APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2016
·Vol. 182
·期 1
·261-275
·
IF 1.606
Jiang Cheng,Song Jinzhu,Cong Hua,Zhang Junzheng,Yang Qian
A novel β-1,3-glucanase gene, designated Ccglu17A , was cloned from the biological control fungus Chaetomium cupreum Ame. Its 1626-bp open reading frame encoded 541 amino acids. The corresponding amino acid sequence showed highest identity (67 %) with a glycoside hydrolase family 17 β-1,3-glucanase from Chaetomium globosum . The recombinant protein Ccglu17A was successfully expressed in Pichia pastoris , and the enzyme was purified to homogeneity with 10.1-fold purification and 47.8 % recovery yield. The protein’s molecular mass was approximately 65 kDa, and its maximum activity appeared at pH 5.0 and temperature 45 °C. Heavy metal ions Fe 2+ , Mn 2+ , Cu 2+ , Co 2+ , Ag + , and Hg 2+ had inhibitory effects on Ccglu17A, but Ba 2+ promoted the enzyme’s activity. Ccglu17A exhibited high substrate specificity, almost exclusively catalyzing β-1,3-glycosidic bond cleavage in various polysaccharoses to liberate glucose. The enzyme had a Km of 2.84 mg/mL and Vmax of 10.7 μmol glucose/min/mg protein for laminarin degradation under optimal conditions. Ccglu17A was an exoglucanase with transglycosylation activity based on its hydrolytic properties. It showed potential antifungal activity with a degradative effect on cell walls and inhibitory action against the germination of pathogenic fungus. In conclusion, Ccglu17A is the first functional exo-1,3-β-glucanase to be identified from C. cupreum and has potential applicability in industry and agriculture.
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高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2016
·Vol. 32
·期 6
·924-928
·
IF 1.086
Qi Pengjia,Wang Ziying,Wang Rui,Xu Yinan,Zhang Tong
Synthetic graphene composite was modified on a transducer of quartz crystal microbalance(QCM) to fabricate a gas sensor for low concentration nitrogen dioxide(NO 2 ) detection. The gas sensing properties of the QCM coated with SnO 2 -rGO and AgNPs-SnO 2 -rGO composites were investigated when exposing QCM to low NO 2 con-centration(2.05—20.5 mg/m 3 ) atmosphere at room temperature. The sensing performances of the QCM with AgNPs-SnO 2 -rGO composites were enhanced by the introduction of Ag nanoparticles, and the QCM modified with AgNPs-SnO 2 -rGO composites could detect NO 2 at room temperature.
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JOURNAL OF POLYMER RESEARCH
·
2015
·Vol. 22
·期 8
·1-7
·
IF 1.92
Zhan Shiping,Qi Qingchun,Wang Weijing,Chen Shuhua,Wang Jingchang,Li Mingming,Ding Shiqiang
The dispersion polymerization of L-lactide(LA) /ε-caprolactone(CL) with stannous octoate (Sn(Oct) 2 ) as a catalyst and n-butanol as an initiator in supercritical carbon dioxide (ScCO 2 ) was studied. The effects of operating parameters, such as pressure, temperature, stirring rate and monomer rate of LA/CL, on the characteristics of L-lactide and ε- caprolactone copolymer (PCLA) were investigated. The experimental results show that the pressure has the greatest effect on the morphology of the copolymer, and the temperature is the most decisive factor in the conversion ratio of the monomer. The changes of the conversion rate of the monomer were observed when the temperature risen from 90 to 110 °C. At the pressure of 18 MPa, the best morphology of the product can be got. Under the optimum reaction condition, PCLA with various ratio of LA/CL were obtained. Finally, fine powder particles of L-lactide and ε-caprolactone copolymer (PCLA) with high molecular weight were obtained.
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JOURNAL OF POLYMER RESEARCH
·
2015
·Vol. 22
·期 5
·1-12
·
IF 1.92
Zhang Qin,Liao Jian-Fang,Shi Xu-Hua,Qiu Yong-Ge,Chen Han-Jia
A macromolecular biocompatible surface modifier for polyurethane (PU), namely, polyurethane-block-poly (chloromethyl styrene) (PU- b -PCMS) copolymer, was synthesized by coupling hydroxyl-terminated PCMS with diisocyanate-terminated PU and further quaternizing. The synthesized surface modifier was blended with PU and heparin was absorbed on PU surface by ion exchange. The modification effectively increased the hydrophilicity and water absorption of PU. To evaluate the hemocompatibility of the modified blend films, the extent of platelet adsorption, plasma recalcification time and hemolysis were measured. To determine if the blend films were toxic to mammalian cells, viability of the cells cultured on the blend films was assayed. All results indicated that the blood and cell compatibilities of the PU films were improved significantly after entrapment of a few quaternized PU- b -PCMS copolymers into PU and further heparinizing.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2015
·Vol. 17
·期 12
·1-15
·
IF 2.184
Qin Zhiguo,Zhang Jie,Chi Huibo,Cao Feng
Abstract This study was mainly aimed to evaluate the potential use of a novel ocular drug delivery system, organic–inorganic hybrid nanocomposites based on chitosan derivatives and layered double hydroxides (LDH). Organic polymers of chitosan–glutathione (CG) and pre-activated chitosan–glutathione (CG-2MNA) were successfully synthesized and characterized. LDH with intercalated phacolysin (PCL), including larger hexagonal LDH–PCL (Lh-LDH–PCL), larger spherical LDH–PCL (Ls-LDH–PCL), smaller hexagonal LDH–PCL (Sh-LDH–PCL), CG hybrid LDH–PCL (LDH–PCL-CG), and CG-2MNA hybrid LDH–PCL (LDH–PCL-CG-2MNA), were prepared. The nanocomposites with particle size of 107.2–274.9 nm were characterized by powder X-ray diffraction, Fourier transform infrared, transmission electron micrographs, etc. In vivo precorneal retention studies showed that the detectable time of all nanocomposites was prolonged from 2 to 6 h in comparison to PCL saline. Accordingly, the AUC 0–6h values of Lh-LDH–PCL, Ls-LDH–PCL, Sh-LDH–PCL, LDH–PCL-CG, and LDH–PCL-CG-2MNA nanocomposites were increased by 2.27-, 2.08-, 3.08-, 4.67-, and 3.36-fold, respectively. The Draize test and hematoxylin and eosin staining demonstrated that modified LDH had no eye irritation after single and repeated administration. These results indicated that chitosan derivatives-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs. Graphical Abstract Thiolated chitosan-LDH hybrid nanocomposite dispersion could be a promising ocular drug delivery system to improve precorneal retention time of drugs and may facilitate penetration of drugs into tissues of the eyes.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 24
·5757-5765
·
IF 3.431
Kong Rong-Mei,Zhang Xiaobin,Ding Lu,Yang Daoshan,Qu Fengli
Fluorescent light-up probes based on aggregation-induced emission (AIE)-active molecules have recently attracted great research interest due to the intelligent fluorescence activation mechanism and high sensitivity. In this work, an AIE-silica nanosphere (SiO 2 NP)-based label-free fluorescent aptasensor for the sensitive “turn-on” detection of prostate-specific antigen (PSA) is reported for the first time. The positively charged amino-functionalized SiO 2 NPs were used as efficient nanocapturer to electrostatically adsorb single-stranded PSA aptamer (PA) to form SiO 2 NP-PA nanocomposite as well as adsorb negatively charged tetraphenylethylene derivative 3 (TPE3) to form AIE-SiO 2 NP nanocomposite. The binding of the aptamer to the target PSA could induce a rigid aptamer conformation, resulting in the release of the PA away from the surface of SiO 2 NPs. This made the AIE molecules TPE3 aggregate on the SiO 2 NP surface and emit high fluorescence. With the advantages of simple design and rapid responses, the proposed aptasensor showed high sensitivity and selectivity for PSA with a detection limit of 0.5 ng/mL. The aptasensor was further applied in human serum samples with satisfactory results. Given its versatility, high selectivity, and sensitivity, the proposed method could be extended to other targets by varying the recognition probes.
An AIE-SiO 2 NP-based label-free fluorescent aptasensor for the sensitive “turn-on” detection of PSA is reported for the first time
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高影响因子
BIOTECHNOLOGY AND BIOPROCESS ENGINEERING
·
2017
·Vol. 22
·期 1
·76-82
·
IF 1.16
Gu Jia-Li,Tong Hong-Fei,Sun Lai-Yu
Macroporous magnetic agarose particles (MMAPs) were prepared with calcium carbonate as the porogent by the water-in-oil suspension thermal regeneration method. MMAPs with good sphericity and appropriate particle size were obtained. The physical properties of the beads were determined and it was found that the water content (92.1%), porosity (94.4%) and mean pore diameter (120.1 nm) of the MMAPs were higher than those for the normal magnetic particles, indicating successful generation of macropores after calcium carbonate addition. Compared with normal magnetic particles, the mass transfer of biomolecules in MMAPs was remarkably enhanced. Finally, MMAPs were modified with 5-amino-benzimidazol (ABI) ligand and the adsorption capacity of IgG reached 153 mg/mL, higher than that of the normal magnetic particles (126 mg/mL). Moreover, adsorption behavior of MMAPs to IgG was little changed after twenty-five recycled use. Hence, MMAPs prepared herein showed great potential for bioseparation.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 8
·2909-2917
·
IF 4.58
Han Caiqin,Li Yuqi,Jia Qin,Bradley Layne Hyer,Gan Yun,Yao Yue,Qu Lulu,Li Haitao,Zhao Yiping
An on-demand, disposable and portable surface-enhanced Raman scattering (SERS) array has been prepared by modifying the surface of cellulose paper and patterning it with silver nanoparticles (AgNPs) via pen-writing technique. The paper is initially modified with hexadecenyl succinic anhydride to generate a hydrophobic top layer that is capable of concentrating melamine (and other hydrophobic analytes) by preventing the mainly aqueous sample from spreading on the paper. The AgNPs are subsequently written onto the hydrophobic paper with a high degree of control to form large-scale SERS sensing arrays. The resulting arrays demonstrate outstanding Raman scattering enhancement as demonstrated for the fluorescent dye Rhodamine 6G which can be detected by SERS with an 80 pM limit of detection (LOD) without interference by fluorescence. The reproducibility in the preparation of spots has a relative standard deviation of <15% (for n = 128 spectra). The arrays were applied to the determination of the illicit milk additive melamine. The plot of SERS intensity at Δν = 681 cm −1 versus the logarithm of melamine concentration is linear in the concentration range from 0.3 to 20 mg·L −1 , and the LOD is 0.27 mg·L −1 . In our perception, the disposable arrays presented here integrate the advantages of easy production and reliable reproducibility, and therefore are an ideal choice for use in SERS detection.
An on-demand, disposable and portable surface-enhanced Raman scattering (SERS) array has been developed by pen writing. Such a SERS array can be applied for the highly sensitive determination of the illicit milk additive melamine, which holds great promise for field-deployable applications.
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Food Analytical Methods
·
2017
·Vol. 10
·期 11
·3565-3571
·
IF 2.038
Yue Mei-E,Lin Qiaoyan,Li Qian,Xu Jie,Jiang Ting-Fu
An integrative coupling approach of headspace in-tube microextraction (HS-ITME) and reverse-flow micellar electrokinetic capillary chromatography (RF-MECC) was proposed for determination of phthalic acid esters (PAEs). In the novel method, by placing a capillary filled with background electrolyte (BGE) of RF-MECC in the HS above the sample solution, the PAEs were extracted into the acceptor phase in the capillary. Then, the extracts were separated and determined by RF-MECC. The influence of some essential BGE components such as sodium dodecyl sulfate (SDS) and organic modifier concentrations were investigated. Extraction parameters were also systematically investigated, including the extraction temperature, extraction time, salt concentration, and volume of the sample solution. Under the optimized conditions, enrichment factors for three PAEs were 169, 2534, and 1526, respectively. The proposed method provided a good linearity, low limits of detection, and good repeatability (RSDs below 5.44%, n = 5). This method was then utilized to analyze the three PAEs in tap water, seawater, and beverage samples. The results indicated that the developed method is an excellent alternative for the PAE routine analysis in the food field.
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BIOTECHNOLOGY LETTERS
·
2017
·Vol. 39
·期 8
·1229-1235
·
IF 1.73
Wang Qianqian,Xu Yixiang,Xu Jiaqi,Wang Xudong,Shen Chen,Zhang Yan,Liu Xiufeng,Yu Boyang,Zhang Jian
Objectives To characterize glycosyltransferases from Bacillus subtilis ATCC 6633 and investigate their substrate specificity towards plant polyphenols. Results Among the cloned and expressed six UDP-glycosyltransferases (BsGT1-6), BsGT-1 showed activity with a wide range of polyphenols: morin, quercetin, alizarin, rehin, curcumin and aloe emodin. The gene of BsGT-1 has an ORF of 1206 bp encoding 402 amino acids. The recombinant enzyme was purified to homogeneity by Ni–NTA affinity chromatograph, and its biochemical characteristics were identified by HPLC–UV/MS, 1 H-NMR and 13 C-NMR. BsGT-1 has an MW of approx. 46 kDa as indicated by SDS-PAGE; its activity was optimal at 40 °C and pH 8.5. The Km value of BsGT-1 towards morin was 110 μM. Conclusions BsGT-1 from B. subtilis was cloned. It had high catalytic capabilities towards polyphenols which would make it feasible for the structural modification of polyphenols.
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高影响因子
BIOTECHNOLOGY LETTERS
·
2017
·Vol. 39
·期 8
·1175-1181
·
IF 1.73
Zhou Youzhi,Liu Ke,Zhang Jinsong,Chu Jianlin,He Bingfang
Objective To improve the stability of β-galactosidase from Bacillus megaterium YZ08 (BMG) in aqueous hydrophilic solvents and promote its application in the galactosylation of natural products. Results The addition of 5 mM Mg 2+ significantly enhanced the stability of BMG in aqueous hydrophilic solvents, and the half-lives of BMG in these solutions reached 56 min to 208 h, while they were only 7 min to 5.9 h without addition of Mg 2+ . Studies on the kinetic parameters in buffer solution and 30% dimethyl sulfoxide (DMSO) indicated that the affinity of BMG to 2-nitrophenyl-β- d -galactopyranoside and its catalytic efficiency ( κ
cat / K
m ) increased with the addition of Mg 2+ . Furthermore, the addition of Mg 2+ facilitated galactosylation reactions in 30% DMSO and increased product conversions by 24–41% due to the reversal of the thermodynamic equilibrium of hydrolysis. Conclusion A convenient approach was established to improve the stability of BMG in aqueous hydrophilic solvents.
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高影响因子
JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 24
·期 6
·1565-1574
·
IF 1.624
Jiao Yuchun,Xu Li,Sun Huiling,Deng Yijie,Zhang Tao,Liu Guoji
In this work, nitrogen-doped mesoporous carbon spheres (NMCS) were synthesized through a hard template method by using benzoxazine resin as precursor and ordered mesoporous silica spheres as template. The obtained N-doped mesoporous carbons were amorphous spherical nanoparticles with worm-like mesoporous channels and possessed high surface area of 789 m 2 /g, large pore volume of 0.49 cm 3 /g and high nitrogen content of 3.50 wt.%. The adsorption capacity of methyl orange (MO) by NMCS could attain 352.1 mg/g at an optimal condition, while the adsorption capacity of MO by non-doped mesoporous carbon spheres (MCS) was 251.9 mg/g at the same condition. The adsorption process fitted the pseudo-second-order kinetic model and the Langmuir isotherm well. Thermodynamic analysis indicated that the removal of MO by NMCS was spontaneous, endothermic and feasible process. In addition, the adsorption capacity of regenerated adsorbent was 89.04% of the initial level after four regeneration cycles.
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