Deposition of β-amyloid protein(Aβ) is the main hallmark of Alzheimer's disease(AD), and it has been well recognized that Cu^(2+)-mediated Aβ aggregation plays a crucial role in AD pathological processes.Cu^(2+...Deposition of β-amyloid protein(Aβ) is the main hallmark of Alzheimer's disease(AD), and it has been well recognized that Cu^(2+)-mediated Aβ aggregation plays a crucial role in AD pathological processes.Cu^(2+)binding to Aβ can promote the production of reactive oxygen species(ROS) through Fenton-like reactions and produce more toxic Aβ-Cu^(2+)species under Cu^(2+)stimulation. Thus, the development of nanomaterials that can inhibit Cu^(2+)-mediated Aβ aggregation and degrade Aβ-Cu^(2+)complexes is considered an effective strategy for the prevention and treatment of AD. In this study, polydopamine nanoparticles(PDA NPs) were prepared and the results reveal that PDA NPs potently inhibit Cu^(2+)-mediated Aβaggregation and effectively reduce the formation of Aβ-Cu^(2+)complexes. In vitro experiments show that PDA NPs efficiently eliminate ROS generation catalyzed by Cu^(2+)or Aβ-Cu^(2+)complexes, thus rescuing cultured cells by reducing intracellular ROS levels. More importantly, PDA NPs can depolymerize Aβ-Cu^(2+)complexes, and the degradation of Aβ-Cu^(2+)complexes is promoted by near-infrared light irradiation due to their high photothermal conversion ability. In vivo studies reveal that PDA NPs significantly reduce the deposition of Aβ plaques in the presence of Cu^(2+)and extend the lifespan of AD nematodes from 11 to 14 d. Thus, the PDA NPs developed herein are multifunctional against Cu^(2+)-mediated Aβ aggregation for the potential prevention and treatment of AD.展开更多
Oriented immobilization of enzymes helps to maintain their native structure and proper orientation for high-performance engineering to meet extensive biocatalysis demands.However,the supporting materials used for orie...Oriented immobilization of enzymes helps to maintain their native structure and proper orientation for high-performance engineering to meet extensive biocatalysis demands.However,the supporting materials used for orientated immobilization are usually costly or complicated in preparation,affecting their practical applications.In this work,a facile purification and immobilization method was proposed for enzyme immobilization based on organic-inorganic hybrid calcium phosphate nanocrystal(Ca Ps)induced by Cu^(2+) modified bovine serum albumin(BSA-Cu).Then,the as-prepared hybrid calcium phosphate nanosheet,BSA-Cu@Ca Ps,was utilized for one-pot purification and immobilization of His-tagged organophosphorus hydrolase(OPH)by metal-affinity binding to the incorporated BSA.BSA-Cu@Ca PsOPH exhibited enhanced p H stability and thermal stability compared to the free enzyme.Moreover,BSA-Cu@Ca Ps-OPH could retain more than 75%and 56%of initial activity after reuse 5 and 10 times,respectively.The results demonstrated that this facile strategy was promising for the effective biodegradation of organophosphorus pesticides with the immobilized enzyme.展开更多
Objective:Intratumoral administration of adenoviral vector encoding herpes simplex virus(HSV)thymidine kinase(TK)gene(Ad-TK)followed by systemic ganciclovir(GCV)is an effective approach in treating experimental hepato...Objective:Intratumoral administration of adenoviral vector encoding herpes simplex virus(HSV)thymidine kinase(TK)gene(Ad-TK)followed by systemic ganciclovir(GCV)is an effective approach in treating experimental hepatocellular carcinoma(HCC).However,hepatotoxicity due to unwanted vector spread and suicide gene expression limited the application of this therapy.miR-122 is an abundant,liver-specific microRNA whose expression is decreased in human primary HCC and HCC-derived cell lines.These different expression profiles provide an opportunity to induce tumor-specific gene expression by miR-122 regulation.Methods:By inserting miR-122 target sequences(miR-122T)in the 3'untranslated region(UTR)of TK gene,we constructed adenovirus(Ad)vectors expressing miR-122-regulated TK(Ad-TK-122T)and report genes.After intratumoral administration of Ad vectors into an orthotopic miR-122-deficient HCC mouse model,we observed the miR-122-regulated transgene expression and assessed the antitumor activity and safety of Ad-TK-122T.Results:Insertion of miR-122T specifically down-regulated transgene expression in vitro and selectively protected the miR-122-positive cells from killing by TK/GCV treatment.Insertion of miR-122T led to significant reduction of tansgene expression in the liver without inhibition of its expression in tumors in vivo,resulting in an 11-fold improvement of tumor-specific transgene expression.Intratumoral injection of Ad vectors mediated TK/GCV system led to a vector dosage-dependent regression of tumor.The insertion of miR-122T does not influence the antitumor effects of suicide gene therapy.Whereas mice administrated with Ad-TK showed severe lethal hepatotoxicity at the effective therapeutic dose,no liver damage was found in Ad-TK-122T group.Conclusions:miR-122-regulated TK expression achieved effective anti-tumor effects and increased the safety of intratumoral delivery of adenovirus-mediated TK/GCV gene therapy for miR-122-deficient HCC.展开更多
Our previous work proved that the thermal stability of Candida rugosa lipase(CRL)immobilized on zwitterionic polymer(poly(carboxybetaine methacrylate))grafted silica nanoparticle(SNP)was much higher than that on poly(...Our previous work proved that the thermal stability of Candida rugosa lipase(CRL)immobilized on zwitterionic polymer(poly(carboxybetaine methacrylate))grafted silica nanoparticle(SNP)was much higher than that on poly(glycidyl methecrylate)(pGMA)grafted SNP,while the latter showed significantly increased activity.Inspired by the research,we have herein proposed to synthesize copolymers of zwitterionic sulfobetaine methacrylate(SBMA)and GMA for CRL immobilization.The copolymers were grafted onto SNP surface at three GMA/SBMA(G/S)molar ratios(G100/S0,G50/S50,G10/S90),followed by the covalent coupling of CRL to the surface copolymers.The immobilized CRLs on the corresponding supports were denoted as p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-CRL.The enzyme loading increased with the increase of GMA content in the copolymer,while the activity varied with the grafted copolymer composition.Kinetic study proved the improvement of enzyme-substrate affinity after immobilization.In comparison to p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-CRL presented remarkably enhanced thermal stability and pH tolerance,and p(G10-S90)-CRL showed the highest stability.These results suggest that the copolymer design is promising for development as a versatile platform for enzyme immobilization.展开更多
In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption...In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.展开更多
The modulation of protein aggregation is involved not only in biochemical engineering processes,but also in in vivo biological events such as Alzheimer's disease(AD)that features amyloid-βprotein(Aβ)deposits.Ins...The modulation of protein aggregation is involved not only in biochemical engineering processes,but also in in vivo biological events such as Alzheimer's disease(AD)that features amyloid-βprotein(Aβ)deposits.Inspired by the different pharmacological efficacy of enantiomers,taking heptapeptide LVFFARK(LK7)as an example,herein the chiral influence of peptide inhibitors on Aβfibrillogenesis and cytotoxicity was investigated by extensive biophysical and biological analyses.It was intriguing to find that although both LLK7 and D-LK7 could inhibit Aβaggregation in a concentration-dependent manner,it was the D-enan-tiomer that exhibited chirality preference and selectivity for modulation of Aβself-assembly.As com-pared with L-LK7 at the same conditions,D-LK7 showed significantly enhanced potency on suppressing cross-βsheet formation,fibrillar Aβaggregates deposition,Aβconformational transition,and Aβ-triggered neurotoxicity on cultured cells.For instance,L.LK7 and D-LK7 rescued cells by increasing cell via-bility from 60%to 62%and 84%at 100μmolL^(-1),respectively.The chiral discrimination of L-LK7 and D-LK7 was further validated by the different elimination efficiency on amyloid accumulation in AD model nematodes.It is considered that the higher binding affinity of D-LK7 to Aβmonomers than that of L LK7 resulted in the stronger inhibition effect.This work provided new insights into understanding chiral-ity in the interaction with Aβand the consequent inhibitory effect,and would contribute to the design of anti-amyloid agents.展开更多
Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L^(-1)(Alg-FF-240).Moreover,the salt-toleran...Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L^(-1)(Alg-FF-240).Moreover,the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy.Inspired by the enhanced adsorption performance of lysozyme,we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees.The adsorption ca pacity of γ-globulin decreased with increa sing alginate-grafting density(IC) from 160 to 230 mmol·L^(-1) at 0 mmol·L^(-1) NaCl because of the steric hindrance caused by the alginate-grafting layer.Effects of ionic strength(IS) indicated that the adsorption capacities of the resins with the IC value of 230-370 mmol·L^(-1) were much higher than CM Sepharose FF at 50-100 mmol·L^(-1) NaCl,and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF.This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior,which would be helpful in the design of Alggrafted resins and the selection of proper IS condition for protein purification.展开更多
Purpose:To construct a novel AAV-mediated gene delivery of the human ND4 complex I subunit and to detect its expression level in mitochondria for potential application in gene therapy for Leber's hereditary optic ...Purpose:To construct a novel AAV-mediated gene delivery of the human ND4 complex I subunit and to detect its expression level in mitochondria for potential application in gene therapy for Leber's hereditary optic neuropathy (LHON). Methods:A novel type of normal human ND4 gene was synthesized artificially to contain a mitochondrial targeting sequence that induces the translocation of this gene into mitochondria.This recombinant adeno-associated virus type 2/serotype 2 (rAAV2/2)-mediated NADH dehydrogenase subunit 4 (ND4) gene was constructed, purified, condensed, and amplified by PCR.The physical titer of rAAV2/2-ND4 was determined by slot-blot hybridization using a digoxigeninlabeled H1 probe.Expression of ND4 in mitochondria was evaluated by immunofluorescence. Results: The constructed rAAV2/2-ND4 specifically amplified the target gene band of ND4 and the physical titer of ND4 gene was 1.0×1011 vg/mL,confirming that the recombinant adenovirus vector contained the ND4 target gene. Expression of the ND4 gene was detected in mitochondria by immunofluorescence. Conclusion:A new type of rAAV2/2-ND4 was successfully constructed and may have potential in gene therapy for LHON.展开更多
Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering.Alzheimer’s disease(AD)is a protein-misfolding disease,and the interactions between ...Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering.Alzheimer’s disease(AD)is a protein-misfolding disease,and the interactions between 40-amino-acid-residueβ-amyloid peptide(Aβ_(40)) and its N-terminal truncated peptide Aβ_(11-40) demonstrate that Aβ_(11-40) may play an important role in the pathological process of AD.However,the effect of inhibitors on Aβ_(11-40) aggregation and on the cross-amyloid aggregation(coassembly)between Aβ_(40) and Aβ_(11-40) has never been studied.Herein,coaggregation and seeding interactions between Aβ_(40) and Aβ_(11-40) as well as the effect of epigallocatechin gallate(EGCG),a small molecule inhibitor,on the cross-amyloid aggregation have been investigated by extensive analyses.It is found that Aβ_(11-40) participates in the aggregation of Aβ_(40) and leads to the formation of coaggregates that contain lessβ-sheet structures than pure Aβ_(40) aggregates.The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ_(40)/Aβ_(11-40) ratio.EGCG accelerates the nucleation of Aβ_(40) but retards that of Aβ_(11-40) by affecting their elongation and secondary nucleation processes in solution and on solid surfaces.Meanwhile,EGCG makes the conformations of the seeding-induced Aβaggregates more compact,especially for the homologous seedings.Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβisoforms by EGCG.The findings of this research have provided new insights into Aβaggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins.展开更多
Enzyme-polymer conjugates are complex molecules with great practical significance.This work was designed to develop a novel enzyme-polymer conjugate by covalently coupling a zwitterionic polymer with side dimethyl cha...Enzyme-polymer conjugates are complex molecules with great practical significance.This work was designed to develop a novel enzyme-polymer conjugate by covalently coupling a zwitterionic polymer with side dimethyl chains(pID)to Candida rugosa lipase(CRL)via the reaction between the anhydrides of polymer chains with the amino groups of the enzyme.The resulting two CRL-pID conjugates with different pID grafting densities were investigated in term of the catalytic activity,stability and structural changes.In comparison with native CRL,both the CRL conjugates displayed 2.2 times higher activity than the native enzyme,and showed an increase in the maximum reaction rate(V_(max))and a decrease in the Michaelis constant(K_(m)),thus resulting in about three-fold increases in the catalytic efficiency(k_(cat)/K_(m)).These are mainly attributed to the activation of lipase by the hydrophobic alky side chains.Moreover,the thermostability and pH tolerance of the lipase conjugates were significantly enhanced due to the stabilizing effect of the zwitterion moieties.For instance,a five-fold increase of the enzyme half-life at 50℃ for the high-pID conjugated CRL was observed.Spectroscopic studies reveal that the pID conjugation protected the enzyme in the changes in its microenvironment and conformation,well correlating with enhanced activity and stability of lipase conjugates.The findings indicate that enzyme conjugation to the zwitterionic polymer is promising for improving enzyme performance and deserves further development.展开更多
Dielectric capacitors with a fast charging/discharging rate,high power density,and long-term stability are essential components in modern electrical devices.However,miniaturizing and integrating capacitors face a pers...Dielectric capacitors with a fast charging/discharging rate,high power density,and long-term stability are essential components in modern electrical devices.However,miniaturizing and integrating capacitors face a persistent challenge in improving their energy density(W_(rec))to satisfy the specifications of advanced electronic systems and applications.In this work,leveraging phase-field simulations,we judiciously designed a novel lead-free relaxor ferroelectric material for enhanced energy storage performance,featuring flexible distributed weakly polar endotaxial nanostructures(ENs)embedded within a strongly polar fluctuation matrix.The matrix contributes to substantially enhanced polarization under an external electric field,and the randomly dispersed ENs effectively optimize breakdown phase proportion and provide a strong restoring force,which are advantageous in bolstering breakdown strength and minimizing hysteresis.Remarkably,this relaxor ferroelectric system incorporating ENs achieves an exceptionally high W_(rec)value of 10.3 J/cm^(3),accompanied by a large energy storage efficiency(η)of 85.4%.This work introduces a promising avenue for designing new relaxor materials capable of capacitive energy storage with exceptional performance characteristics.展开更多
High-performance lead-free dielectric ceramics with simultaneously high energy storage density and power density are in high demanded for pulse power systems.To realize excellent energy-storage characteristics,a strat...High-performance lead-free dielectric ceramics with simultaneously high energy storage density and power density are in high demanded for pulse power systems.To realize excellent energy-storage characteristics,a strategy to enhance antiferroelectricity and construct a local random field simultaneously was proposed in this study.Based on the above strategy,a series of(1-x)NaNbO_(3)-xBi(Ni_(1/2)Sn_(1/2))O3[xBNS,x=0.05,0.10,0.15,0.20,and 0.22]solid solutions were designed and fabricated.An ultrahigh energy storage density(Utotal)of 7.35 J/cm^(3),and recoverable energy density(Urec)of 5.00 J/cm^(3) were achieved in the 0.10BNS ceramics.In addition,an adequate stability of energy storage properties at a range of temperatures(20e140℃),frequencies(1e100 Hz),and fatigue test durations(1e1-10^(4) cycles)were realized in 0.10BNS ceramics.0.10BNS ceramics displayed a high current density of 1005 A/cm2,an ultrahigh power density of 100.5 MW/cm^(3,)and an ultrashort discharge time of 46.5 ns?This remarkable performance not only justified our strategy but also confirmed 0.10BNS ceramics as a promising candidate for energy storage.展开更多
Recent studies have shown that PM_(2.5) may activate the hypothalamus-pituitary-adrenal(HPA)axis by inducing hormonal changes,potentially explaining the increase in neurological and cardiovascular risks.In addition,an...Recent studies have shown that PM_(2.5) may activate the hypothalamus-pituitary-adrenal(HPA)axis by inducing hormonal changes,potentially explaining the increase in neurological and cardiovascular risks.In addition,an association between PM_(2.5) and gut microbiota and metabolites was established.The above evidence represents crucial parts of the gut-brain axis(GBA).In view of this evidence.展开更多
Pregnancy is a unique immunologic and microbial condition that requires an adequate level of awareness to provide a fast and protective response against pathogens as well as to maintain a state of tolerance to paterna...Pregnancy is a unique immunologic and microbial condition that requires an adequate level of awareness to provide a fast and protective response against pathogens as well as to maintain a state of tolerance to paternal antigens.Dysregulation of inflammatory pathways in the placenta triggered by pathogens is one of the main factors responsible for pregnancy complications.Type I IFNs are key molecules modulating immune responses at the level of the placenta and are crucial for protection of the pregnancy via their antiviral and immune modulatory properties.In this study,we elucidate the mechanisms controlling the basal expression of IFNβand its negative feedback.Using in vitro and in vivo animal models,we found that TLR signaling maintains basal IFNβlevels through the TLR4-MyD88-independent TBK/IRF3 signaling pathway.We describe the role of the TAM receptor Axl in the regulation of IFNβfunction in human and mouse trophoblast cells.The absence of TAM receptors in vivo is associated with fetal demise due to dysregulation of IFNβexpression and its pro-apoptotic downstream effectors.Collectively,our data describe a feedback signaling pathway controlling the expression and function of IFNβin the trophoblast that is essential for an effective response during viral and microbial infections.展开更多
Anion-exchange superporous cellulose(DEAE-SC)and microporous cellulose(DEAE-MC)adsorbents were packed in an electrochromatographic column,and the effect of external electric field(eEF)on the dynamic adsorption was inv...Anion-exchange superporous cellulose(DEAE-SC)and microporous cellulose(DEAE-MC)adsorbents were packed in an electrochromatographic column,and the effect of external electric field(eEF)on the dynamic adsorption was investigated.The column was designed to provide longitudinal,transverse or 2-dimensional(2D)eEF.It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents.The dynamic binding capacity(DBC)in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF.The effect of flow velocity on the DBC of the two adsorbents was also demonstrated.It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate,whereas the DEAE-SC column showed higher DBC and adsorption efficiency(AE)than the DEAE-MC column.With increasing flow rate,the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF.For example,a DBC of 21.4mg/mL and an AE of 57.7%were obtained even at a flow rate as high as 900cm/h.The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.展开更多
Ceramic dielectric capacitors have a broad scope of application in pulsed power supply devices.Relaxor behavior has manifested decent energy storage capabilities in dielectric materials due to its fast polarization re...Ceramic dielectric capacitors have a broad scope of application in pulsed power supply devices.Relaxor behavior has manifested decent energy storage capabilities in dielectric materials due to its fast polarization response.In addition,an ultrahigh energy storage density can also be achieved in NaNbO_(3)(NN)-based ceramics by combining antiferroelectric and relaxor characteristics.Most of the existing reports about lead-free dielectric ceramics,nevertheless,still lack the relevant research about domain evolution and relaxor behavior.Therefore,a novel lead-free solid solution,(1-x)NaNbO_(3)-xBi(Zn_(0.5)Sn_(0.5))O_(3)(abbreviated as xBZS,x=0.05,0.10,0.15,and 0.20)was designed to analyze the domain evolution and relaxor behavior.Domain evolutions in xBZS ceramics confirmed the contribution of the relaxor behavior to their decent energy storage characteristics caused by the fast polarization rotation according to the low energy barrier of polar nanoregions(PNRs).Consequently,a high energy storage density of 3.14 J/cm^(3)and energy efficiency of 83.30%are simultaneously available with 0.10 BZS ceramics,together with stable energy storage properties over a large temperature range(20-100℃)and a wide frequency range(1-200 Hz).Additionally,for practical applications,the 0.10 BZS ceramics display a high discharge energy storage density(W_(dis)≈1.05 J/cm^(3)),fast discharge rate(t_(0.9)≈60.60 ns),and high hardness(H≈5.49 GPa).This study offers significant insights on the mechanisms of high performance lead-free ceramic energy storage materials.展开更多
基金funded by the National Natural Science Foundation of China (21978207 and 21621004)the Natural Science Foundation of Tianjin from Tianjin Municipal Science and Technology Commission (19JCZDJC36800)。
文摘Deposition of β-amyloid protein(Aβ) is the main hallmark of Alzheimer's disease(AD), and it has been well recognized that Cu^(2+)-mediated Aβ aggregation plays a crucial role in AD pathological processes.Cu^(2+)binding to Aβ can promote the production of reactive oxygen species(ROS) through Fenton-like reactions and produce more toxic Aβ-Cu^(2+)species under Cu^(2+)stimulation. Thus, the development of nanomaterials that can inhibit Cu^(2+)-mediated Aβ aggregation and degrade Aβ-Cu^(2+)complexes is considered an effective strategy for the prevention and treatment of AD. In this study, polydopamine nanoparticles(PDA NPs) were prepared and the results reveal that PDA NPs potently inhibit Cu^(2+)-mediated Aβaggregation and effectively reduce the formation of Aβ-Cu^(2+)complexes. In vitro experiments show that PDA NPs efficiently eliminate ROS generation catalyzed by Cu^(2+)or Aβ-Cu^(2+)complexes, thus rescuing cultured cells by reducing intracellular ROS levels. More importantly, PDA NPs can depolymerize Aβ-Cu^(2+)complexes, and the degradation of Aβ-Cu^(2+)complexes is promoted by near-infrared light irradiation due to their high photothermal conversion ability. In vivo studies reveal that PDA NPs significantly reduce the deposition of Aβ plaques in the presence of Cu^(2+)and extend the lifespan of AD nematodes from 11 to 14 d. Thus, the PDA NPs developed herein are multifunctional against Cu^(2+)-mediated Aβ aggregation for the potential prevention and treatment of AD.
基金supported by the National Key Research and Development Program of China(2021YFC2102801)the National Natural Science Foundation of China(21621004)。
文摘Oriented immobilization of enzymes helps to maintain their native structure and proper orientation for high-performance engineering to meet extensive biocatalysis demands.However,the supporting materials used for orientated immobilization are usually costly or complicated in preparation,affecting their practical applications.In this work,a facile purification and immobilization method was proposed for enzyme immobilization based on organic-inorganic hybrid calcium phosphate nanocrystal(Ca Ps)induced by Cu^(2+) modified bovine serum albumin(BSA-Cu).Then,the as-prepared hybrid calcium phosphate nanosheet,BSA-Cu@Ca Ps,was utilized for one-pot purification and immobilization of His-tagged organophosphorus hydrolase(OPH)by metal-affinity binding to the incorporated BSA.BSA-Cu@Ca PsOPH exhibited enhanced p H stability and thermal stability compared to the free enzyme.Moreover,BSA-Cu@Ca Ps-OPH could retain more than 75%and 56%of initial activity after reuse 5 and 10 times,respectively.The results demonstrated that this facile strategy was promising for the effective biodegradation of organophosphorus pesticides with the immobilized enzyme.
基金funded by the National 863 Program (No.2012AA020810)Beijing city strategic emerging industry (No.Z121102002912040)
文摘Objective:Intratumoral administration of adenoviral vector encoding herpes simplex virus(HSV)thymidine kinase(TK)gene(Ad-TK)followed by systemic ganciclovir(GCV)is an effective approach in treating experimental hepatocellular carcinoma(HCC).However,hepatotoxicity due to unwanted vector spread and suicide gene expression limited the application of this therapy.miR-122 is an abundant,liver-specific microRNA whose expression is decreased in human primary HCC and HCC-derived cell lines.These different expression profiles provide an opportunity to induce tumor-specific gene expression by miR-122 regulation.Methods:By inserting miR-122 target sequences(miR-122T)in the 3'untranslated region(UTR)of TK gene,we constructed adenovirus(Ad)vectors expressing miR-122-regulated TK(Ad-TK-122T)and report genes.After intratumoral administration of Ad vectors into an orthotopic miR-122-deficient HCC mouse model,we observed the miR-122-regulated transgene expression and assessed the antitumor activity and safety of Ad-TK-122T.Results:Insertion of miR-122T specifically down-regulated transgene expression in vitro and selectively protected the miR-122-positive cells from killing by TK/GCV treatment.Insertion of miR-122T led to significant reduction of tansgene expression in the liver without inhibition of its expression in tumors in vivo,resulting in an 11-fold improvement of tumor-specific transgene expression.Intratumoral injection of Ad vectors mediated TK/GCV system led to a vector dosage-dependent regression of tumor.The insertion of miR-122T does not influence the antitumor effects of suicide gene therapy.Whereas mice administrated with Ad-TK showed severe lethal hepatotoxicity at the effective therapeutic dose,no liver damage was found in Ad-TK-122T group.Conclusions:miR-122-regulated TK expression achieved effective anti-tumor effects and increased the safety of intratumoral delivery of adenovirus-mediated TK/GCV gene therapy for miR-122-deficient HCC.
基金funded by the National Natural Science Foundation of China(21621004)the National Key Research and Development Program of China(2018YFA0900702)。
文摘Our previous work proved that the thermal stability of Candida rugosa lipase(CRL)immobilized on zwitterionic polymer(poly(carboxybetaine methacrylate))grafted silica nanoparticle(SNP)was much higher than that on poly(glycidyl methecrylate)(pGMA)grafted SNP,while the latter showed significantly increased activity.Inspired by the research,we have herein proposed to synthesize copolymers of zwitterionic sulfobetaine methacrylate(SBMA)and GMA for CRL immobilization.The copolymers were grafted onto SNP surface at three GMA/SBMA(G/S)molar ratios(G100/S0,G50/S50,G10/S90),followed by the covalent coupling of CRL to the surface copolymers.The immobilized CRLs on the corresponding supports were denoted as p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-CRL.The enzyme loading increased with the increase of GMA content in the copolymer,while the activity varied with the grafted copolymer composition.Kinetic study proved the improvement of enzyme-substrate affinity after immobilization.In comparison to p(G100-S0)-CRL,p(G50-S50)-CRL and p(G10-S90)-CRL presented remarkably enhanced thermal stability and pH tolerance,and p(G10-S90)-CRL showed the highest stability.These results suggest that the copolymer design is promising for development as a versatile platform for enzyme immobilization.
基金supported by the National Natural Science Foundation of China (Nos. 21878222 and 21621004).
文摘In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.
基金supported by the National Natural Science Foundation of China(Nos.21621004 and 21978207)the Natural Science Foundation of Tianjin from Tianjin Municipal Science and Technology Commission(No.19JCZDJC36800).
文摘The modulation of protein aggregation is involved not only in biochemical engineering processes,but also in in vivo biological events such as Alzheimer's disease(AD)that features amyloid-βprotein(Aβ)deposits.Inspired by the different pharmacological efficacy of enantiomers,taking heptapeptide LVFFARK(LK7)as an example,herein the chiral influence of peptide inhibitors on Aβfibrillogenesis and cytotoxicity was investigated by extensive biophysical and biological analyses.It was intriguing to find that although both LLK7 and D-LK7 could inhibit Aβaggregation in a concentration-dependent manner,it was the D-enan-tiomer that exhibited chirality preference and selectivity for modulation of Aβself-assembly.As com-pared with L-LK7 at the same conditions,D-LK7 showed significantly enhanced potency on suppressing cross-βsheet formation,fibrillar Aβaggregates deposition,Aβconformational transition,and Aβ-triggered neurotoxicity on cultured cells.For instance,L.LK7 and D-LK7 rescued cells by increasing cell via-bility from 60%to 62%and 84%at 100μmolL^(-1),respectively.The chiral discrimination of L-LK7 and D-LK7 was further validated by the different elimination efficiency on amyloid accumulation in AD model nematodes.It is considered that the higher binding affinity of D-LK7 to Aβmonomers than that of L LK7 resulted in the stronger inhibition effect.This work provided new insights into understanding chiral-ity in the interaction with Aβand the consequent inhibitory effect,and would contribute to the design of anti-amyloid agents.
基金supported by the National Natural Science Foundation of China (Nos. 21878222 and 21621004)。
文摘Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L^(-1)(Alg-FF-240).Moreover,the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy.Inspired by the enhanced adsorption performance of lysozyme,we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees.The adsorption ca pacity of γ-globulin decreased with increa sing alginate-grafting density(IC) from 160 to 230 mmol·L^(-1) at 0 mmol·L^(-1) NaCl because of the steric hindrance caused by the alginate-grafting layer.Effects of ionic strength(IS) indicated that the adsorption capacities of the resins with the IC value of 230-370 mmol·L^(-1) were much higher than CM Sepharose FF at 50-100 mmol·L^(-1) NaCl,and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF.This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior,which would be helpful in the design of Alggrafted resins and the selection of proper IS condition for protein purification.
基金financially supported by National Natural Science Fund.Molecule mechanism of the resistance of HRD1 against diabetic retinopathy (NO.81271015)Molecule mechanism of the resistance of P58IPK against diabetic retinopathy (NO.30872823)
文摘Purpose:To construct a novel AAV-mediated gene delivery of the human ND4 complex I subunit and to detect its expression level in mitochondria for potential application in gene therapy for Leber's hereditary optic neuropathy (LHON). Methods:A novel type of normal human ND4 gene was synthesized artificially to contain a mitochondrial targeting sequence that induces the translocation of this gene into mitochondria.This recombinant adeno-associated virus type 2/serotype 2 (rAAV2/2)-mediated NADH dehydrogenase subunit 4 (ND4) gene was constructed, purified, condensed, and amplified by PCR.The physical titer of rAAV2/2-ND4 was determined by slot-blot hybridization using a digoxigeninlabeled H1 probe.Expression of ND4 in mitochondria was evaluated by immunofluorescence. Results: The constructed rAAV2/2-ND4 specifically amplified the target gene band of ND4 and the physical titer of ND4 gene was 1.0×1011 vg/mL,confirming that the recombinant adenovirus vector contained the ND4 target gene. Expression of the ND4 gene was detected in mitochondria by immunofluorescence. Conclusion:A new type of rAAV2/2-ND4 was successfully constructed and may have potential in gene therapy for LHON.
基金funded by the National Natural Science Foundation of China (21978207 and 21621004)the Natural Science Foundation of Tianjin from Tianjin Municipal Science and Technology Commission (19JCZDJC36800)。
文摘Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering.Alzheimer’s disease(AD)is a protein-misfolding disease,and the interactions between 40-amino-acid-residueβ-amyloid peptide(Aβ_(40)) and its N-terminal truncated peptide Aβ_(11-40) demonstrate that Aβ_(11-40) may play an important role in the pathological process of AD.However,the effect of inhibitors on Aβ_(11-40) aggregation and on the cross-amyloid aggregation(coassembly)between Aβ_(40) and Aβ_(11-40) has never been studied.Herein,coaggregation and seeding interactions between Aβ_(40) and Aβ_(11-40) as well as the effect of epigallocatechin gallate(EGCG),a small molecule inhibitor,on the cross-amyloid aggregation have been investigated by extensive analyses.It is found that Aβ_(11-40) participates in the aggregation of Aβ_(40) and leads to the formation of coaggregates that contain lessβ-sheet structures than pure Aβ_(40) aggregates.The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ_(40)/Aβ_(11-40) ratio.EGCG accelerates the nucleation of Aβ_(40) but retards that of Aβ_(11-40) by affecting their elongation and secondary nucleation processes in solution and on solid surfaces.Meanwhile,EGCG makes the conformations of the seeding-induced Aβaggregates more compact,especially for the homologous seedings.Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβisoforms by EGCG.The findings of this research have provided new insights into Aβaggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins.
基金funded by the National Key Research and Development Program of China(2018YFA0900702)the National Natural Science Foundation of China(21621004).
文摘Enzyme-polymer conjugates are complex molecules with great practical significance.This work was designed to develop a novel enzyme-polymer conjugate by covalently coupling a zwitterionic polymer with side dimethyl chains(pID)to Candida rugosa lipase(CRL)via the reaction between the anhydrides of polymer chains with the amino groups of the enzyme.The resulting two CRL-pID conjugates with different pID grafting densities were investigated in term of the catalytic activity,stability and structural changes.In comparison with native CRL,both the CRL conjugates displayed 2.2 times higher activity than the native enzyme,and showed an increase in the maximum reaction rate(V_(max))and a decrease in the Michaelis constant(K_(m)),thus resulting in about three-fold increases in the catalytic efficiency(k_(cat)/K_(m)).These are mainly attributed to the activation of lipase by the hydrophobic alky side chains.Moreover,the thermostability and pH tolerance of the lipase conjugates were significantly enhanced due to the stabilizing effect of the zwitterion moieties.For instance,a five-fold increase of the enzyme half-life at 50℃ for the high-pID conjugated CRL was observed.Spectroscopic studies reveal that the pID conjugation protected the enzyme in the changes in its microenvironment and conformation,well correlating with enhanced activity and stability of lipase conjugates.The findings indicate that enzyme conjugation to the zwitterionic polymer is promising for improving enzyme performance and deserves further development.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFB3807402National Science Foundation of China,Grant/Award Number:51972215。
文摘Dielectric capacitors with a fast charging/discharging rate,high power density,and long-term stability are essential components in modern electrical devices.However,miniaturizing and integrating capacitors face a persistent challenge in improving their energy density(W_(rec))to satisfy the specifications of advanced electronic systems and applications.In this work,leveraging phase-field simulations,we judiciously designed a novel lead-free relaxor ferroelectric material for enhanced energy storage performance,featuring flexible distributed weakly polar endotaxial nanostructures(ENs)embedded within a strongly polar fluctuation matrix.The matrix contributes to substantially enhanced polarization under an external electric field,and the randomly dispersed ENs effectively optimize breakdown phase proportion and provide a strong restoring force,which are advantageous in bolstering breakdown strength and minimizing hysteresis.Remarkably,this relaxor ferroelectric system incorporating ENs achieves an exceptionally high W_(rec)value of 10.3 J/cm^(3),accompanied by a large energy storage efficiency(η)of 85.4%.This work introduces a promising avenue for designing new relaxor materials capable of capacitive energy storage with exceptional performance characteristics.
基金supported by Natural Science Foundation of China(Nos.12064007,11664008 and 61761015)Natural Science Foundation of Guangxi(Nos.2018GXNSFFA050001,2017GXNSFDA198027and 2017GXNSFFA198011)。
文摘High-performance lead-free dielectric ceramics with simultaneously high energy storage density and power density are in high demanded for pulse power systems.To realize excellent energy-storage characteristics,a strategy to enhance antiferroelectricity and construct a local random field simultaneously was proposed in this study.Based on the above strategy,a series of(1-x)NaNbO_(3)-xBi(Ni_(1/2)Sn_(1/2))O3[xBNS,x=0.05,0.10,0.15,0.20,and 0.22]solid solutions were designed and fabricated.An ultrahigh energy storage density(Utotal)of 7.35 J/cm^(3),and recoverable energy density(Urec)of 5.00 J/cm^(3) were achieved in the 0.10BNS ceramics.In addition,an adequate stability of energy storage properties at a range of temperatures(20e140℃),frequencies(1e100 Hz),and fatigue test durations(1e1-10^(4) cycles)were realized in 0.10BNS ceramics.0.10BNS ceramics displayed a high current density of 1005 A/cm2,an ultrahigh power density of 100.5 MW/cm^(3,)and an ultrashort discharge time of 46.5 ns?This remarkable performance not only justified our strategy but also confirmed 0.10BNS ceramics as a promising candidate for energy storage.
基金This work was supported by the National Natural Science Foundation of China （Nos. 31071171 and 81170532） and the National High Technology Research and Development Program of China （863 Program, No. 2012AA020810）.
基金This study was supported by the National Research Program for Key Issues in Air Pollution Control of China(no.DQGG0401)the National Natural Science Foundation of China(nos.82025030 and 81941023)the National Key Research and Development Program of China(no.2016YFC0206500).
文摘Recent studies have shown that PM_(2.5) may activate the hypothalamus-pituitary-adrenal(HPA)axis by inducing hormonal changes,potentially explaining the increase in neurological and cardiovascular risks.In addition,an association between PM_(2.5) and gut microbiota and metabolites was established.The above evidence represents crucial parts of the gut-brain axis(GBA).In view of this evidence.
基金This study is in part funded by grants P01HD054713,R56AI124356,and 3N01 HD23342 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development,National Institutes of Health,Department of Health and Human Services.
文摘Pregnancy is a unique immunologic and microbial condition that requires an adequate level of awareness to provide a fast and protective response against pathogens as well as to maintain a state of tolerance to paternal antigens.Dysregulation of inflammatory pathways in the placenta triggered by pathogens is one of the main factors responsible for pregnancy complications.Type I IFNs are key molecules modulating immune responses at the level of the placenta and are crucial for protection of the pregnancy via their antiviral and immune modulatory properties.In this study,we elucidate the mechanisms controlling the basal expression of IFNβand its negative feedback.Using in vitro and in vivo animal models,we found that TLR signaling maintains basal IFNβlevels through the TLR4-MyD88-independent TBK/IRF3 signaling pathway.We describe the role of the TAM receptor Axl in the regulation of IFNβfunction in human and mouse trophoblast cells.The absence of TAM receptors in vivo is associated with fetal demise due to dysregulation of IFNβexpression and its pro-apoptotic downstream effectors.Collectively,our data describe a feedback signaling pathway controlling the expression and function of IFNβin the trophoblast that is essential for an effective response during viral and microbial infections.
基金This work was supported by the Natural Science Foundation of Tianjin from Tianjin Municipal Science and Technology Commission(Grant No.08JCZDJC17100).
文摘Anion-exchange superporous cellulose(DEAE-SC)and microporous cellulose(DEAE-MC)adsorbents were packed in an electrochromatographic column,and the effect of external electric field(eEF)on the dynamic adsorption was investigated.The column was designed to provide longitudinal,transverse or 2-dimensional(2D)eEF.It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents.The dynamic binding capacity(DBC)in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF.The effect of flow velocity on the DBC of the two adsorbents was also demonstrated.It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate,whereas the DEAE-SC column showed higher DBC and adsorption efficiency(AE)than the DEAE-MC column.With increasing flow rate,the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF.For example,a DBC of 21.4mg/mL and an AE of 57.7%were obtained even at a flow rate as high as 900cm/h.The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.
基金supported by the National Natural Science Foundation of China(Nos.12064007,11664008,and 61761015)the Natural Science Foundation of Guangxi(Nos.2018GXNSFFA050001,2017GXNSFDA198027,and 2017GXNSFFA198011)High Level Innovation Team and Outstanding Scholar Program of Guangxi Institutes。
文摘Ceramic dielectric capacitors have a broad scope of application in pulsed power supply devices.Relaxor behavior has manifested decent energy storage capabilities in dielectric materials due to its fast polarization response.In addition,an ultrahigh energy storage density can also be achieved in NaNbO_(3)(NN)-based ceramics by combining antiferroelectric and relaxor characteristics.Most of the existing reports about lead-free dielectric ceramics,nevertheless,still lack the relevant research about domain evolution and relaxor behavior.Therefore,a novel lead-free solid solution,(1-x)NaNbO_(3)-xBi(Zn_(0.5)Sn_(0.5))O_(3)(abbreviated as xBZS,x=0.05,0.10,0.15,and 0.20)was designed to analyze the domain evolution and relaxor behavior.Domain evolutions in xBZS ceramics confirmed the contribution of the relaxor behavior to their decent energy storage characteristics caused by the fast polarization rotation according to the low energy barrier of polar nanoregions(PNRs).Consequently,a high energy storage density of 3.14 J/cm^(3)and energy efficiency of 83.30%are simultaneously available with 0.10 BZS ceramics,together with stable energy storage properties over a large temperature range(20-100℃)and a wide frequency range(1-200 Hz).Additionally,for practical applications,the 0.10 BZS ceramics display a high discharge energy storage density(W_(dis)≈1.05 J/cm^(3)),fast discharge rate(t_(0.9)≈60.60 ns),and high hardness(H≈5.49 GPa).This study offers significant insights on the mechanisms of high performance lead-free ceramic energy storage materials.
