APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2015
·Vol. 178
·期 8
·1471-1480
·
IF 1.735
Zheng Jian-yong,Liu Yin-yan,Luo Wei-feng,Zheng Ren-chao,Ying Xiang-xian,Wang Zhao
A new esterase-producing strain ( Bacillus cereus WZZ001) which exhibiting high hydrolytic activity and excellent enantioselectivity on rac -α-ethyl-2-oxo-pyrrolidineacetic acid methyl ester ( R , S - 1 ) has been isolated from soil sample by our laboratory. In this study, the stereoselective hydrolysis of ( R , S - 1 ) was performed using the recombinant Bacillus cereus esterase which expressed in Escherichia coli BL21 (DE3). Under the optimized conditions of pH 8.0, 35 °C, and concentration of substrate 400 mM, a successful enzymatic resolution was achieved with an e.e.
s of 99.5 % and conversion of 49 %. Immobilization considerably increased the reusability of the recombinant esterase; the immobilized enzyme showed excellent reusability during 6 cycles of repeated 2 h reactions at 35 °C. Thereby, it makes the recombinant B. cereus esterase a usable biocatalyst for industrial application.
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 49
·25933-25939
·
IF 3.708
Qingfeng Liu,Yansen Zhang,Zhiguo Zhang,Tongxin Liu,Lei Shi,Guisheng Zhang
This paper describes a highly efficient and facile transformation of substituted oxazolidin-2-ones to methylene-bridged 3,3′-bis(oxazolidin-2-one) derivatives in a mixture solvent of CH2Cl2 (DCM) and N,N-dimethylformamide (DMF) in the presence of NaH at ambient temperature. Isotopic labeling experiments indicated that the C of the bridged methylene group was derived from CH2Cl2 instead of DMF and other unknown substances in the NaH reagent (60% dispersion in mineral oil).
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POLYMER COMPOSITES
·
2014
·Vol. 36
·期 9
·1597-1605
·
IF 1.455
Ruxangul Jamal,Ahmat Ali,Li Zhang,Yakupjan Osman,Adalet Rahman,Tursun Abdiryim
Poly(3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene)/ZnO(poly(TET)/ZnO) composites with the ratio of poly(TET) and nano-ZnO from 3:1 to 1:3 were synthesized by hand grinding and ball milling methods, respectively. The photocatalytic activities of the composites were examined through the degradation processes of methylene blue (MB) solution under UV light irradiation, and the possible mechanism for the photocatalytic activity enhancement by synergetic effects between nano-ZnO and poly(TET) was proposed. The results showed that the strong interactions between the poly(TET) and nano-ZnO occurred in the case of ball milling method. The results also proved that the crystallinity of ZnO was not disturbed in both of methods, and the nano-ZnO was uniformly distributed in polymer matrix in the case of ball milling method. The comparative studies showed that the addition of the nano-ZnO could enhance the photocatalytic activities of the composites. The highest degradation efficiency (100%) at 3 h under UV light irradiation occurred in the case of poly(TET)/ZnO(1:1) synthesized by ball milling method. Furthermore, the nanocompsosite displayed higher photocatalytic activity than nano-ZnO, which was due to the holes ( h + ) transferring from the valence band of ZnO to the polymer backbone and the adsorption of MB molecules in polymer matrix via π–π conjugation between MB and aromatic regions of the poly(TET). POLYM. COMPOS., 36:1597–1605, 2015. © 2014 Society of Plastics Engineers
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JOURNAL OF APPLIED POLYMER SCIENCE
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2016
·Vol. 133
·期 31
·
IF 1.866
Wu Kuang,Zhongnan Liu,Guodong Kang,Dandan Liu,Meiqing Zhou,Yiming Cao
The poly(2-hydroxyethyl methacrylate) grafted titanium dioxide nanoparticles were synthesized and added to the substrate of flat-sheet thin film composite forward osmosis (TFC-FO) membranes. The hydrophilicity of substrate was improved, which was advantageous to enhance the water flux of TFC-FO membranes. The membranes containing a 3 wt % TiO 2 -PHEMA in the substrate exhibited a finger-like structure combined with sponge-like structure, while those with lower or without TiO 2 -PHEMA content showed fully finger-like structures. As for FO performance, the TFC-FO membranes with 3 wt % TiO 2 -PHEMA content achieved the highest water flux of 42.8 LMH and 24.2 LMH against the DI water using 2 M NaCl as the draw solution tested under the active layer against draw solution (AL-DS) mode and active layer against feed solution (AL-FS) mode, respectively. It was proven that the hydrophilic property of membrane substrates was a strong factor influencing the water flux in FO tests. Furthermore, the structural parameter was remarkably decreased with an increase of TiO 2 -PHEMA content in membrane substrate, indicating the reducing of internal concentration polarization. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43719.
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Polymer Chemistry
·
2016
·Vol. 7
·期 20
·3423-3433
·
IF 5.687
Ke Wang,Zefeng Song,Chonggao Liu,Wangqing Zhang
The thermo- and pH/CO2-responsive poly[N-[2-(dialkylamino)ethyl]acrylamide]s containing a polyacrylamide backbone but different N-substitutes of dialkylamine were synthesized and their solution properties were comparatively checked. A controllable RAFT synthesis of poly[N-[2-(dialkylamino)ethyl]acrylamide]s was achieved when a typical trithiocarbonate containing an easily cleavable R group was employed. The RAFT polymerization rate decreases with the increasing C-number in the N-substitutes. The thermo- and pH/CO2-responsive property of poly[N-[2-(dialkylamino)ethyl]acrylamide]s is firmly correlative to the N-substitutes. With the C-number in the R-substitute increasing, the solution properties of poly(N-[2-(dialkylamino)ethyl]acrylamide)s undergo a soluble-to-thermoresponsive-to-insoluble evolution, and the critical pH of poly[N-[2-(dialkylamino)ethyl]acrylamide]s gradually decreases. The dialkylamine moieties in the poly[N-[2-(dialkylamino)ethyl]acrylamide]s lead to a characteristic CO2-response during CO2/N2 bubbling. The present study reveals the structure-dependent solution properties of the thermo- and pH/CO2-responsive poly[N-[2-(dialkylamino)ethyl]acrylamide]s, and these multistimuli-responsive polymers are believed to be very useful due to the controllable RAFT synthesis and tunable solution properties.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2017
·
IF 3.012
Waqar Uddin,Gang Hu,Lin Hu,Yanyang Hu,Zhaohui Fang,Rooh Ullah,Xuanxuan Sun,Yu Zhang,Jimei Song
A new technique for identification of two aromatic isomers between 2-hydroxy benzoic acid (2-HBA) and 3-hydroxy benzoic acid (3-HBA) was finalized by using their perturbation effects on a Briggs-Rauscher (BR) oscillator, in which a tetraazamacrocyclic Ni complex, [NiL](ClO 4 ) 2 was used as catalyst. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. By putting two isomers into this BR oscillator, the 2-HBA caused a decrease in potential (amplitudes), an increase in the period of oscillation (∆ T) and a decrease in number of the oscillation cycle (n) while no influences of 3-HBA on the BR oscillation were observed. Hence, these two aromatic isomers of hydroxy benzoic acid (HBA) were identified in the range from 1 × 10 − 5 to 2.2 × 10 − 4 mol L − 1 . Reaction mechanism of BR has been proposed with reference to the NF and FCA models. An explanation of perturbation mechanism for the BR is that, only 2-HBA reacted with IO 2 • to form 1,2-quinone while the 3-HBA didn't.
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RSC Advances
·
2016
·Vol. 6
·期 18
·15210-15219
·
IF 3.289
Zhi Cheng,Shi Mo,Jing Jia,Ji Feng,Hong Qun Luo,Nian Bing Li
The inhibition effect of 4,6-diamino-2-mercaptopyrimidine (DAMP) as a copper corrosion inhibitor in 3.5 wt% NaCl solution was investigated by weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization. The inhibition efficiency increased with increasing DAMP concentration in the range of 1.0 to 2.0 mM DAMP and decreased with increasing temperature. The obtained results showed that DAMP inhibited both the anodic and cathodic currents and the maximum inhibition efficiency reached 93.2% at 2.0 mM DAMP. The inhibition performance of DAMP was confirmed by SEM and EDS. Quantum chemical calculations revealed that the DAMP molecule was adsorbed on the copper surface in a paralleled way through S and N atoms and the pyrimidine ring. Adsorption of DAMP was found to obey the Langmuir adsorption isotherm.
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GENE
·
2016
·
IF 2.319
Jing Qian,Chunhua Ren,Jianjun Xia,Ting Chen,Zonghe Yu,Chaoqun Hu
The non-specific protease inhibitor alpha-2-macroglobulin (A 2 M) is a key macromolecular glycoprotein that involved in host immune defense against pathogens in vertebrates and invertebrates. However, no research regarding A 2 M has been developed in echinoderms to date. In this study, the full-length cDNA of A 2 M was cloned from the sea cucumber ( Holothuria atra ), which is a tropical species widely distributed along the coasts of the South China Sea and designated HaA 2 M . HaA 2 M possesses all three conserved functional domains of known A 2 M proteins, including the bait region domain, thioester domain and receptor-binding domain. Compared to fish and shrimp A 2 Ms, the histidine residue from the catalytical regions is well conserved in HaA 2 M. HaA 2 M mRNA was predominantly expressed in coelomocytes and, to a lesser extent, in the body wall, intestine and respiratory tree. A 2 M activity was detected in the coelomic fluids of H. atra . The mRNA expression and activity levels were investigated in the major immune tissues and coelomic fluids of H. atra after challenge with inactivated Vibrio alginolyticus or polyriboinosinic polyribocytidylic acid [Poly (I: C)]. RNA interference (RNAi)-mediated knockdown of HaA 2 M resulted in a significant reduction of HaA 2 M gene transcript level (86%). RNAi-mediated silencing of HaA 2 M gene significantly decreased the A 2 M activity (38%) and increased the number of viable bacteria (2.8-fold) in the coelomic fluids of H. atra infected by V. alginolyticus . Our study, as a whole, supplied the evidences for HaA 2 M as an immune-relevant molecule and it might have multiple functions in the innate immune system of H. atra .
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 25
·7067-7075
·
IF 3.125
Dang Qian,Gao Hongfang,Li Zhejian,Qi Honglan,Gao Qiang,Zhang Chengxiao
A simple and sensitive electrogenerated chemiluminescence biosensor was developed to monitor matrix metalloproteinase 2 (MMP-2) by employing a specific peptide (CGPLGVRGK) as a molecular recognition substrate. Bis(2,2′-bipyridine)-4′-methyl-4-carboxybipyridine-ruthenium N -succinimidyl ester-bis(hexafluorophosphate) (Ru(bpy) 2 (mcbpy-O-Su-ester)(PF 6 ) 2 (Ru1) was used as ECL-emitting species and covalently labeled onto the peptide through NH 2 -containing lysine on the peptide via acylation reaction to form Ru1-peptide as an ECL probe. An ECL peptide-based biosensor was fabricated by self-assembling the ECL probe onto the surface of gold electrode. MMP-2 can specifically cleave the Ru1-peptide on the electrode surface, which led the partly Ru1-peptide to leave the electrode surface and resulted in the decrease of the ECL intensity obtained from the resulted electrode in 0.1 M phosphate-buffered saline (pH 7.4) containing tri- n -propylamine. The decreased ECL intensity was piecewise linear to the concentration of MMP-2 in the range from 1 to 500 ng/mL. Moreover, the ECL biosensor is successfully applied to detection of MMP-2 secreted by living cell, such as HeLa cells. Additionally, the biosensor was also applied to the evaluation of matrix metalloproteinase inhibitors. The strategy presented here is promising for other disease-related matrix metalloproteinase assay and matrix metalloproteinase inhibitor profiling with sensitivity and simplicity.
Detection of MMP-2 released from living cells by ECL peptide-based biosensor
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高影响因子
PROGRESS IN ORGANIC COATINGS
·
2016
·
IF 2.632
Jiahui Su,Xiaoxuan Liu,Chengjing Xiong,Hong Huang,Yanyan Cui
In this study, we prepared a novel triblock copolymer, PDMS- b -(PMAEBB- co -PDMAEMA) 2 ( tri -PI) bearing side-chain benzophenone (BP) and coinitiator amine, as a macro-photoinitiator via reversible addition-fragmentation chain transfer (RAFT) copolymerization of the polymerizable photoinitiator 2-(methacryloyloxy)ethyl-2-benzoylbenzoate (MAEBB) and the unsaturated coinitiator amine 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a bifunctional polydimethylsiloxane (PDMS) macro-chain transfer agent (macro-CTA). The structure of synthesized copolymer was confirmed by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance ( 1 H NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The effects of the photoinitiator/coinitiator ratio, concentration, and photoinitiator systems on the photopolymerization kinetics of tri(propylene glycol) diacrylate (TPGDA) were investigated by real-time FT-IR. The mobility of the tri -PI chain segments was proven by X-ray photoelectron spectroscopy (XPS), and the surface morphology of TPGDA curing coatings was studied by scanning electron microscopy (SEM). Results showed that tri-PI strongly suppressed the effect of oxygen inhibition on the photopolymerization system. Tri-PI was also used in the curing of UV-curable waterborne polyurethane acrylate (UV-WPUA) resin to determine its versatility.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2016
·Vol. 18
·期 7
·1-11
·
IF 2.101
He Juan,Lu Xingping,Yu Jie,Wang Li,Song Yonghai
Abstract A novel Co(OH) 2 /glassy carbon electrode (GCE) has been fabricated via metal–organic framework (MOF)-directed method. In the strategy, the Co(BTC, 1,3,5-benzentricarboxylic acid) MOFs/GCE was firstly prepared by alternately immersing GCE in Co 2+ and BTC solution based on a layer-by-layer method. And then, the Co(OH) 2 with hierarchical flake nanostructure/GCE was constructed by immersing Co(BTC) MOFs/GCE into 0.1 M NaOH solution at room temperature. Such strategy improves the distribution of hierarchical Co(OH) 2 nanostructures on electrode surface greatly, enhances the stability of nanomaterials on the electrode surface, and increases the use efficiency of the Co(OH) 2 nanostructures. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and Raman spectra were used to characterize the Co(BTC) MOFs/GCE and Co(OH) 2 /GCE. Based on the hierarchical Co(OH) 2 nanostructures/GCE, a novel and sensitive nonenzymatic glucose sensor was developed. The good performance of the resulted sensor toward the detection of glucose was ascribed to hierarchical flake nanostructures, good mechanical stability, excellent distribution, and large specific surface area of Co(OH) 2 nanostructures. The proposed preparation method is simple, efficient, and cheap . Graphical Abstract
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JOURNAL OF MEMBRANE SCIENCE
·
2016
·
IF 5.557
Yupeng He,Zhi Wang,Songlin Dong,Song Zhao,Zhihua Qiao,Xiaochang Cao,Jixiao Wang,Shichang Wang
Improvement of the performance of CO 2 separation membrane under high temperature is of great importance in industrial applications. In this work, 2-aminoterephthalic acid (AA) was used to chemically cross-link polyvinylamine (PVAm) to fabricate PVAm-AA aqueous solution. PVAm-AA/polysulfone(PSf) composite membrane was then prepared by coating PVAm-AA aqueous solution on PSf support membrane. Through the chemical cross-linking by AA, the polymer chain mobility was restrained, resulting in the enhancement of thermal stability. The introduction of AA also increased the effective carrier content for CO 2 separation. Therefore, CO 2 permeance and CO 2 /gas selectivity of PVAm-AA/PSf membrane under relatively high temperature were greatly improved. For CO 2 /N 2 mixed gas (15/85 by volume), PVAm-AA/PSf membrane showed a CO 2 permeance of 661 Gas Permeation Unit (GPU) and CO 2 /N 2 selectivity of 95 at 0.3 MPa and 120 °C. Excellent performance stability was shown during the operation for 250 h at 120 °C. Moreover, PVAm-AA/PSf membrane displayed excellent separation performance and thermal stability for the separation of CO 2 /CH 4 and CO 2 /H 2 mixed gases.
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