Structural characterization of a Chlorella heteropolysaccharide by analyzing its depolymerized product and finding an inducer of human dendritic cell maturation.

Chlorella polysaccharides have been gaining increasing attention because of their high yield from dried Chlorella powder and their remarkable immunomodulatory activity. In this study, the major polysaccharide fraction, CPP-3a, in Chlorella pyrenoidosa, was isolated, and its detailed structure was investigated by analyzing the low-molecular-weight product prepared via free radical depolymerization. The results indicated that CPP-3a with a molecular weight of 195.2 kDa was formed by →2)-α-L-Araf-(1→, →2)-α-D-Rhap-(1→, →5)-α-L-Araf-(1→, →3)-ß-D-Glcp-(1→, →4)-α-D-Glcp-(1→, →4)-α-D-GlcpA-(1→, →2,3)-α-D-Manp-(1→, →3,4)-α-D-Manp-(1→, →3,4)-ß-D-Galp-(1→, →3,6)-ß-D-Galp-(1→, and →2,3,6)-α-D-Galp-(1→ residues, branched at C2, C3, C4, or C6 of α/ß-D-Galp and α-D-Manp, and terminated by α/ß-L-Araf, α-L-Arap, α-D-Galp, and ß-D-Glcp. Biological assays showed that CPP-3a significantly altered the dendritic morphology of immature dendritic cells (DCs). Enhanced CD80, CD86, and MHC I expression on the cell surface and decreased phagocytic ability indicated that CPP-3a could induce the maturation of DCs. Furthermore, CPP-3a-stimulated DCs not only stimulated the proliferation of allogeneic naïve CD4+ T cells and the secretion of IFN-γ, but also directly stimulated the activation and proliferation of CD8+ T cells through cross-antigen presentation. These findings indicate that CPP-3a can promote human DC maturation and T-cell stimulation and may be a novel DC maturation inducer with potential developmental value in DC immunotherapy.

Biochemistry behind firmness retention of jujube fruit by combined treatment of acidic electrolyzed water and high-voltage electrostatic field.

Harvested jujube (Zizyphus jujuba Mill) is prone to softening due to active metabolism. This study investigated the effects of acidic electrolyzed water (AEW), high-voltage electrostatic field (HVEF) and their combination (AEW + HVEF) on softening and associated cell wall degrading enzymes (CWDEs), cell membrane integrity and antioxidant system of 'Huping' jujube during storage at 0 ± 1 °C. The results indicated that fruit subjected to AEW + HVEF, AEW or HVEF treatments maintained firmness 15.7%, 10.7%, and 5.3% higher than that of untreated control fruit at the end of 90 days cool storage. Fruit treated with AEW + HVEF could better maintain cell membrane integrity and exhibit lower activities of CWDEs and higher antioxidant capacity than that treated with either AEW or HVEF. Correlation analysis suggested that inhibition of softening was associated with reduction of CWDEs activities, and maintenance of membrane integrity and antioxidant system.

Hydrophilic chitosan/graphene oxide composite sponge for rapid hemostasis and non-rebleeding removal.

Hydrophilic hemostatic sponge plays an important role in trauma bleeding control because of its robust coagulant functions. However, its strong tissue adhesion can easily result in wound tear and rebleeding during removing the sponge. Herein, the design of a hydrophilic anti-adhesive chitosan/graphene oxide composite sponge (CSAG) that possesses stable mechanical strength, rapid liquid absorption and strong intrinsic/extrinsic coagulation stimulations, is reported. For one thing, CSAG exhibits outstanding hemostatic performance, which significantly outperforms two commercial hemostats in two in vivo serious bleeding models. For another, CSAG shows low tissue adhesion; its peeling force is approximately 79.3 % lower than the commercial gauze. Moreover, in the peeling process, CSAG triggers partial detachment of the blood scab, because of the exist of bubbles or cavities at the interface, allowing the CSAG to be easily and safely peeled off from the wound without rebleeding. This study opens new avenues in constructing anti-adhesive trauma hemostatic materials.

Roles of the peroxisome proliferator-activated receptors (PPARs) in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease phenotypes which start with simple steatosis and lipid accumulation in the hepatocytes - a typical histological lesions characteristic. It may progress to non-alcoholic steatohepatitis (NASH) that is characterized by hepatic inflammation and/or fibrosis and subsequent onset of NAFLD-related cirrhosis and hepatocellular carcinoma (HCC). Due to the central role of the liver in metabolism, NAFLD is regarded as a result of and contribution to the metabolic abnormalities seen in the metabolic syndrome. Peroxisome proliferator-activated receptors (PPARs) has three subtypes, which govern the expression of genes responsible for energy metabolism, cellular development, inflammation, and differentiation. The agonists of PPARα, such as fenofibrate and clofibrate, have been used as lipid-lowering drugs in clinical practice. Thiazolidinediones (TZDs) - ligands of PPARγ, such as rosiglitazone and pioglitazone, are also used in the treatment of type 2 diabetes (T2D) with insulin resistance (IR). Increasing evidence suggests that PPARß/δ agonists have potential therapeutic effects in improving insulin sensitivity and lipid metabolism disorders. In addition, PPARs ligands have been considered as potential therapeutic drugs for hypertension, atherosclerosis (AS) or diabetic nephropathy. Their crucial biological roles dictate the significance of PPARs-targeting in medical research and drug discovery. Here, it reviews the biological activities, ligand selectivity and biological functions of the PPARs family, and discusses the relationship between PPARs and the pathogenesis of NAFLD and metabolic syndrome. This will open new possibilities for PPARs application in medicine, and provide a new idea for the treatment of fatty liver and related diseases.

The combined treatments of brassinolide and zeaxanthin better alleviate oxidative damage and improve hypocotyl length, biomass, and the quality of radish sprouts stored at low temperature.

The rot and deterioration of sprouts are closely related to their physiological state and postharvest storage quality. The study investigated the influences of brassinolide, zeaxanthin, and their combination on physiological metabolism, chlorophyll fluorescence, and nutritional quality of radish sprouts stored at 4 °C. The combined treatments enhanced hypocotyl length, fresh weight, contents of secondary metabolites, nutritional ingredients, glutathione, the photoprotective capacity of PSII, and FRAP level in radish sprouts compared with zeaxanthin alone. The combined treatments enhanced hypocotyl length, fresh weight, glutathione content, Fv/Fm value, and antioxidant capacity in sprouts compared to brassinolide alone. The combined treatment of zeaxanthin and brassinolide could make radish sprouts keep high biomass and antioxidant capacity by increasing the contents of stress-resistant metabolites and by weakening the photoinhibition of PSII in radish sprouts stored at 4 °C.

Hyaluronic acid-guided assembly of ceria nanozymes as plaque-targeting ROS scavengers for anti-atherosclerotic therapy.

Oxidative stress is a distinguishing feature in atherosclerosis disease. Reactive oxygen species (ROS) can increase the oxidized low density lipoprotein (ox-LDL) and oxidative damage to macrophages in the plaque. Although antioxidant agents such as N-acetylcysteine are used to treat atherosclerosis, but provide a poor clinical benefit to the majority of patients with atherosclerosis. Here we have designed hyaluronic acid-guided assemblies of ceria nanozymes (HA-CeO2 NPs) as novel plaque-targeting ROS scavengers. The introduction of hyaluronic acid not only provide the stability and biocompatibility, but also surprisingly enhance SOD-mimic activities of ceria nanozymes compared to bare CeO2 precipitates, dextran or poly-aspartic acid coated ceria nanozymes. Interestingly, we find HA-CeO2 NPs not only actively target plaque-associated macrophages in atherosclerosis to remove superfluous ROS and protect macrophages from ROS-caused damages, but also effectively inhibit endocytosis of ox-LDL by activated macrophages. We believe HA-CeO2 nanozymes can serve as a simple and promising platform for anti-atherosclerotic therapy.

Chronic kidney disease: Which role for xanthine oxidoreductase activity and products?

The present review explores the role of xanthine oxidoreductase (XOR) in the development and progression of chronic kidney disease (CKD). Human XOR is a multi-level regulated enzyme, which has many physiological functions, but that is also implicated in several pathological processes. The main XOR activities are the purine catabolism, which generates uric acid, and the regulation of cell redox state and cell signaling, through the production of reactive oxygen species. XOR dysregulation may lead to hyperuricemia and oxidative stress, which could have a pathogenic role in the initial phases of CKD, by promoting cell injury, hypertension, chronic inflammation and metabolic derangements. Hypertension is common in CKD patients and many mechanisms inducing it (upregulation of renin-angiotensin-aldosterone system, endothelial dysfunction and atherosclerosis) may be influenced by XOR products. High XOR activity and hyperuricemia are also risk factors for obesity, insulin resistance, type 2 diabetes and metabolic syndrome that are frequent CKD causes. Moreover, CKD is common in patients with gout, which is characterized by hyperuricemia, and in patients with cardiovascular diseases, which are associated with hypertension, endothelial dysfunction and atherosclerosis. Although hyperuricemia is undoubtedly related to CKD, controversial findings have been hitherto reported in patients treated with urate-lowering therapies.

Introduction of octenylsuccinate and carboxymethyl onto starch for strong bonding to fiber and easy removal from sized yarn.

Amphipathic starch (AS) with hydrophobic octenylsuccinate (OS) and hydrophilic carboxymethyl (CM) substituents was prepared by the carboxymethylation and octenylsuccinylation of starch for strong bonding to fiber and easy removal from sized yarn. Two series of AS derivatives with differential degrees of substitution (DS) and differential mole percentages of OS to total substituents (Pos) were examined to reveal the effects of Pos and DS values on bonding of the starch to cotton and polyester fibers. It was found that the amphipathic modification was able to significantly increase bonding strength of the starch. Combination of the CM and OS substituents could increase the bonding strength more than each one alone. Furthermore, desizing trial proved that the AS was desizable by either enzyme or oxidant desizing. Starch octenylsuccinylation and carboxymethylation was a good way for corn starch to achieve strong bonding to fibers and easy removal from sized yarns.

Synergistic antioxidant effects of phenolic acids and carotenes on H2O2-induced H9c2 cells: Role of cell membrane transporters.

Phenolic acids (caffeic acid, p-coumaric acid,) and carotenes (ß-carotene, lycopene) were mixed in different ratios to investigate antioxidant interactions on H2O2-induced H9c2 cells with ezetimibe (inhibitor of carotenes membrane transporters). Cellular uptake of carotenes, expression of membrane transporters, reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H dehydrogenase quinone1 (NQO1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC) were analyzed. Results revealed that phenolic acids increased cellular uptake of carotenes and expression of their membrane transporters. Combination groups contained more phenolic acids showed synergistic effects. For example, ß-carotene: caffeic acid = 1:2 significantly suppressed the intracellular ROS (+EZT, 66.34 ±â€¯51.53%) and enhanced the accumulation of nucleus-Nrf2 (+EZT, 30.23 ±â€¯5.30) compared to the groups contained more ß-carotene (+EZT, ROS: 75.48 ±â€¯2.55%, nucleus-Nrf2: 19.48 ±â€¯4.22). This study provided an implication of functional foods formulation and demonstrated that antioxidant synergism may due to the up-regulation of carotenes membrane transporters by phenolic acids.

Effect of washing, soaking and pH in combination with ultrasound on enzymatic rancidity, phytic acid, heavy metals and coliforms of rice bran.

Simultaneous reduction in activity of fat destabilizing enzymes (lipase and lipoxygenase), contaminants heavy metals (As, Cd, Pb, and Hg), antinutrient phytic acid and hazardous coliforms in rice bran was investigated. Application of washing, soaking the washed sample at different pH values (2, 6 and 9) alone or in combination with ultrasonication were examined. While washing was beneficial, its low efficiency acquired further treatment, which was prevailed by application of acidic pH and ultrasound (28 kHz) treatments. Free fatty acids and peroxide value, as indicators of enzymes activity, implied the effectiveness of treatments with adverse impact of sonication on peroxide value. Remarkably, reduction of dominant heavy metals (As, Pb and Zn) and phytic acid were synergistically facilitated by sonication. Coliforms growth was inhibited at pH 2 even at the absence of ultrasonic treatment. Evidently, combination of acidic pH and ultrasound is a practical approach to improve rice bran stability and safety.

Opportunities for fraudsters: When would profitable milk adulterations go unnoticed by common, standardized FTIR measurements?

Milk is regarded as one of the top food products susceptible to adulteration where its valuable components are specifically identified as high-risk indicators for milk fraud. The current study explores the impact of common milk adulterants on the apparent compositional parameters of milk from the Dutch market as measured by standardized Fourier transform infrared (FTIR) spectroscopy. More precisely, it examines the detectability of these adulterants at various concentration levels using the compositional parameters individually, in a univariate manner, and together in a multivariate approach. In this study we used measured boundaries but also more practical variance-adjusted boundaries to set thresholds for detection of adulteration. The potential economic impact of these adulterations under a milk payment scheme is also evaluated. Twenty-four substances were used to produce various categories of milk adulterations, each at four concentration levels. These substances comprised five protein-rich adulterants, five nitrogen-based adulterants, seven carbohydrate-based adulterants, six preservatives and water, resulting in a set of 360 samples to be analysed. The results showed that the addition of protein-rich adulterants, as well as dicyandiamide and melamine, increased the apparent protein content, while the addition of carbohydrate-based adulterants, whey protein isolate, and skimmed milk powder, increased the apparent lactose content. When considering the compositional parameters univariately, especially protein- and nitrogen-based adulterants did not raise a flag of unusual apparent concentrations at lower concentration levels. Addition of preservatives also went unnoticed. The multivariate approach did not improve the level of detection. Regarding the potential profit of milk adulteration, whey protein and corn starch seem particularly interesting. Combining the artificial inflation of valuable components, the resulting potential profit, and the gaps in detection, it appears that the whey protein isolates deserve particular attention when thinking like a criminal.

Effects of exogenous application of citrulline on prolonged water stress damages in hyssop (Hyssopus officinalis L.): Antioxidant activity, biochemical indices, and essential oils profile.

This study examined the effects of exogenous citrulline (control, 1 and 2 mM) and water availability (100%, 50% and 25% WA) on antioxidant attributes and essential oil constituents of Hyssopus officinalis L. in two successive harvests. Hyssop tolerantly responded to water deficiency by well-promoted antioxidant enzymes (i.e., superoxide dismutase, and catalase), strong DPPH-scavenging activity, and increasing polyphenols; however, the essential oil content was negatively reduced by water stress. External citrulline further increased the activity of antioxidant enzymes. Citrulline application at 2 mM under severe water stress could also improve essential oil (EO) content in the first and second harvests by about 15 and 30%, respectively. Furthermore, under severe drought, citrulline at 2 mM could obtain the highest yield of isopinocamphone (47%) as the main component of EO. The results showed the high potential of this novel applied metabolite agent to be used in a well-fulfilled production of this medicinal plant.

Preparation of low-molecular-weight chondroitin sulfates by complex enzyme hydrolysis and their antioxidant activities.

Chondroitin sulfate (CS) has attracted widespread attention because of its numerous pharmacological activities. Low-molecular-weight chondroitin sulfates (LMWCSs) derived from the degradation of CS are reported to have better biological properties than whole CS. In this study, to obtain LMWCSs with high antioxidant activity, we depolymerized CS using complex enzymes, namely, chondroitinase ABC I (ChSase ABC I) and ChSase ABC II. The conditions of the complex enzyme hydrolysis (CEH) were optimized, and the structures and antioxidant activities of CS and LMWCSs were investigated. The results showed that the CEH conditions enhanced the antioxidant activities of the products as compared to CS. The basic structures of the LMWCSs and sulfate groups were well preserved after hydrolysis. Therefore, CEH provides an efficient and safe strategy to obtain LMWCSs, which can be used in antioxidant drugs, healthy foods, and cosmetics.

Immunoenhancing glucuronoxylomannan from Tremella aurantialba Bandoni et Zang and its low-molecular-weight fractions by radical depolymerization: Properties, structures and effects on macrophages.

In this study, a glucuronoxylomannan named TAP-3 was obtained from high-value Tremella aurantialba Bandoni et Zang. Physicochemical analysis revealed that TAP-3, which had a molecular weight of ∼624 kDa, mainly consisted of d-mannose (Man), d-xylose (Xyl), and d-glucuronic acid (GlcA) in a molar ratio of 3.0:1.0: 1.0. Structural analyses of its depolymerized fragments clarified that TAP-3 contained a (1 → 3) and (1 → 2)-linked α-Manp backbone, side chains formed by ß-Xylp and ß-GlcpA linked to the C-2 position of α-Manp, and acetyl groups connected to the sixth hydroxyl positions of Manp. TAP-3 showed marked immune enhancement activity, promoting NO, IL-1ß and TNF-α secretion from macrophages. The critical membrane receptor of TAP-3 was identified to be TLR4, and the chain length was essential for its immunoregulatory activity. These findings expand knowledge of the structural types of glucuronoxylomannan and illustrate its biological activity as an immunopotentiator.

Structural characterization of a low-molecular-weight polysaccharide from Angelica pubescens Maxim. f. biserrata Shan et Yuan root and evaluation of its antioxidant activity.

A novel heteropolysaccharide with about twenty sugar residues named DF80-2 was obtained from Angelica pubescens Maxim. f. biserrata Shan et Yuan root, one of the most widely used traditional Chinese medicines for thousands of years in China. The possible structure of DF80-2 was proposed considering the comprehensive results of physicochemical properties, methylation analysis, and 1D/2D NMR spectroscopy, which showed that its main chain was composed of (1→3)-, and (1→4)-linked-α-d-Glcp, (1→4)-linked-ß-d-Galp, (1→6)-linked-α-d-Manp, and (1→3)-linked-α-l-Araf, and the branch was present as the α-d-Glcp-(1→3)-ß-d-GalpA disaccharides stretched from O-6 position of (1→4)-linked-α-d-Glc moiety in the main chain. Congo red analysis, scanning electron microscopy and atomic force microscopy showed that DF80-2 possessed a triple helical conformation, and its branched monomers were interlaced with one another forming a regular network structure. DF80-2 exhibited antioxidant activity by effectively scavenging DPPH, and hydroxyl radicals, and chelating ferrous ions.

Low frequency magnetic fields modification on hydrogen peroxide oxidized myoglobin-isolate and mechanisms underlying the chain reaction process.

The effects of low frequency magnetic field (0-12 mT) on hydrogen peroxide oxidized myoglobin-isolate (MbI) were investigated. The results indicate that the primary target of the hydrogen peroxide oxidation was Met(FeIII)Mb, leading to the fall off of iron ions from the porphyrin ring. Additionally, the increased magnetic field (≥9 mT) enhanced the release of more iron ions to react with H2O2, giving rise to the production of more hydroxyl radicals and the shift of oxidation site from porphyrin ring to Mb skeleton. Moreover, the directional movement of iron ions induced by magnetic field caused the generation of local micro-electric field and the rearrangement of charged groups on the protein surface or near-surface, thus affecting Mb aggregation. Overall, the magnetic field interfered with the hydrogen peroxide chain reaction process, changed the redox equivalents of Mb, and shifted the oxidation sites of Mb.

Peroxide-periodate co-modification of carboxymethylcellulose to prepare polysaccharide-based tanning agent with high solid content.

Dialdehyde carboxymethylcellulose (DCMC) solution generally has quite low solid content, which inevitably limits its industrial application. In this work, carboxymethylcellulose sodium (Na-CMC) was pre-degraded using H2O2 followed by periodate oxidation for preparing DCMC with high solid content as practical tanning agent. Pre-degradation conditions optimization showed that H2O2 dosage most impacted the tanning effect of DCMC, and the Mw and viscosity of Na-CMC underwent remarkable reduction. FT-IR and 1H NMR illustrated that aldehyde group was successfully introduced into DCMC after periodate oxidation. Under the optimized conditions, the solid content of DCMC could be improved to around 30%. This DCMC could endow tanned leather with high shrinkage temperature and satisfactory fiber dispersion. Besides, DCMC tanned leather had comparable physical and organoleptic properties to those of leathers tanned by chrome tanning agent and commercial polyaldehyde tanning agent TWT. This suggests the prospect of DCMC with high solid content as useful tanning agent.

Effects of oxidative modification on textural properties and gel structure of pork myofibrillar proteins.

Isolated myofibrillar protein (MP) was treated by the oxidation system of FeCl3 (0.01 mM) at four different H2O2 concentrations (0, 1, 10, 20 mM). The oxidation degree was determined by measuring the carbonyl and total sulphydryl values. The structure and physicochemical properties of MP gels were investigated by water holding capacity (WHC) evaluation, sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE), texture profile analysis (TPA), Raman spectroscopy, and NMR transverse relaxation (T2). The results of carbonyls and total sulphydryls indicated that oxidation degree of MP increased with increasing H2O2 concentration. TPA showed that moderate oxidation (10 mM H2O2) could improve the hardness, springiness, gumminess and cohesiveness of MP gels, but not contribute to the maintenance of their WHC, probably due to severe depolymerization of MPs, unfolding of α-helix, exposure of the hydrophobic groups and the migration of protein-associated water (T2b) and intra-myofibrillar water (T21) to the longer relaxation time.

Amperometric biosensors based on oxidases and PtRu nanoparticles as artificial peroxidase.

Catalytically active nanomaterials have several advantages over their natural analogues when used as artificial enzymes (nanozymes), namely, higher stability and lower cost. Nanozymes with metallic nanocomposites are promising catalysts for biosensing applications. The aim of the current research is to construct oxidase-based bioelectrodes for food analysis using nanozymes as peroxidase mimetics. Bimetallic PtRu nanoparticles (nPtRu) coupled with alcohol oxidase (AO) and methylamine oxidase (AMO) were chosen to construct amperometric biosensors (ABSs) for primary alcohols and methylamine (MA). Both ABSs show high sensitivities (336 A·M-1·m-2 for the AO-ABS and 284 A·M-1·m-2 for the AMO-ABS), broad linear ranges (25-200 µM ethanol and 20-600 µM MA) and satisfactory storage stabilities. Practical feasibility of the constructed ABSs was demonstrated on food samples. High correlation between contents of MA and ethanol in foods determined by the ABSs and reference methods was observed.

Structural, rheological and antioxidant properties of pectins from Equisetum arvense L. and Equisetum sylvaticum L.

The pectins were isolated from sterile stems of E. arvense (EA, yield 5.9%) and E. sylvaticum (ES, yield 4.8%) (Equisetaceae) using ammonium oxalate extraction after preliminary treatment with dilute HCl (рH 4.0). The pectins possessed high molecular weight (Mw, 340-360 kDa), high GalA content (ca. 85%), low degrees of methyl-esterification (14-16%) and acetylation (3-8%). NMR analysis indicated extensive regions of partially methyl-etherified and 3-O-acetylated HG and minor regions of low branched RG in the fragment isolated after hydrolysis of pectin EA by pectinase. Pectin EA produced a higher viscosity solution, formed a stronger and more rigid ionotropic hydrogel than pectin ES. The pectins scavenged DPPH and hydroxyl radicals, but not the superoxide radical and hydrogen peroxide. Phenolic compounds (0.11 and 0.23%) associated with polysaccharide moieties were apparently responsible for the differences in the anti-DPPH scavenging activity of pectins EA and ES (63 and 49%). The findings suggested that pectin from E. arvense should be more perspective than pectin from E. sylvaticum on their use as components of wound healing remedies.