Antidiabetic activity of a polysaccharide-protein complex from Asian Clam (Corbicula fluminea) in streptozotoxin-induced diabetic rats and its underlying mechanism.

The antidiabetic activity and potential underlying mechanism of a polysaccharide-protein (PSP) complex from Corbicula fluminea were determined in streptozotoxin (STZ)-induced diabetic rats. PSP exhibited inhibitory activity (in vitro) against α-glucosidase and α-amylase via a reversible competitive inhibition pattern with a stronger inhibition for α-glucosidase. Dietary administration of PSP had potential antidiabetic activities in vivo, which was evidenced by the fact that PSP alleviates body weight loss and organ injuries, reduced fasting blood glucose levels, elevated glucose tolerance, and ameliorated lipid metabolism and hepatic functions, as well as attenuated oxidative stress in STZ-treated diabetic rats. Furthermore, our results demonstrated that the antidiabetic activities of PSP were associated with the activation of the phosphoinositide 3-kinase/protein kinase B signaling pathway in STZ-treated rats. These findings supported the potential of PSP to be used as a functional ingredient in the preparation of functional and medicinal foods to inhibit diabetes mellitus and its complications.

Conformational and rheological properties of a quaternary ammonium salt of curdlan.

This study investigated the chain conformation, microstructure, and rheological properties of a quaternary ammonium salt of curdlan (Qcurd) in aqueous medium. Results showed that Qcurd exhibited typical polyelectrolyte behavior in pure water, and the normal viscosity character was observed in 0.1 M NaCl aqueous solution. The weight-average molecular weight (Mw), z-average radius of gyration (Rg), hydrodynamic radius (Rh), conformational parameter (α), characteristic constant (a) and structure parameter (ρ) for Qcurd were determined as 8.08 × 104 g/mol, 26.7 nm, 15.0 nm, 0.54, 0.62, and 1.78, respectively, indicating that Qcurd existed as a flexible chain conformation in 0.1 M NaCl solution, verified by atomic force microscopy. Qcurd exhibited more pronounced shear-thinning behavior at higher concentrations. The flow behavior of Qcurd at different concentrations and temperature was well evaluated by power-law model and Arrhenius equation. Dynamic tests revealed that Qcurd showed oscillatory behaviors between a dilute solution and a weak elastic gel.

Three-phase partitioning for the direct extraction and separation of bioactive exopolysaccharides from the cultured broth of Phellinus baumii.

In this study, three-phase partitioning (TPP) was used to directly extract and separate bioactive exopolysaccharides (EPSs) from a cultured broth of Phellinus baumii. The maximum extraction yield of EPS was 52.09% under the following optimal conditions: 20% (w/v) ammonium sulfate concentration, 1.0:1.5 (v/v) ratio of cultured broth to t­butanol, 30 min, and 35 °C. A multifrequency power ultrasound in a sequential mode coupled with TPP resulted in ~9.12% increment in extraction yield and ~80% reduction in extraction time compared with those of traditional TPP. The carbohydrate (88.21%) and uronic acid (3.37%) contents of partially purified EPS were higher than those of EPS-C obtained through conventional ethanol precipitation and separation methods. EPS and EPS-C exhibited similar preliminary structural characteristics and different monosaccharide compositions and molecular weights. The radical-scavenging abilities, antioxidant capacities, α­amylase and α­glycosidase inhibitory activities, and macrophage stimulation activities of EPS were also higher than those of EPS-C. Therefore, it could be concluded that TPP as a simple and green separation technique could be used to directly extract and separate bioactive EPS from the fermentation broths of mushrooms and other fungi.

Comparative study of physicochemical properties and bioactivity of Hericium erinaceus polysaccharides at different solvent extractions.

In this study, hot water, 0.9% NaCl, citric acid, and 1.25 M NaOH/0.05% NaBH4 were separately used for the extraction of water-soluble H. erinaceus polysaccharides (HEPs; HEP-W, HEP-S, HEP-C, and HEP-A) from the fruit body of Hericium erinaceus. The physicochemical properties and biological activities were then investigated and compared. Results showed that the extraction solvents exhibited significant effects on the extraction yields, molecular weights, monosaccharide compositions, preliminary structural characteristics, microstructures of HEPs and on their contents, such as neutral sugar, uronic acid, protein, and ß-(1 → 3)-glucan. In vitro antioxidant activity assays indicated that HEP-C extracted with citric acid solution showed stronger scavenging abilities on hydroxyl and DPPH radicals and antioxidant capacities than HEP-W and HEP-S. Moreover, HEP-C exhibited the strongest inhibitory effects on α-glycosidase and α-amylase activities. Therefore, HEP-C extracted with citric acid can be developed as a potential bioactive ingredient for applications in food, medicine, and cosmetics industries.

pH dependent green synthesis of gold nanoparticles by completely C6-carboxylated curdlan under high temperature and various pH conditions.

A C6-carboxylated curdlan (C6-Cc) obtained from 4-acetamido-TEMPO-mediated oxidation of curdlan was used both as a reducing and stabilizing agent for green synthesis of pH-responsive AuNPs, which was carried out by controlling the pH of the C6-Cc solution at a high temperature (100°C). C6-Cc presented a semi-flexible random coil chain in the aqueous medium at pH 5.5 and became more expanded and rigid in alkaline conditions (pH 7.1-12.0), though the primary chemical structure of C6-Cc was virtually unchanged with the pH variation. The AuNPs prepared with C6-Cc at various pHs were characterized by various instrumental measurements. The shapes and sizes of AuNPs were found to be strongly dependent on the pH of the C6-Cc solution. The C6-Cc-decorated AuNPs exhibited a more well-dispersed spherical morphology with smaller particle sizes under alkaline conditions (pH 7.1-12.0). Through this study, a facile, simple, and green method has been demonstrated for preparation of stimuli-sensitive AuNPs using biocompatible polyanionic polysaccharides.

Purification, structural characterization and bioactivity evaluation of a novel proteoglycan produced by Corbicula fluminea.

A novel proteoglycan, named CFPS-11, was isolated from Corbicula fluminea, which is a food source of freshwater bivalve mollusk. CFPS-11 had an average molecular weight of 807.7kDa and consisted of d-glucose and d-glucosamine in a molar ratio of 12.2:1.0. The protein moiety (∼5%) of CFPS-11 was covalently bonded to the polysaccharide chain in O-linkage type through both serine and thereonine residues. The polysaccharide chain of CFPS-11 was composed of (1→4)-α-d-glucopyranosyl and (1→3,6)-α-d-glucopyranosyl residues, which branched at O-6. The branch chain consisted of (1→)-α-d-glucopyranosyl and (1→)-α-d-N-acetylglucosamine residues. CFPS-11 exhibited significant antioxidant activity in a dose-dependent manner and remarkable inhibition activities against α-amylase and α-glucosidase by in vitro assays. These findings indicated that the CFPS-11 from C. fluminea has the potential for development as a health food ingredient.

Progress and prospects in stem cell therapy.

In the past few years, progress being made in stem cell studies has incontestably led to the hope of developing cell replacement based therapy for diseases deficient in effective treatment by conventional ways. The induced pluripotent stem cells (iPSCs) are of great interest of cell therapy research because of their unrestricted self-renewal and differentiation potentials. Proof of principle studies have successfully demonstrated that iPSCs technology would substantially benefit clinical studies in various areas, including neurological disorders, hematologic diseases, cardiac diseases, liver diseases and etc. On top of this, latest advances of gene editing technologies have vigorously endorsed the possibility of obtaining disease-free autologous cells from patient specific iPSCs. Here in this review, we summarize current progress of stem cell therapy research with special enthusiasm in iPSCs studies. In addition, we compare current gene editing technologies and discuss their potential implications in clinic application in the future.