BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY
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2021
·Vol. 69
·期 4
·1428-1437
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IF 2.431
Di Liu,Linbo Gou,Yajun Bai,Tai-Ping Fan,Xiaohui Zheng,Yujie Cai
In this study, the 3-quinuclidinone reductase from Agrobacterium tumefaciens (AtQR) was modified by site-directed mutagenesis. And we further obtained a saturation mutant library in which the residue 197 was mutated. A single-point mutation converted the wild enzyme that originally had no catalytic activity in reduction of ethyl 4-chloroacetoacetate (COBE) into an enzyme with catalytic activity. The results of enzyme activity assays showed that the seven variants could asymmetrically reduce COBE to ethyl ( S )-4-chloro-3-hydroxybutyrate (( S )-CHBE) with NADH as coenzyme. In the library, the variant E197N showed higher catalytic efficiency than others. The E197N was optimally active at pH 6.0 and 40°C, and the catalytic efficiency ( k cat / K m ) for COBE was 51.36 s –1 ·mM –1 . This study showed that the substrate specificity of AtQR could be changed through site-directed mutagenesis at the residue 197.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Sleshi Fentie Tadesse,Dong-Hau Kuo,Worku Lakew Kebede,Girma Sisay Wolde
Developing low-cost and visible-light-driven metal oxide and sulfide-based photocatalysts for the degradation of organic dyes has been a major area of research to mitigate environmental pollution. In this study, a low-cost and facile precipitation method at low temperature of 95 °C was used to synthesize visible-light-driven Nd 2 O 3 /Mo(S,O) 3-x ·0.34H 2 O heterojunctions (NdMoOS). The crystal structure, elemental composition, optical, and electrical properties of as-prepared materials were investigated using various analytical techniques. Organic dyes of methyl orange (MO), Rhodamine B (RhB), and Methylene blue (MB) were selected as model organic pollutants to evaluate the photocatalytic efficiency of as-synthesized materials under visible light irradiation. 20 mol% NdMoOS nanocomposite showed excellent degradation efficiency and it decomposed 98.8%, 99.9%, and 99.8% of MO, RhB, and MB after 120 min, 90 min, and 90 min visible light irradiation, respectively. HPLC-MS analysis further confirms the complete removal of dyes. The formation of heterojunction, high charge separation, and low recombination rate of photoinduced e - -h + pairs can contribute to the enhanced photocatalytic activity. Superoxide radicals (O 2–• ), hydroxyl radicals (HO • ), and holes (h + ) were identified as major oxidative species involved in the photocatalytic degradation mechanisms of MO, RhB, and MB dyes.
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ADVANCED POWDER TECHNOLOGY
·
2019
·
IF 3.25
Zepeng Lv,Dong Liu,Yijie Wu,Run Zhang,Haibo Sun,Jie Dang,Liwen Hu
Tungsten, one of the refractory metals, has lots of excellent properties, making tungsten powders become a choice of raw material for many applications. This work reported a simple method (the salt-assisted hydrogen reduction of WO 3 powders) for preparing tungsten powders with desired morphologies and size. By adjusting the amount of additive (Y(NO 3 ) 3 ) and reduction temperature, metallic tungsten particles with different morphologies and size were obtained. It was found that both temperature and additive had apparent effects on the morphology and size of metallic W particles, and the large parallelepiped-shaped powders disappeared and large irregular blocky-shaped powders were degraded under the influence of additive. With the increase of temperature and amount of salt, particles became more dispersed and the size increased at higher temperatures, and the shape of particles was changed from spherical to polyhedral as well. On the contrary, the size of sub-particles became smaller as increasing amount of Y(NO 3 ) 3 at lower temperatures. Based on the results, the reaction and refining mechanisms for preparing tungsten were proposed as well.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Jin Feng,Yinghui Wu,Lixia Zhang,Ying Li,Songbai Liu,Hua Wang,Chunyang Li
A composite nanogel was developed for cyanidin-3-O-glucoside (C3G) delivery by combining Maillard reaction and heat gelation. The starting materials utilized were ovalbumin, dextran, and pectin. C3G-loaded nanogel was spherical with a diameter of ∼185 nm, which was maintained over a wide range of pH and NaCl concentrations. The composite nanogel enhanced the chemical stability of C3G under accelerated degradation models and a simulated gastrointestinal tract. Clathrin-mediated, caveolae-mediated, and macropinocytosis-related endocytosis contributed to the higher cellular uptake of nano-C3G than that of free-C3G. The apparent permeability coefficients of C3G increased 2.16 times after nanoencapsulation. The transcytosis of the C3G-bearing nanogel occurred primarily through the clathrin-related pathway and macropinocytosis and followed the “common recycling endosomes–endoplasmic reticulum–Golgi complex–basolateral plasma membrane” route. Moreover, nano-C3G was more efficient in restoring the viability of cells and activities of endogenous antioxidant enzymes than free-C3G in oxidative models, which may be attributed to the former’s high cellular absorption.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2019
·
IF 3.571
Jinling Cui,Mingzhu Yan,Xiaoyi Liu,Shutao Yin,Shangyun Lu,Lihong Fan,Hongbo Hu
Previous studies have shown that selenite, a representative of inorganic form selenium, exerts its anticancer effect by inducing apoptosis in androgen-dependent LNCaP prostate cancer cells, but few studies have determined the nature of cell death induced by selenite in metastatic androgen-refractory PC-3 cells. Our study showed that necrosis-like cell death rather than apoptosis, pyroptosis, or autophagic cell death was caused by selenite in PC-3 cells. Mechanistically, this type of cell death was caused by ATP depletion (26.28 ± 3.39 nmol/mg of control versus 9.12 ± 2.44 nmol/mg of 10 μM selenite treatment) that resulted from phosphofructokinase activity reduction (100.17 ± 0.17% of control versus 21.74 ± 6.65% of 10 μM selenite treatment). Our study also showed that ROS production is necessary for the decrease in cellular ATP levels and in phosphofructokinase activity. To our knowledge, this is the first study showing that selenite can induce necrosis-like cell death in PC-3 cells. Our findings support selenite as an effective compound for the therapy of apoptosis-resistant prostate cancer.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Anish Bhattacharya,Xiangfeng Chu,Qi Gao,Xue Li,Yongping Dong,Shiming Liang,Amit K. Chakraborty
Ethanol sensing is an important area of research given its relevance to human health, traffic control and various industries. Metal oxide semiconductor nanostructures are most commonly used as gas sensors. In this study, enhanced ethanol sensing properties were obtained by incorporation of Gd 3+ ions into Barium Stannate (GBSO), a bimetallic oxide microrods prepared through a simple co-precipitation method. The GBSO films, when exposed to ethanol, showed that incorporation of Gd improved the sensing response till 3 wt% of Gd (3GBSO) loading while further increase in Gd content resulted in reduced response. 3GBSO sample showed response as high as 76 to 500 ppm of ethanol vapor at an operating temperature of 220 °C along with a very low detection limit of 0.1 ppm (response of 1.5). Good repeatability and moderate stability were also observed suggesting its potential as low-cost ethanol sensor. Significant increase in both specific surface area as well as oxygen content (as measured by x-ray photoelectron spectroscopy) was observed in 3GBSO sample compared to that of BSO. Thus, we showed that incorporation of Gd improved the surface area of BSO microrods and in turn the surface adsorption of oxygen which led to their enhanced response to ethanol.
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RSC Advances
·
2019
·Vol. 9
·期 70
·40887-40894
·
IF 3.049
Xue Yang,Ke Ma,Libo Yang,Yujuan Chen,Yingmin Qu,Ying Wang,Xinyue Wang,Fan Yang,Qi Sun,Zhengxun Song,Zuobin Wang
This paper employs a spin-coated method to construct conductive polypyrrole (PPy) substrates which present superior properties for controlling the morphological structures and functions of bEnd.3 cells. The PPy substrates with a homogeneous particle size, uniform distribution and proper roughness show enhanced hydrophilic characteristics and improve cell adhesion to the substrates. The changes in the mechanical properties of cells and the responses to the designed substrates and magnetic field are also explored. Due to the synergistic effect between the magnetic field and the conductive PPy substrate, the cells cultured in such an environment exhibit applanate shapes with more branches and enhanced cell viability. In addition, the cells preferentially extend along the magnetic field direction. The mechanical characteristics of cells change significantly under varying magnetic intensity stimulations (5–16 mT). The satisfying effect on cells' morphology and outgrowth is acquired at the magnetic intensities of 9–10 mT and duration of 20 min, compared with other stimulated groups, while retaining cell viability. Moreover, the cells express higher adhesion up to 5.2 nN. The results suggest that the application of the PPy substrates and magnetic field is a promising candidate for the protection of neurovascular units and treatment of neurological diseases.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Bowen Zhang,Yufei Wang,Jiao Zhang,Sanyuan Qiao,Zhenzhong Fan,Jiaqi Wan,Kezheng Chen
The application of magnetite (Fe 3 O 4 ) nanoparticles (MNPs) as adsorbent materials in solving wastewater treatment problems has attracted increasing attention. In this work, well-defined 3-Aminopropyltriethoxysilane (APTES) functionalized MNPs (APTES-MNPs) were synthesized by two-step method, in which a simple and scalable polyol method was used to initially synthesize MNPs with relatively large sizes and provide a defect site enriched surface to enable the APTES to coat on Fe 3 O 4 uniformly without using SiO 2 coating. The structure, morphology and properties of the APTES-MNPs were studied by TEM, XRD, FTIR, XPS and MPMS. The APTES-MNPs showed enhanced adsorption capacity towards HPAM due to the presence of high density of amino groups on the surface. Kinetics study revealed that the adsorption process followed the pseudo-second-order model, whereas the equilibrium isotherm data matched well with the Langmuir model. The APTES-MNPs could be rapidly separated from aqueous solution under magnetic field and be repeatedly used up to three cycles without significant loss of adsorption capacity. This new type of APTES-MNPs is expected to be a promising candidate for HPAM removal from aqueous solution.
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PHYTOMEDICINE
·
2019
·
IF 4.18
Licong Zhao,Jiaqi Zhang,Lingyun Pan,Long Chen,Yu Wang,Xinhua Liu,Lisha You,Yiqun Jia,Cheng Hu
Background Acetaminophen (APAP) overdose is a leading cause of drug-induced acute liver failure in clinic. Fisetin (FST) is a phenolic compound that has been isolated from many natural products. Purpose Our aim is to study the protection effect and mechanisms of FST on APAP-induced hepatotoxicity in endogenous metabolism and metabolomics in vitro and in vivo . Methods FST was i.g. administered to mice at 10 , 20 and 40 mg/kg for 7 days and a single dose of APAP (400 mg/kg) was given on the last day. Serum and tissue were collected for biochemical analysis . L-02 cells were used to assess cell viability . LC–MS was used to study the metabolic fingerprinting in vivo and vitro . PCA and OPLS-DA were used to search the potential biomarkers (VIP > 1, p < 0.05). The pathway analysis was conducted on Metaboanalyst 4.0. Then liver oxidative stress indices and glutathione markers were examined using PCR and kits. Results ALT , AST, liver histological observation and cell viability results showed that FST could reverse APAP induced toxicology in mice and L-02 cells. In metabolomics study, 26 metabolites in vitro and 60 metabolites in vivo were identified by searching in the library and most of them decreased to normal level in FST treatment . It is observed in pathway analysis that the most significant pathway was glutathione metabolism. Furthermore, the results of mRNA and immunofluorescence showed that FST suppressed ROS formation in liver tissue and L-02 cells, as well as restored the expression of GPX1 , GST and other antioxidative enzymes genes. Conclusion Our results indicate that FST prevented APAP-induced hepatotoxicity by regulating glutathione metabolism and the expression of related antioxidative signals.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 4
·1-9
·
IF 5.479
Lin Bingyong,Chen Jiaming,Kannan Palanisamy,Zeng Yanbo,Qiu Bin,Guo Longhua,Lin Zhenyu
A rapid method is described for the preparation of a highly uniform and sensitive SERS substrate by an improved ‘drop-and-dry’ method. Gold nanobipyramids (Au NBPs) were prepared inside the nanoholes (nanowalls) of anodic aluminum oxide (AAO) templates with a typically 5-μm nanohole depth. The SERS substrate can be prepared by this method within 40 s and on large scale. The SERS signals obtained with this Au NBPs-AAO substrate is stronger by four-orders of magnitude compared to conventional a silicon wafer substrate. The SERS signal for dopamine (DA; measured at 1311 cm −1 ) is found to be enhanced by a factor of 2.2 × 10 8 . The response to DA extends from 10 nM to 0.1 mM, and the limit of detection is 6.5 nM (at S/ N = 3). The assay was applied to the determination of DA in spiked human serum.
Schematic presentation of a highly active and uniform 3-dimensional substrate composed of gold nanobipyramids and anodic aluminum oxide (Au NBP/AAO). It was used for on-spot sensing of dopamine.
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MOLECULES
·
2019
·Vol. 24
·期 17
·3060
·
IF 3.06
Shuang Gao,Yan-Yan Liu,Jing-Yu Jiang,Ying Fu,Li-Xia Zhao,Chun-Yan Li,Fei Ye
Herbicide safeners selectively protect crops from herbicide injury while maintaining the herbicidal effect on the target weed. To some extent, the detoxification of herbicides is related to the effect of herbicide safeners on the level and activity of herbicide target enzymes. In this work, the expression of the detoxifying enzyme glutathione S-transferase (GST) and antioxidant enzyme activities in maize seedlings were studied in the presence of three potential herbicide safeners: 3-dichloroacetyl oxazolidine and its two optical isomers. Further, the protective effect of chiral herbicide safeners on detoxifying chlorsulfuron in maize was evaluated. All safeners increased the expression levels of herbicide detoxifying enzymes, including GST, catalase (CAT), and peroxidase (POD) to reduce sulfonylurea herbicide phytotoxicity in maize seedlings. Our results indicate that theR-isomer of 3-(dichloroacetyl)-2,2,5-trimethyl-1,3-oxazolidine can induce glutathione (GSH) production, GST activity, and the ability of GST to react with the substrate 1-chloro-2,4-dinitrobenzene (CDNB) in maize, meaning that theR-isomer can protect maize from damage by chlorsulfuron. Information about antioxidative enzyme activity was obtained to determine the role of chiral safeners in overcoming the oxidative stress in maize attributed to herbicides. The interaction of safeners and active target sites of acetolactate synthase (ALS) was demonstrated by molecular docking modeling, which indicated that both isomers could form a good interaction with ALS. Our findings suggest that the detoxification mechanism of chiral safeners might involve the induction of the activity of herbicide detoxifying enzymes as well as the completion of the target active site between the safener and chlorsulfuron.Keywords:chiral safener;biological activity;antioxidative enzyme activity;protection mechanism;chlorsulfuron
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Journal of Materials Chemistry A
·
2018
·Vol. 7
·期 1
·172-187
·
IF 9.931
Wenyi Wang,Chengcheng Xie,Liuyong Zhu,Bojin Shan,Caini Liu,Fangyan Cui
Graphene-based separation membranes exhibit great potential for the application of wastewater purification, but it is difficult to achieve a balance between water flux and rejection. To overcome the “trade-off” effect between permeability and selectivity, a novel 3-dimensional graphene-based membrane with superior water flux was fabricated using a simple, viable and green method. In addition, electrocatalytic technology is coupled to the membrane separation process. Comprehensive characterization indicates that the TiO2 nanoparticles were successfully mounted on the moderately reduced graphene oxide (rGO) surface. By introducing oxygen-functionalized carbon nanotubes (oCNTs), the rGO-TiO2/oCNT membrane has more pronounced 3-dimensional water channels. More importantly, the rGO-TiO2/oCNT membrane acts as both a separation membrane and an anode to couple the membrane process to the electrocatalytic technique. The small-molecule contaminants that are difficult to remove by physical exclusion would be degraded when the matter passes through the channels with the electrocatalyst. The TiO2 nanoparticles act as both a nano-wedge to expand the water channels and an electrocatalyst to promote the degradation of the contaminants. The rGO-TiO2/oCNT membranes showed a removal rate up to 95% at a high liquid hourly space velocity of 88 h−1 under the applied electrocatalysis conditions, which is two times more than that obtained without the electrocatalyst. The rGO-TiO2/oCNT membrane could not only achieve a superior water flux (the maximum was 44.14 L m−2 h−1 bar−1) but also maintain excellent dye removal performance (>90%) via membrane process coupling electrocatalysis. The optimum component ratio of the rGO-TiO2/oCNT membrane was investigated, and it was found that 30% oCNT content accounts for a stable catalytic performance. The graphene-based membrane coupled electrocatalysis in this study would provide a new approach to break the bottleneck of the trade-off effect and inspire the design of a functional membrane.
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