Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating ...Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating excitationcontraction(E-C)coupling.Mutations in JPH2 have been associated with hypertrophic cardiomyopathy(HCM),but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus(MORN)repeat motifs remain incompletely understood.This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis.Methods A recombinant N-terminal fragment of mouse JPH2(residues 1-440),encompassing the MORN repeats and an adjacent helical region,was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain.Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features.Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells.In addition,site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations,including R347C,was used to evaluate their effects on membrane interaction and subcellular localization.Results The crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6Å,revealing a compact,elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration,forming a continuous hydrophobic core stabilized by alternating aromatic residues.A C-terminalα-helix further reinforced structural integrity.Conservation analysis identified the inner groove of the MORN array as a highly conserved surface,suggesting its role as a protein-binding interface.A flexible linker segment enriched in positively charged residues,located adjacent to the MORN motifs,was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes.Functional assays demonstrated that mutation of these basic residues impaired membrane association,while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays,despite preserving the overall MORN-Helix fold in structural modeling.Conclusion This study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2,highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions.The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis.These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.展开更多
Chloride ions(Cl^(-))have been shown to impact the long-lasting nature of reinforced concrete.However,Cl^(-)that are already bound inside the concrete will not lead to the deterioration of the concrete’s characterist...Chloride ions(Cl^(-))have been shown to impact the long-lasting nature of reinforced concrete.However,Cl^(-)that are already bound inside the concrete will not lead to the deterioration of the concrete’s characteristics.The composition of the cement-based material,including the type of cement and auxiliary materials,greatly influences the ability of the material to bind Cl^(-),and varied components result in varying binding beha-vior of the Cl^(-).Simultaneously,the Cl^(-)binding process in concrete is influenced by both the internal and exterior surroundings,as well as the curing practices.These factors impact the hydration process of the cement and the internal pore structure of the concrete.Currently,mathematical theories and molecular dynamics simulations have increasingly been employed as the prevalent methods for examining the binding behaviors of Cl^(-)in concrete.These techniques are extensively utilized for predicting the lifespan and conducting microscopic studies of reinforced concrete in Cl^(-)settings.This work proposes recommendations for future research based on a summary of experimental and simulation investigations on Cl^(-)binding.Which will offer theoretical guidance for studying the binding of Cl^(-)in cement-based materials.展开更多
Aptamers are a type of single-chain oligonucleotide that can combine with a specific target.Due to their simple preparation,easy modification,stable structure and reusability,aptamers have been widely applied as bioch...Aptamers are a type of single-chain oligonucleotide that can combine with a specific target.Due to their simple preparation,easy modification,stable structure and reusability,aptamers have been widely applied as biochemical sensors for medicine,food safety and environmental monitoring.However,there is little research on aptamer-target binding mechanisms,which limits their application and development.Computational simulation has gained much attention for revealing aptamer-target binding mechanisms at the atomic level.This work summarizes the main simulation methods used in the mechanistic analysis of aptamer-target complexes,the characteristics of binding between aptamers and different targets(metal ions,small organic molecules,biomacromolecules,cells,bacteria and viruses),the types of aptamer-target interactions and the factors influencing their strength.It provides a reference for further use of simulations in understanding aptamer-target binding mechanisms.展开更多
Exogenous alanyl-glutamine（Aln-Gln） was evaluated for its effects on growth performance, intestinal structure and function, antioxidant status and non-specific immunity of young carp（Cyprinus carpio L.）. Six diets...Exogenous alanyl-glutamine（Aln-Gln） was evaluated for its effects on growth performance, intestinal structure and function, antioxidant status and non-specific immunity of young carp（Cyprinus carpio L.）. Six diets supplemented with 0, 2.5, 5.0, 7.5, 10.0, or 15.0 g · kg-1 of Aln-Gln were fed to fish for 12 weeks. Supplementation with 7.5, 10.0, or 15.0 g · kg-1 of Aln-Gln significantly increased weight gain rate（WGR）, protein efficiency ratio（PER）, but feed conservation rate（FCR） and survival were not affected（P〉0.05）. The intestinal fold height and number, digestive enzyme, Na＋, K＋-ATPase activities was found to be significantly high（P〈0.05） with increasing dietary Aln-Gln supplementation up to 7.5 g · kg-1, but there were no significant differences for Aln-Gln supplementation from 7.5 to 15.0 g · kg-1. The glutathione peroxidase（GPX） activity, glutathione（GSH）, superoxide dismutase（SOD） activity increased and malondialdehyde（MDA） levels decreased significantly（P〈0.05） in the intestine, hepatopancreas, plasma and muscles. The plasma complement-3（C3） and complement-4（C4） levels were significantly（P〈0.05） improved at 5.0 g · kg-1 level and decreased when over 7.5 g · kg-1. The plasma lysozyme（LSZ） activity increased significantly（P〈0.05） at 7.5, 10.0, or 15.0 g · kg-1 level. In summary, the results showed that Aln-Gln improved growth performance, development and function of the intestine, the activity of the antioxidant defense system and the plasma non-specific immunity of the carps. The optimal Aln-Gln level was 8.24 g · kg-1 diet for WGR based on broken-line regression model analysis.展开更多
The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold wate...The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold water,and higher total flavonoid contents were detected in the former extracts than the latter ones.All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals,which indicates the health benefits of the water extracts of citrus fruits peels.For DPPH radical,the IC50values of hot extract follow as Navel orange(NO)≈Mandarin orange(MO)< Lemon(LE)< Lo tangerine(LO)< Pomelo(PO),while the rank is NO< PO<LE≈MO<LO for ABTS radical.The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species.MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts.Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L.The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract.The plasma binding rates decrease with the increasing concentrations of flavonoids,and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates.In addition,the plasma binding rates of flavonoids with saturated C3-C4 bond decrease significantly with the increasing concentrations.展开更多
A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were establish...A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.展开更多
Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d a...Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d at superhigh pressure and high temperature(HP-HT) are reported in this paper.展开更多
OBJECTIVE To identify the involvement of flumazenil-insensitive benzodiazepine(BZD) binding site in mediating BZD-induced immobility.The distribution of this nonclassical binding site and its key amino acid residues i...OBJECTIVE To identify the involvement of flumazenil-insensitive benzodiazepine(BZD) binding site in mediating BZD-induced immobility.The distribution of this nonclassical binding site and its key amino acid residues in GABAAreceptors(GABAARs) were also investigated.METHODS Using a zebrafish larvae locomotion model,we investigated the detailed dose-dependent effects of diazepam and other BZDs on zebrafish larvae behaviors,with a focus on their high-dose effects.We then evaluated the influence of the classical BZD antagonist flumazenil,GABAARs antagonist bicuculline,and the antagonist of a proposed BZD binding site in α4/6β3δ subtype receptor Ro15-4513 on BZDs induced immobility.Using wholecell patch clamp electrophysiological recordings on recombinant GABAARs,we investigated the modulation of diazepam alone or combined with flumazenil on GABA-elicited current in wildtype and mutated receptors.RESULTS Diazepam dose-dependently decreased the locomotor activities of zebrafish larvae at doses of 0.4,2,10,20,30,50 and 75 mg·L^(-1).The hypolocomotion(sedation-like state) induced by diazepam at10 and 20 mg·L^(-1) were effectively antagonized by flumazenil with EC150 of 0.086 mg·L-and1.295 mg·L^(-1),while the immobility(anesthesialike state) induced by diazepam at 30 mg·L^(-1) was abolished by bicuculline(3 mg·L^(-1)),but not affected by flumazenil(even at concentration up to150 mg·L^(-1)) or Ro15-4513(100 mg·L^(-1)).The immobility induced by clonazepam and lorazepam(100 mg·L^(-1)) was also resistant to flumazenil(100 mg·L^(-1)).In the α1β2γ2 subtype receptor expressed in HEK293 T cells,diazepam dose-dependently potentiated GABA-elicited current,and this potentiation was effectively antagonized by flumazenil(100 μmol·L^(-1)).However,in α1β2 subtype receptor,diazepam(150 μmol·L^(-1)) induced potentiation was insensitive to flumazenil(100 μmol·L^(-1)),but was abolished by the mutation of β2 N265 I.CONCLUSION These results provide direct in vivo evidence for the nonclassical binding sites,which may be located at the second transmembrane domain of GABAAR,mediate BZD-induced anesthesia.展开更多
A copper-bispyridylpyrrolide complex [Cu(PDPH)Cl](PDPH = 2,5-bis(2′-pyridyl)pyrrole) was synthesized and characterized. The complex crystallizes in the orthorhombic system with space group Pccn, a = 0.9016(3) nm, b =...A copper-bispyridylpyrrolide complex [Cu(PDPH)Cl](PDPH = 2,5-bis(2′-pyridyl)pyrrole) was synthesized and characterized. The complex crystallizes in the orthorhombic system with space group Pccn, a = 0.9016(3) nm, b = 1.0931(4) nm, c =2.5319(8) nm, and V = 2.4951(15) nm3. The copper center is situated in a square planar geometry. The interaction of the copper(II)complex with calf thymus DNA(CT-DNA) was investigated by electronic absorption, circular dichroism(CD) and fluorescence spectra. It is proposed that the complex binds to CT-DNA through groove binding mode. Nuclease activity of the complex was also studied by gel electrophoresis method. The complex can efficiently cleave supercoiled p BR322 DNA in the presence of ascorbate(H2A) via oxidative pathway. The preliminary mechanism of DNA cleavage by the complex with different inhibiting reagents indicates that the hydroxyl radicals were involved as the active species in the DNA cleavage process.展开更多
In order to study the gene sequence of Min pig Y-box binding protein （YB-1） gene, the complete coding sequence of Min pig YB-1 gene was cloned by RT-PCR, the sequence features were analyzed by some software and onli...In order to study the gene sequence of Min pig Y-box binding protein （YB-1） gene, the complete coding sequence of Min pig YB-1 gene was cloned by RT-PCR, the sequence features were analyzed by some software and online website. The results showed that the complete CDS of Min pig Y-box was found to be 975 bp long, encoding 324 amino acids. It contained a conserved cold shock domain and several phosphorylation sites, but had no transmembrane domains, and was consistent with a protein found in the cytoplasm. Min pig YB-1 nucleotides shared high similarity （61.37%- 97.66%） with other mammals.展开更多
To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-...To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-Lys-Gly-D-Ala-D-Ala） was investigated by flow injection surface plasmon resonance （FI-SPR） and flow injection quartz crystal microbalance （FI-QCM）. To facilitate the formation of a compact vancomycin adsorbates layer with a uniform surface orientation, vancomycin molecules were attached onto a preformed alkanethiol self-assembled monolayer. By optimizing the conditions for the binding between Lys-Lys-Gly-D-Ala-D-Ala and vancomycin on the assembled chip, the detecting limit of Lys-Lys-Gly-D-Ala-D-Ala was greatly improved （reaching 0.5 ×10^- 6 mol/L or 7.5 × 10^-12 mol）. The equilibrium constant of the association of Lys-Lys-Gly-D-Ala-D-Ala with vancomycin was also obtained （KAds=5.0×10^4 L/tool）.展开更多
Objective DUF538(domain of unknown function 538) domain containing proteins are known as putative hypothetical proteins in plants. Until yet, there is no much information regarding their structure and function. Method...Objective DUF538(domain of unknown function 538) domain containing proteins are known as putative hypothetical proteins in plants. Until yet, there is no much information regarding their structure and function. Methods In the present research work, the homologous structures and binding potentials were identified between plant/mammalian lipocalins and plant DUF538 protein by using bioinformatics and experimental tools including molecular dynamics simulation, molecular docking and recombinant technology-based techniques. Results Molecular docking analysis of their interactions with lipidic ligands including cholesterol and palmitic acid revealed the similar and comparable binding potentials between DUF538 and lipocalin proteins. Both the test proteins were found to have more affinity to cholesterol molecule in compare to palmitic acid. By using recombinant technology-based experiments, the heterologously expressed and purified fused product of DUF538 protein exhibited about 61% cholesterol binding ability. Conclusion As a conclusion, plants DUF538 protein family was predicted to be the structural and may be the functional homologues of plants/animals lipocalin superfamily.展开更多
The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE ...The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.展开更多
Integrins are heterodimers that mediate cell adhesion and transduce signals bidirectionally across the cell membrane.Integrins often exist in low affinity(or inactive) states for
The variational method using a multiconfiguration wavefunction is carried out on the core-excited state 1s2s2p 4P0 for helium negative ion,including mass polarization and relativistic corrections.Binding energy and fi...The variational method using a multiconfiguration wavefunction is carried out on the core-excited state 1s2s2p 4P0 for helium negative ion,including mass polarization and relativistic corrections.Binding energy and fine structure are reported.The results are compared with other theoretical and experimental date in the literature.展开更多
OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like g...OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like growth factor-binding protein-3(IGFBP-3)suppresses HCC cell proliferation in both IGF-dependent and independent manners.The present study is to investigate whether treatment with exogenous IGFBP-3 inhibits bF GF and PDGF production and the cell proliferation of HCC cells.METHODS Cell Counting Kit 8 assay were designed to detect HCC cell proliferation,transcription factor early growth response-1(EGR1)involving in IGFBP-3 regulation of b FGF and PDGF were detected by RT-PCR and Western blot assays.Western blot assay was adopted to detect the IGFBP-3 regulating insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS The present study demonstrates that IGFBP-3 suppressed IGF-1-induced b FGF and PDGF expression while it does not affect their expression in the absence of IGF-1.To delineate the underlying mechanism,Western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1(EGR1)is involved in IGFBP-3 regulation of b FGF and PDGF.IGFBP-3 inhibition of type 1 insulin-like growth factor receptor(IGF1R),ERK and AKT activation is IGF-1-dependent.Furthermore,transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1,b FGF and PDGF expression.CONCLUSION In conclusion,these findings suggest that IGFBP-3suppresses transcription of EGR1 and its target genes b FGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation.It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation,suggesting that IGFBP-3 could be a target for the treatment of HCC.展开更多
文摘Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating excitationcontraction(E-C)coupling.Mutations in JPH2 have been associated with hypertrophic cardiomyopathy(HCM),but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus(MORN)repeat motifs remain incompletely understood.This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis.Methods A recombinant N-terminal fragment of mouse JPH2(residues 1-440),encompassing the MORN repeats and an adjacent helical region,was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain.Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features.Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells.In addition,site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations,including R347C,was used to evaluate their effects on membrane interaction and subcellular localization.Results The crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6Å,revealing a compact,elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration,forming a continuous hydrophobic core stabilized by alternating aromatic residues.A C-terminalα-helix further reinforced structural integrity.Conservation analysis identified the inner groove of the MORN array as a highly conserved surface,suggesting its role as a protein-binding interface.A flexible linker segment enriched in positively charged residues,located adjacent to the MORN motifs,was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes.Functional assays demonstrated that mutation of these basic residues impaired membrane association,while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays,despite preserving the overall MORN-Helix fold in structural modeling.Conclusion This study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2,highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions.The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis.These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.
文摘Chloride ions(Cl^(-))have been shown to impact the long-lasting nature of reinforced concrete.However,Cl^(-)that are already bound inside the concrete will not lead to the deterioration of the concrete’s characteristics.The composition of the cement-based material,including the type of cement and auxiliary materials,greatly influences the ability of the material to bind Cl^(-),and varied components result in varying binding beha-vior of the Cl^(-).Simultaneously,the Cl^(-)binding process in concrete is influenced by both the internal and exterior surroundings,as well as the curing practices.These factors impact the hydration process of the cement and the internal pore structure of the concrete.Currently,mathematical theories and molecular dynamics simulations have increasingly been employed as the prevalent methods for examining the binding behaviors of Cl^(-)in concrete.These techniques are extensively utilized for predicting the lifespan and conducting microscopic studies of reinforced concrete in Cl^(-)settings.This work proposes recommendations for future research based on a summary of experimental and simulation investigations on Cl^(-)binding.Which will offer theoretical guidance for studying the binding of Cl^(-)in cement-based materials.
文摘Aptamers are a type of single-chain oligonucleotide that can combine with a specific target.Due to their simple preparation,easy modification,stable structure and reusability,aptamers have been widely applied as biochemical sensors for medicine,food safety and environmental monitoring.However,there is little research on aptamer-target binding mechanisms,which limits their application and development.Computational simulation has gained much attention for revealing aptamer-target binding mechanisms at the atomic level.This work summarizes the main simulation methods used in the mechanistic analysis of aptamer-target complexes,the characteristics of binding between aptamers and different targets(metal ions,small organic molecules,biomacromolecules,cells,bacteria and viruses),the types of aptamer-target interactions and the factors influencing their strength.It provides a reference for further use of simulations in understanding aptamer-target binding mechanisms.
基金Supported by the Earmarked Fund for China Agriculture Research System(CARS-46)the Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences(2014A08XK03)
文摘Exogenous alanyl-glutamine（Aln-Gln） was evaluated for its effects on growth performance, intestinal structure and function, antioxidant status and non-specific immunity of young carp（Cyprinus carpio L.）. Six diets supplemented with 0, 2.5, 5.0, 7.5, 10.0, or 15.0 g · kg-1 of Aln-Gln were fed to fish for 12 weeks. Supplementation with 7.5, 10.0, or 15.0 g · kg-1 of Aln-Gln significantly increased weight gain rate（WGR）, protein efficiency ratio（PER）, but feed conservation rate（FCR） and survival were not affected（P〉0.05）. The intestinal fold height and number, digestive enzyme, Na＋, K＋-ATPase activities was found to be significantly high（P〈0.05） with increasing dietary Aln-Gln supplementation up to 7.5 g · kg-1, but there were no significant differences for Aln-Gln supplementation from 7.5 to 15.0 g · kg-1. The glutathione peroxidase（GPX） activity, glutathione（GSH）, superoxide dismutase（SOD） activity increased and malondialdehyde（MDA） levels decreased significantly（P〈0.05） in the intestine, hepatopancreas, plasma and muscles. The plasma complement-3（C3） and complement-4（C4） levels were significantly（P〈0.05） improved at 5.0 g · kg-1 level and decreased when over 7.5 g · kg-1. The plasma lysozyme（LSZ） activity increased significantly（P〈0.05） at 7.5, 10.0, or 15.0 g · kg-1 level. In summary, the results showed that Aln-Gln improved growth performance, development and function of the intestine, the activity of the antioxidant defense system and the plasma non-specific immunity of the carps. The optimal Aln-Gln level was 8.24 g · kg-1 diet for WGR based on broken-line regression model analysis.
基金Project(21176263) supported by the National Natural Science Foundation of China
文摘The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC.The flavonoids were extracted separately by hot and cold water,and higher total flavonoid contents were detected in the former extracts than the latter ones.All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals,which indicates the health benefits of the water extracts of citrus fruits peels.For DPPH radical,the IC50values of hot extract follow as Navel orange(NO)≈Mandarin orange(MO)< Lemon(LE)< Lo tangerine(LO)< Pomelo(PO),while the rank is NO< PO<LE≈MO<LO for ABTS radical.The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species.MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts.Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L.The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract.The plasma binding rates decrease with the increasing concentrations of flavonoids,and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates.In addition,the plasma binding rates of flavonoids with saturated C3-C4 bond decrease significantly with the increasing concentrations.
基金Project(51178333)supported by the National Natural Science Foundation of ChinaProject(SLDRCE09-D-03)supported by the Ministry of Science and Technology of China
文摘A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.
文摘Experimental and theoretical researches on the doping effect of interface binding state with homologous and heterogeneous dopants(d) in the system of PCD etc,as well as the action of intermediate layers between D /d at superhigh pressure and high temperature(HP-HT) are reported in this paper.
基金Foundation for Young Scientists of Beijing Institute of Pharmacology and Toxicology.
文摘OBJECTIVE To identify the involvement of flumazenil-insensitive benzodiazepine(BZD) binding site in mediating BZD-induced immobility.The distribution of this nonclassical binding site and its key amino acid residues in GABAAreceptors(GABAARs) were also investigated.METHODS Using a zebrafish larvae locomotion model,we investigated the detailed dose-dependent effects of diazepam and other BZDs on zebrafish larvae behaviors,with a focus on their high-dose effects.We then evaluated the influence of the classical BZD antagonist flumazenil,GABAARs antagonist bicuculline,and the antagonist of a proposed BZD binding site in α4/6β3δ subtype receptor Ro15-4513 on BZDs induced immobility.Using wholecell patch clamp electrophysiological recordings on recombinant GABAARs,we investigated the modulation of diazepam alone or combined with flumazenil on GABA-elicited current in wildtype and mutated receptors.RESULTS Diazepam dose-dependently decreased the locomotor activities of zebrafish larvae at doses of 0.4,2,10,20,30,50 and 75 mg·L^(-1).The hypolocomotion(sedation-like state) induced by diazepam at10 and 20 mg·L^(-1) were effectively antagonized by flumazenil with EC150 of 0.086 mg·L-and1.295 mg·L^(-1),while the immobility(anesthesialike state) induced by diazepam at 30 mg·L^(-1) was abolished by bicuculline(3 mg·L^(-1)),but not affected by flumazenil(even at concentration up to150 mg·L^(-1)) or Ro15-4513(100 mg·L^(-1)).The immobility induced by clonazepam and lorazepam(100 mg·L^(-1)) was also resistant to flumazenil(100 mg·L^(-1)).In the α1β2γ2 subtype receptor expressed in HEK293 T cells,diazepam dose-dependently potentiated GABA-elicited current,and this potentiation was effectively antagonized by flumazenil(100 μmol·L^(-1)).However,in α1β2 subtype receptor,diazepam(150 μmol·L^(-1)) induced potentiation was insensitive to flumazenil(100 μmol·L^(-1)),but was abolished by the mutation of β2 N265 I.CONCLUSION These results provide direct in vivo evidence for the nonclassical binding sites,which may be located at the second transmembrane domain of GABAAR,mediate BZD-induced anesthesia.
基金Project(21001118)supported by National Natural Science Foundation of ChinaProject(12JJ3016)supported by Natural Science Foundation of Hunan Province,China
文摘A copper-bispyridylpyrrolide complex [Cu(PDPH)Cl](PDPH = 2,5-bis(2′-pyridyl)pyrrole) was synthesized and characterized. The complex crystallizes in the orthorhombic system with space group Pccn, a = 0.9016(3) nm, b = 1.0931(4) nm, c =2.5319(8) nm, and V = 2.4951(15) nm3. The copper center is situated in a square planar geometry. The interaction of the copper(II)complex with calf thymus DNA(CT-DNA) was investigated by electronic absorption, circular dichroism(CD) and fluorescence spectra. It is proposed that the complex binds to CT-DNA through groove binding mode. Nuclease activity of the complex was also studied by gel electrophoresis method. The complex can efficiently cleave supercoiled p BR322 DNA in the presence of ascorbate(H2A) via oxidative pathway. The preliminary mechanism of DNA cleavage by the complex with different inhibiting reagents indicates that the hydroxyl radicals were involved as the active species in the DNA cleavage process.
基金Supported by China Agricultural Research System(CARS-36)
文摘In order to study the gene sequence of Min pig Y-box binding protein （YB-1） gene, the complete coding sequence of Min pig YB-1 gene was cloned by RT-PCR, the sequence features were analyzed by some software and online website. The results showed that the complete CDS of Min pig Y-box was found to be 975 bp long, encoding 324 amino acids. It contained a conserved cold shock domain and several phosphorylation sites, but had no transmembrane domains, and was consistent with a protein found in the cytoplasm. Min pig YB-1 nucleotides shared high similarity （61.37%- 97.66%） with other mammals.
基金Projects(20773165,20876179) supported by the National Natural Science Foundation of ChinaProject(09JJ1002) supported by the Hunan Provincial Natural Science Foundation,China+1 种基金Project(NCET-07-0865) for New Century Excellent Talents in Chinese UniversityProject(2007AA022006) supported by the National High Technology Research and Development Program of China
文摘To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-Lys-Gly-D-Ala-D-Ala） was investigated by flow injection surface plasmon resonance （FI-SPR） and flow injection quartz crystal microbalance （FI-QCM）. To facilitate the formation of a compact vancomycin adsorbates layer with a uniform surface orientation, vancomycin molecules were attached onto a preformed alkanethiol self-assembled monolayer. By optimizing the conditions for the binding between Lys-Lys-Gly-D-Ala-D-Ala and vancomycin on the assembled chip, the detecting limit of Lys-Lys-Gly-D-Ala-D-Ala was greatly improved （reaching 0.5 ×10^- 6 mol/L or 7.5 × 10^-12 mol）. The equilibrium constant of the association of Lys-Lys-Gly-D-Ala-D-Ala with vancomycin was also obtained （KAds=5.0×10^4 L/tool）.
基金supported by a grant from Department of Animal Biology and Research Center for Bioscience and Biotechnology(RCBB),University of Tabriz(6906).
文摘Objective DUF538(domain of unknown function 538) domain containing proteins are known as putative hypothetical proteins in plants. Until yet, there is no much information regarding their structure and function. Methods In the present research work, the homologous structures and binding potentials were identified between plant/mammalian lipocalins and plant DUF538 protein by using bioinformatics and experimental tools including molecular dynamics simulation, molecular docking and recombinant technology-based techniques. Results Molecular docking analysis of their interactions with lipidic ligands including cholesterol and palmitic acid revealed the similar and comparable binding potentials between DUF538 and lipocalin proteins. Both the test proteins were found to have more affinity to cholesterol molecule in compare to palmitic acid. By using recombinant technology-based experiments, the heterologously expressed and purified fused product of DUF538 protein exhibited about 61% cholesterol binding ability. Conclusion As a conclusion, plants DUF538 protein family was predicted to be the structural and may be the functional homologues of plants/animals lipocalin superfamily.
基金Supported by Basic and Applied Basic Research Project of Guangdong Province(2021B0301030006)。
文摘The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.
文摘Integrins are heterodimers that mediate cell adhesion and transduce signals bidirectionally across the cell membrane.Integrins often exist in low affinity(or inactive) states for
文摘The variational method using a multiconfiguration wavefunction is carried out on the core-excited state 1s2s2p 4P0 for helium negative ion,including mass polarization and relativistic corrections.Binding energy and fine structure are reported.The results are compared with other theoretical and experimental date in the literature.
基金supported by National Natural Science Foundation of China(81502123 and81330081)Natural Science Foundation of Anhui Province(1308085QH130)Anhui Province Nature Science Foundation in University(KJ2014A119)
文摘OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like growth factor-binding protein-3(IGFBP-3)suppresses HCC cell proliferation in both IGF-dependent and independent manners.The present study is to investigate whether treatment with exogenous IGFBP-3 inhibits bF GF and PDGF production and the cell proliferation of HCC cells.METHODS Cell Counting Kit 8 assay were designed to detect HCC cell proliferation,transcription factor early growth response-1(EGR1)involving in IGFBP-3 regulation of b FGF and PDGF were detected by RT-PCR and Western blot assays.Western blot assay was adopted to detect the IGFBP-3 regulating insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS The present study demonstrates that IGFBP-3 suppressed IGF-1-induced b FGF and PDGF expression while it does not affect their expression in the absence of IGF-1.To delineate the underlying mechanism,Western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1(EGR1)is involved in IGFBP-3 regulation of b FGF and PDGF.IGFBP-3 inhibition of type 1 insulin-like growth factor receptor(IGF1R),ERK and AKT activation is IGF-1-dependent.Furthermore,transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1,b FGF and PDGF expression.CONCLUSION In conclusion,these findings suggest that IGFBP-3suppresses transcription of EGR1 and its target genes b FGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation.It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation,suggesting that IGFBP-3 could be a target for the treatment of HCC.
