheng Jian-Nong Ye Qing-Cui Chu 《中国化学快报》2014,25(4):640-644
A hollow-fiber liquid-phase microextraction (HF-LPME) method has been developed for the purification and preconcentration of biogenic polyamines and their precursor amino acids in human saliva. Putrescine (Put), cadaverine (Cad), spermidine (Spe), ornithine (Orn), lysine (Lys), and arginine (Arg) were determined by the CE-LIF detection after microextraction. Several factors that affect extraction efficiency, separation, and detection were investigated. Under the optimum conditions, six analytes could achieve baseline separation within 30 min, exhibiting a linear calibration at three orders of magnitude (r2 〉 0.998); the obtained enrichment factors of HF-LPME were between 19 (for Orn) and 2] 8 (for Cad), and the LODs were in the range of 0.0072-0.26 nmol/L. The proposed HF-LPME/CE-LIF method has been successfully applied for the sensitive analyses of the real-world saliva samples collected from healthy volunteers and different patients with oral diseases, providing a potential method for primary non-invasive diagnosis of some oral diseases. 相似文献
182.
Hong Zhu Feng Wen Peng Li Xiang Liu Jianmei Cao Min Jiang Feng Ming Zhaoqing Chu 《Applied biochemistry and biotechnology》2014,172(6):3163-3175
Brachypodium distachyon has been proposed as a new model system for gramineous plants with a sequenced genome and an efficient transformation system. Many transgenic B. distachyon plants have been generated in recent years. To develop a reliable fast method for detecting transgenic B. distachyon and quantifying its transgene copy numbers, a species-specific reference gene is of great priority to be validated both in qualitative PCR and quantitative real-time PCR detection. In this study, we first proved that the BdFIM (B. distachyon fimbrin-like protein) gene is a suitable reference gene in qualitative PCR and quantitative real-time PCR for B. distachyon. Fourteen different B. distachyon varieties were tested by both qualitative and quantitative PCRs, and identical amplification products of BdFIM were obtained with all of them, while no amplification products were observed with samples from 14 other plant species, suggesting that BdFIM gene was specific to B. distachyon. The results of Southern blot analysis revealed that the BdFIM gene was low copy number in seven tested B. distachyon varieties. In conclusion, the BdFIM gene can be used as a reference gene, since it had species specificity, low heterogeneity, and low copy number among the tested B. distachyon varieties. Furthermore, the copy number of inserted sequences from transgenic B. distachyon obtained by real-time PCR methods and Southern blot confirmed that the BdFIM gene was an applicable reference gene in B. distachyon. 相似文献
183.
Cheng-Li Wang Weng-Sing Hwang Hsueh-Liang Chu Feng-Lin Yen Chi-Yuen Hwang Chi-Shiung Hsi Huey-Er Lee Moo-Chin Wang 《Journal of Sol-Gel Science and Technology》2014,70(3):428-440
The phase transformation and crystalline growth of 4 mol% yttria partially stabilized zirconia (4Y-PSZ) precursor powders have been investigated using the coprecipitation route, using zirconium oxide chloride octahydrate (ZrOCl2·8H2O) and yttrium nitrate (Y(NO3)3·6H2O) as the initial materials. Differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), nano beam electron diffraction (NBED), and high resolution TEM (HRTEM) were utilized to characterize the behavior of phase transformation and crystalline growth of the 4Y-PSZ precursor powders after calcined. Tetragonal ZrO2 crystallization occurred at about 718.2 K. The activation energy of tetragonal ZrO2 crystallization was 227.0 ± 17.4 kJ/mol, obtained by a non-isothermal method. The growth morphology parameter (n) and growth mechanism index were close to 2.0, showing that tetragonal ZrO2 had a plate-like morphology. The crystalline size of tetragonal ZrO2 increased from 7.9 to 27.6 nm when the calcination temperature was increased from 973 to 1,273 K. The activation energies of tetragonal ZrO2 growth were 14.97 ± 0.33 and 84.46 ± 6.65 kJ/mol when precursor powders after calcined from 723–973 and 973–1,273 K, respectively. 相似文献
184.
Dr. Nan Chen Dr. Yuan Liu Yuanpei Li Prof. Dr. Chu Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16203-16209
Protein 4′-phosphopantetheinylation is an essential post-translational modification (PTM) in prokaryotes and eukaryotes. So far, only five protein substrates of this specific PTM have been discovered in mammalian cells. These proteins are known to perform important functions, including fatty acid biosynthesis and folate metabolism, as well as β-alanine activation. To explore existing and new substrates of 4′-phosphopantetheinylation in mammalian proteomes, we designed and synthesized a series of new pantetheine analogue probes, enabling effective metabolic labelling of 4′-phosphopantetheinylated proteins in HepG2 cells. In combination with a quantitative chemical proteomic platform, we enriched and identified all the currently known 4′-phosphopantetheinylated proteins with high confidence, and unambiguously determined their exact sites of modification. More encouragingly, we discovered, using targeted chemical proteomics, a potential 4′-phosphopantetheinylation site in the protein of mitochondrial dehydrogenase/reductase SDR family member 2 (DHRS2). 相似文献
185.
Qingyun Zheng Tian Wang Guo-Chao Chu Chong Zuo Rui Zhao Xin Sui Linzhi Ye Yuanyuan Yu Jingnan Chen Xiangwei Wu Wenhao Zhang Prof. Haiteng Deng Prof. Jing Shi Dr. Man Pan Prof. Yi-Ming Li Prof. Lei Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13598-13603
Triazole-based deubiquitylase (DUB)-resistant ubiquitin (Ub) probes have recently emerged as effective tools for the discovery of Ub chain-specific interactors in proteomic studies, but their structural diversity is limited. A new family of DUB-resistant Ub probes is reported based on isopeptide-N-ethylated dimeric or polymeric Ub chains, which can be efficiently prepared by a one-pot, ubiquitin-activating enzyme (E1)-catalyzed condensation reaction of recombinant Ub precursors to give various homotypic and even branched Ub probes at multi-milligram scale. Proteomic studies using label-free quantitative (LFQ) MS indicated that the isopeptide-N-ethylated Ub probes may complement the triazole-based probes in the study of Ub interactome. Our study highlights the utility of modern protein synthetic chemistry to develop structurally and new families of tool molecules needed for proteomic studies. 相似文献
186.
Dr. Chao Wang Min Hu Dr. Yueying Chu Xue Zhou Dr. Qiang Wang Dr. Guodong Qi Dr. Shenhui Li Prof. Dr. Jun Xu Prof. Dr. Feng Deng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7265-7269
The understanding of catalyst deactivation represents one of the major challenges for the methanol-to-hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π-interactions in catalyst deactivation in the MTH reaction on zeolites H-SSZ-13 and H-ZSM-5. π-interaction-induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two-dimensional solid-state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology. 相似文献
187.
Chaonan Mu Wei Wang Jie Wang Chu Gong Dongmei Zhang Prof. Dr. Xinxing Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(48):21699-21703
While Type I and Type II photosensitizers are often carefully tailored to achieve their respective advantages in treating different cancers, the identifications of the Type I and II mechanisms as such, the key reaction intermediates, and the consequent oxidation products of the substrates have never been easy. Using our unique home-built field-induced droplet ionization mass spectrometry (FIDI-MS) method that selectively samples molecules at the air–water interface, here we show the facile determination of both Type I and II mechanisms of a poster-child photosensitizer, temoporfin, without the addition of any probes. The unstable doublet radical resulting from the hydrogen abstraction by the triplet temoporfin through the Type I mechanism is captured, manifesting the in situ advantage of FIDI-MS. We anticipate that the method developed in this study can be widely utilized in the future designs of novel photosensitizers and the screening of their photosensitization mechanisms. 相似文献
188.
Two new fluorescent coordination polymers based on pamoic acid and different polydentate N-donor ligands, namely {[Cd(PA)(TPTZ)(H2O)](DMF)2}n ( 1 ) and [Cd(PA)(BIB)]n ( 2 ) [H2PA = pamoic acid, TPTZ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, BIB = 1,4-bis(1-imidazolyl)benzene], were synthesized and characterized. Complex 1 showed a 1D zigzag chain structure with intramolecular hydrogen bonds. The 2D supramolecular structure in 1 was formed through π–π stacking interactions and intermolecular hydrogen bonds. Complex 2 displayed a 2D network structure. Intramolecular hydrogen bonds and π–π stacking interactions were observed in 2 . By studying the fluorescence sensing performance of two coordination polymers, complex 1 exhibited high selectivity for tracking Al3+ ion and complex 2 could discriminately detect inorganic or aliphatic amines with high selectivity. 相似文献
189.
Zhen Zhang Ying-Lin Gu Zheng-Yang Wang Huan-Nan Wang Yan Zhao Xue-Mei Chu Chun-Yan Zhang Mao-Cai Yan 《Journal of heterocyclic chemistry》2020,57(3):1165-1172
Novel indole amide derivatives C1-C10 were successfully synthesized and characterized by 1H NMR, 13C NMR, IR, MS, and elemental analysis, and their molecular formulas were C14H10N6O, C13H10N4O, C16H13N3O2, C19H14N2O2, C16H11N3OS, C15H13N3O, C12H9N5O, C16H10ClN3OS, C15H17N3O2, and C13H14N2O3, respectively. The primary biological activities of these compounds were evaluated in vitro by the DPPH assay, H2O2-induced oxidative stress injury assay, and cytotoxicity assay. The results indicated that compounds C1, C2, C4, C7, and C9 exhibited DPPH·scavenging ability, while C3, C4, C5, and C8 showed potent growth-inhibitory activities against various human tumor cells, including MDA-MB-231, Hela, A549, and HT29. Interestingly, compound C4 showed potent scavenging effects on the DPPH radical and possessed protective effect on H2O2-induced oxidative stress injury in human neuroblastoma SH-SY5Y cells at low concentrations; however, C4 exhibited significant toxicity against four human tumor cells at a higher concentration in all treatments, and the range of IC50 value was 7.91 to 13.35 μM. 相似文献
190.
ABSTRACTA short-focus microlens array using dielectric layer and inhomogeneous electric field over a homogeneous nematic liquid crystal (LC) layer is proposed. The top substrate has a planar indium tin oxide (ITO) electrode which is coated on the inner surface. The bottom substrate has strip ITO electrodes which are embedded in the dielectric layers. The inhomogeneous electric field generates a required gradient refractive index profile within the LC layer which, in turn, causes the focusing effect. Due to the thinner LC layer (15 μm), the spherical aberration should be negligible. Moreover, the fabrication process of the proposed microlens array can be easily carried out because of the layer-by-layer configuration. The simulation results show that the focal length of the LC microlens can be continuously tuned from infinity to 0.988 mm with the change of applied voltage. 相似文献