Biotechnology for Biofuels
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2018
·Vol. 11
·期 1
·1-12
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IF 5.497
Wen Jingbai,Xiao Yanqiu,Liu Ting,Gao Qiuqiang,Bao Jie
Background Lignocellulose is one of the most promising alternative feedstocks for glutamic acid production as commodity building block chemical, but the efforts by the dominant industrial fermentation strain Corynebacterium glutamicum failed for accumulating glutamic acid using lignocellulose feedstock.Results We identified the existence of surprisingly high biotin concentration in corn stover hydrolysate as the determining factor for the failure of glutamic acid accumulation by Corynebacterium glutamicum. Under excessive biotin content, induction by penicillin resulted in 41.7 ± 0.1 g/L of glutamic acid with the yield of 0.50 g glutamic acid/g glucose. Our further investigation revealed that corn stover contained 353 ± 16 μg of biotin per kg dry solids, approximately one order of magnitude greater than the biotin in corn grain. Most of the biotin remained stable during the biorefining chain and the rich biotin content in corn stover hydrolysate almost completely blocked the glutamic acid accumulation. This rich biotin existence was found to be a common phenomenon in the wide range of lignocellulose biomass and this may be the key reason why the previous studies failed in cellulosic glutamic acid fermentation from lignocellulose biomass. The extended recording of the complete members of all eight vitamin B compounds in lignocellulose biomass further reveals that the major vitamin B members were also under the high concentration levels even after harsh pretreatment.Conclusion sThe high content of biotin in wide range of lignocellulose biomass feedstocks and the corresponding hydrolysates was discovered and it was found to be the key factor in determining the cellulosic glutamic acid accumulation. The highly reserved biotin and the high content of their other vitamin B compounds in biorefining process might act as the potential nutrients to biorefining fermentations. This study creates a new insight that lignocellulose biorefining not only generates inhibitors, but also keeps nutrients for cellulosic fermentations.
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2018
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IF 2.891
Xing Du,Weixin Li,Lei Zhao,Xuan He,Hui Chen,Wei Fang
A facile in-situ modification of photoanode is proposed to construct a unique hierarchical TiO 2 /ZnO structure with the aim at suppressing charge recombination rate and enhancing light harvest efficiency. Foam is not only employed as the soft template to fabricate hierarchical porous TiO 2 films but also as the carrier to realize in-situ growth of one dimensional ZnO nanowires among the TiO 2 nanoparticles. The results revealed that the hierarchical porous TiO 2 nanoparticles could provide both large surface areas and suitable porosity for the loading of quantum dots. In the meantime, ZnO nanowire can act as scattering centers for light absorption and offer direct pathways for electron transportation, thus decreasing the undesired charge recombination process. Consequently, the novel ZnO nanowires in-situ modified hierarchical porous TiO 2 photoanode are used as photoanode material to boost the performances of CdSe sensitized solar cells by virtue of controlling the moderate growth of ZnO nanowires. As a result, a power conversion efficiency of 3.07% is obtained based on this modified photoanode, which manifests 39.5% improvement compared to that of the cells based on bare TiO 2 hierarchical porous films (2.20%) due to the improved interconnections between TiO 2 nanoparticles and FTO substrate caused by ZnO nanowires.
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Contrast Media & Molecular Imaging
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2018
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IF 2.934
Weiyue Li,Xiang Xiao,Xiaodan Li,Yikai Xu,Lichao Ma,Liuji Guo,Chenggong Yan,Yuankui Wu
Objective. To investigate the potential of L5 peptide-guided pretargeting approach to identify GPC3-expressing hepatocellular carcinoma (HCC) using ultrasmall superparamagnetic iron oxide (USPIO) as the MR probe. Methods. Immunofluorescence with carboxyfluorescein- (FAM-) labeled L5 peptide was performed in HepG2 cells. Polyethylene glycol-modified USPIO (PEG-USPIO) and its conjugation with streptavidin (SA-PEG-USPIO) were synthesized, and their hydrodynamic diameters, zeta potential, T2 relaxivity, and cytotoxicity were measured. In vitro and in vivo two-step pretargeting MR imaging was performed on HepG2 cells and tumor-bearing mice after the administration of biotinylated L5 peptide (first step), followed by SA-PEG-USPIO (second step). Prussian blue staining was performed to assess iron deposition in tumors. Results. The high specificity of L5 peptide for GPC3 was demonstrated. Generation of SA-PEG-USPIO nanoparticles with good biocompatibility (an average hydrodynamic diameter of 35.97 nm and a zeta potential of −7.91 mV), superparamagnetism (R2 = 0.1039 × 103 mM−1s−1), and low toxicity was achieved. The pretargeting group showed more enhancement than the nonpretargeting group both in vitro (60% vs 20%, ) and in vivo (32% vs 6%, ). Substantial iron deposition was only observed in HepG2 cells and tumors in the pretargeting group. Conclusion. L5 peptide-guided, two-step pretargeting approach with USPIO as the MR imaging probe is a lucrative strategy to specifically identify GPC3-expressing HCC.
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JOURNAL OF DRUG DELIVERY SCIENCE AND TECHNOLOGY
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2018
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IF 2.297
Hao Liu,Xuemei Zhou,Yingying Wang,Menglu Yang,Xiaohui Xu,Ailing Wu
Etomidate is one of the first-line general anesthetic agents , with distinguished properties such as rapid onset, excellent cardiovascular stability, minimal impact on respiratory system, etc . However, the clinical application of etomidate preparation is often confined by the notable defects of both the drug and its current formulations. Previously, we reported a new etomidate formulation based on Pluronic F108 micelle which demonstrated improved anesthetic effects. Nevertheless, the micellar encapsulation of etomidate was limited using only one kind of Pluronic, which required organic solvents to modulate the hydrophobicity . Besides, the biocompatibility of this formulation was not yet clear. Herein, we reported that mixed nanomicelles consisting of different Pluronic could make full advantage of each loading material, which led to improved physicochemical properties for the delivery of etomidate. Moreover, in vivo studies demonstrated that, the etomidate-loaded mixed micelle (Eto-PFM) maintained the anesthetic effects and rapid onset property of etomidate, with a broad safe dose range. The potential mechanisms of the acute toxicity were also discussed. The results suggest that Eto-PFM is a promising etomidate preparation with the potential to further develop as an alternative to the current etomidate preparations.
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PROCESS BIOCHEMISTRY
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2018
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IF 2.616
Feng Xue,Xiangju Ya,Qi Tong,Yuansong Xiu,He Huang
A new halohydrin dehalogenase-like gene (HHDH) in the genome of Pseudomonas umsongensis YCIT1612 was identified, cloned and over-expressed in Escherichia coli . HHDH-Pu exhibited the highest sequence identity of 45% in comparison with the previously reported HHDHs. The recombinant HHDH-Pu was purified to homogeneity and its catalytic characteristics in epoxide ring opening was explored. Compared to other reported HHDHs, HHDH-Pu showed higher catalytic activity, exhibiting varied activities (2.4–50.4 U/mg) toward all the tested epoxides. It catalyzed the ring opening of epoxides with low to moderate enantioselectivity ( E =1.13-10.89). Rac- PGE was found to be the most selective among the tested epoxides. In the ring opening of rac -PGE, nucleophiles such as Cl − , N 3 − , NO 2 − , Br − or SCN − were accepted. N 3 − was selected as the optimal nucleophile. Some parameters that may alter this bio-resolution, such as the concentration of N 3 − , temperature and pH were evaluated. By optimizing the reaction conditions, the residual ( S )-PGE could be obtained in 23.5% yield and more than 99% ee from 40 mM rac -PGE.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2018
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IF 3.141
Pan Sun,Kun Huang,Jieyuan Lin,Huizhou Liu
PEG-based aqueous two-phase systems (ATPS) for extraction and removal of metal ions from industrial wastewaters is a promising strategy to replace traditional organic-aqueous two phase systems, due to its environmentally friendly advantages and excellent separation efficiency from controllable phase structure and physicochemical properties. However, controversy still remains about the partitioning mechanism of metal ions into the PEG-rich phase in ATPS. The present contribution revealed that a specific hydrophobic interaction was a main driving force for the transferring of Cr(VI) ions into the PEG-rich phase in ATPS. The properties of aqueous media around the PEG molecules and Cr(VI) ions also played a crucial role in the partitioning of Cr(VI) ions in the PEG-base ATPS. The PEG-rich phase in the ATPS exhibited a specific affinity toward poorly hydrated HCrO4– ions, compared to the strongly hydrated CrO42– ions. The difference in the properties of aqueous media in the coexisting liquid phases was response for the partitioning of Cr(VI) ions in the PEG-base ATPS. It was confirmed by combined application of UV–vis spectroscopy and molecular dynamics simulations. The present work provides a new understanding into the microscopic mechanism of the partitioning of metal ions in the polymer-based ATPS.
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ACS Applied Materials & Interfaces
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2018
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IF 8.097
Wuhui Li,Yixi Zhuang,Peng Zheng,Tian-Liang Zhou,Jian Xu,Jumpei Ueda,Setsuhisa Tanabe,Le Wang,Rong-Jun Xie
Deep-trap persistent luminescent materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of deep-trap persistent luminescent materials Y3Al5–xGaxO12:Ce3+,V3+ (x = 0–3) with a garnet structure and developed novel phosphor-in-glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently deep traps, narrow trap depth distributions, high trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in the reported phosphor-in-silicone films. Moreover, the trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV, thanks to the bandgap engineering effect, and the emission color was simultaneously changed from green to yellow due to the variation of crystal field strength. Image information was recorded on the PiG films by using a 450 nm blue-light laser in a laser direct writing mode and the recorded information was retrieved under high-temperature thermal stimulation or photostimulation. The Y3Al5–xGaxO12:Ce3+,V3+ PiG films as presented in this work are very promising in the applications of multidimensional and rewritable optical information storage.
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ANALYST
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2019
·Vol. 144
·期 12
·3807-3816
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IF 4.019
Xiaojun He,Chenglin Wu,Yuna Qian,Yahui Li,Lilei Zhang,Feng Ding,Hong Chen,Jianliang Shen
Over the past decades, gallium (Ga) compounds have gained importance in the field of cancer treatment. Gallium acts as an iron mimic and disturbs iron-dependent propagation and other processes in tumor cells. However, the toxicity of gallium was also well documented in vitro and in vivo in animals. Though the oral administration of gallium in humans is less toxic, it has also been shown that a long period of administration could induce tumor fibrosis. Chromium (Cr), a naturally occurring heavy metal, is commonly used in industrial processes and can cause severe health problems in humans. It has been found to be closely involved in the metabolism of nucleic acids, proteins and fats in humans. Cr(III) salts can be used as micronutrients and dietary supplements. However, similar to gallium (Ga3+), chromium (Cr3+) can build up to an excessive degree that is harmful to the human body. Therefore, it would be of great interest to develop chemosensing for the selective and sensitive detection of gallium and chromium ions in vitro and in vivo. Herein, we reported that an NBD-based (4-chloro-7-nitrobenzo-2-oxa-1,3-diazole) fluorescent probe (NBDT) was fabricated with demonstrated extraordinary specificity and sensitivity. A swift response toward Ga3+ and Cr3+ ions was discovered using fluorescence enhancement over a wide pH range and with cycle stability. Furthermore, lighted up by Ga3+ and Cr3+ ions in vitro, this NBDT sensor was successfully applied to detect exogenous Ga3+ and Cr3+ ions in MDA-MB-231 and HepG2 cells. Additionally, using zebrafish as the in vivo model, we demonstrated the capability of this NBDT for detecting and imaging Ga3+ and Cr3+ ions in zebrafish. Taken together, this NBDT has indicated great potential for detecting and monitoring Ga3+ and Cr3+ ions in vitro and in vivo.
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FOOD CHEMISTRY
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2018
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IF 4.946
Zhen Shi,Dan Chen,Tian-Tian Chen,Ge Wei,Chun-Yan Yin,Hui Xu,Guang-Fu Yang
A novel solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC–MS) method was developed to quantify two new fungicide residuals (Y13149, Y12196) in mung bean sprouts. With a stable and biocompatible elcetrospinning nanofiber (polystyrene/graphene@silica, PS/G@SiO 2 ) as coating, the SPME fiber was directly inserted into the stem of mung bean sprout to in-situ in-vivo sampling and extraction, followed by GC–MS analysis. Under the optimal conditions, satisfactory average recoveries of 99% and 72% were obtained for Y13149 and Y12196 with the relative standard deviations (RSDs) under 16.3%, indicating good precision and anti-matrix ability of the method. The result also exhibited low detection limit (0.06–0.08 μg·L −1 ) and wide liner range (0.3–100 μg·L −1 ) with the correlation coefficients (R 2 ) of 0.9989. The established method was applied successfully to trace the accumulation and distribution of fungicides in mung bean sprouts, and it provides a simple, rapid and reliable quantitative method for food analysis .
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Scientific Reports
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2018
·Vol. 8
·期 1
·1-9
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IF 4.122
Li Aoqi,Duan Wanyi,Liu Jianming,Zhuo Kelei,Chen Yujuan,Wang Jianji
Deep eutectic solvents (DESs), called a new generation of green solvents, have broad applied in synthesis of nanomaterials due to their remarkable physicochemical properties. In this work, we used a unique strategy (adding moderate water (10%) to DES) to effectively prepare nanomaterials. Flower-like AuPt alloy nanoparticles were successfully synthesized using one-step electrochemical reduction method at a low potential of −0.30 V ( vs . Pt) and a low temperature of 30 °C. In this process, the DES acted as solvent and shape-directing agent. More importantly, we used the electrode modified with the as-prepared nanomaterials as the anode to the electrochemical oxidation synthesis. The glassy carbon electrode modified with the AuPt nanoflowers was directly employed to the electro-oxidation of xanthene (XT) to xanthone (XO) under a constant low potential of 0.80 V ( vs . Ag/AgCl) and room temperature, with a high yield of XO. Moreover, the synthesis process was milder and more environment-friendly than conventional organic syntheses. This new strategy would have a promising application in electroorganic synthesis fields.
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DIGESTIVE DISEASES AND SCIENCES
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2018
·Vol. 63
·期 12
·3329-3338
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IF 2.819
Lin Meng-juan,Yu Bao-ping
Background Irritable bowel syndrome (IBS) is a common disease with intestinal dysmotility, whose mechanism remains elusive. TMEM16A is a calcium-activated chloride channel (CaCC) involved in intestinal slow-wave generation. Aims To investigate whether TMEM16A is involved in colonic dysmotility in IBS. Methods A rat model of IBS was established by chronic water avoidance stress (WAS). Colonic pathological alterations were evaluated histologically, and intestinal motility was assessed by intestinal transit time (ITT) and fecal water content (FWC). Visceral sensitivity was determined by visceromotor response (VMR) to colorectal distension (CRD). TMEM16A expression was evaluated by RT-PCR, Western blot, and immunofluorescence. Colonic muscle strip contractility was measured by isometric transducers, and the effect of niflumic acid (NFA), a CaCC antagonist, on colonic motility was examined. Results After 10 days of WAS exposure, ITT was decreased and FWC was elevated. Furthermore, VMR magnitude of WAS rats in response to CRD was significantly enhanced. Protein and mRNA levels of TMEM16A in colon were considerably increased after WAS. The percentage of TMEM16A-positive neurons in myenteric plexus (MP) of WAS rats was significantly higher than controls. Pharmacological blockade of TMEM16A activity by NFA considerably enhanced ITT, with concentration-dependent declines in FWC and VMR magnitude in NFA-treated rats. Further, spontaneous contraction of colonic strips of NFA-treated rats was significantly ameliorated in a concentration-dependent manner in vitro. Conclusions Upregulation of TMEM16A in MP neurons may play an important role in chronic stress-induced colonic hypermotility, making CaCC-blocking drugs a putatively effective treatment method for colonic hypermotility in IBS.
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Nanoscale
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2018
·Vol. 10
·期 37
·17834-17841
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IF 7.233
Wenxiang Xu,Jingqin Chen,Shan Sun,Zhongdi Tang,Kai Jiang,Liang Song,Yuhui Wang,Chengbo Liu,Hengwei Lin
Photoacoustic imaging (PAI) has emerged as a promising clinical technology, thanks to its high-resolution in deep tissues. However, the lack of specificity towards analytes limits further application of the PA probe in molecular imaging. To this end, we herein report a PA and fluorescence (FL) dual-modal probe for the selective detection of ascorbic acid (AA). To realize this design, cobalt oxyhydroxide (CoOOH) was adopted as a multifunctional platform (PA contrast agent, FL quencher and specific oxidant to AA) and hybridized with red-emissive carbon dots (RCDs). In the presence of AA, CoOOH is reduced to Co2+ and meanwhile releases RCDs, resulting in the decrease of PA and recovery of FL signals. We demonstrated the AA detection capabilities of the probe in complicated biological fluids (human serum and urine), living cells, and dual-modal FL/PA imaging in vivo. This work revealed the PAI capacity of CoOOH for the first time, which may inspire researchers to design other CoOOH-based PA probes and further employ RCDs in biology and the clinic.
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