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Spirulina platensis (S. platensis) is regarded as an ideal source for antioxidant peptides. Microbial fermentation is an effective strategy to increase the utilization of these peptides from S. platensis. This study isolated peptides from the co-fermentation products (STF) of S. platensis extracts with Thermus thermophilus HB27, and Saccharomyces cerevisiae CH006. Compared to the original extracts, amino acid, and protein contents in STF were increased. Using in vitro antioxidant activities guided fractionation by DEAE-52 chromatography, the fraction, STFP-3, were conducted for structure characterization and in vitro zebrafish embryos evaluations. The amino acid composition, LC-MS/MS, circular dichroism, molecular docking analysis revealed that STFP-3 contained 260 peptides and the top ten peptide sequences were identified. Two peptides, Thr-Phe-Arg-Gly-Pro-Pro (TFRGPP) and Phe-Thr-Arg-Pro-Pro (FTRPP) exhibited more stable inhibitory activity against myeloperoxidase (MPO), and the Pro-Pro structures might play an important role. STFP-3 significantly decreased the production of reactive oxygen species (ROS) (P < 0.05) and inhibited the melanin content (P < 0.05) in zebrafish embryos model. These findings demonstrated the potential of using microbial fermentation treatment to produce antioxidant peptides from S. platensis with T. thermophilus and S. cerevisiae. • S. platensis extracts was fermented to obtain S. platensis peptides. • STFP-3 contained 260 peptides and identified top ten peptide sequences by UPLC-MS/MS. • TFRGPP and FTRPP were screened as novel antioxidant peptides. [ABSTRACT FROM AUTHOR]

Polysaccharide from seeds of Plantago asiatica L. is rich in Ara and Xyl. However, it contains small amounts of other monosaccharides, such as Rha, Gal and GalA. It is the first time to systematically elucidate structural features as well as fractionation, physicochemical properties of non-arabinoxylan polysaccharide from the seeds of Plantago asiatica L.. Non-arabinoxylan polysaccharide named as PLWE-NAX was successfully isolated and separated from the water extract of the seeds at a temperature of 50 °C. PLWE-NAX was purified into five fractions by anion exchange chromatography and gel permeation chromatography. The non-arabinoxylan fractions included arabinogalactan (PLWE-1), xylan (PLWE-2) and pectin (PLWE-3, PLWE-4, PLWE-5). PLWE-2, PLWE-3, PLWE-4 and PLWE-5 were acidic polysaccharide. PLWE-4 was subjected for structural characterization by methylation analysis and 1D/2D NMR. It was mainly consisted of α-1,2-linked Rha p (25.01%), T-linked Ara f (12.11%) and β-1,3,4-linked Xyl p (20.01%) residues. Uronic acid in PLWE-4 was α-1,4-linked GalA p (31.55%). PLWE-4 had the back bone as following, →1)-α-GalA p -(4 → 1)-α-Rha p -(2 → 1)-α-GalA p -(4 → . [ABSTRACT FROM AUTHOR]

Dynamical control of plasmon-induced transparency (PIT) in metamaterials promises essential application opportunities. In this paper, we design a novel disk/rod hybrid metasurface to investigate an actively controlled PIT spectral response through polarization-dependent near-field coupling between the disk (bright) and the rod (dark) resonator. It is found that an on-to-off amplitude modulation of the PIT transparency window is achieved by the rotation of polarization, allowing for dynamically tunable group delays of incident waves. An analytic model based on the dipole-dipole interactions is developed for the proposed configuration, which agrees well with the numerical results. The disk/rod metasurface offers great promise for optical switching and compact slow light devices. [ABSTRACT FROM AUTHOR]

Sulfated modification was carried out to modify a water-insoluble polysaccharide from Ganoderma atrum (AGAP). The effects of sulfation on structure, physicochemical and functional properties of AGAP were investigated. Three sulfated derivatives were prepared, designated as S-1, S-2 and S-3 with degree of substitution (DS) of 0.35, 0.74 and 1.14, respectively. AGAP was elucidated as an α-(1→3)-glucan with few branches terminated by single mannose or xylose residues. The molecular weight ( M w ) and radius of gyration ( R g ) were estimated to be 1665 kDa and 65.49 nm, respectively. After sulfated modification, non-selective sulfation occurred preferably at O -6, partially at O -2 and O -4 positions of the glucosyl residues. The water-solubility of the derivatives was significantly improved in a DS-dependent manner. M w of the derivatives showed a sharp decrease, and the chain conformation was estimated to be expanded stiff in phosphate buffer. In vitro tests showed that sulfated modification improved its antioxidant activities and anti-proliferative ability against S-180 tumor cells. This study suggested that sulfated modification was an effective approach to improve the water-solubility and functional properties of insoluble polysaccharides. [ABSTRACT FROM AUTHOR]

We theoretically investigate the photonic band gap in one-dimensional photonic crystals with a graded multilayer structure. The proposed structure constitutes an alternating composite layer (metallic nanoparticles embedded in TiO2 film) and an air layer. Regarding the multilayer as a series of capacitance, effective optical properties are derived. The dispersion relation is obtained with the solution of the transfer matrix equation. With a graded structure in the composite layer, numerical results show that the position and width of the photonic band gap can be effectively modulated by varying the number of the graded composite layers, the volume fraction of nanoparticles and the external stimuli. [ABSTRACT FROM AUTHOR]

[Display omitted] • Progress of NMR analysis in polysaccharide structure and conformation is summarized. • NMR spectra data of typical polysaccharides are collected. • NMR analysis in cell wall structure in situ and other applications are hotspots. • Challenges and perspertives of NMR analysis in polysaccharides are pointed out. Nuclear magnetic resonance (NMR) has been widely used as an analytical chemistry technique to investigate the molecular structure and conformation of polysaccharides. Combined with 1D spectra, chemical shifts and coupling constants in both homo- and heteronuclear 2D NMR spectra are able to infer the linkage and sequence of sugar residues. Besides, NMR has also been applied in conformation, quantitative analysis, cell wall in situ , degradation, polysaccharide mixture interaction analysis, as well as carbohydrates impurities profiling. This review summarizes the principle and development of NMR in polysaccharides analysis, and provides NMR spectra data collections of some common polysaccharides. It will help to promote the application of NMR in complex polysaccharides of biochemical interest, and provide valuable information on commercial polysaccharide products. [ABSTRACT FROM AUTHOR]

We theoretically investigate the optical transmission properties of a specific type of plasmonic metamaterial crystal layer that exhibits polarization and angle independence inside a band of electromagnetically induced transparency (EIT). The hybridization of the plasmons associated with two interleaved arrays of nanorings of different radii leads to destructive interference between their respective plasmon transmission modes. Both plasmon resonances produce bright modes associated with electric dipole oscillation. The EIT is produced by destructive interference between emitted fields of these modes. The presented metamaterial crystal offers new insights into designing optical metamaterials with wide field of view, quasi-omnidirectional polarization, and quasi-isotropic transmission. [ABSTRACT FROM AUTHOR]

Highlights: [•] We examined the possibility of TLR4 as the candidate receptor for PSG-1. [•] We investigated the role of ROS in PSG-1-mediated macrophage activation. [•] TLR4 is the major receptor involved in interaction of PSG-1 and macrophages. [•] NADPH oxidase-derived ROS act as upstream of PI3K/Akt/MAPKs/NF-κB signaling pathway. [•] PSG-1 activates macrophage via a TLR4/ROS/PI3K/Akt/MAPKs/NF-κB signal pathway. [ABSTRACT FROM AUTHOR]

Highlights: [•] PSG-1 could provide protection against myelosuppression induced by Cy. [•] PSG-1 can restore the immunosuppression induced by Cy treatment. [•] PSG-1 was able to protect against oxidative stress induced by Cy. [•] PSG-1 may be applied to antineoplastic immunotherapy with chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thermal expansion of (1−x)NaAl(MoO4)2–xNaEr(MoO4)2 ceramics is studied. [•] The ceramics display relatively strong near ultraviolet, green and weak red PL. [•] The energy transfer from hosts to Er3+ ions is investigated. [•] Relatively strong UC green emissions are exhibited with a 980nm laser. [Copyright &y& Elsevier]

Abstract: Al is an important industry material with large positive coefficient of thermal expansion (CTE) while Zr2(WO4)(PO4)2 (ZWP) is one of negative thermal expansion materials. Al–ZWP cermets/alloys with controllable coefficients of thermal expansion and impedance are successively synthesized without decomposition of ZWP. SEM imaging and elemental mapping show that the cermets comprise relatively uniform nanoparticles with sizes around 100nm and that the Al and ZWP in the cermets are homogeneously dispersed. The CTEs of the cermets can be well controlled from negative (−2.74×10−6 K−1) to large positive (∼25.68×10−6 K−1). The electric response of the cermets is studied and a capacitor- and/or resistor-like behavior are revealed, depending on the Al:ZWP mass ratio. The results may pave the way toward broad applications of Al–ZWP cermets/alloys in near-zero-strain Al alloy as construction materials and fine electrical components. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate the signaling pathways involved in the macrophage activation by Ganoderma atrum polysaccharide (PSG-1) and elucidate the molecular mechanism of PSG-1-induced signal transduction in the regulation of tumor necrosis factor (TNF)-α secretion. Our results illustrated that the mitogen-activated protein kinase (MAPK) pathways were simultaneously activated and involved in PSG-1-induced TNF-α secretion in RAW264.7 cells. Moreover, our results also demonstrated that the phosphoinositide 3-kinase (PI3K)/Akt pathway was stimulated and played an important role in the PSG-1 induced TNF-α secretion. Additionally, the present study showed that nuclear factor (NF)-κB activation by PSG-1 was triggered by PI3K/Akt/MAPK pathway and NF-κB participated in PSG-1 stimulated TNF-α production. In conclusion, we have elucidated the mechanism of PSG-1-mediated immunomodulatory activities, and provide a theoretical basis for the potential of PSG-1 as a novel immunomodulating agent. [Copyright &y& Elsevier]

[Display omitted] • A low-esterified pectin was isolated from the tuber of Dioscorea opposita Thunb. • It contained ~59.4% homogalacturonan and ~38.3% rhamnogalacturonan I regions. • It had the M w of 1.3 × 104 g/mol and adopted a flexible chain conformation. A low methyl-esterified pectin (33.2% methyl-esterification degree) was isolated from the tuber of Dioscorea opposita Thunb., which was an edible and medicinal material in China. This pectin (M w of 1.3 × 104 g/mol) contained the ~59.1% homogalacturonan (HG) and ~38.1% highly branched rhamnogalacturonan I (RG-I) region with possible side chains embracing arabinogalactan II, arabinan or arabinogalactan I. The fragments including HG backbone consisting of → 4)-α-Gal p A-(1 → and → 4)-α-Gal p A-6- O -methyl-(1 → with molar ratio of ~2:1, and repeating unit of arabinogalactan II side chain composed of α-Ara f -(1 → and → 3,6)-β-Gal p -(1→, were speculated through methylation analysis and NMR spectra. However, the linkage pattern for RG-I backbone and side chains were indiscernible due to limited resolution of NMR spectra. Besides, the pectin adopted a flexible chain conformation in 0.1 M NaNO 3 solution. These results provided a structural basis for study on polysaccharide from D. opposite , which was benefit for development of functional food of yam. [ABSTRACT FROM AUTHOR]

Polysaccharides are important constituents in Dolichos lablab hull. Herein, pectin-glucuronoxylan complex from D. lablab hull designated as DLHP-3 (D. lablab hull polysaccharide,) was prepared by ion exchange and gel permeation chromatography, and further characterized by acid degradation and enzymatic hydrolysis, methylation combined with GC–MS, NMR and MALDI-TOF-MS analysis. Both of pectin and glucuronoxylan regions were found in DLHP-3. The glucuronoxylan region consisted of a →4)-β-Xyl p -(1→ backbone with branches of α-Glc p A-(1→ substituted at O -2 site, and the ratio of xylose to glucuronic acid was about 5:1. Acetyl groups were mainly attached to O -3 site of →2,4)-β-Xyl p -(1→ residues. The main chain of pectin region could be represented by →4)-α-Gal p A-(1→4)-α-Gal p A-(1→ and →2)-α-Rha p -(1→4)-α-Gal p A-(1→ with partial methyl-esterification. The side chains were deduced to embrace arabinan and arabinogalactan linked to rhamnogalacturonan-I region. Pectin was probably covalently bound to glucuronoxylan. Our findings uncovered the molecular structure of pectin-glucuronoxylan complex from D. lablab hull. [Display omitted] • The pectin-glucuronoxylan complex (DLHP-3) was isolated from Dolichos lablab L. hull. • The main chain of pectin fraction was composed of HG and RG-I regions. • Glucuronoxylan fraction had a →4)-β-Xyl p -(1→ backbone branched at O -2 by α-Glc p A. [ABSTRACT FROM AUTHOR]

In this study, two sulfated polysaccharides (S-CP 1–4 and S-CP 1–8 ) from Cyclocarya paliurus were produced by chlorosulfonic acid–pyridine method. Hydrogen peroxide (H 2 O 2 ) was used to develop an oxidative stress model in the mouse macrophage cell line RAW264.7. Effects of the two sulfated polysaccharides on H 2 O 2 -induced oxidative stress were investigated. The results showed that S-CP 1–8 improved the viability of the H 2 O 2 -induced stressed RAW264.7 cells, as well as inhibited the lipid oxidation as determined by the level of malondialdehyde (MDA). Meanwhile, treatment with S-CP 1–4 increased superoxide dismutase (SOD) activity in these cells. The sulfated polysaccharides were found to have a better protective effect against H 2 O 2 -induced oxidative stress as compared to the native polysaccharide. Scanning electron microscopy also showed a significant change in the surface morphology of sulfated polysaccharides, but the degradation of main chain of polysaccharides was unconspicuous according to the results of monosaccharide composition. In addition, the sulfated polysaccharides had noticeable DPPH radical scavenging activity. In summary, our results demonstrated that H 2 O 2 was able to induce oxidative stress in RAW264.7 cells, and sulfated group might play an important role in resistance to H 2 O 2 -induced oxidative damage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water-extracted polysaccharides from M. albuminosa (MAWP) were purified into three sub-fractions. • Three purified fractions exhibited significant polysaccharide structural heterogeneity. • MAWP contained glucomannogalactans and galactoglucans with different viscosity. • Three fractions adapted random coil conformation in aqueous solution. Macrolepiota albuminosa (Berk.) Pegler is abundant in active polysaccharides, but little is known about their structures and solution properties. In this study, water-extracted polysaccharides from M. albuminosa (MAWP) were purified into three fractions with structural heterogeneity, which was attributed to the diversity in molecular weight, monosaccharide composition and linkage patterns, further affecting their solution properties. Methylation and NMR analysis revealed MAWP-60p and MAWP-70 were a 3- O -methylated glucomannogalactan and a previously unreported glucomannogalactan, whereas MAWP-80 was elucidated as a branched galactoglucan. Besides, three fractions exhibited random coil conformation in aqueous solution, while MAWP-60p had the highest viscosity due to its highest molecular weight, mean square radius of gyration (R g) and O -methyl group attached to the backbone. The molecular weight, monosaccharide composition and glycosidic linkages might be the major contributors to the flexibility, molecular size and stereochemistry of mushroom polysaccharide chains. [ABSTRACT FROM AUTHOR]

Glucans of multiple architecture and bioactivities are widely distributed in cereals. In our previous study, the barley water-soluble fiber (BSF) has been proved to possess hypoglycaemic and hypolipidaemic effects. A further attempt in the present study is to comprehensively demonstrate the structures and solution properties of main constituents in BSF. Two mainly homogeneous fractions (BSF-20 and BSF-80r) were purified from BSF, and their physicochemical and structural characterization were investigated. Methylation and 1D/2D NMR experiments indicated that BSF-20 was a linear β-glucan, composed of β-D-Glc p residues via (1 → 4)-linkages, and occasionally single (1 → 3)-linkage. The high performance size-exclusion chromatography coupled with multiangle laser light scattering, X-ray diffraction, rheological measurements and scanning electron microscopy were further conducted to analyze its solution property and morphology. BSF-20 adopted a linear flexible chain in aqueous solution, and exhibited high viscosity and strong gelling properties. Intertwined fibrous filaments were visualized by SEM observation. Besides, BSF-80r was a limit dextrin, which was an artefact caused by the incomplete hydrolysis of starch during the isolation of barley soluble fiber. Therefore, the highly viscous β-glucan is the main biomacromolecule occurring in BSF. This work lays the groundwork for the potential application of barley soluble fiber in beverages and other liquid products as new thickeners and stabilizers. Image 1 • Two main fractions were purified from barley soluble fiber (BSF). • BSF-20 was a typical mixed-linkage β-(1 → 3), (1 → 4)-glucan. • BSF-80r was a limit dextrin caused by incomplete hydrolysis of starch. • BSF-20 exhibited a linear flexible chain in aqueous solution with high viscosity and strong gelling properties. [ABSTRACT FROM AUTHOR]