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Artificial bone materials are in great need due to a lot of bone injuries. Herein, collagen/nano-hydroxyapatite (Col/nHA, C-H) composite nanospheres were obtained by in-situ mineralization, and poly L-lactic acid/collagen/nano-hydroxyapatite (PLLA/Col/nHA, P-C-H) was further prepared by high-speed shear emulsification method. The interfacial properties and structure between PLLA and nHA are regulated by the adhesive property of Col. The morphology, structure and properties of P-C-H microsphere were characterized in detail by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and simulated degradation of PBS in vitro. The results show that C-H is uniformly distributed in P-C-H microspheres, and a mesoporous material with a "pomegranate" structure and a particle size of 5–30 μm is self-assembled based on C-H multiple composite microspheres. It is beneficial to the sustained-release degradation of P-C-H and the retention/release of Ca2+. The 60-day PBS degradation shows that PLLA delays the degradation of nHA, making the degradation rate of P-C-H basically consist with the human bone healing cycle. The co-culture of P-C-H with MC3T3-E1 cells shows that P-C-H has high biocompatibility and no cytotoxicity. The cell viability is higher than 100 % in 72 h, indicating P-C-H has a proliferation effect on cell growth. Alkaline phosphatase and quantitative real-time PCR test show a positive promotion of P-C-H in cell proliferation and differentiation. The multi-layered P-C-H microspheres have an application potential in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Many by-products that are harmful to the environment and human health are generated during food processing. However, these wastes are often potential resources with high-added value. For example, crustacean waste contains large amounts of chitin. Chitin is one of the most abundant polysaccharides in natural macromolecules, and is a typical component of crustaceans, mollusks, insect exoskeleton and fungal cell walls. Chitosan is prepared by deacetylation of chitin and a copolymer of D-glucosamine and N -acetyl-D-glucosamine through β-(1 → 4)-glycosidic bonds. Chitosan has better solubility, biocompatibility and degradability compared with chitin. This review introduces the preparation, physicochemical properties, chemical and physical modification methods of chitosan, which could help us understand its biological activities and applications. According to the latest reports, the antibacterial activity, antioxidant, immune and antitumor activities of chitosan and its derivatives are summarized. Simultaneously, the various applications of chitosan and its derivatives are reviewed, including food, chemical, textile, medical and health, and functional materials. Finally, some insights into its future potential are provided, including novel modification methods, directional modification according to structure-activity relationship, activity and application development direction, etc. • The utilization of chitosan is effective solution to improve the value of waste. • The physicochemical properties and modification of chitosan were reviewed. • Chitosan and its derivatives have many biological activities. • Chitosan and its derivatives can be used in various industrial fields. [ABSTRACT FROM AUTHOR]

Ionizing radiation is increasingly used to successfully diagnose many human health problems, but ionizing radiation may cause damage to organs/tissues in the living organisms such as the spleen, liver, skin, and brain. Many radiation protective agents have been discovered, with the deepening of radiation research. Unfortunately, these protective agents have many side effects, which cause drug resistance, nausea, vomiting, osteoporosis, etc. The polysaccharides extracted from natural sources are widely available and low in toxicity. In vivo and in vitro experiments have demonstrated that polysaccharides have anti-radiation activity through anti-oxidation, immune regulation, protection of hematopoietic system and protection against DNA damage. Recently, some studies have shown that polysaccharides were resistant to radiation. In the review, the anti-radiation activities of polysaccharides from different sources are summarized, and the anti-radiation mechanisms are discussed as well. It can be used to develop more effective anti-radiation management drugs. • Natural polysaccharides have shown great potential for anti-radiation activity. • Summarize the anti-radiation activity of polysaccharides from different sources • The mechanism of polysaccharide radiation resistance was reviewed. [ABSTRACT FROM AUTHOR]

Canine distemper virus (CDV) is an economically important virus responsible for canine distemper (CD), a highly contagious disease that afflicts various animal species worldwide. The hemagglutinin (H) protein is the major neutralizing target of virus. Therefore, it is often considered as immunogen to prepare neutralizing antibodies. The accurate identification of neutralizing epitope will provide important antigenic information and extend the knowledge of mechanisms of virus neutralization. In this study, we generated a neutralizing monoclonal antibody (mAb) 4C6 against CDV H protein, and defined the minimal linear epitope 238DIEREFDT245, which was highly conserved in America-1 genotype of CDV strains (vaccines). The mAb 4C6 could not react with a CDV strain that had two substitutions of D238Y and R241G in the epitope, which appeared in most CDV strains of the other genotypes. Besides, a few different amino acid mutations in the epitope were also included. Collectively, the epitope 238DIEREFDT245 was variable in the other genotypes of CDV strains. The epitope 238DIEREFDT245 was exposed to the surface of CDV H protein, showing good antigenicity. These data will provide insights into structure, function and antigenicity of H protein and lay the foundation for the development of diagnostic technologies and vaccine design for CDV. • CDV H-specific mAb 4C6 recognizing a novel variable neutralizing epitope was successfully prepared and characterized. • The epitope 238DIEREFDT245 of the mAb 4C6 was conserved in America-1 genotype (vaccines) but variable in the other genotypes of CDV strains. • The D238Y and R241G substitutions of a strain which was not recognized by the mAb 4C6 appeared in most CDV strains of the other genotypes. • The novel variable epitope was exposed to the surface of H protein, showing good antigenicity. [ABSTRACT FROM AUTHOR]

Diabetic chronic wound is a worldwide medical burden related to overdosed methylglyoxal (MGO) synthesis, which is the major precursor of glycation of proteins and DNA and is related to the dysfunction of dermal cells thus leading to chronic refractory wounds. Previous studies proved that earthworm extract accelerates diabetic wound healing and possesses cell proliferation and antioxidative effects. However, the effects of earthworm extract on MGO-damaged fibroblasts, the inner mechanisms of MGO-induced cell damage and the functional components in earthworm extract are still poorly understood. Firstly, we evaluated the bioactivities of the earthworm extract PvE-3 on the diabetic wound model and the diabetic related cell damage model. Then the mechanisms were investigated through transcriptomics, flow cytometry and fluorescence probe. The results revealed that PvE-3 promoted diabetic wound healing and protected fibroblast function in cell-damaged conditions. Meanwhile, the high-throughput screening implied the inner mechanisms of diabetic wound healing and PvE-3 cytoprotection effect were involved in the muscle cell function, the cell cycle regulation and the mitochondrial transmembrane potential depolarization. The functional glycoprotein isolated from PvE-3 possessed EGF-like domain which had a strong binding affinity with EGFR. The findings provided references to explore the potential treatments of diabetic wound healing. [ABSTRACT FROM AUTHOR]

Dialdehyde-based cross-linking agents are widely used in the cross-linking of amino group-containing macromolecules. However, the most commonly used cross-linking agents, glutaraldehyde (GA) and genipin (GP), have safety issues. In this study, a series of dialdehyde derivatives of polysaccharides (DADPs) were prepared by oxidation of polysaccharides, and their biocompatibility and cross-linking properties were tested using chitosan as a model macromolecule. The DADPs showed outstanding cross-linking and gelation properties comparable to GA and GP. The DADPs and hydrogels cross-linked with the DADPs exhibited excellent cytocompatibility and hemocompatibility with different concentrations while significant cytotoxicity was observed in GA and GP. The experimental results showed that the cross-linking effect of DADPs increased along with their oxidation degree. The outstanding cross-linking effect of the DADPs show a potential for use in the cross-linking of biomacromolecules with amino groups and could be an adequate alternative to existing cross-linkers. [ABSTRACT FROM AUTHOR]

Scutellaria baicalensis is a medicinal plant possessing abundant bioactive polysaccharides. This study aimed to optimize the ultrasound-assisted enzymatic extraction of S. baicalensis root polysaccharide (SRP) and investigate its hypoglycemic and immunomodulatory activities. The optimal extraction conditions found in this study were as follows: cellulase concentration 165.6 U/mL, temperature 57.3 °C, liquid-solid ratio 44.8 mL/g, time 50 min, and ultrasonic power 225 W; with the yield reached up to 12.27 %. The ion exchange and gel filtration chromatographies were used to obtain a purified SRP. The carbohydrate content of SRP was 85.09 %, with a relatively high content of uronic acids (11.27 %). The SRP had a molecular weight of 89.7 kDa and was composed of eight monosaccharides. The inhibitory activity of SRP against α-amylase and α-glucosidase was determined. It was revealed that SRP could effectively inhibit these two enzymes with IC 50 values of 1.23 and 0.63 mg/mL, respectively. Finally, the immunomodulatory effect of SRP on the dendritic cell activation was investigated, and the expressions of MHC II, CD80, CD86, and CD40 increased by 1.56, 1.96, 1.75, and 1.70 times, respectively, by the SRP treatment. This work will provide a foundation for SRP's efficient extraction and utilization for diabetes and immune therapy. [Display omitted] • SRP was extracted by the optimized ultrasound-assisted enzymatic method. • The maximum extraction yield of SRP reached up to 12.27 %. • SRP (molecular weight 89.7 kDa) was composed of eight monosaccharides. • SRP has strong inhibitory activities against α-amylase and α-glucosidase. • SRP has a potent immunomodulatory activity on dendritic cell maturation. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the potential application of chitosan coatings incorporating epigallocatechin gallate (EGCG) for preserving fillets of bighead carp during chilled storage. The fillets were coated with acetic acid and glycerol, chitosan, and chitosan-EGCG, respectively, and the changes in their physicochemical, microbiological, and sensory characteristics during storage at 4 °C were determined. Notably, total volatile basic nitrogen, thiobarbituric-acid-reactive substances, and K value of chitosan-EGCG coated fillets sampled on day 15 were 48.04 %, 60.19 %, and 32.91 % lower than untreated fillets, respectively. Microbial enumeration suggested that the inclusion of EGCG significantly improved the inhibitory effect of pure chitosan coating on the proliferation of microorganisms. Furthermore, the chitosan-EGCG coated fillets also performed the best in terms of color, texture, and sensory analysis, and extended the shelf-life of the fillets for at least 6 days. A principal component analysis further confirmed the preserving effect of the chitosan-EGCG coating. Mantel test results suggested that the fillets' organoleptic characteristics strongly correlated with physicochemical and microbiological indicators. Overall, this work provides an effective protocol for food quality control and the extension of shelf life during chilled storage, and it clarifies the relationships between organoleptic characteristics and physicochemical and microbiological indexes. [Display omitted] • EGCG significantly enhanced the antibacterial activity of pure chitosan coating. • Chitosan-EGCG coating was effective in maintaining the quality of chilled fillets. • Chitosan-EGCG coating extended the shelf-life of the fillets for at least 6 days. • Fillets' organoleptic characteristics strongly correlated with microbial properties. [ABSTRACT FROM AUTHOR]

Novel chitosan films incorporating epigallocatechin gallate (EGCG) were prepared and demonstrated the ideal physical and mechanical properties required of candidate food packaging materials alongside desirable antioxidant and antibacterial activity. Compared with traditional chitosan films, chitosan films incorporated with EGCG were thicker, had higher tensile strength and water solubility, and had lower elongation at break, moisture content, degree of swelling, and water contact angles. Although EGCG-containing films were slightly darker in color than pure chitosan films, they exhibited a greater inhibitory effect on light-induced oxidation with obviously improved UV–vis barrier capability and opacity. Scanning electron microscopy results suggested that EGCG-incorporated samples had a rougher surface structure. This was further confirmed by atomic force microscopy and indicated that the addition of EGCG facilitated the formation of protective barriers through the interaction between the film and food surface. FTIR spectroscopy confirmed that EGCG interacted with chitosan by intermolecular hydrogen bonding and effectively improved the thermal stability of chitosan films. Notably, the incorporation of EGCG significantly enhanced the antioxidant and antibacterial activity of chitosan films. Hence, chitosan films incorporating EGCG have potential applications in the food industry as a novel active packaging material, especially in preventing food oxidation and spoilage in perishable foods. [Display omitted] • Chitosan films incorporated with EGCG were developed and characterized. • EGCG improved the mechanical and UV–vis barrier properties of chitosan films. • Chitosan films carrying EGCG showed higher antioxidant and antibacterial activities. • Chitosan-EGCG films were suggested as a novel active packaging material. [ABSTRACT FROM AUTHOR]

In this study, the effects of Mesona chinensis polysaccharide (MCP) on the pasting, thermal, rheological, and textural properties of wheat starch were investigated. Rapid viscosity analysis results showed that MCP protects the integrity of starch granules at low concentration in the early stage of pasting. The gelatinization temperature of wheat starch–MCP gels was markedly increased with the increase in polysaccharide concentration, whereas gelatinization enthalpy (Δ H gel ) decreased. Rheological analysis showed that the starch:MCP = 8.5:1.5 system exhibited a strong thixotropic property and the highest G′ and G″ among the other systems. The same results were observed in the textural experiment, indicating the existence of strong intermolecular interactions between starch granules and MCP. These results indicated that MCP can improve the thermal stability in the early stage of pasting and enhance the rheological properties of wheat starch. [ABSTRACT FROM AUTHOR]