A novel complex [Zn(Im)2(A-glu)]-0.5H2O(Im = imidazole, A-glu = N-acetyi- L-glutamic acid) has been synthesized from the reaction of A-glu with Zn(CH3COO)2·2H20 in the presence of Im at 65 ℃, and structu...A novel complex [Zn(Im)2(A-glu)]-0.5H2O(Im = imidazole, A-glu = N-acetyi- L-glutamic acid) has been synthesized from the reaction of A-glu with Zn(CH3COO)2·2H20 in the presence of Im at 65 ℃, and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in tetragonai, space group P43212 with a = b = 8.9078(6), c = 43.458(6) A, C26H36N10O11Zn2, Mr = 795.39, V= 3448.3(6) A^3, De = 1.532 g/cm^3, Z = 4,μ(MoKα) = 1.461 mm^-1, F(000) = 1640, the final R = 0.0453 and wR = 0.0992. X-ray analysis reveals that the crystal structure is constructed by mixed iigands. A-glu adopts the bis-monodentate coordination mode linking two adjacent metal ions to form a one-dimensional chain. Zinc(Ⅱ) ions are four-coordinated with a distorted tetrahedral geometry. Luminescent properties of the complex have been inves- tigated.展开更多
A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding proper...A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.展开更多
Combretastatin A4(CA4) possesses varying ability to cause vascular disruption in tumors,while the short half-life, low water solubility and deactivation of many CA4 analogs during storage limited its antitumor efficac...Combretastatin A4(CA4) possesses varying ability to cause vascular disruption in tumors,while the short half-life, low water solubility and deactivation of many CA4 analogs during storage limited its antitumor efficacy and drug stability. A novel macromolecular conjugate of CA4(CA4-PL) was synthesized by covalent bonding of CA4 onto poly(L-glutamic acid)-graft-polyethylene glycol(PLG-g-PEG) via Yamaguchi reaction. The obtained CA4-PL was characterized by ~1H NMR, GPC, and UV methods, and the properties of the nanoparticles composed of CA4-PL, including critical aggregation concentration, size and size distribution, and morphology, were investigated. CA4-PL can self-assemble to form micelle-like nanoparticles of 80~120 nm in diameter, which may have potential to improve the blood circulation period as well as the targetability of CA4, and find applications to treat various tumors when combined with traditional chemotherapy or radio therapy.展开更多
L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward pr...L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward preparation of LA-based light-responsive polyesters(PLTDs)under mild conditions.PLTDs with molar masses up to 8500 g/mol and high yields exceeding 90%are obtained.The chemical structures and light-responsive self-immolative behavior of PLTDs are comprehensively characterized by employing ultraviolet-visible(UV-Vis)spectroscopy,size exclusion chromatography(SEC),nuclear magnetic resonance(NMR)spectroscopy,and liquid chromatography mass spectrometry(LC-MS).Meanwhile,monodisperse PLTD-based doxorubicin-loaded nanoparticles(PLTD-DOX-NP)(size=193 nm,PDI=0.018)are formulated by nanoprecipitation method.Upon light-induced depolymerization,the PLTD-DOX-NP undergoes rapid decomposition,resulting in a burst release of 80%cargo within 13 s.Furthermore,according to biological toxicity tests,the PLTD-NP possesses adequate biosafety,both before and after irradiation.Overall,the incorporation of P-3CP with biorenewable LA-based monomer adheres to the principles of green chemistry,significantly simplifying the synthetic pathway of light-responsive polymers.展开更多
The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists...The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.展开更多
PEGylation has been widely applied to prolong the circulation times of nanomedicines via the steric shielding effect,which consequently improves the intratumoral accumulation.However,cell uptake of PEGylated nanoformu...PEGylation has been widely applied to prolong the circulation times of nanomedicines via the steric shielding effect,which consequently improves the intratumoral accumulation.However,cell uptake of PEGylated nanoformulations is always blocked by the steric repulsion of PEG,which limits their therapeutic effect.To this end,we designed and prepared two kinds of poly(L-glutamic acid)-cisplatin(PLG-CDDP)nanoformulations with detachable PEG,which is responsive to specific tumor tissue microenvironments for prolonged circulation time and enhanced cell internalization.The extracellular pH(pHe)-responsive cleavage 2-propionic-3-methylmaleic anhydride(CDM)-derived amide bond and matrix metalloproteinases-2/9(MMP-2/9)-sensitive degradable peptide PLGLAG were utilized to link PLG and PEG,yielding pHe-responsive PEG-pHe-PLG and MMP-sensitive PEG-MMP-PLG.The corresponding smart nanoformulations PEG-pHe-PLG-Pt and PEG-MMP-PLG-Pt were then prepared by the complexation of polypeptides and cisplatin(CDDP).The circulation half-lives of PEG-pHe-PLG-Pt and PEG-MMP-PLG-Pt were about 4.6 and 4.2 times higher than that of the control PLG-Pt,respectively.Upon reaching tumor tissue,PEG on the surface of nanomedicines was detached as triggered by pHe or MMP,which increased intratumoral CDDP retention,enhanced cell uptake,and improved antitumor efficacy toward a fatal high-grade serous ovarian cancer(HGSOC)mouse model,indicating the promising prospects for clinical application of detachable PEGylated nanoformulations.展开更多
A concise synthesis of the mosquito oviposition attractant pheromone, (-)-(5R, 6S)- and (+)-(5S 6R)-6-acetoxy hexadecanolide from L-glutamic acid is described. The key steps are the inversion of the configuration at C...A concise synthesis of the mosquito oviposition attractant pheromone, (-)-(5R, 6S)- and (+)-(5S 6R)-6-acetoxy hexadecanolide from L-glutamic acid is described. The key steps are the inversion of the configuration at C-4 of 7, and the formation of δ-lactone from the γ-lactone through ring enlargement.展开更多
Three solvent-dependent chiral copper(II) compounds, {[Cu2(bzgluO)2(HzO)2]-4HzO}n (1), {[Cu2(bzgluO)2-(DMSO)2].H2O}, (2) and [Cuz(bzgluO)2(DMF)2], (3) (H2bzgluO=N-benzoyl-L-glutamic acid) have be...Three solvent-dependent chiral copper(II) compounds, {[Cu2(bzgluO)2(HzO)2]-4HzO}n (1), {[Cu2(bzgluO)2-(DMSO)2].H2O}, (2) and [Cuz(bzgluO)2(DMF)2], (3) (H2bzgluO=N-benzoyl-L-glutamic acid) have been synthe-sized under ambient temperature conditions and characterized by elemental analysis, IR spectra, UV spectra, ther- mogravimetric analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compounds 1 and 2 both crystallize in the orthorhombic space group P212121. Compound 3 crystallizes in the tetragonal space group P43. Compound 1 exhibits a ladder-like 1D chain structure, which is extended by hydrogen-bonding interactions to form a 3D supramolecular network. Compounds 2 and 3 both give a diamond-like 3D structure. Besides, there are hydrogen-bonding interactions in 2. The structural difference indicates that the solvent system plays a crucial role in modulating structures of coordination compounds. Circular dichroism (CD) and the magnetic properties of the compounds have also been investigated.展开更多
In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic...In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.展开更多
The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving c...The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.展开更多
Sweet osmanthus(Osmanthus fragrans) is a having general approval aromatic tree in China that is widely applied to landscaping and gardening. However, the evergreen tree adaptability is limited by many environmental st...Sweet osmanthus(Osmanthus fragrans) is a having general approval aromatic tree in China that is widely applied to landscaping and gardening. However, the evergreen tree adaptability is limited by many environmental stresses. Currently, limited information is available regarding the genetic analysis and functional identification of expansin genes in response to abiotic stress in sweet osmanthus. In this study, a total of 29 expansin genes were identified and divided into four groups by genome-wide analysis from the sweet osmanthus genome. Transcriptome and quantitative Real-time PCR analysis showed that the cell wall-localized protein expansin-like A(OfEXLA1) gene was significantly induced by salt and drought treatment. Histochemical GUS staining of transgenic Arabidopsis lines in which GUS activity was driven with the OfEXLA1 promoter, GUS activity was significantly induced by salt, drought, and exogenous abscisic acid(ABA). In yeast, we found OfEXLA1overexpression significantly improved the population of cells compared with wild-type strains after NaCl and polyethylene glycol(PEG)treatment. Additionally, OfEXLA1 overexpression not only promoted plant growth, but also improved the salt and drought tolerance in Arabidopsis. To gain insight into the role of ABA signaling in the regulation of OfEXLA1 improving abiotic tolerance in sweet osmanthus, four differentially expressed ABA Insensitive 5(ABI5)-like genes(OfABL4, OfABL5, OfABL7, and OfABL8) were identified from transcriptome, and dualluciferase(dual-LUC) and yeast one hybrid(Y1H) assay showed that OfABL4 and OfABL5 might bind to OfEXLA1 promoter to accumulate the OfEXLA1 expression by responding to ABA signaling to improve abiotic tolerance in sweet osmanthus. These results provide the information for understanding the molecular functions of expansin-like A gene and molecular breeding of sweet osmanthus in future.展开更多
Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver malignancy.The interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and progression.Under normal ...Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver malignancy.The interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and progression.Under normal conditions,BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and BAs.The gut microbiota plays a critical role in BA metabolism,and BAs are endogenous signaling molecules that help maintain liver and intestinal homeostasis.Of note,dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis,thereby leading to liver inflammation and fibrosis,and ultimately contributing to HCC development.Therefore,understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying hepatocarcinogenesis.In this review,we comprehensively explore the roles and functions of BA metabolism,with a focus on the interactions between BAs and gut microorganisms in HCC.Additionally,therapeutic strategies targeting BA metabolism and the gut microbiota are discussed,including the use of BA agonists/antagonists,probiotic/prebiotic and dietary interventions,fecal microbiota transplantation,and engineered bacteria.In summary,understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.展开更多
α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in var...α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.展开更多
The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely un...The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties.展开更多
The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
Polypeptides and polypeptoids were widely used as biomedical materials because of their good biocompatibility. In this work we reported a series of pH-responsive copolypeptides and polypeptide-polypeptoid block copoly...Polypeptides and polypeptoids were widely used as biomedical materials because of their good biocompatibility. In this work we reported a series of pH-responsive copolypeptides and polypeptide-polypeptoid block copolymers, i.e. random copolymers of L-glutamic acid (Glu) with L-leucine (Leu) [poly(Glu-r-Leu)s], as well as their block copolymers with polysarcosine (polySar). Well-defined poly(Glu-r-Leu)s with predictable compositions and molecular weights were synthesized by ring opening polymerization of corresponding N-carboxyanhydride monomers. We investigated the relationship between hydrophilicity-hydrophobicity transition and copolymer composition. With increasing Leu fraction, both the pH value of cloud point and the micellar size increased. Poly(Glu-r-Leu) with 60% Leu exhibited a cloud point at the pH of 5.0 to 6.0 the same as that in endosome and lysosome. Poly(Glu-r-Leu)-b-polySars assembled in phosphate buffer and performed pH-responsive morphology change from orbicular micelles at high pH to worm-like micelles at low pH. They were potential pH-responsive carriers for drug and gene delivery to enhance cargo release in cellules.展开更多
The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed ...The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.展开更多
Elaidic acid(EA)stimulation can lead to endoplasmic reticulum stress(ERS),accompanied by a large release of Ca^(2+),and ultimately the activation of NLRP3 inflammasome in Kupffer cells(KCs).Mitochondrial instability o...Elaidic acid(EA)stimulation can lead to endoplasmic reticulum stress(ERS),accompanied by a large release of Ca^(2+),and ultimately the activation of NLRP3 inflammasome in Kupffer cells(KCs).Mitochondrial instability or dysfunction may be the key stimulating factors to activate NLRP3 inflammasome,and sustained Ca^(2+)transfer can result in mitochondrial dysfunction.We focused on KCs to explore the damage to mitochondria by EA.After EA stimulation,cells produced an oxidative stress(OS)response with a significant increase in ROS release.Immunoprecipitation experiments and the addition of inhibitors revealed that the increase in the level of intracellular Ca^(2+)led to Ca^(2+)accumulation in the mitochondrial matrix via mitochondria-associated membranes(MAMs).This was accompanied by a significant release of m ROS,loss of MMP and ATP,and a significant increase in mitochondrial permeability transition pore opening,ultimately leading to mitochondrial instability.These findings confirmed the mechanism that EA induced mitochondrial Ca^(2+)imbalance in KCs via MAM,ultimately leading to mitochondrial dysfunction.Meanwhile,EA induced OS and the decrease of MMP and ATP in rat liver,and significant lesions were found in liver mitochondria.Swelling of the inner mitochondrial cristae and mitochondrial vacuolization occurred,with a marked increase in lipid droplets.展开更多
Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity ag...Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.展开更多
Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects ...Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 20471026), the Natural Science Foundation of Henan Province (No. 0311021200) and the Foundation of Education Committee of Henan Province (2006150017)
文摘A novel complex [Zn(Im)2(A-glu)]-0.5H2O(Im = imidazole, A-glu = N-acetyi- L-glutamic acid) has been synthesized from the reaction of A-glu with Zn(CH3COO)2·2H20 in the presence of Im at 65 ℃, and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in tetragonai, space group P43212 with a = b = 8.9078(6), c = 43.458(6) A, C26H36N10O11Zn2, Mr = 795.39, V= 3448.3(6) A^3, De = 1.532 g/cm^3, Z = 4,μ(MoKα) = 1.461 mm^-1, F(000) = 1640, the final R = 0.0453 and wR = 0.0992. X-ray analysis reveals that the crystal structure is constructed by mixed iigands. A-glu adopts the bis-monodentate coordination mode linking two adjacent metal ions to form a one-dimensional chain. Zinc(Ⅱ) ions are four-coordinated with a distorted tetrahedral geometry. Luminescent properties of the complex have been inves- tigated.
文摘A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
基金supported by National Natural Science Foundation of China (No. 51373168)
文摘Combretastatin A4(CA4) possesses varying ability to cause vascular disruption in tumors,while the short half-life, low water solubility and deactivation of many CA4 analogs during storage limited its antitumor efficacy and drug stability. A novel macromolecular conjugate of CA4(CA4-PL) was synthesized by covalent bonding of CA4 onto poly(L-glutamic acid)-graft-polyethylene glycol(PLG-g-PEG) via Yamaguchi reaction. The obtained CA4-PL was characterized by ~1H NMR, GPC, and UV methods, and the properties of the nanoparticles composed of CA4-PL, including critical aggregation concentration, size and size distribution, and morphology, were investigated. CA4-PL can self-assemble to form micelle-like nanoparticles of 80~120 nm in diameter, which may have potential to improve the blood circulation period as well as the targetability of CA4, and find applications to treat various tumors when combined with traditional chemotherapy or radio therapy.
基金This work was financially supported by the International Science and Technology Assistance Program of the Ministry of Science and Technology(No.KY202001016)Shandong Provincial Natural Science Foundation Magnitude Fundamental Research,China(No.ZR2022ZD11)Qingdao New Energy Shandong Laboratory Open Project(No.QNESL OP202312).
文摘L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward preparation of LA-based light-responsive polyesters(PLTDs)under mild conditions.PLTDs with molar masses up to 8500 g/mol and high yields exceeding 90%are obtained.The chemical structures and light-responsive self-immolative behavior of PLTDs are comprehensively characterized by employing ultraviolet-visible(UV-Vis)spectroscopy,size exclusion chromatography(SEC),nuclear magnetic resonance(NMR)spectroscopy,and liquid chromatography mass spectrometry(LC-MS).Meanwhile,monodisperse PLTD-based doxorubicin-loaded nanoparticles(PLTD-DOX-NP)(size=193 nm,PDI=0.018)are formulated by nanoprecipitation method.Upon light-induced depolymerization,the PLTD-DOX-NP undergoes rapid decomposition,resulting in a burst release of 80%cargo within 13 s.Furthermore,according to biological toxicity tests,the PLTD-NP possesses adequate biosafety,both before and after irradiation.Overall,the incorporation of P-3CP with biorenewable LA-based monomer adheres to the principles of green chemistry,significantly simplifying the synthetic pathway of light-responsive polymers.
基金The Applied Fundamental Foundation of Jiangsu province P. R. China. Contract No BJ98041.
文摘The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.
基金The study was financially supported by the National Natural Science Foundation of China(Grant Nos.52073280,51973216,and 51673187).
文摘PEGylation has been widely applied to prolong the circulation times of nanomedicines via the steric shielding effect,which consequently improves the intratumoral accumulation.However,cell uptake of PEGylated nanoformulations is always blocked by the steric repulsion of PEG,which limits their therapeutic effect.To this end,we designed and prepared two kinds of poly(L-glutamic acid)-cisplatin(PLG-CDDP)nanoformulations with detachable PEG,which is responsive to specific tumor tissue microenvironments for prolonged circulation time and enhanced cell internalization.The extracellular pH(pHe)-responsive cleavage 2-propionic-3-methylmaleic anhydride(CDM)-derived amide bond and matrix metalloproteinases-2/9(MMP-2/9)-sensitive degradable peptide PLGLAG were utilized to link PLG and PEG,yielding pHe-responsive PEG-pHe-PLG and MMP-sensitive PEG-MMP-PLG.The corresponding smart nanoformulations PEG-pHe-PLG-Pt and PEG-MMP-PLG-Pt were then prepared by the complexation of polypeptides and cisplatin(CDDP).The circulation half-lives of PEG-pHe-PLG-Pt and PEG-MMP-PLG-Pt were about 4.6 and 4.2 times higher than that of the control PLG-Pt,respectively.Upon reaching tumor tissue,PEG on the surface of nanomedicines was detached as triggered by pHe or MMP,which increased intratumoral CDDP retention,enhanced cell uptake,and improved antitumor efficacy toward a fatal high-grade serous ovarian cancer(HGSOC)mouse model,indicating the promising prospects for clinical application of detachable PEGylated nanoformulations.
文摘A concise synthesis of the mosquito oviposition attractant pheromone, (-)-(5R, 6S)- and (+)-(5S 6R)-6-acetoxy hexadecanolide from L-glutamic acid is described. The key steps are the inversion of the configuration at C-4 of 7, and the formation of δ-lactone from the γ-lactone through ring enlargement.
文摘Three solvent-dependent chiral copper(II) compounds, {[Cu2(bzgluO)2(HzO)2]-4HzO}n (1), {[Cu2(bzgluO)2-(DMSO)2].H2O}, (2) and [Cuz(bzgluO)2(DMF)2], (3) (H2bzgluO=N-benzoyl-L-glutamic acid) have been synthe-sized under ambient temperature conditions and characterized by elemental analysis, IR spectra, UV spectra, ther- mogravimetric analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compounds 1 and 2 both crystallize in the orthorhombic space group P212121. Compound 3 crystallizes in the tetragonal space group P43. Compound 1 exhibits a ladder-like 1D chain structure, which is extended by hydrogen-bonding interactions to form a 3D supramolecular network. Compounds 2 and 3 both give a diamond-like 3D structure. Besides, there are hydrogen-bonding interactions in 2. The structural difference indicates that the solvent system plays a crucial role in modulating structures of coordination compounds. Circular dichroism (CD) and the magnetic properties of the compounds have also been investigated.
基金The Guangdong Basic and Applied Basic Research Foundation(2022A1515010730)National Natural Science Foundation of China(32001647)+2 种基金National Natural Science Foundation of China(31972022)Financial and moral assistance supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515011996)111 Project(B17018)。
文摘In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.
基金financial support from the King Abdullah University of Science and Technology(KAUST).
文摘The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.
基金supported by the National Natural Science Foundation of China (Grant Nos.31902057 and 32072615)Zhejiang Provincial Natural Science Foundation of China (Grant No.LQ19C160012)the key research and development program of Zhejiang Province (Grant No.2021C02071)。
文摘Sweet osmanthus(Osmanthus fragrans) is a having general approval aromatic tree in China that is widely applied to landscaping and gardening. However, the evergreen tree adaptability is limited by many environmental stresses. Currently, limited information is available regarding the genetic analysis and functional identification of expansin genes in response to abiotic stress in sweet osmanthus. In this study, a total of 29 expansin genes were identified and divided into four groups by genome-wide analysis from the sweet osmanthus genome. Transcriptome and quantitative Real-time PCR analysis showed that the cell wall-localized protein expansin-like A(OfEXLA1) gene was significantly induced by salt and drought treatment. Histochemical GUS staining of transgenic Arabidopsis lines in which GUS activity was driven with the OfEXLA1 promoter, GUS activity was significantly induced by salt, drought, and exogenous abscisic acid(ABA). In yeast, we found OfEXLA1overexpression significantly improved the population of cells compared with wild-type strains after NaCl and polyethylene glycol(PEG)treatment. Additionally, OfEXLA1 overexpression not only promoted plant growth, but also improved the salt and drought tolerance in Arabidopsis. To gain insight into the role of ABA signaling in the regulation of OfEXLA1 improving abiotic tolerance in sweet osmanthus, four differentially expressed ABA Insensitive 5(ABI5)-like genes(OfABL4, OfABL5, OfABL7, and OfABL8) were identified from transcriptome, and dualluciferase(dual-LUC) and yeast one hybrid(Y1H) assay showed that OfABL4 and OfABL5 might bind to OfEXLA1 promoter to accumulate the OfEXLA1 expression by responding to ABA signaling to improve abiotic tolerance in sweet osmanthus. These results provide the information for understanding the molecular functions of expansin-like A gene and molecular breeding of sweet osmanthus in future.
基金supported by Fujian Provincial Natural Science(2020J01122587)National Natural Science Foundation of China(82103355,82102255,and 82222901)+1 种基金RGC Theme-based Research Scheme(T12-703/19-R)Research grants Council-General Research Fund(14117422 and 14117123)。
文摘Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver malignancy.The interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and progression.Under normal conditions,BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and BAs.The gut microbiota plays a critical role in BA metabolism,and BAs are endogenous signaling molecules that help maintain liver and intestinal homeostasis.Of note,dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis,thereby leading to liver inflammation and fibrosis,and ultimately contributing to HCC development.Therefore,understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying hepatocarcinogenesis.In this review,we comprehensively explore the roles and functions of BA metabolism,with a focus on the interactions between BAs and gut microorganisms in HCC.Additionally,therapeutic strategies targeting BA metabolism and the gut microbiota are discussed,including the use of BA agonists/antagonists,probiotic/prebiotic and dietary interventions,fecal microbiota transplantation,and engineered bacteria.In summary,understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.
基金supported by the General Research Fund of Hong Kong (14105820)。
文摘α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.
基金partially supported by the National Natural Science Foundation of China (Grant No.31772285)the National Key R&D Program Project Funding (Grant No.2018YFD1000607)Foundation for 100 Innovative Talents of Hebei Province(Grant No.SLRC2019031)。
文摘The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties.
基金supported by the Taishan Scholar Program of Shandong Province,China (tsqn202211162)the National Natural Science Foundation of China (22102079)the Natural Science Foundation of Shandong Province of China (ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金financially supported by the National Natural Science Foundation of China(Nos.21174122 and 51390481)
文摘Polypeptides and polypeptoids were widely used as biomedical materials because of their good biocompatibility. In this work we reported a series of pH-responsive copolypeptides and polypeptide-polypeptoid block copolymers, i.e. random copolymers of L-glutamic acid (Glu) with L-leucine (Leu) [poly(Glu-r-Leu)s], as well as their block copolymers with polysarcosine (polySar). Well-defined poly(Glu-r-Leu)s with predictable compositions and molecular weights were synthesized by ring opening polymerization of corresponding N-carboxyanhydride monomers. We investigated the relationship between hydrophilicity-hydrophobicity transition and copolymer composition. With increasing Leu fraction, both the pH value of cloud point and the micellar size increased. Poly(Glu-r-Leu) with 60% Leu exhibited a cloud point at the pH of 5.0 to 6.0 the same as that in endosome and lysosome. Poly(Glu-r-Leu)-b-polySars assembled in phosphate buffer and performed pH-responsive morphology change from orbicular micelles at high pH to worm-like micelles at low pH. They were potential pH-responsive carriers for drug and gene delivery to enhance cargo release in cellules.
基金supported by National Natural Science Foundation of China(Nos.31871861 and 31501548)The Apicultural Industry Technology System(NCYTI-43-KXJ17)The Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2015-IAR)。
文摘The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.
基金supported by fund from the National Natural Science Foundation of China(32172322)。
文摘Elaidic acid(EA)stimulation can lead to endoplasmic reticulum stress(ERS),accompanied by a large release of Ca^(2+),and ultimately the activation of NLRP3 inflammasome in Kupffer cells(KCs).Mitochondrial instability or dysfunction may be the key stimulating factors to activate NLRP3 inflammasome,and sustained Ca^(2+)transfer can result in mitochondrial dysfunction.We focused on KCs to explore the damage to mitochondria by EA.After EA stimulation,cells produced an oxidative stress(OS)response with a significant increase in ROS release.Immunoprecipitation experiments and the addition of inhibitors revealed that the increase in the level of intracellular Ca^(2+)led to Ca^(2+)accumulation in the mitochondrial matrix via mitochondria-associated membranes(MAMs).This was accompanied by a significant release of m ROS,loss of MMP and ATP,and a significant increase in mitochondrial permeability transition pore opening,ultimately leading to mitochondrial instability.These findings confirmed the mechanism that EA induced mitochondrial Ca^(2+)imbalance in KCs via MAM,ultimately leading to mitochondrial dysfunction.Meanwhile,EA induced OS and the decrease of MMP and ATP in rat liver,and significant lesions were found in liver mitochondria.Swelling of the inner mitochondrial cristae and mitochondrial vacuolization occurred,with a marked increase in lipid droplets.
基金supported by National Natural Science Foundation of China(31972021)R&D Projects in Key Areas of Guangdong Province(2019B020212003)+4 种基金the Science and Technology Program of Guangzhou,China(202206010177)Guangdong key research and development program(2021B0202060001)Foshan and agricultural academy cooperation projectGuangdong Modern Agriculture project(2022KJ117)Aquatic Products Center Project of GAAS。
文摘Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1605000)National Natural Science Foundation of China(Grant No.31871806)the Beijing Livestock Industry Innovation Team(BAIC05-2023)。
文摘Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.