APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2020
·Vol. 104
·期 6
·2481-2488
·
IF 3.53
Xu Da,Fang Mengjun,Wang Haijiao,Huang Lei,Xu Qinyang,Xu Zhinan
5-Hydroxytryptophan (5-HTP) is the precursor of the neurotransmitter serotonin and has been used for the treatment of various diseases such as depression, insomnia, chronic headaches, and binge eating associated obesity. The production of 5-HTP had been achieved in our previous report, by the development of a recombinant strain containing two plasmids for biosynthesis of L-tryptophan (L-trp) and subsequent hydroxylation. In this study, the L-trp biosynthetic pathway was further integrated into the E. coli genome, and the promoter strength of 3-deoxy-7-phosphoheptulonate synthase, which catalyzes the first step of L-trp biosynthesis, was engineered to increase the production of L-trp. Hence, the 5-HTP production could be manipulated by the regulation of copy number of L-trp hydroxylation plasmid. Finally, the 5-HTP production was increased to 1.61 g/L in the shaking flasks, which was 24% improvement comparing to the original producing strain, while the content of residual L-trp was successfully reduced from 1.66 to 0.2 g/L, which is beneficial for the downstream separation and purification. Our work shall promote feasible progresses for the industrial production of 5-HTP.
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FIBERS AND POLYMERS
·
2020
·Vol. 21
·期 1
·111-118
·
IF 1.797
Liu Jiajia,Wang Wei,Yu Dan,Zhao Kai
Polyester (PET) fabric is an important fabric to make sportswear due to its good mechanical strength, wear resistance and low cost, but poor hygroscopicity will accumulate moisture and excessive heat of human body which thereby causing thermo-physiological dicomfort. To obtain satisfying moisture-wicking, hydroscopic and fast-dry properties, facile and efficient single-sided click chemistry was used to substitute traditional methods. Firstly, PET fabric was alkali treated and modified with 3-mercaptopropyltrimethoxysilane to obtain thiol groups. Then it was gradiently grafted with potassium 3-sulfopropyl acrylate by thiol-ene click chemistry under single-sided ultraviolet (UV) irradiation to enlarge effects. The reaction was proved by FTIR and Ellman method, the surface morphology was observed by SEM, and the mass loss at different temperatures in thermalgravimetry (TG) test illustrated the quantity change of grafting. The results demonstrated that the resultant fabric has good performance of moisture absorbing and sweat releasing, fast drying as well as outstanding antistatic and soil release properties.
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FIBERS AND POLYMERS
·
2020
·Vol. 21
·期 6
·1251-1258
·
IF 1.797
Liang Huazhe,Cao Meng,Yang Desheng,Sun Tingting,Chu Xiaomeng,Liu Shaojie
A series of polyamidoamine (PAMAM) immobilized TEMPO macromolecular catalysts were prepared by condensation reduction reactions between carbonyl groups in 4-O-TEMPO and primary amines in PAMAM. The macromolecular catalyst and NaBr/NaClO were used as catalytic system for selective oxidation of cellulose in aqueous medium. Effects of various factors, such as TEMPO loading ratios and PAMAM generations, were studied on the catalytic performances. Compared with free TEMPO, the macromolecular catalyst with less than 50 % TEMPO loading ratio had a higher reaction rate in the initial stage of the reaction. Especially, the reaction rate of G1.0 PAMAM with 30 % TEMPO loading ratio was comparable to free TEMPO in the whole reaction process. Its cellulose oxidation degree (or catalytic activity) was also equivalent to the level of free TEMPO. Interestingly, the cellulose depolymerization degree of macromolecular catalyst was not affected by the cellulose oxidation degree and was lower than that of free TEMPO. The macromolecular catalyst could be recycled efficiently by the combination of supernatant circulation and salting-out extraction, and the recycling performance was excellent.
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Journal of Neuroinflammation
·
2020
·Vol. 17
·期 1
·1-13
·
IF 5.793
Bian Hetao,Wang Gaohua,Huang Junjie,Liang Liang,Zheng Yage,Wei Yanyan,Wang Hui,Xiao Ling,Wang Huiling
Background Recently, depression has been identified as a prevalent and severe mental disorder. However, the mechanisms underlying the depression risk remain elusive. The neuroinflammation and NLRP3 inflammasome activation are known to be involved in the pathology of depression. Dihydrolipoic acid (DHLA) has been reported as a strong antioxidant and exhibits anti-inflammatory properties in various diseases, albeit the direct relevance between DHLA and depression is yet unknown. The present study aimed to investigate the preventive effect and potential mechanism of DHLA in the lipopolysaccharide (LPS)-induced sickness behavior in rats. Methods Adult male Sprague–Dawley rats were utilized. LPS and DHLA were injected intraperitoneally every 2 days and daily, respectively. Fluoxetine (Flu) was injected intraperitoneally daily. PD98059, an inhibitor of ERK, was injected intraperitoneally 1 h before DHLA injection daily. Small interfering ribonucleic acid (siRNA) for nuclear factor erythroid 2-like (Nrf2) was injected into the bilateral hippocampus 14 days before the DHLA injection. Depression-like behavior tests were performed. Western blot and immunofluorescence staining detected the ERK/Nrf2/HO-1/ROS/NLRP3 pathway-related proteins. Results The DHLA and fluoxetine treatment exerted preventive effects in LPS-induced sickness behavior rats. The DHLA treatment increased the expression of ERK, Nrf2, and HO-1 but decreased the ROS generation levels and reduced the expression of NLRP3, caspase-1, and IL-1β in LPS-induced sickness behavior rats. PD98059 abolished the effects of DHLA on preventive effect as well as the levels of Nrf2 and HO-1 proteins. Similarly, Nrf2 siRNA reversed the preventive effect of DHLA administration via the decreased expression of HO-1. Conclusions These findings suggested that DHLA exerted a preventive effect via ERK/Nrf2/HO-1/ROS/NLRP3 pathway in LPS-induced sickness behavior rats. Thus, DHLA may serve as a potential therapeutic strategy for depression.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 38
·期 11
·1171-1177
·
IF 3.154
Lang Mu-Ning,Chi Wei-Wen,Han Ting,Zhao Qing-Zhen,Li Hong-Kun,Tang Ben Zhong,Li Yong-Fang
Azide-alkyne click polymerization has become a powerful tool for polymer synthesis. However, the click polymerization between internal alkynes and azides is rarely utilized to prepare functional polymers. In this work, the polymerization reactions of activated internal alkyne monomers of tris(2-butynoate)s ( 1 ) with tetraphenylethene-containing diazides ( 2 ) were performed in dimethylformamide (DMF) under simple heating, affording four hyperbranched poly(methyltriazolylcarboxylate)s ( hb -PMTCs) with high molecular weights ( M w up to 2.4 × 10 4 ) and regioregularities (up to 83.9%) in good yields. The hb -PMTCs are soluble in common organic solvents, and thermally stable with 5% weight loss temperatures up to 400 °C. They are non-emissive in dilute solution, but become highly emissive in aggregated state, exhibiting aggregation-induced emission characteristics. The polymers can generate fluorescent photopatterns with high resolution, and can work as fluorescent sensors to detect nitroaromatic explosive with high sensitivity.
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JOURNAL OF MOLECULAR MODELING
·
2020
·Vol. 26
·期 8
·1-10
·
IF 1.346
Huang Xusheng,Zhang Wencheng,Wu Zeyu,Li Honghong,Yang Chengying,Ma Wanru,Hui Ailing,Zeng Qingmei,Xiong Baoyi,Xian Zhaojun
In this study, the preparation of molecularly imprinted polymers for bilobalide (BBMIPs) was successfully achieved by bulk polymerization with methacrylamide (MAM), trimethylolpropane triacrylate (TMPTA), and acetonitrile (ACN) as functional monomer, cross-linker, and solvent, respectively. After Gaussian software simulation and single factor experiments, the prepared MIPs with a molar ratio of 1:4:15 for BB-MAM-TMPTA were systematically characterized. The hydrogen bonding interaction between BB and MAM was confirmed by a combination of FTIR and NMR analysis. Thermal gravimetric analysis results displayed that MIPs have excellent thermal stability under high temperature. Additionally, the average pore size and surface area of MIPs were found to be higher than those of NIPs through nitrogen adsorption results. The results of static adsorption and kinetic adsorption suggested that the adsorption equilibrium concentration was 0.6 mg/mL and the equilibrium time was 5 h, and the Langmuir and pseudo-second-order kinetic models were proven to fit with static and kinetic adsorption behaviors, respectively. Meanwhile, the selective adsorption study revealed that MIPs show high adsorption and great selectivity towards BB in comparison with other substances having similarly structure. MIPs also possessed a good performance on reusability, maintaining a high recovery rate after being reused 5 times. The application experiment further indicated that MIPs can effectively separate BB from low purity samples. Therefore, the prepared MIPs had a great potential for BB separation.
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CELLULOSE
·
2020
·Vol. 27
·期 12
·7023-7036
·
IF 4.21
Zhou Man,Chen Jingwen,Jiang Mengting,Zhang Yakang,Liang Qian,Xu Song,Yao Chao,Li Zhongyu
A series of thickness-controlled SrTiO 3 (commonly abbreviated ST) anchored on carbonized bacterial cellulose (CBC) was successfully prepared by a novel route of freeze-drying assisted crystallization/carbonization. For the first time, the cross-linked bacterial cellulose served as a carbon source as well as structure-directing scaffold for the construction of ST/CBC composites. Characterizations exhibited cracks and defects on the surface of CBC which provided ideal anchoring sites for the dispersion and crystallization of ST. Additionally, the relationship between morphology and photocatalytic activity of ST/CBC was carefully investigated by photocatalytic reduction of potassium dichromate (K 2 Cr 2 O 7 ) and degradation of tetracycline in water. This unique biomass-derived carbon fibers provide an ideal platform for further design of perovskite based materials with enhanced catalytic performance.
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Nature Energy
·
2020
·Vol. 5
·期 6
·440-449
·
IF 46.495
Zhong Cheng,Liu Bin,Ding Jia,Liu Xiaorui,Zhong Yuwei,Li Yuan,Sun Changbin,Han Xiaopeng,Deng Yida,Zhao Naiqin,Hu Wenbin
Aqueous battery systems feature high safety, but they usually suffer from low voltage and low energy density, restricting their applications in large-scale storage. Here, we propose an electrolyte-decoupling strategy to maximize the full potential of Zn–MnO 2 batteries by simultaneously enabling the optimal redox chemistry of both the Zn and MnO 2 electrodes. The decoupled Zn–MnO 2 battery exhibits an open-circuit voltage of 2.83 V (in contrast to the typical voltage of 1.5 V in conventional Zn–MnO 2 batteries), as well as cyclability with only 2% capacity fading after deep cycling for 200 h. Benefiting from the full utilization of MnO 2 , the Zn–MnO 2 battery is also able to maintain approximately 100% of its capacity at various discharge current densities. We also demonstrate the feasibility of integrating the Zn–MnO 2 battery with a wind and photovoltaic hybrid power generating system. This electrolyte-decoupling strategy is shown to be applicable for other high-performance zinc-based aqueous batteries such as Zn–Cu and Zn–Ag batteries.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 4
·1-8
·
IF 6.232
Ren Lei,Li Hongdan,Du Jianxiu
Black phosphorus quantum dots (BP QDs) with small size are synthesized using an easy to operate thermal method. It was found that BP QDs possess oxidase-mimicking activity. They can catalyze the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine to produce a blue-colored product even in the absence of hydrogen peroxide. Active oxygen species are proved to be involved in the reaction through the experiments of radical scavenging and electron spin resonance. Biothiols including reduced glutathione and cysteine inactivate the oxidase-mimicking activity of BP QDs, concomitant to the fading of the blue solution. This provides the base for a colorimetric method for the determination of glutathione and cysteine. The decreased absorbance at 652 nm displays linear response to the concentrations of glutathione ranging from 0.1 to 5.0 μmol L −1 , and cysteine from 0.1 to 10.0 μmol L −1 . The detection limits are 0.02 μmol L −1 and 0.03 μmol L −1 for glutathione and cysteine, respectively. Successive determinations of 1.0 μmol L −1 glutathione and 5.0 μmol L −1 cysteine solution give relative standard deviations of 0.8% and 1.7% ( n = 11), respectively. As a preliminary application, the practicability of the method was evaluated by the determination of glutathione in pharmaceutical preparations. This work not only discovers a useful oxidase mimics but also sets up a reliable platform based on BP QDs in colorimetric detection.
Schematic representation of colorimetric determination for biothiols through inactivating oxidase mimetic−like catalytic activity of black phosphorus quantum dots (BP QDs) on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with dissolved oxygen to produce its blue oxidized product (oxTMB).
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Frontiers of Chemical Science and Engineering
·
2020
·Vol. 15
·期 1
·118-126
·
IF 3.552
Liu Jie,Shen Jiahao,Wang Jingjing,Liang Yuan,Wu Routeng,Zhang Wenwen,Shi Delin,Shi Saixiang,Wang Yanping,Wang Yimin,Xia Yumin
To enhance the solubility of polyanilines (PANI), polymeric ionic liquid (PIL) was introduced into the polymerization synthesis of PANI with various proportions. The structure and properties of the modified PANIs were characterized by 1 H NMR, Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet-visible spectrum, etc. It was found that the obtained PANIs doped with PILs were soluble in various organic solvents such as N , N -dimethyl formamide and acetonitrile. Compared with the pure PANI, the PANIs doped by PILs showed remarkable solubility and their chemical structure and conductivity kept integrated.
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Nature Communications
·
2020
·Vol. 11
·期 1
·1-10
·
IF 12.121
Ji Bifa,Yao Wenjiao,Zheng Yongping,Kidkhunthod Pinit,Zhou Xiaolong,Tunmee Sarayut,Sattayaporn Suchinda,Cheng Hui-Ming,He Haiyan,Tang Yongbing
Potassium-ion batteries are a compelling technology for large scale energy storage due to their low-cost and good rate performance. However, the development of potassium-ion batteries remains in its infancy, mainly hindered by the lack of suitable cathode materials. Here we show that a previously known frustrated magnet, KFeC 2 O 4 F, could serve as a stable cathode for potassium ion storage, delivering a discharge capacity of ~112 mAh g −1 at 0.2 A g −1 and 94% capacity retention after 2000 cycles. The unprecedented cycling stability is attributed to the rigid framework and the presence of three channels that allow for minimized volume fluctuation when Fe 2+ /Fe 3+ redox reaction occurs. Further, pairing this KFeC 2 O 4 F cathode with a soft carbon anode yields a potassium-ion full cell with an energy density of ~235 Wh kg −1 , impressive rate performance and negligible capacity decay within 200 cycles. This work sheds light on the development of low-cost and high-performance K-based energy storage devices.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 3
·1-10
·
IF 6.232
Zhao Yu,Pang Bo,Chen Jie,Xiao Lizhi,Liu Hou,Lian Wenhui,Sun Tianxia,Jiang Yingnan,Lin Quan
Doubly charged pH-responsive core/shell hydrogel nanoparticles with green fluorescence were prepared and were shown to be viable bioprobes for active targeting tumor tissue and imaging of cancer cells. Via emulsionfree copolymerization hydrogel nanoparticles as VANPs were prepared, the core of which was polystyrene (Ps) and the shell was comprised of strongly positive electrolyte (ar-vinylbenzyl)trimethylammonium (VBTAC) with weak negative electrolyte acrylic acid (AA). Through conventional amidation, the shell was conjugated with cell-specific folic acid (FA), denoted as VANPs-FA. Then, negatively charged sulfonated 9,10-distyrylanthracene derivatives (SDSA) based on aggregation induced emission (AIE), was binding tightly to positively charged VBTAC of VANPs-FA shell. The prepared double charged fluorescent core/shell hydrogel nanoparticles abbreviated as VANPs-FS, showed excitation/emission wavelengths at ~420/528 nm. Dynamic light scattering (DLS) measurements were performed to determine the size and surficial zeta potential of VANPs-FS. Under proper ratio of VBTAC to AA, the VANPs-FS was stable (~ 64.63 nm, −20.2 mV) at high pH (> 7), started to aggregate (~ 683.0 nm, −3.2 mV) at pH around 6, and can redispers at low pH (< 5). The MTT analysis proved that VANPs-FS had good biocompatibility and low cytotoxicity. The targeting effectiveness of VANPs-FS was confirmed by confocal laser scanning microscopy (CLSM).
Detailed synthetic route of VANPs-FS (top) and schematic cancer tumor-target aggregation of pH-sensitive VANPs-FS with enhanced retention and rapid cancer cell imaging (bottom).
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