Fabrication of Poly（y-glutamic acid）-coated Fe3O4 Magnetic Nanoparticles and Their Application in Heavy Metal Removal

In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs

Research of Dyeing Thermodynamics and Supramolecular Structure of Luteolin on Wool Fabric

Natural dyestuff of luteolin was isolated and used to dye wool fabric in this paper. Ethanol extraction and high-speed countercurrent chromatography (HSCCC) were used to extract and purify the luteolin from the peanut shell, and the structure of the isolated luteolin was characterized with FTIR techniques. The interaction between dyestuff and fiber was preliminarily discussed through thermodynamic study and supramolecular structure simulation to explain the intrinsic reasons why the color fastness was low when luteolin was applied to dyeing wool fabric. The extraction condition and purification parameter were as follows: 65% ethanol, ratio of material to liquid 1:20, 80°C, 3 h, chloroform-methanol-water (4/3/2, V/V), 800 rmp/min, 2.0 Mkpa, 0.5 mL/ min and 280 nm. The results of dyeing thermodynamics showed that the sorption isotherm of luteolin on wool fabric was consistent with Nernst model and similar to the disperse dyestuff. With molecular simulation, luteolin and glycin composed 8 stable complexes whose Laplacian values all were greater than 0, which suggested typical hydrogen bonds existing. The complex with three hydrogen bonds was proved the most stable. Both studies on thermodynamics and supramolecular simulation revealed that luteolin on wool fabric mainly depended on the weak hydrogen bonds interaction that determined the low dyefastness.

Efficient reduction ofβ-lactoglobulin allergenicity in milk using Clostridium tyrobutyricum Z816

Milk allergy is one of the most common food allergies,affecting 6%of young children,andβ-lactoglobulin(β-LG)is the main milk allergen.Clostridium tyrobutyricum Z816 was selected for the degradation ofβ-LG,which was successfully reduced by about 90%using permeabilized bacteria under the optimized conditions.The hydrolyzed peptides were identified by liquid chromatography-tandem mass spectrometry(LC-MS/MS)and analyzed by molecular modeling,which indicated that C.tyrobutyricum Z816 could effectively degrade the antigenic epitopes ofβ-LG.Finally,the concentration and digestibility ofβ-LG in actual samples was quantified using enzyme-linked immunosorbent assay(ELISA)and gastrointestinal digestion simulation experiments.The results showed more than 92%ofβ-LG in actual samples was hydrolyzed,and the gastric and total digestibility of whey protein isolate(WPI)was improved by 85.96%and 64.51%,respectively.Therefore,C.tyrobutyricum Z816 offers an effective method to degradeβ-LG and reduce the occurrence of milk allergies,which has great significance for the development of hypoallergenic dairy products.

In situ formation of self-antistacking FeCoO_(x) on N-doped graphene:A 3D-on-2D nanoarchitecture for long-life Zn-air batteries

Before the practical application of rechargeable Zn-air batteries(ZABs),a critical issue regarding the inherent slow reaction kinetics of the oxygen reduction(ORR)and oxygen evolution(OER)must be addressed.Here,we fabricate a cost-effective bifunctional oxygen electrocatalyst with a self-antistacking structure,where three-dimensional(3D)Fe-Co bimetallic oxide particles(FeCoO_(x))are directly grown on 2D N-doped graphene(NG).The in situ grown FeCoO_(x)particles can alleviate the NG interlaminar restacking,ensuring abundant channels for diffusion of O_(2)/OH−species,while the NG allows rapid electron flow.Benefiting from this self-antistacking 3D-on-2D structure and synergetic electrocatalysis,FeCoO_(x)@NG demonstrated excellent activity for both ORR and OER(ΔE=0.78 V),which is superior to that of the binary mixtures of Pt/C and RuO_(2)(ΔE=0.83 V).A homemade ZAB with 20%-FeCoO_(x)@NG delivers a specific capacity of 758.9 mAh g^(−1),a peak power density of 215 mW cm^(−2),and long-term cyclability for over 400 h.These research results suggest that designing a bimetallic oxide/N-doped carbon 3D-on-2D nanoarchitecture using an in situ growth strategy is an attractive and feasible solution to overcome electrocatalytic problems in ZABs.

Synthesis and Density Functional Theory(DFT) Calculation of Haptens for PAHs

Five PAHs haptens 3 a～3 e were synthesized from naphthalene, anthracene, chrysene, pyrene and acenaphthene via two steps including Friedel-Crafts acylation and WolffKishner-Huang reduction. The sixth hapten 4-(acenaphthylen-3-yl)butanoic acid(3 f) was prepared from hapten 3 e via three steps including esterification, bromination and elimination. Their structures were confirmed by melting point, ~1H NMR and ^(13)C NMR. Their optical properties and crystal structures were also investigated. The results of density functional theory(DFT) calculation provided the supports that the size, shape(geometry) and electronic properties at the corresponding parts of 3 a～3 f did not change significantly, compared to those of PAHs. The haptens 3 a～3 f were coupled with bovine serum albumin(BSA) to make antigens. The coupling ratios were 1:20～1:38. These results show that the haptens could be used to induce specific antibodies for PAHs.

Comparison of Fungicidal Difference of Two Arylpyrazoles Based on the Crystal Structures, Density Functional Theory Calculation and Molecular Docking

Two arylpyrazoles I andⅡwere synthesized and characterized by NMR and single-crystal X-ray diffraction.Compound I displayed 71.4%fungicidal inhibition rate against Rhizoctonia solani at 0.1 ppm,better than the control pyraclostrobin,whereasⅡhad little activity.Their fungicidal difference was discussed from theoretic level based on the crystal structure,density functional theory(DFT)calculation and molecular docking.The B3 LYP/6-31G^**level was employed to explore the HOMO-LUMO energy gap and charge distribution.Molecular docking was performed on the probable target protein bc1-enzyme complex.DFT calculation and docking studies supported the in vitro findings.

Dyeing Thermodynamics and Supramolecular Structure of Lac Red on Protein Fibers

The dyeing temperature of natural dye lac red on two kinds of natural protein fibers was studied, and the interaction between dyestuff and fiber was discussed through thermodynamic study and density functional theory (DFT) calculation. The optimum temperature for lac red dyed silk was 60˚C and wool showed a better response at 90˚C. The thermodynamics study revealed good Nernst isotherm and Freundlich adsorption models respectively, and the lac dye adsorption processes were both spontaneous and exothermic. The potential interaction of Laccaic acid A with the external environment by electrostatic potential and atomic charge distribution was first explored. With molecular simulation, Laccaic acid A and glycine composed 8 stable complexes. Then, typical hydrogen bonds, bond length, and binding energy, etc. were analyzed. The results revealed lac red on silk and wool fabric mainly depended on the weak hydrogen bonds and van der Waals force which determined the low dye fastness.

Bifidobacterium longum CCFM1077 Attenuates Hyperlipidemia by Modulating the Gut Microbiota Composition and Fecal Metabolites:A Randomized,Double-Blind,Placebo-Controlled Clinical Trial

An increasing number of studies have indicated that gut microbiota and its metabolites are crucial in the development of hyperlipidemia.Bifidobacterium longum(B.longum)CCFM1077 has been shown to have lipid-lowering effects in animals.This study aimed to evaluate the potential of B.longum CCFM1077 in lowering the lipid levels in patients with hyperlipidemia and investigate the effect of this bacterium on serum lipid abnormalities,gut microbiota,and fecal metabolites in these patients.This study was a six-week,randomized,double-blind,and placebo-controlled pilot clinical trial.Subjects with hyperlipidemia(N=62)were randomly assigned to receive placebo(N=31)or B.longum CCFM1077(1×1010colony-forming units(CFUs)per day;N=31).Serum lipid levels including total cholesterol(TC),lowdensity lipoprotein cholesterol(LDL-C),total triglyceride(TG),and high-density lipoprotein cholesterol(HDL-C)were examined at the baseline and interventio nal endpoints.Changes in the gut microbiota composition and diversity were measured based on 16S ribosomal RNA(rRNA)sequencing of the V3-V4region at the end of the intervention period.Non-targeted metabolomics of the feces was performed using ultra-performance liquid chromatography(UPLC)-Q-Exactive Orbitrap/mass spectrometer.Oral administration of B.longum CCFM1077 for six weeks significantly decreased the serum levels of TC(p<0.01)and LDL-C(p<0.01)in patients with hyperlipidemia.B.longum CCFM1077 treatment markedly increased gut microbiota diversity and the relative abundance of anti-obesity-related genera,including Lactobacillus,Butyricicoccus,Bifidobacterium,and Blautia,whereas it decreased the relative abundance of obesity-related genera,including Alistipes,Megamonas,and Catenibacterium.Additionally,some key metabolites(bile acids(BAs),biotin,and caffeine)and their corresponding metabolic pathways(primary BA biosynthesis,and taurine and hypotaurine,biotin,purine,and caffeine metabolisms)were enriched by B.longum CCFM1077,and thus it may lower lipid levels.B.longum CCFM1077 is a probiotic strain with the potential to lower serum TC and LDL-C levels patients with hyperlipidemia.The underlying mechanism may be related to the increased abundance of anti-obesity-related genera and fecal metabolites.These findings provide a foundation for future clinical applications of lipid-lowering probiotics in managing individuals with hyperlipidemia.

Optical and electrochemical dual detection ofβ-lactoglobulin based on the methylene blue@copper-based metal-organic framework

β-lactoglobulin is an effective indicator of allergic protein detection.Herein,we produced a copper-based metal-organic framework coated with methylene blue,to realize the optical and electrochemical dual detection ofβ-lactoglobulin.Methylene blue was successfully encapsulated inside the copper-based metal-organic framework and released after addition ofβ-lactoglobulin.As the concentration ofβ-lactoglobulin increased,the intensity of the ultraviolet absorption band and the response current increased with the increasing concentration of methylene blue released from the copper-based metal-organic framework.The optical detection range is from 0.10 mg/mL to 10 mg/mL,and the detection limit is 0.10 mg/mL.The electrochemical detection range is from 1.0×10^(-7) mg/mL to 8.0×10^(-7) mg/mL,the detection limit is 2.0×10^(-8) mg/mL.The dual detection strategy,with no interfere with each other,played a synergetic role in the quick qualitative and precise quantitative analyses ofβ-lactoglobulin in a wide range of applications.

Enhanced Succinic Acid Production from Sake Lees Hydrolysate by Dilute Sulfuric Acid Pretreatment and Biotin Supplementation

Succinic acid is valued as a potential starting point for the production of chemicals of the C4 family or in the prepara-tion of biodegradable polymers. For sustainable development in this era of petroleum shortage, production of succinic acid by microbial fermentation of renewable feedstock has attracted great interest. In this study, pretreatment with sulfuric acid and biotin supplementation were used to enhance succinic acid production by Actinobacillus succinogenes 130Z from sake lees, a byproduct of Japanese rice wine. Pretreatment with sulfuric acid resulted in little change of glucose, total nitrogen and succinic acid content in the sake lees hydrolysate but had a positive effect on succinic acid fermentation, which caused a 25.0% increase in succinic acid yield in batch fermentation. Biotin supplementation was used to further enhance the fermentability of sake lees hydrolysate. As a result, a 30 h batch fermentation of 0.5% sulfuric acid pretreated sake lees hydrolysate with 0.2 mg/L biotin gave a succinic acid yield of 0.59 g/g from 61.6 g/L of glucose, with a productivity of 1.21 g/(L?h). A 22.9% increase in succinic acid yield and a 101.7% increase in succinic acid productivity were obtained compared with untreated sake lees hydrolysate.

Artificial multi-enzyme cascades and whole-cell transformation for bioconversion of C1 compounds: Advances, challenge and perspectives

Artificial multi-enzyme cascades bear great potential for bioconversion of C1 compounds to value-added chemicals.Over the past decade,massive efforts have been devoted to constructing multi-enzyme cascades to produce glycolic acid,rare functional sugars and even starch from C1 compounds.However,in contrast to traditional fermentation utilizing C1 compounds with the expectation of competitive economic performance in future industrialization,multi-enzyme cascades systems in the proof-of-concept phase are facing the challenges of upscaling.Here,we offered an overview of the recent advances in the construction of in vitro multi-enzyme cascades and whole-cell transformation using C1 compounds as substrate.In addition,the existing challenges and possible solutions were also discussed aiming to combine the strengths of in vitro and in vivo multi-enzyme cascades systems for upscaling.

Regulatory mechanisms of dopamine metabolism in a marine Meyerozyma guilliermondii GXDK6 under NaCl stress as revealed by integrative multi-omics analysis

Dopamine can be used to treat depression,myocardial infarction,and other diseases.However,few reports are available on the de novo microbial synthesis of dopamine from low-cost substrate.In this study,integrated omics technology was used to explore the dopamine metabolism of a novel marine multi-stress-tolerant aromatic yeast Meyerozyma guilliermondii GXDK6.GXDK6 was found to have the ability to biosynthesize dopamine when using glucose as the substrate.14 key genes for the biosynthesis of dopamine were identified by whole genome-wide analysis.Transcriptomic and proteomic data showed that the expression levels of gene AAT2 encoding aspartate aminotransferase(regulating dopamine anabolism)were upregulated,while gene AO-I encoding copper amine oxidase(involved in dopamine catabolism)were downregulated under 10%NaCl stress compared with non-NaCl stress,thereby contributing to biosynthesis of dopamine.Further,the amount of dopamine under 10%NaCl stress was 2.51-fold higher than that of zero NaCl,which was consistent with the multi-omics results.Real-time fluorescence quantitative PCR(RT-qPCR)and high-performance liquid chromatography(HPLC)results confirmed the metabolic model of dopamine.Furthermore,by overexpressing AAT2,AST enzyme activity was increased by 24.89%,the expression of genes related to dopamine metabolism was enhanced,and dopamine production was increased by 56.36%in recombinant GXDK6AAT2.In conclusion,Meyerozyma guilliermondii GXDK6 could utilize low-cost carbon source to synthesize dopamine,and NaCl stress promoted the biosynthesis of dopamine.

Biofilm-inspired adhesive and antibacterial hydrogel with tough tissue integration performance for sealing hemostasis and wound healing

Uncontrolled bleeding and infection can cause significant increases in mortalities.Hydrogel sealants have attracted extensive attention for their ability to control bleeding.However,because interfacial water is a formidable barrier to strong surface bonding,a challenge remains in finding a product that offers robust tissue adhesion combined with anti-infection properties.Inspired by the strong adhesive mechanism of biofilm and mussels,we report a novel dual bionic adhesive hydrogel(DBAH)based on chitosan grafted with methacrylate(CS-MA),dopamine(DA),and N-hydroxymethyl acrylamide(NMA)via a facile radical polymerization process.CS-MA and DA were simultaneously included in the adhesive polymer for imitating the two key adhesive components:polysaccharide intercellular adhesin(PIA)of staphylococci biofilm and 3,4-dihydroxy-L-phenylalanine(Dopa)of mussel foot protein,respectively.DBAH presented strong adhesion at 34 kPa even upon three cycles of full immersion in water and was able to withstand up to 168 mm Hg blood pressure,which is significantly higher than the 60–160 mm Hg measured in most clinical settings.Most importantly,these hydrogels presented outstanding hemostatic capability under wet and dynamic in vivo movements while displaying excellent antibacterial properties and biocompatibility.Therefore,DBAH represents a promising class of biomaterials for high-efficiency hemostasis and wound healing.

Evolving strategies for marine enzyme engineering:recent advances on the molecular modification of alginate lyase

Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential applications in the food,medicine,and agriculture fields.However,the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability.In recent years,various structural features of alginate lyase have been determined,resulting in modification strategies that can increase the applicability of alginate lyase,making it important to summarize and discuss the current evidence.In this review,we summarized the structural features and catalytic mechanisms of alginate lyase.Molecular modification strategies,such as rational design,directed evolution,conserved domain recombination,and non-catalytic domain truncation,are also described in detail.Lastly,the application of alginate lyase is discussed.This comprehensive summary can inform future applications of alginate lyases.

Comparison of Two Rhodamine-Polyamine Polystyrene Solid-phase Fluorescence Sensors for Hg(Ⅱ) Detection Based on Theoretical Calculation

Two novel rhodamine-based polystyrene solid-phase fluorescence sensors PS-PA-Ⅰ and PS・PA-Ⅱ with different lengths of polyamines were synthesized for Hg(Ⅱ)determination.Thedetection mechanism involving the Hg(Ⅱ)chelation-induced spirocycle open of rhodamine was proposed with the aid of theoretical calculation.The stronger N—Hg bond and the longer polyamine chain in PS-PA-Ⅱ led to a better selectivity,much higher and more quickly fluorescence response to Hg(Ⅱ).

Injectable Hyaluronic Acid/Poly(y-glutamic acid)Hydrogel with Step-by-step Tunable Properties for Soft Tissue Engineering

Injectable hydrogels as an important class of biomaterials have gained much attention in tissue engineering.However,their crosslinking degree is difficult to be controlled after being injected into body.As we all know,the crosslinking degree strongly influences the physicochemical properties of hydrogels.Therefore,developing an injectable hydrogel with tunable crosslinking degree in vivo is important for tissue engineering.Herein,we present a dual crosslinking strategy to prepare injectable hydrogels with step-by-step tunable crosslinking degree using Schiff base reaction and photopolymerization.The developed hyaluronic acid/poly(y-glutamic acid)(HA/y-PGA)hydrogels exhibit step-by-step tunable swelling behavior,enzymatic degradation behavior and mechanical properties.Mechanical performance tests show that the storage moduli of HA/y-PGA hydrogels are all less than 2000 Pa and the compressive moduli are in kilopascal,which have a good match with soft tissue.In addition,NIH 3T3 cells encapsulated in HA/y-PGA hydrogel exhibit a high cell viability,indicating a good cytocompatibility of HA/y-PGA hydrogel.Therefore,the developed HA/y-PGA hydrogel as an injectable biomaterial has a good potential in soft tissue engineering.

A mitochondria-targeted fluorescent probe for ratiometric detection of hypochlorite in living cells

Hypochlorous acid（HOCl） plays a vital role in many physiological and pathological processes as one of reactive oxygen species（ROS）. Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response（within 30 s） as well as low detection limit（0.18 mmol/L）. Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of He La cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.

Colorimetric detection of glucose using a boronic acid derivative receptor attached to unmodified AuNPs

A simple, cheap and non-enzymatic colorimetric strategy for glucose detection has been designed based on the interactions between a phenylboronic acid （PBA） derivative, which is coupled with gold nanoparticles （AuNPs） as the colorimetric reporters, and glucose. The PBA-AuNPs hybrid system proposed here exhibits ordered photochemistry behaviors upon the addition of glucose at different pH values. There are two linear regions of glucose concentration for the glucose sensor at different pH values, i.e., between 0.1 mmol/L and 9.8 mmol/L at pH 6 with the detection limit of 64μmol/L and between 0 and 6.5 mmol/L with the detection limit of 48 μmol/L at pH 9, respectively. To test the practicality of the sensor system, we also applied this assay to detect a glucose sample in the artificial saliva.

Nitric oxide-releasing polyurethane/S-nitrosated keratin mats for accelerating wound healing

Nitric oxide(NO)plays an important role in wound healing,due to its ability to contract wound surfaces,dilate blood vessels,participate in inflammation as well as promote collagen synthesis,angiogenesis and fibroblast proliferation.Herein,keratin was first nitrosated to afford S-nitrosated keratin(KSNO).As a NO donor,KSNO was then co-electrospun with polyurethane(PU).These as-spun PU/KSNO biocomposite mats could release NO sustainably for 72 h,matching the renewal time of the wound dressing.Moreover,these mats exhibited excellent cytocompatibility with good cell adhesion and cell migration.Further,the biocomposite mats exhibited antibacterial properties without inducing severe inflammatory responses.The wound repair in vivo demonstrated that these mats accelerated wound healing by promoting tissue formation,collagen deposition,cell migration,re-epithelialization and angiogenesis.Overall,PU/KSNO mats may be promising candidates for wound dressing.