Zein and tannic acid hybrid particles improving physical stability, controlled release properties, and antimicrobial activity of cinnamon essential oil loaded Pickering emulsions.

Pickering emulsion loading essential oil has demonstrated a promising strategy as delivery system in food preservation, but localization in stability and antimicrobial activity limits application. In this study, Pickering emulsions co-loaded with tannic acid and cinnamon essential oil (ZTC) have been developed based on zein and tannic acid complexes (ZT) mediated interfacial engineering. Fourier transform infrared, fluorescence spectroscopy, and molecular docking results indicated tannic acid altered the structural of zein. Interfacial tension results indicated that tannic acid accelerated the adsorbed speed of zein particles by decreased interfacial tension (11.99-9.96 mN/m). ZT5 formed a viscoelastic and dense layer in oil-water interface than that for other ZTs, which improved stability and control release performance of ZTC. Furthermore, the ZTC showed an effective antimicrobial activity against spoilage organisms Pseudomonad paralactis MN10 and Lactobacillus sakei VMR17. These findings provide new insight for developing co-loaded multiple antimicrobial agents within Pickering emulsion as a delivery system.

Characterisation, slow-release, and antibacterial properties of carboxymethyl chitosan/inulin hydrogel film loaded with novel antilisterial durancin GL.

This paper reports the development of a hydrogel film with antibacterial activity and controlled release characteristics. Carboxymethyl chitosan (CMCS) is grafted onto durancin GL and inulin via a mediated reaction between N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Rheology tests, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and lap shear tests confirmed the formation of a stable chemical cross-linking and excellent adhesion hydrogel with 4 % CMCS and 8 % inulin. The CMCS/inulin hydrogel film loaded with durancin GL appears transparent and uniform. FTIR spectroscopy results reveal the interaction mode among CMCS, inulin, durancin GL, and the hydrogel film structure. Cross-linking improved thermal stability and water-vapour barrier performance. The hydrophobicity of CMCS/inulin @Durancin GL increased under a durancin GL concentration of 0.036 g/30 mL, and the release of active substances is prolonged. In-vitro antibacterial capacity and salmon preservation experiments show that the addition of durancin GL enhanced the antibacterial activity of the hydrogel film. Therefore, CMCS/inulin@Durancin GL hydrogel films can be used as fresh-keeping packaging materials in practical applications.

Surface engineering of carbon-coated cobalt-doped nickel phosphides bifunctional electrocatalyst for boosting 5-hydroxymethylfurfural oxidation coupled with hydrogen evolution.

Multiple surface/interface engineering is an effective approach to develop efficient electrocatalysts for promoting the practical application of electrocatalysis and achieving carbon neutrality. Herein, a deep eutectic liquid precursor containing phosphorus was designed. The self-supported three-dimensional (3D) cobalt-doped Ni12P5/Ni3P nanowire networks coated with a thin layer of carbon (Co-NixP@C) were prepared by using an in-situ one-step pyrolysis method. The as-obtained Co-NixP@C hybrid possesses a superaerophobic/superhydrophilic surface, which could promote electrolyte diffusion and enhance bubble release. Density functional theory (DFT) calculations reveal that Co-doping in NixP@C can promote the adsorption and activation of 5-hydroxymethylfurfural (HMF) molecules, and optimize the energy barrier of H* absorption. The self-supported Co-NixP@C was used as an efficient bifunctional electrocatalyst for HMF oxidation coupled with hydrogen evolution reaction (HER) in a 1.0 M KOH solution. A nearly 100 % yield of 2,5-furandicarboxylic acid (FDCA) was achieved. The self-supported Co-NixP@C displayed high activity and stability for both HER and HMF conversion. The HMF oxidation coupled with HER can be efficiently driven by a 1.5 V commercial photovoltaic panel under sunlight. This study lays the foundation for large-scale industrialization in sustainable fine-chemical and energy engineering.

Antibacterial and Antibiofilm Effect of Ultrasound and Mild Heat Against a Multidrug-Resistant Klebsiella pneumoniae Stain Isolated from Meat of Yellow-Feathered Chicken.

Klebsiella pneumoniae is an important foodborne pathogen with high biofilm-forming ability, which is continuously detected in food products in recent years. The antibacterial and antibiofilm activities and mechanism of ultrasonication in combination with heat treatment against K. pneumoniae were studied. K. pneumoniae planktonic and biofilm cells were treated with ultrasound (US), mild heat treatment (HT50, HT60, and HT70), and combinations of US and mild heat treatment (UH50, UH60, and UH70) for 5, 10, 20, 30, and 60 min. Results showed that the combination of US and mild heat treatment was more effective in inactivating K. pneumoniae planktonic and biofilm cells than the single treatment by counting viable bacteria. In addition, confocal laser scanning microscopy, scanning electron microscopy, and analysis of leakage of intracellular substances have revealed that the combination treatment effectively damaged the integrity of bacterial cell membrane and increased cell permeability, which led to the quick release of adenosine triphosphate (ATP) and macromolecular substances of nucleic acids and proteins. Moreover, the activities of respiratory chain dehydrogenase in planktonic and biofilm cells significantly decreased after UH treatment. The results indicated that ultrasonication and mild heat treatment had a synergistic effect on the inactivation of K. pneumoniae planktonic and biofilm cells by damaging the cell membrane and inhibiting intercellular cell respiration.

Physicochemical characteristics of ginger essential oil nanoemulsion encapsulated by zein/NaCas and antimicrobial control on chilled chicken.

An efficient antibacterial nanoemulsion was prepared using zein and NaCas to encapsulate ginger essential oil (GEO). Physical, optical, and mechanical properties as well as the antibacterial activities of GEO nanoemulsion were investigated. At 1:1 mass ratio of zein/NaCas, the GEO nanoemulsion possessed the highest solubility, entrapment efficiency and stability. The GEO/zein/NaCas complex was confirmed by ultraviolet and fluorescence spectroscopy. The addition of GEO led to more amorphous structure formation and the secondary structure changes of zein/NaCas improved the solubility and stability of GEO. GEO nanoemulsion inactivated two common foodborne bacteria, namely, Staphylococcus aureus and Pseudomonas aeruginosa, by destroying the cell membrane. Meanwhile, the GEO nanoemulsion exhibited better preservation effects on chilled chicken breasts than non-emulsified GEO and could effectively prolong the shelf life of chicken breasts for 6 days. This research provides a green and low-cost method for preparing GEO nanoemulsion to control the risk of foodborne pathogens.

Preparation and characterization of polylactic acid nanofiber films loading Perilla essential oil for antibacterial packaging of chilled chicken.

Biodegradable and eco-friendly food packaging materials have attracted attention. Novel blending films were prepared with polylactic acid (PLA) and Perilla essential oil (PEsO). The morphological features of the nanofibers were modulated by adjusting process parameters (e.g. PLA solution concentration, applied voltage and ultrasonic power). The optimal spinning concentrations, applied voltages and ultrasonic power of the PLA solutions were set at 15% (m/v), 20 kV and 640 W, respectively. Compared with the PLA films, the addition of PEsO increased the diameter of the nanofibers and solvent resistance and reduced the swelling rate of the PLA/PEsO films. The breakage elongation and the gas barrier properties significantly improved when 2% (w/w) PEsO was used. Fourier infrared spectroscopy, X-ray diffractometer, thermogravimetry and differential scanning were used in analyzing the potential interactions of the film matrices. The PLA/PEsO films had good biocompatibility and antibacterial and antioxidant properties. The PLA/PEsO (1:0.02) film loaded with 2% PEsO extended the shelf life of chilled chicken to 12 days, as indicated by the measured total volatile basic nitrogen (TVB-N), total viable count and pH value. Therefore, PLA/PEsO films have great potential as fresh-keeping packaging.

Synergistic Antibiofilm Effects of Ultrasound and Phenyllactic Acid against Staphylococcus aureus and Salmonella enteritidis.

This study evaluated the effect of the combination of ultrasound and phenyllactic acid (PLA) on inactivating Staphylococcus aureus and Salmonella enteritidis biofilm cells and determined the possible antibiofilm mechanism. S. aureus and S. enteritidis biofilm cells were separately treated with ultrasound (US, 270 W), phenyllactic acid (PLA, 0.5% and 1%), and their combination (US + 0.5% PLA, and US + 1% PLA) for 5, 10, 20, 30, and 60 min. Biofilm inactivation, polysaccharide, and respiratory chain dehydrogenase assays were conducted. US and PLA had a synergistic effect on inactivating bacterial cells in S. aureus and S. enteritidis biofilms. The combination of US and PLA significantly decreased the contents of soluble and insoluble polysaccharides and the activity of respiratory chain dehydrogenase in the biofilm cells compared to the single treatment. Confocal laser scanning microscopy, scanning electron microscopy, and intracellular adenosine-triphosphate (ATP) analyses indicated that the combination of US and PLA seriously destroyed the cell membrane integrity of the S. aureus and S. enteritidis biofilms and caused the leakage of intracellular ATP. These findings demonstrated the synergistic antibiofilm effect of US combined with PLA and offered a research basis for its application in the food industry.

The Effects of Allopurinol on the Carotid Intima-media Thickness in Patients with Type 2 Diabetes and Asymptomatic Hyperuricemia: A Three-year Randomized Parallel-controlled Study.

OBJECTIVE: The aim of this study was to investigate the long-term effective control of serum uric acid by allopurinol on the carotid intima-media thickness (IMT) in patients with type 2 diabetes (T2DM) and asymptomatic hyperuricemia (HUA). METHODS: This was a randomized open parallel-controlled study. In this study, 176 patients with T2DM and asymptomatic HUA were randomly allocated to the conventional or allopurinol treatment groups on the basis of a computer-generated random number table. Changes in the carotid IMT, biochemical indexes, high sensitive C-reactive protein (hs-CRP) and the incidence of hypertension in patients before and after three years of treatment were examined and compared between the groups. RESULTS: There were no statistically significant differences in the baseline characteristics of the study participants between the two treatment groups (p>0.05 for all). Nevertheless, the serum uric acid, triglyceride, and hs-CRP levels and the homeostasis assessment for insulin resistance (HOMA-IR), systolic blood pressure, diastolic blood pressure and the carotid IMT in the allopurinol group were significantly lower than those in the conventional group after three years of treatment (p<0.01 for all). The intention-to-treat analysis indicated that the incidence of new-onset hypertension in the allopurinol group showed a declining trend compared to that in the conventional treatment group (6.8% vs. 13.6%, p>0.05). CONCLUSION: The long-term effective control of serum uric acid by allopurinol may improve insulin resistance, decrease the serum levels of hs-CRP, reduce the carotid IMT, and may delay the development of atherosclerosis in patients with T2DM and asymptomatic HUA.

Allopurinol treatment improves renal function in patients with type 2 diabetes and asymptomatic hyperuricemia: 3-year randomized parallel-controlled study.

OBJECTIVE: To investigate the effects of long-term effective control of serum uric acid on renal function in patients with type 2 diabetes and asymptomatic hyperuricemia. METHODS: Application of randomized open parallel-controlled methods, a total of 176 patients with type 2 diabetes and asymptomatic hyperuricemia were selected, and was randomly divided into two groups for allopurinol or conventional treatments, respectively. Changes in urinary albumin excretion rate (UAER), the levels of serum creatinine and glomerular filtration rate (GFR) and the incidence of new-onset diabetic nephropathy (DN) and hypertension in patients before and after 3 years of treatment were measured and compared between groups. RESULTS: There were no statistically significant difference in the baseline clinical characteristics of study participants between two treatment groups (P > 0·05 for all). After 3 years of treatment, compared to the conventional treatment, the allopurinol treatment was more effective in reducing serum uric acid, UAER, serum creatinine (P < 0·01 for all) and increasing GFR (P < 0·01). The intention-to-treat (ITT) analysis indicated that the incidence of new-onset DN and hypertension in the allopurinol group showed a declining trend compared to that in the conventional treatment group, despite a lack of significant difference (P > 0·05). CONCLUSION: Long-term effective control of serum uric acid can decrease UAER and serum creatinine, increase GFR and may exert kidney protection effects in patients with type 2 diabetes and asymptomatic hyperuricemia.

Fabrication of hollow spheres and thin films of nickel hydroxide and nickel oxide with hierarchical structures.

Hollow spheres and thin films of Ni(OH)(2) and NiO with unusual form and hierarchical structures have been synthesized by a simple solution chemistry method. First, in situ formed Ni(OH)(2) nanoflakelets organized on the surface of styrene-acrylic acid copolymer (PSA) latex particles to form core/shell structures. Ni(OH)(2) hollow shells built up with nanoflakelets were obtained after subsequent removal of the core latex particles by dissolving PSA latex in toluene; the removal of the cores by calcinations would result in NiO hollow shells, also with hierarchical structures. BET calculation showed the surface area of the NiO hollow spheres was 156 m(2)/g. The nanoflakelets could also organize themselves into thin films with hierarchical structures. It is anticipated that these novel structures will have some unique applications in Ni-based batteries and other potentials.

Preparation and characterization of silver/TiO2 composite hollow spheres.

Silver-coated poly(methyl acrylic acid) (PSA) core-shell colloid particles were prepared by an in situ chemical reduction method. Crystalline silver/titania composite hollow spheres were obtained by coating the as-prepared PSA/silver particles with an amorphous titania layer and subsequently calcining in Ar atmosphere. SEM and TEM investigation indicated that the size of the as-prepared PSA/silver and PSA/silver/TiO(2) core-shell particles and silver/titania composite hollow particles was fairly uniform and the wall thickness of the hollow spheres was in the range of 40-80 nm. UV-vis absorption spectra were recorded to investigate their optical properties.

Expression, purification, and characterization of human tyrosyl-tRNA synthetase.

Human tyrosyl-tRNA synthetase is a homodimeric enzyme and each subunit is near 58 KD. It catalyzes the aminoacylation of tRNA(Tyr) by L-tyrosine. The His(6)-tagged human TyrS gene was obtained by RT-PCR from total RNA of human lung giant-cell cancer strain 95 D. It was confirmed by sequencing and cloned into the expression vector pET-24 a (+) to yield pET-24 a (+)-HTyrRS, which was transfected into Escherichia coli BL21-CodonPlus-RIL. The induced-expression level of His(6)-tagged human TyrRS was about 24% of total cell proteins under IPTG inducing. The recombinant protein was conveniently purified in a single step by metal (Ni(2+)) chelate affinity chromatography. About 22.3mg purified enzyme could be obtained from 1L cell culture. The k(cat) value of His(6)-tagged human TyrRS in the second step of tRNA(Tyr) aminoacylation was 1.49 s(-1). The K(m) values of tyrosine and tRNA(Tyr) were 0.3 and 0.9 microM. Six His residues at the C terminus of human TyrRS have little effect on the activities of the enzyme compared with other eukaryotic TyrRSs.

Two essential regions for tRNA recognition in Bacillus subtilis tryptophanyl-tRNA synthetase.

Bacillus subtilis tryptophanyl-tRNA synthetase (TrpRS) is a homodimeric enzyme. A model for its ability to recognize tRNA(Trp) in B. subtilis was proposed by using computer modelling. This was based on the the fact that there is high homology among bacterial TrpRSs [Chen, Jiang, Jin and Wang (2001) Acta Biochim. Biophys. Sinica 33, 687-690], in which the enzyme dimer binds to two tRNA(Trp) molecules and each tRNA(Trp) is bound to two different domains across the surface of the dimer. In this work, three deletion mutants of TrpRS were constructed and their products were purified. After determining the kinetic parameters of the mutants in the two-step reaction, it was found that the relative activities of wild-type and mutant enzymes had changed little in the ATP-pyrophosphate exchange reaction. In contrast, the activities of three mutant proteins were much decreased in the tRNA(Trp) aminoacylation assay. Deletion of residues 108-122 and residues 234-238 caused 44% and 80% reductions in the activity, respectively. When both regions were deleted, the aminoacylation activity of the TrpRS mutant was too low to be determined using tRNA(Trp) at the limiting concentration. Gel-retardation assays showed that the acceptor minihelix and the anticodon microhelix were recognized by the domains of TrpRS spanning residues 108-122 and residues 234-238 respectively. In addition, the deletion of amino acids 234-238 affected the normal induced expression of TrpRS at 37 degrees C. In conclusion, residues 108-122 and 234-238 were found essential for tRNA(Trp) recognition.

Construction and Expression of hTNFalpha-hTGF3 Fused Gene.

Human tumor necrosis factor was fused with hTGF3, the third loop region of hTGFalpha specifically binding to EGF receptor, through a flexible linker by recombinant DNA techniques. The constructed plasmid containing hTNFalpha-hTGF3 fused gene, pSB92-TLT, was expressed under the control of P(L) promoter and after the induction at 42 degrees it gave a high level of expression of the fused gene, ranging in 50%-60% of total bacterial protein. 95% of the expressed product was inclusion body, and only 5% was soluble. When the fused gene was constructed into the constitutive plasmid pLC, a new plasmid controlled by P(L) promoter but without cIts857, and expressed at 30 degrees, the expression yield reached 50% and a high proportion of soluble protein, 35% of total bacterial protein, was obtained. Western blot analysis indicated that the fusion protein could specifically bind to anti-hTNFalpha antibody. Comparing to original hTNFalpha, the fused hTNFalpha derivative showed about equal cytotoxicity to L929 cell line and higher cytotoxicity to some human tumor cell lines. This shows that the fusion protein TLT may be promising in application.

Expression in BHK Cells of Two Human TNF Receptors and Their Interaction with hTNF-alpha.

Two human tumor necrosis factor receptor genes were cloned into eukaryotic expression vectors pcDNA3, pDR2 and pXJ-41, respectively. Those vectors were transfected into BHK-21 cells and the expression of hTNFRs was identified and demonstrated by binding of (125)I hTNF-alpha and Scatchard analysis. The expression of two hTNFRs in BHK cells at the RNA transcriptional and the protein translation levels were also demonstrated by RT-PCR and indirect ELISA. However, hTNF-alpha did not appear cytotoxic to these cells. The competitive binding activity of mutant hTNF-alpha-R2K and wild type hTNF-alpha with these two receptors, respectively, were assayed. These results laid basis for further studies on structure-function relationships of these receptors as well as the hTNF-alpha.