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Zhou R.,Shenzhen University | Shi X.,Shenzhen University | Cai N.,Shenzhen University | Jiang Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Xu X.,Shenzhen University
Journal of Agricultural and Food Chemistry | Year: 2015

Alginate has notably diverse pharmacological activities. The present study investigated the anti-inflammatory activity of the guluronate oligosaccharides prepared by oxidative degradation (GOS-OD) from alginate. GOS-OD significantly attenuated the production of nitric oxide (NO), prostaglandin E2 (PGE2), and reactive oxygen species (ROS), the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and the secretion of pro-inflammatory cytokines in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cells. Moreover, GOS-OD potently decreased the binding of LPS to the cell surface and LPS-induced Toll-like receptor 4 (TLR4) and cluster of differentiation (CD) 14 expression. Additionally, GOS-OD could remarkably inhibit the LPS-induced activation of nuclear factor (NF)-κB and mitogen-activated protein (MAP) kinase pathways in RAW 264.7 cells. These results indicate that GOS-OD may reduce the LPS-stimulated inflammatory responses through blocking the activation of NF-κB and MAP kinases, suggesting that GOS-OD may be considered as a potential nutraceutical for inflammation. © 2014 American Chemical Society.


Chen X.,Jimei University | Zhao L.,Jimei University | Tian X.,Jimei University | Lian S.,Jimei University | And 3 more authors.
Talanta | Year: 2014

A novel method for the determination of tetracyclines (TCs) using electrochemiluminescence (ECL) based on a Ru(bpy)3 2+-doped silica nanoparticles (RuSiNPs)/Nafion film modified electrode is presented in this paper. The RuSiNPs were prepared by a water-in-oil microemulsion method. The characterization results indicated that the thus-prepared RuSiNPs presented a uniform size of 45 nm and retained the original electrochemical properties of Ru(bpy)3 2+. Importantly, the ECL response on RuSiNPs/Nafion film modified electrode was greatly enhanced by TCs. Under the optimum conditions, the ECL intensity versus the concentration of TCs was found to be linear over the range of 1-100 μmol L-1 for tetracycline (TC), 0.1-100 μmol L-1 for oxytetracycline (OTC) and 1-100 μmol L-1 for chlortetracycline (CTC). The detection limits (S/N=3) were 0.23 μmol L-1 for TC, 0.10 μmol L-1 for OTC and 0.16 μmol L-1 for CTC. Moreover, due to the electrostatic interaction between Ru(bpy)3 2+ and silica matrix, the leaching of Ru(bpy)3 2+ was greatly reduced, therefore, the ECL sensor exhibited excellent repeatability and stability in the detection of TCs. Based on these investigations, the proposed ECL approach was successfully used to analyze the TCs content in drugs. © 2014 Elsevier B.V.


Gao Z.-H.,Jimei University | Lin Z.-Z.,Jimei University | Lin Z.-Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Chen X.-M.,Jimei University | And 4 more authors.
Sensors and Actuators, B: Chemical | Year: 2016

A facile and green method was developed to prepare amino-functionalized fluorescent carbon dots (FCDs) for the detection of Hg2+ in aqueous solution. The water-soluble FCDs with the diameter around 3-5 nm were synthesized using anhydrous citric acid as carbon sources, NaBH4 as reducing agent and ammonia as passivation agent. The as-prepared FCDs exhibit blue emission at 440 nm with quantum yield as high as 36% using quinine sulfate as reference. The fluorescence intensity of the FCDs can be quantitatively quenched by Hg2+ with high sensitivity and selectivity. The FCDs were successfully applied to the measurement of Hg2+ in water samples with a detection limit of 20 nmol L-1 (3σ, n = 9), indicating that the amino-functionalized FCDs probe can be potentially applied to the detection of trace Hg2+ in water samples. © 2015 Elsevier B.V. All rights reserved.


Lin Z.-Z.,Jimei University | Lin Z.-Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Zhang H.-Y.,Jimei University | Li L.,Jimei University | And 2 more authors.
Reactive and Functional Polymers | Year: 2016

Magnetic molecularly imprinted polymers (MMIPs) synthesized through suspension polymerization were used as the adsorbent for the detection of malachite green (MG) in fish samples. The morphological, thermal and magnetic properties of the MMIPs were characterized. The influence of polymerization condition on the absorption capacity of the MMIPs for MG was explored. The results gave the optimum polymerization condition as follows: using MG (0.25 mmol) as template, methacrylic acid (1 mmol) as monomer, ethylene dimethacrylate (5 mmol) as cross linker, 2,2′-Azobis(2-methylpropionitrile) (100 mg) as initiator, Fe3O4 (100 mg) as magnetic nuclei, and PVA (1%) as dispersant. Under the optimum condition the apparent maximum adsorption capacity of MMIPs is 5693 μg·g- 1 with dissociation constant being 23.5 mg·L- 1. The MMIPs also have strong magnetic responses to an external magnet, which enable the rapid separation from the sample solution. The MMIPs were employed for the detection of MG residue in fish samples combined with HPLC. The recoveries of spiked MG in fish samples ranged from 82.7% to 111% with RSD in the range of 2.0%-12.8%. The MMIPs can retain 90% of the original adsorption capacity even if used for 5 times. Thus, the prepared MMIPs can be applied to the sample pretreatment for separation and enrichment of MG residue in fish samples. © 2015 Elsevier B.V.


Chen S.,Jimei University | Tang L.,Jimei University | Su W.,Jimei University | Su W.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | And 4 more authors.
Food Chemistry | Year: 2015

Alpha-chain subunits were separated from tilapia skin gelatin using ultrafiltration, and the physicochemical properties of obtained subunits were investigated. As a result, α1-subunit and α2-subunit could be successfully separated by 100 kDa MWCO regenerated cellulose membranes and 150 kDa MWCO polyethersulfone membranes, respectively. Glycine was the most dominant amino acid in both α1-subunit and α2-subunit. However, the tyrosine content was higher in α2-subunit than in α1-subunit, resulting in strong absorption near 280 nm observed in the UV absorption spectrum. Based on the DSC analysis, it was found that the glass transition temperatures of gelatin, α1-subunit and α2-subunit were 136.48 °C, 126.77 °C and 119.43 °C, respectively. Moreover, the reduced viscosity and denaturation temperature of α1-subunit were higher than those of α2-subunit, and the reduced viscosity reached the highest when α-subunits were mixed with α12 ratio of approximately 2, suggesting that α1-subunit plays a more important role in the thermostability of gelatin than α2-subunit. © 2015 Elsevier Ltd. All rights reserved.


An D.,Jimei University | Li Y.,Jimei University | Jiang Z.,Jimei University | Jiang Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Wang L.,Jimei University
Journal of Chinese Institute of Food Science and Technology | Year: 2014

Based on biogenic amine have significant sensitization effect on the electrochemical luminescence signal of [Ru (bpy)3 2+], a CE-ECL systerm for the electrochemical luminescence is established. In this paper, on the basis of the electrochemical luminescence of [Ru(bpy)3 2+] signal, focuses on testing conditions in the detection cell. The results indicate that under the optimized conditions, detection potential at 1.15 V, 5 mmol/L [Ru(bpy)3 2+](pH=7.00), sample injection at 13kV × 10s, 50 mmol/L of phosphate buffer at pH 7.00. Under the optimized conditions, the ECL intensity was linear with concentration of histamine dihydrochloride in the range of 1~100 μmol/L. The linear equation for I=149.48c + 45.141, correlation coefficient r=0.9961 (n=5) with detection limit (S/N=3) of 0.496 μmol/L. Spermidine, under its optimal conditions, the ECL intensity was linear with concentration of histamine dihydrochloride in the range of 1.5~7.5 μmol/L. The linear equation for I=6426.7c + 4.72, correlation coefficient r=0.9978(n=5) with detection limit (S/N=3) of 0.6 μmol/L. Optimal conditions for sample of histamine and spermine were measured, are not detected in the samples of histamine. The method used to determinate spermidine in the green moth samples, the relative standard deviation (RSD) of peak height and migration time were 0.48% and 1.67%, recovery is 115.14%~118.02%. In the clam samples, the relative standard deviation (RSD) of peak height and migration time were 0.48% and 1.67%, recovery is 108.82%~112.34%. In the sea seeds samples, the relative standard deviation (RSD) of peak height and migration time were 2.03% and 1.82%, recovery is 107.26%~119.50%. ©, 2014, Chinese Institute of Food Science and Technology. All right reserved.


Zhu Y.,Jimei University | Zhu Y.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Zhu Y.,Fujian University of Technology | Wang G.,Xinxiang Medical University | And 9 more authors.
World Journal of Microbiology and Biotechnology | Year: 2014

A new gene encoding a superoxide dismutase (SOD) was identified from a thermophile Geobacillus sp. EPT3 isolated from a deep-sea hydrothermal field in east Pacific. The open reading frame of this gene encoded 437 amino acid residues. It was cloned, overexpressed in Escherichia coli (DE3), and the recombinant protein was purified to homogeneity. Geobacillus sp. EPT3 SOD was of the manganese-containing SOD type, as judged by the insensitivity of the recombinant enzyme to both KCN and H2O2, and the activity analysis of Fe or Mn reconstituted SODs by polyacrylamide gel electrophoresis. The recombinant SOD was determined to be a homodimer with monomeric molecular mass of 59.0 kDa. In comparison with other Mn-SODs, the manganese-binding sites are conserved in the sequence (His260, His308, Asp392, His396). The recombinant enzyme had high thermostability at 50 °C. It retained 57 % residual activity after incubation at 90 °C for 1 h, which indicated that this SOD was thermostable. The enzyme also showed striking stability over a wide range of pH 5.0-11.0. At tested conditions, the recombinant SOD from Geobacillus sp. EPT3 showed a relatively good tolerance to some inhibitors, detergents, and denaturants, such as β-mercaptoethanol, dithiothreitol, phenylmethylsulfonyl fluoride, Chaps, Triton X-100, urea, and guanidine hydrochloride. © 2013 Springer Science+Business Media Dordrecht.


Lin Z.,Jimei University | Lin Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Wang D.,Jimei University | Peng A.,Jimei University | And 4 more authors.
Journal of Separation Science | Year: 2016

A selective sample cleanup method using molecularly imprinted polymers was developed for the separation of domoic acid (a shellfish toxin) from shellfish samples. The molecularly imprinted polymers for domoic acid was prepared by emulsion polymerization using 1,3,5-pentanetricarboxylic acid as the template molecule, 4-vinyl pyridine as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, and Span80/Tween-80 (1:1 v/v) as the composite emulsifiers. The molecularly imprinted polymer showed high affinity to domoic acid with a dissociation constant of 13.5 μg/mL and apparent maximum adsorption capacity of 1249 μg/g. They were used as a selective sorbent for the detection of domoic acid from seafood samples coupled with high-performance liquid chromatography. The detection limit of 0.17 μg/g was lower than the maximum level permitted by several authorities. The mean recoveries of domoic acid from clam samples were 93.0–98.7%. It was demonstrated that the proposed method could be applied to the determination of domoic acid from shellfish samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Tang L.,Jimei University | Chen S.,Jimei University | Su W.,Jimei University | Su W.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | And 4 more authors.
Process Biochemistry | Year: 2015

Acid soluble collagens (ASCs) were extracted from tilapia, grass carp and silver carp skins, and the physicochemical properties and film-forming ability of ASCs were examined. Similar amino acid composition and electrophoretic patterns were observed in the obtained skin ASCs, but differences were found in the peptide maps of collagen digested by V8 protease, trypsin and lysyl endopeptidase. The reduced viscosity value of tilapia skin ASC was higher than that of grass carp and silver carp skin ASCs at 25 °C. Furthermore, the tensile strength of films based tilapia skin collagen was 51.24 MPa, and much higher than that of films based grass carp or silver carp skin collagen. On the other hand, the nucleation time of fibril formation of skin collagen from tilapia, grass carp and silver carp was about 2 min, 6 min and 3 min, respectively. The obvious coarser microstructure was found on the upper surface of films prepared from grass carp skin collagen by scanning electron microscopy. It is concluded that difference in the film-forming ability of collagen from freshwater fish skins could be correlated with the primary structures and conformation of collagen molecules. © 2014 Elsevier Ltd. All rights reserved.


Weng W.,Jimei University | Weng W.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Tang L.,Jimei University | Wang B.,Jimei University | And 6 more authors.
Journal of Functional Foods | Year: 2014

Antioxidative fractions were isolated from hydrolyzed blue shark skin gelatin with Protamex, and the DPPH and hydroxyl radical scavenging abilities were investigated. The IC50 values of hydrolysates to scavenge DPPH and hydroxyl radical signals were 13.30 and 4.30 mg/mL, respectively. Three fractions (I, II, III) were obtained after separated by Sephadex G-15 gel filtration. The IC50 values of fraction III to scavenge DPPH and hydroxyl radical signals were 0.57 and 2.04 mg/mL, respectively, which were close to glutathione. It was found that fraction III was mainly composed of four peptides and four amino acids by RP-HPLC and ESI-MS/MS analysis, including Glu-Gly-Pro, Gly-Pro-Arg, Gly-Tyr, Gly-Phe, Leu, Arg, Tyr and Phe. The activity assessments for these components indicated that the dipeptide of Gly-Tyr and amino acid of Tyr were important for the excellent antioxidant activities. It is concluded that fraction III has a great potential as natural functional materials for supplement. © 2014 Elsevier Ltd.

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