NEUROTOXICOLOGY
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2018
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IF 3.076
Jing Zheng,Juan Chen,Xiaohan Zou,Fang Zhao,Mengqi Guo,Hongbo Wang,Tian Zhang,Chunlei Zhang,Wei Feng,Isaac N. Pessah,Zhengyu Cao
Saikosaponins (SSs) are a class of naturally occurring oleanane-type triterpenoid saponins found in Radix bupleuri that has been widely used in traditional Chinese medicine. As the main active principals of Radix bupleuri , SSs have been shown to suppress mouse motor activity, impair learning and memory, and decrease hippocampal neurogenesis. In the present study, we investigated the effect of five SSs (SSa, SSb1, SSb2, SSc, and SSd) on neuronal viability and the underlying mechanisms in cultured murine neocortical neurons. We demonstrate that SSa, SSb1 and SSd produce concentration-dependent apoptotic neuronal death and induce robust increase in intracellular Ca 2+ concentration ([Ca 2+ ] i ) at low micromolar concentrations with a rank order of SSd > SSa > SSb1, whereas SSb2 and SSc have no detectable effect on both neuronal survival and [Ca 2+ ] i . Mechanistically, SSd-induced elevation in [Ca 2+ ] i is the primary result of enhanced extracellular Ca 2+ influx, which likely triggers Ca 2+ -induced Ca 2+ release through ryanodine receptor activation, but not SERCA inhibition. SSd-induced Ca 2+ entry occurs through a non-selective mechanism since blockers of major neuronal Ca 2+ entry pathways, including L-type Ca 2+ channel, NMDA receptor, AMPA receptor, Na + -Ca 2+ exchanger, and TRPV1, all failed to attenuate the Ca 2+ response to SSd. Further studies demonstrate that SSd increases calcein efflux and induces an inward current in neocortical neurons. Together, these data demonstrate that SSd elevates [Ca 2+ ] i due to its ability to increase membrane permeability, likely by forming pores in the surface of membrane, which leads to massive Ca 2+ influx and apoptotic neuronal death in neocortical neurons.
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MATERIALS SCIENCE FORUM
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2019
·
IF 0
Ji Fu Du,Zhen Dong,Xin Yang,Long Zhao
Glycidyl methacrylate (GMA) was grafted onto the surface of HDPE particles by radiation grafting and emulsion graft copolymerization. And subsequent ring-opening reaction of expoxy groups in poly-GMA graft chains with N-methylglucamine (NMG) was conducted to synthesis the boron adsorbent. The synthesis condition (radiation dose and NMG concentration) was optimized and characterized by IR and SEM. Adsorption behaviors of the boron adsorbent for boron removal presented that adsorption kinetics was well described by pseudo-second-order kinetic mode. The adsorption isothermal was well fitted with both Langmuir and Freundlich isotherm models. The adsorption capacity for boron reached 15.63 mg/g at optimal pH 8. Dynamic experiment revealed that boron could be efficiently adsorbed by the boron adsorbent and fully desorbed using 13 BV of 1 mol/L HCl.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2019
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IF 3.571
Feier Cheng,Lin Han,Yao Xiao,Chuanying Pan,Yunlong Li,Xinhui Ge,Yao Zhang,Shaoqing Yan,Min Wang
d-chiro-Inositol (DCI) is a biologically active component found in tartary buckwheat, which can reduce hyperglycemia and ameliorate insulin resistance. However, the mechanism underlying the antidiabetic effects of DCI remains largely unclear. This study investigated the effects and underlying molecular mechanisms of DCI on hepatic gluconeogenesis in mice fed a high fat diet and saturated palmitic acid-treated hepatocytes. DCI attenuated free fatty acid uptake by the liver via lipid trafficking inhibition, reduced diacylglycerol deposition, and hepatic PKCε translocation. Thus, DCI could improve insulin sensitivity by suppressing hepatic gluconeogenesis. Subsequent analyses revealed that DCI decreased hepatic glucose output and the expression levels of PEPCK and G6 Pase in insulin resistant mice through PKCε-IRS/PI3K/AKT signaling pathway. Likewise, such effects of DCI were confirmed in HepG2 cells with palmitate-induced insulin resistance. These findings indicate a novel pathway by which DCI prevents hepatic gluconeogenesis, reduces lipid deposition, and ameliorates insulin resistance via regulation of PKCε-PI3K/AKT axis.
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Food Science & Nutrition
·
2019
·Vol. 7
·期 6
·2043-2049
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IF 1.747
Yujing Sun,Li Zeng,Yuanzhong Xue,Tianbao Yang,Zongming Cheng,Peilong Sun
β- d -glucosidase can release aroma precursors to improve the flavor of plant food, but the hydrolysis efficiency of the enzyme is low; the purpose of this study was to improve the enzyme activity using ultrasound. The effects of ultrasound parameters on β- d -glucosidase activity were investigated, and the respective structures of enzyme activated and enzyme inhibited were further analyzed. Low temperature (20–45°C), low ultrasonic intensity (<181.53 W/cm 2 ), and short treatment time (<15 min) led to the activation of β- d -glucosidase, whereas high temperature (45–60°C), high ultrasonic intensity (>181.53 W/cm 2 ), and long treatment time (>15 min) led to its inhibition. Application of ultrasound lowered the optimum temperature for β- d -glucosidase activity from 50 to 40°C. Ultrasound did not change the primary structures of the enzyme, but changed the secondary structures. When ultrasound activated β- d -glucosidase, the α-helix contents were increased, the β-fold and irregular coil content were reduced. When ultrasound inhibited β- d -glucosidase, the contents of β-folds were increased, the α-helix and irregular coil contents were reduced.. In summary, activation or inhibition of β- d -glucosidase under ultrasound was determined by the ultrasound conditions. This study suggests that ultrasound combined with β-D-glucosidase can be used in aroma-enhancing.
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Journal of Functional Foods
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2019
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IF 3.197
Ze-hua Li,Ming Cai,Kai Yang,Pei-long Sun
Nanoemulsion loading finger citron essential oil (FCEO) can maintain bioactivities of FCEO and increase its water solubility. In this study, stability of FCEO nanoemulsions during digestion in vitro were evaluated and the release kinetics of d-limonene (the main component in the oil) were developed. Compared with free oil released to maximum for 6 min, all nanoemulsions kept sustainably releasing for 300 min or longer. Droplet size of the nanoemulsions increased from 10–18 nm of initial to 105–1106 nm after digestion, indicating coalescence or aggregation occurred. Zero-order, Hixcon-Crowell, Higuchi, Ritger-Peppas and Niebergull models were used to describe the release kinetics. The results showed zero-order and Ritger-Peppas models were the best fit models at mouth and intestinal stage, respectively. Both zero-order and Higuchi models were appropriate at gastric stage. This study could demonstrate the digestion mechanisms of FCEO loaded nanoemulsion and facilitate the design of hydrophobic nutraceuticals delivery systems in food industry.
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Polymer Chemistry
·
2019
·Vol. 10
·期 21
·2706-2715
·
IF 4.76
Yongjie Yuan,Lifang He,Jindi Li,Hailiang Zhang
A series of luminescent side chain polymers containing a D–π-A structure and different flexible spacer lengths, namely, poly[(Z)-ω-(4-(1-cyano-2-(4-cyanophenyl)vinyl)phenoxy)alkyl methacrylate]s (PMmPVPCN, m = 2, 4, 6, 8), were successfully prepared. With the combination of aggregation-induced emission enhancement (AIEE) luminogens and mesogens, the resultant polymers are expected to possess both liquid crystal characteristics and AIEE characteristics. The phase structure of PMmPVPCN was explored by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and one-dimensional wide-angle X-ray diffraction (1D WAXD). Photophysical properties of PMmPVPCN were studied by UV spectra and fluorescence spectra. Test results suggested that the phase structure of PMmPVPCN transformed from the amorphous phase (PMmPVPCN, m = 2, 4) to the nematic phase (PMmPVPCN, m = 6, 8) with the increase of polymer spacer length. All the synthetic monomers and polymers exhibited AIEE properties and the luminescence behavior of PMmPVPCN was associated with their chemical structure. The solid fluorescence quantum yields of PMmPVPCN increased from 22.4% to 42.7% with increasing spacer length. The polymer films also showed reversible fluorescence photo-responsive properties. The emission color and the emission intensity of polymer films changed when exposed to a 365 nm UV lamp. The change process was reversible and they could turn back to their original state when irradiated with a 254 nm UV lamp or heated at higher temperature.
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JOURNAL OF MOLECULAR STRUCTURE
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2018
·
IF 2.011
Yi-bao Jiang,Chao Gao,Xian Zhang,Jin-shui Yao,Qin-ze Liu,Xiao-xia Cai
A novel triphenylamine derivative, 4,4′ -bis-([1,10]phenanthrolin-2-yl) imidazo -triphenylamine (IPTPA) with an A-π-D-π-A structure, has been synthesized and characterized. The UV absorption , single and two-photon fluorescence spectra showed that IPTPA was highly sensitive to Ag + with a lower detection limit of 3.97 nmoL/L and a moderate binding constant of 2.16 × 10 5 /M at room temperature . The two-photon active cross-section of IPTPA was calculated with a value of 94.68 GM at 800 nm in the tris-HCl buffer solution. The binding mechanism between IPTPA and Ag + were explored by the Job plot, ESI-MS and 1 H NMR. The A-π-D-π-A structure of IPTPA was substituted by the A-π-D-π-D structure of IPTPA-Ag to improve the fluorescence. Furthermore, the fluorescence microscopy images indicated that IPTPA could detect Ag + in living cells.
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ANALYTICAL CHEMISTRY
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2018
·
IF 6.042
Xiaohua Zhu,Lin Fan,Shigong Wang,Chunyang Lei,Yan Huang,Zhou Nie,Shouzhuo Yao
As one of the emerging inorganic graphene analogues, two-dimensional titanium carbide (Ti3C2) nanosheets have attracted extensive attention in recent years because of their remarkable structural and electronic properties. Herein, a sensitive and selective nanoprobe to fluorescently probe phospholipase D activity was developed on the basis of an ultrathin Ti3C2 nanosheets-mediated fluorescence quenching effect. Ultrathin Ti3C2 nanosheets with ∼1.3 nm in thickness were synthesized from bulk Ti3AlC2 powder by a two-step exfoliation procedure and further modified by a natural phospholipid that is doped with rhodamine B-labeled phospholipid (RhB-PL-Ti3C2). The close proximity between RhB and Ti3C2 leads to efficient fluorescence quenching (>95%) of RhB by energy transfer. Phospholipase D-catalyzed lipolysis of the phosphodiester bond in RhB-PL results in RhB moving away from the surface of Ti3C2 nanosheets and subsequent fluorescence recovery of RhB, providing a fluorescent “switch-on” assay for the phospholipase D activity. The proposed nanoprobe was successfully applied to quantitatively determine phospholipase D activity with a low limit of detection (0.10 U L–1) and to measure its inhibition. Moreover, in situ monitoring and imaging the activity of phospholipase D in living cells were achieved using this biocompatible nanoprobe. These results reveal that Ti3C2 nanosheets-based probes exhibit great potential in fluorometric assay and clinical diagnostic applications.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 102
·期 14
·6039-6046
·
IF 3.34
Tigu Fitsum,Zhang Junli,Liu Guoxia,Cai Zhen,Li Yin
d -Pantothenic acid (vitamin B 5 ) has wide applications in the feed, food, chemical, and pharmaceutical industries. Its biological production routes which employ pantothenate synthetase (PS) as the key enzyme are attractive since they avoid the tedious and time-consuming optical resolution process. However, little data is available on the activity and kinetics of this enzyme, hampering the rational selection of an efficient enzyme for the biological production of d -pantothenic acid. In this study, six phylogenetically distant PS-encoding genes, from Escherichia coli , Corynebacterium glutamicum , Bacillus subtilis , Bacillus thuringiensis , Bacillus cereus , and Enterobacter cloacae , were expressed in E. coli . The PS from C. glutamicum exhibited a specific activity of 205.1 U/mg and a turnover number of 127.6 s -1 , which to our best knowledge are the highest values ever reported. The addition of substrates ( d -pantoic acid and β-alanine) to the E. coli strain harboring this enzyme during the early log phase of fermentation resulted in the production of 97.1 g/L of d -pantothenic acid within 32 h, corresponding to a conversion yield of 99.1% and a productivity of 3.0 g/L/h. To the best of our knowledge, this is the highest productivity reported to date.
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Ganqiao Ran,Dan Tan,Jiping Zhao,Fan Fan,Qiang Zhang,Xingjuan Wu,Peiyao Fan,Xinlei Fang,Xiaoyun Lu
d -Allulose is a promising low-calorie sweetener especially for diabetes and obesity patients. The functionalized polyhydroxyalkanoate (PHA) nano-beads decorated with d -tagatose 3-epimerase (DTE) was produced in recombinant endotoxin-free ClearColi , whereby the expression, purification, and immobilization of the active DTE were efficiently combined into one step. The immobilized DTE exhibited remarkable enzyme activity of 649.3 U/g beads and extremely high stability at a harsh working condition (pH 7.0–8.0, 65 °C). When DTE-PHA beads were subjected to enzymatic synthesis of d -allulose, a maximum conversion rate of 33% can be achieved at pH 7.0 and 65 °C for 3 h, and DTE-PHA beads retained about 80% of its initial activity after 8 continuous cycles. Moreover, the d -allulose/ d -fructose binary mixture can be simply separated by a single cation exchange resin-equipped chromatography. Taken together, DTE-PHA beads are promising and robust nano-biocatalysts that will remarkably simplify the production procedures of d -allulose, contributing to its cost-effective production.
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Materials Science & Engineering C-Materials for Biological Applications
·
2017
·
IF 4.164
Lihong Qiao,Tingting Sun,Xiaohua Zheng,Min Zheng,Zhigang Xie
Targeting imaging to the desired site of action can increase the accuracy and effectiveness of diagnostic and treatment. In this work, a series of fluorescent carbon dots (CDs) were prepared by varying molar ratios of d -glucose (Glu) to l -aspartic acid (Asp). Their photophysical properties, morphologies and structures were investigated in detail. More important, the targeting ability was screened by confocal laser scanning microscopy and flow cytometry. The results indicate that CDs prepared from the optimal molar ratio of Glu/Asp (7:3) exhibit the highest targeting ability on C6 glioma cells. This work highlights the interplay of molecular design and corresponding functions, and open new possibility of developing state-of-art nanoparticles for biomedical applications.
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Nanoscale
·
2017
·Vol. 10
·期 4
·1631-1640
·
IF 7.367
Lingcan Kong,Xuefeng Chu,Chuanxi Wang,Hong Zhou,Yukang Wu,Wenwei Liu
The aggregation-induced emission (AIE) behavior of metal nanoclusters has attracted much attention owing to their extensive application prospects in bio-imaging and chemical sensors. However, the intrinsic mechanism of metal nanoclusters’ aggregation-induced emission is still not very clear. Herein, Cu nanoclusters S1 and Ag(I)-doped Cu/Ag nanoclusters S2 and S3 coated with D-penicillamine are designed and synthesized by a self-assembly strategy. S1–S3 show strong luminescence properties with luminescence quantum yields as high as 11.4%–14.2%. Moreover, their luminescence peak position shows an obvious hypsochromic shift from 615 (S1) to 570 nm (S3). With the introduction of Ag(I) ions, the assembly morphology also shows clear changes from the irregular assembly structure (S1) to large spherical particles with the average size of 0.18 μm for S2 and 0.47 μm for S3. A detailed investigation of high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD) patterns, ESI-TOF-mass spectra, UV-vis absorption spectra, photoluminescence spectra and luminescence lifetimes of Cu/Ag nanoclusters S2 and S3 indicates that Cu/Ag nanoclusters are actually a Cu/Ag alloy nanocluster superstructure and the microscopic arrangement of S2 and S3 is more compact and ordered relative to S1. The more compact and ordered Cu/Ag alloy nanocluster superstructure enhances the metal–metal interaction of inter-nanoclusters and intra-nanoclusters and facilitates the radiative transition of ligand-to-metal charge transfer (LMCT) and/or ligand-to-metal–metal charge transfer (LMMCT), which results in the aggregation-induced emission phenomenon. In addition, an enhanced metal–metal interaction increases the average metal–metal distance of the Cu/Ag nanocluster superstructure, leading to a hypsochromic shift of emission spectra. Furthermore, the Cu/Ag alloy nanoclusters show good stability and reversibility on pH cycling between pH = 3 and 7 and temperature cycling between 5 °C and 48 °C. The Cu/Ag alloy nanoclusters can be used as probes for Ag(I) ion and halide anion detection in real water samples by the ratiometric PL method (I570/I615).
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