Activity

17 ± 0.29%.Tremendous awareness of determination of chitosan content accurately is increasing, due to it has great significance to the quality control of chitosan. In this article, two kinds of chitosan-Schiff base derivatives (BCSB and PCSB) were synthesized by the different average degrees of deacetylation (DD) of chitosan with benzaldehyde or propanal, respectively. The total mass of Schiff base derivative product was dried and obtained without washing and loss. Then, a certain amount of the prepared Schiff base compound was taken to hydrolyze into glucosamine hydrochloride (GAH) in strong hydrochloric acidic environment, whose concentration was quantified by HPLC, and the mass of GAH contained in hydrolysis solution could be calculated. Subsequently, the total quality of GAH obtained by hydrolysis of all of the Schiff base product was calculated and obtained, and then the theoretical mass of chitosan could be deduced and calculated by further converse calculation. Finally, the chitosan content was obtained by combining the sample mass used in Schiff base reaction and the theoretical mass of chitosan. This method was accurate and convenient, providing a preeminent idea and method for the determination of chitosan content.A chitinase gene (PxChi52) from Paenibacillus xylanexedens Z2-4 was cloned and heterologously expressed in Escherichia coli BL21 (DE3). PxChi52 shared the highest identity of 91% with a glycoside hydrolase family 18 chitinase (ChiD) from Bacillus circulans. The recombinant enzyme (PxChi52) was purified and biochemically characterized. PxChi52 had a molecular mass of 52.8 kDa. It was most active at pH 4.5 and 65 °C, respectively, and stable in a wide pH range of 4.0-13.0 and up to 50 °C. The enzyme exhibited the highest specific activity of 16.0 U/mg towards colloidal chitin, followed by ethylene glycol chitin (5.4 U/mg) and ball milled chitin (0.4 U/mg). The Km and Vmax values of PxChi52 towards colloidal chitin were determined to be 3.06 mg/mL and 71.38 U/mg, respectively, PxChi52 hydrolyzed colloidal chitin and chitooligosaccharides with degree of polymerization 2-5 to release mainly N-acetyl chitobiose. In addition, PxChi52 displayed inhibition effects on the growth of some phytopathogenic fungi, including Alternaria alstroemeriae, Botrytis cinerea, Rhizoctonia solani, Sclerotinia sclerotiorum and Valsa mali. The unique properties of PxChi52 may enable it potential application in agriculture field as a biocontrol agent.Herpes simplex virus type 1(HSV-1) attaches to cell surface heparan sulfate aiming to enter into susceptible cells. In this work, we utilized a sulfur trioxide-pyridine in N,N-dimethylformamide (SO3·Pyr/DMF) based amalgamated extraction-sulfation procedure for producing arabinogalactan sulfates from Anogeissus latifolia gum. BI 1015550 Chemical, chromatographic, spectroscopic and chemical data revealed that the derived polymers contained varying molecular masses (31-69 kDa) and degrees of sulfation (0.1-0.5), but similar saccharide compositions. The highly active polymer (HSV-1 IC50 and SI, respectively, of 127 μg/mL and 15.7) was a 69 kDa arabinogalactan holding sulfates at O-5 of arabinofuranosyl residues and showed no cytotoxicity as far as 2 mg/mL concentration. This chemically sulfated macromolecule acted by obstructing viral attachment and entry. Thus, SO3·Pyr/DMF is suitable for producing new molecules with varied structures and altered pharmacological activities from plant sources.Chitosan, a naturally occurring biodegradable and biocompatible polymer, has found use as a food additive, nutraceuticals, and functional foods in recent years. In this study, gallic acid-g-chitosan (GAC) was prepared by the insertion of GA onto plain chitosan (PC) via free radical-mediated grafting and its osteogenic effects were investigated in murine bone marrow-derived mesenchymal stem cells (mBMMSCs). Structural characterization of PC and GAC was performed using 1H NMR and FT-IR spectroscopy. The amount of GA successfully grafted onto PC was 111 mg GA/g GAC via the Folin-Ciocalteu’s method. While PC and GAC promoted the increase in alkaline phosphatase activity and mineralization, GAC increased these factors significantly more than PC, indicating that the grafting of GA onto chitosan increased its osteogenic potential. Mechanistic study revealed that GAC activated Wnt1 and Wnt3a mRNA and protein expression as well as increased the translocation of β-catenin into the nucleus and upregulated the expression of β-catenin targeted genes including Runx2, osterix, type I collagen and cyclin D1. In addition, DKK-1, a Wnt antagonist, decreased GAC-mediated osteoblast differentiation in mBMMSCs through blocking the Wnt/β-catenin signaling pathway.To increase the drug loading and prolong the drug release time, novel hollow organic/inorganic hybrid nanoparticles based on dextran-b-poly(L-glutamate-graft-3-mercaptopropyltrimethoxysilane) (Dex-b-P(ALG-g-MTPMS)) were prepared. First, a polysaccharide block polypeptide diblock copolymer, dextran-block-poly(γ-allyl-L-glutamate) (Dex-b-PALG) bearing allyl side-groups, has been synthesized by the combination of ring-opening polymerization and alkyne-azide [2 + 3] Huisgen’s cycloaddition. Next, the allyl side-groups residing in the poly(γ-allyl-L-glutamate) block were further functionalized with 3-mercaptopropyltrimethoxysilane(MPTMS) by radical “thiol-ene” addition reactions. Finally, after a sol-gel process of the obtained copolymers, the novel organic/inorganic hybrid nanoparticles were prepared. The molecular structures, physicochemical, and self-assembly of these copolymers were characterized through FTIR, 1H NMR, dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The cross-linked hybrid nanoparticles have a higher drug loading ability and slower release rate as compared to the uncross-linked counterparts. The MTT evaluation demonstrated that the organic/inorganic hybrid nanoparticles with good biocompatibility.A microcrystalline cellulose-based temperature sensitivity paclitaxel molecular imprinted hydrogel (MCC-TSMIHs-PTX) was successfully prepared by temperature-sensitive monomer N-isopropylacrylamide, functional monomer 4-vinylpyridine, cross-linking agent N, N’-methylenebisacrylamide and microcrystalline cellulose. They showed imprinting effective responses to the temperature changes. The results of adsorption kinetics, adsorption equilibrium, thermodynamics, selectivity and reusability showed the successful formation of a grafting thermosensitivity hydrogel with higher adsorption capacity and specific recognition. When the temperature reached 308 K, imprinting effect of hydrogel cavities would be most effective and conducive to capture template molecules. When the temperature reached 288 K, the lowest imprinting effect would facilitate the desorption of PTX. Finally, the MCC-TSMIHs-PTX was applied to enrich the paclitaxel in Taxus × media extracts samples, the relative contents of PTX in the samples were increased greatly from 7.