BIORESOURCE TECHNOLOGY
·
2014
·
IF 5.039
Yu-Cai He,Zhi-Cheng Tao,Xian Zhang,Zhen-Xing Yang,Jian-He Xu
An NADH-dependent reductase (CmCR) from Candida magnoliae was discovered by genome mining for carbonyl reductases. After CmCR was overexpressed in Escherichia coli BL21, a robust reductase-producing strain, recombinant E. coli CCZU-K14, was employed for the efficient synthesis of ethyl ( S )-4-chloro-3-hydroxybutanoate (( S )-CHBE) from the reduction of ethyl 4-chloro-3-oxobutanoate (COBE). After the optimization, the optimum reaction conditions were obtained. Notably, E. coli CCZU-K14 had broad substrate specificity in reducing both aliphatic and aromatic substrates, and excellent enantioselectivity of CCZU-K14 was observed for most of the tested substrates, resulting in chiral alcohols of over 99.9% ee . Moreover, COBE at a high concentration of (3000 mM) could be asymmetrically reduced to ( S )-CHBE in the high yield (>99.0%) and high enantiometric excess value (>99.9% ee ) after 14 h. Significantly, E. coli CCZU-K14 shows high potential in the industrial production of ( S )-CHBE and its derivatives (>99.9% ee ).
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高影响因子
NEUROSCIENCE LETTERS
·
2013
·
IF 2.026
Jieming Ye,Zhenhua Liu,Jipeng Wei,Lingli Lu,Yanjun Huang,Lili Luo,Huifang Xie
Sirtuin1 (SIRT1) has protective effects in some neurodegenerative disease models, but it is not clear whether SIRT1 play the same role on inflammation-mediated Parkinson's disease (PD) models. In this study, we firstly established an inflammation environment by stimulating microglial BV-2 cells with the inflammatory agent lipopolysaccharides (LPS), which demonstrated by increasing of the levels of TNF-a, and IL-6 in cultured medium. Then we exposed PC12 cells (a model of catecholaminergic neuronal cells) with the supernant from LPS stimulated BV-2 cells (activated BV-2). PC12 cell apoptosis and SIRT1 involved protection were investigated. The results indicated that treatment with LPS caused significant decrease in SIRT1 expression in activated BV-2 cells, and increased the levels of TNF-a and IL-6, as measured by ELISA, whereas resveratrol (a known SIRT1 activator) suppressed this effect, which was conversely strengthened by sirtinol (a SIRT1 inhibitor), suggesting that SIRT1 may be involved in regulating proinflammatory cytokines from microglial activation. Further, we found that factors derived from activated microglia significantly decreased the level of deacetylation of p53 by reducing the expression of SIRT1, an effect that increased the apoptosis of PC12 and reduced cell viability. The addition of resveratrol could protect PC12 cells from inflammation-mediated damage above-mentioned, while nicotinamide (another SIRT1 inhibitor) treatment had the opposite effect of resveratrol. Together, these data suggests that: SIRT1 inhibits LPS-mediated proinflammatory cytokines release in microglia, and circumvents dopaminergic neurons injury induced by activated microglial-derived factors via p53-caspase-3-dependent mechanism of apoptosis. Thus, upregulation of SIRT1 provides a promising research field for therapeutic intervention in neuroinflammation diseases.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2013
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IF 2.906
Zhixiong Hu,Peng Cheng,Mingli Guo,Weinong Zhang,Yutang Qi
A novel approach of periodate oxidation coupled with high-performance liquid chromatography (HPLC)–fluorescence detection (FLD) for the quantitative determination of 3-chloro-1,2-propanediol (3-MCPD) has been established. The essence of this approach lies in the production of chloroacetaldehyde by the oxidization cleavage of 3-MCPD with sodium periodate and the HPLC analysis of chloroacetaldehyde monitored by an FLD detector after fluorescence derivatization with adenine. The experimental parameters relating to the efficiency of the derivative reaction such as concentration of adenine, chloroacetaldehyde reaction temperature, and time were studied. Under the optimized conditions, the proposed method can provide high sensitivity, good linearity (r2 = 0.999), and repeatability (percent relative standard deviations between 2.57% and 3.44%), the limits of detection and quantification were 0.36 and 1.20 ng/mL, respectively, and the recoveries obtained for water samples were in the range 93.39–97.39%. This method has been successfully applied to the analysis of real water samples. Also this method has been successfully used for the analysis of vegetable oil samples after pretreatment with liquid–liquid extraction; the recoveries obtained by a spiking experiment with soybean oil ranged from 96.27% to 102.42%. In comparison with gas chromatography or gas chromatography–mass spectrometry, the proposed method can provide the advantages of simple instrumental requirement, easy operation, low cost, and high efficiency, thus making this approach another good choice for the sensitive determination of 3-MCPD.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2013
·Vol. 37
·期 8
·2509-2514
·
IF 2.966
Kun Shang,Bing Sun,Jianchao Sun,Jun Li,Shiyun Ai
A novel poly-(3-thiopheneacetic acid) coated Fe3O4@LDHs photocatalyst was prepared and used for the photocatalytic disinfection of bacteria under solar light irradiation. The influencing parameters of the photocatalytic antibacterial activity of the Fe3O4@PTAA-LDHs photocatalyst were optimized against E. coli and S. aureus. Results showed that the Fe3O4@PTAA-LDHs photocatalyst could effectively absorb ultraviolet and visible light. The antibacterial rate could achieve 99.99% when irradiated by solar light with 0.8 mg mL−1 Fe3O4@PTAA-LDHs during 140 min. Moreover, it was confirmed that the ˙OH were generated during the photocatalytic process, which was the major reason for the photocatalytic disinfection. The structural destruction of the bacteria cells that occurred during the bactericidal procedure was observed by TEM images. The novel photocatalyst could have potential applications in the related bactericidal fields.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2017
·
IF 3.615
Bo Xu,Xuejiao Li,Zhiming Chen,Tao Zhang,Cuncheng Li
Pd@MIL-100(Fe) composite nanoparticles were synthesized and characterized by high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction analysis, nitrogen adsorption-desorption analysis, X-ray photoelectron spectroscopic (XPS) analysis, energy-dispersive X-ray spectroscopy (EDS) and element mapping. Due to the local restriction or confinement effect of the unique pore/surface structure within the MIL-100(Fe) nanospheres , small Pd nanoparticle (4–6 nm) were obtained with high stability without using any surfactant as stabilizer . The as-synthesized Pd@MIL-100(Fe) composite nanoparticles were then employed for the catalytic reduction of 2/3/4-nitrophenol, which exhibiting high catalytic activity and recyclability attributed to the synergistic effect between Pd nanoparticles and MIL-100(Fe) nanospheres.
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TETRAHEDRON
·
2017
·
IF 2.651
Bing Lin,Wen-Hui Zhang,Dan-Dan Wang,Yi Gong,Qi-Di Wei,Xiong-Li Liu,Ting-Ting Feng,Ying Zhou,Wei-Cheng Yuan
Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3 via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties and a polycyclic pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 85% yield) with good diastereoselectivity (up to >20:1). Valuable features of this method were application of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles and the design of new hybrid architectures for biological screenings through the adequate fusion of these sub-units of isoxazole and 3,3′-pyrrolidinyl-dispirooxindole, generating drug-like molecules.
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JOURNAL OF MOLECULAR LIQUIDS
·
2016
·
IF 2.74
Dongren Cai,Jinbei Yang,Hairong Da,Ling Li,Hongxing Wang,Ting Qiu
Densities, ρ and viscosities, η of N , N -dimethyl-N-(3-sulfopropyl)cyclohexylammo-nium tosylate ([CyN 1,1 PrSO 3 H][Tos]) with water and methanol were measured, at temperatures from 303.15 K to 328.15 K with 5 K interval and 0.1013 MPa, as a function of [CyN 1,1 PrSO 3 H][Tos] molality (or mass fraction). The isobaric thermal expansion coefficient , molecular volume, standard molar entropy, and lattice energy of the pure IL were obtained based on the density data of pure IL . The apparent molar volume , V φ , infinite dilution apparent molar expansibility, E φ ∞ and energy barrier, E were calculated from the experimental data. The Redlich-Mayer equation was used to evaluate infinite dilution apparent molar volume , V φ ∞ . In addition, viscosities can be described satisfactorily by Vogel-Fulcher-Tammann (VFT) equation. The V φ ∞ values of the IL in water are higher than those in methanol, which suggests that the ion-solvent interactions for [CyN 1,1 PrSO 3 H][Tos] + water binary system are stronger than those for [CyN 1,1 PrSO 3 H][Tos] + methanol. And the energy barrier values decrease with the drop of IL mass fraction in both systems, indicating that the viscosity changes of binary mixtures are more sensitive to the temperature at high composition of the IL.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Sai Lian,Zhiyong Huang,Zhengzhong Lin,Xi Chen,Munetaka Oyama,Xiaomei Chen
In this work, a novel and highly selective molecularly imprinted sensor for the detection of melamine in milk using electrochemiluminescence (ECL) is reported. The preparation was carried out by modification of a glassy carbon electrode with a composite of silica nanoparticles doped with [Ru(bpy) 3 ] 2+ (RUDS) and molecularly imprinted polymer (MIP). The keys of the sensor were to employ RUDS as an ECL luminophore to prevent [Ru(bpy) 3 ] 2+ leaching from the modified electrode and MIP as a material for selective recognition. Taking advantage of the MIP pre-concentration effect, melamine could be extracted from the solution and detected by the resulting ECL signal enhancement of [Ru(bpy) 3 ] 2+ . Under optimized conditions, the relative ECL signal was proportional to the logarithm of melamine concentration in the range of 1 × 10 −12 –1 × 10 −7 mol L −1 , with a detection limit as low as 5 × 10 −13 mol L −1 . Compared with the RUDS/non-imprinted polymer, the RUDS/MIP modified electrode displayed high recognition ability, good reproducibility, and stability. To verify its reliability, the fabricated ECL sensor was used for determining the concentration of melamine in milk.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Teng Zheng,Laihui Luo,Peng Du,Anmeng Deng,Weiping Li
The (0.98- x )(0.6Pb(Mg 1/3 Nb 1/3 )O 3 -0.4PbTiO 3 )- x Pb(Yb 1/3 Nb 1/3 )O 3 -0.02Pb(Er 1/2 Nb 1/2 )O 3 ((0.98- x )(PMN-PT)- x PYN:Er 3+ ) ceramics were prepared through a solid-state reaction method. The phase structure, piezoelectric response, ferroelectric performance and upconversion emission of the ceramics were systematically investigated. The phase structure, the electrical and optical properties are strongly related to the content of PYN. The optimized piezoelectric response and upconversion emissions of the ceramics were achieved near x = 0.12, which locates in the morphotropic phase boundary (MPB) composition. Furthermore, the temperature sensing behaviors of the resultant compounds based on the thermally coupled levels of 2 H 11/2 and 4 S 3/2 of Er 3+ ions in the temperature range of 133–573 K were studied by utilizing the fluorescence intensity ratio technique. Additionally, the thermal effect, which is induced by the laser pump power, of the studied ceramics is also investigated and the produced temperature is enhanced from 268 to 348 K with the pump power rising from 109 to 607 mW.
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RSC Advances
·
2017
·Vol. 7
·期 5
·2650-2657
·
IF 3.108
Zhike Wang,Cunling Ye,Lingyun Chen,Haili Wu
Adsorptive removals of naphthols are often interfered by some coexisting anions of aqueous solutions. In this work, 1-vinyl-3-octadecylimidazolium cations and p-styrenesulphonate anions were chemically co-modified on silica (denoted as Sil-PImC18-SS) via the click chemistry reaction and were characterized. This material was created with the aim to explore the feasibility of removal of 1-naphthol (1-NAP) and 2-naphthol (2-NAP) from aqueous solutions. The prepared Sil-PImC18-SS was used as an adsorbent to remove 1-NAP and 2-NAP from aqueous solutions and the effects of various variables for the adsorption of 1-NAP and 2-NAP were systematically studied. Among the coexisting anions tested, 0.2 mol L−1 background NaCl or Na2SO4 aqueous solutions had no significant effect on the adsorption of 1-NAP and 2-NAP. The adsorption behaviors of 1-NAP and 2-NAP were well described by the pseudo-second order kinetic and the Dubinin–Radushkevich models with the maximum adsorption capacities of 84.4 mg g−1 and 71.9 mg g−1 for 1-naphthol and 2-naphthol, respectively. The adsorption was a spontaneous and exothermic process, and an adsorption mechanism was speculated to be the cooperative contributions from the hydrophobic interaction, hydrogen bonding interaction, and π–π stacking. Thus, Sil-PImC18-SS can be potentially used as an effective adsorption material for naphthol pollutant removal from the water environment.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Shengdi Gu,Junjie Yu,Lei Du,Daihui Zhang,Li Zhao,Jingli Xie
PepXLcMY-3, an X-prolyl dipeptidyl aminopeptidase derived from Lactobacillus lactis MY-3, was screened and recombinantly expressed in Escherichia coli. The enzyme could exhibit about 40% activity within the pH range of 6.0–10. To further improve the pH robustness, site E396 located in the active pocket was discovered through alanine scanning. The mutant E396I displayed both developed activity and kcat/Km. The optimal pH of E396I shifted from 6.0 to 10 compared to WT, with the relative activity within the pH range of 6.0–10 significantly increased. The site K648 was then proposed by semirational design. The activity of mutant E396I/K648D reached 4.03 U/mg. The optimal pH was restored to 6.0, and the pH stability was further improved. E396I/K648D could totally hydrolyze β-casomorphin 7 within 30 min. The hydrolysate showed 64.5% inhibition on angiotensin I converting enzyme, which was more efficient than those produced by E396I and WT, 23.2 and 44.7%, respectively.
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Arabian Journal of Chemistry
·
2017
·
IF 4.553
Waqar Uddin,Gang Hu,Xuanxuan Sun,Hui Zhang,Yegui Wang,Lin Hu
A novel method for identification of two aromatic isomers of mono hydroxy benzoic acid (HBA) was reported by using their different perturbation effects on the potential oscillations of a Belousov-Zhabotinsky (BZ) system. In such a system, a macrocyclic complex of Cu [CuL](ClO 4 ) 2 was used as catalyst in which ligand L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. To the BZ system, 3-hydroxy benzoic acid (3-HBA) could temporarily quench and regenerate potential oscillations with damping characters after inhibition time (t in ) while 4-hydroxy benzoic acid (4-HBA) could only change the oscillation amplitude (ΔA) to give damping oscillations with no inhibition time. Thus, these two isomers of HBA were identified. Reaction mechanisms of BZ have been proposed by FKN model. An explanation of perturbation mechanism is that, although 3-HBA reacted with BrO 2 while 4-HBA reacted with BrO 3 − , they all produced 1,4-quinone.
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