For the uracil-BX3 (X = F, Cl) systems, geometries and binding energies have been calculated by using the Lee-Young-Parr correlation functionals (B3LYP) method of density functional theory (DFT) and the second-o...For the uracil-BX3 (X = F, Cl) systems, geometries and binding energies have been calculated by using the Lee-Young-Parr correlation functionals (B3LYP) method of density functional theory (DFT) and the second-order Moller-Plesset (MP2) method of ab initio at the 6- 311 +G^* or 6-311 ++G^* basis set. Four isomers were found for each system, and then the single-point energy evaluations were performed using the larger basis sets of (6-311 +G(2df, p) and aug-cc-pVDZ with DFF method. In the most stable isomer of uracil-BF3 or uracil-BCl3, the boron atom of BX3 (X = F, Cl) connects to the carbonyl oxygen O7 of uracil with a stabilization energy of -46.56 or -31.10 kJ/mol at the B3LYP/6-31 1+G^* level (BSSE corrected). The analyses for combining interaction between BX3 and uracil with the atom-in-molecule theory (AIM) and natural bond orbital method (NBO) have been performed. The results indicate that all isomers were formed with σ-p type interactions between uracil and BX3, in which the carbonyl oxygen offers its lone pair electrons to the empty p orbital of boron atom and the concomitances of charge transfer from uracil to BX3 occur. Moreover, there exists one or two hydrogen bonds in most isomers of uracil-BX3 system and these hydrogen bonds contribute to the stability of the complex systems. Frequency analysis suggests that the stretching vibration of BX3 undergoes a red shift in complexes. Uracil-BF3 complex is more stable than uracil-BCl3 although the distance of B-O is shorter in the latter. Besides, the conversion mechanisms between different isomers of uracil-BF3 have been obtained.展开更多
Radix Bupleuri(RB)is commonly used to treat depression,but it can also lead to hepatotoxicity after longterm use.In many anti-depression prescriptions,RB is often used in combination with Radix Paeoniae Alba(RPA)as an...Radix Bupleuri(RB)is commonly used to treat depression,but it can also lead to hepatotoxicity after longterm use.In many anti-depression prescriptions,RB is often used in combination with Radix Paeoniae Alba(RPA)as an herb pair.However,whether RPA can alleviate RB-induced hepatotoxicity remain unclear.In this work,the results confirmed that RB had a dose-dependent antidepressant effect,but the optimal antidepressant dose caused hepatotoxicity.Notably,RPA effectively reversed RB-induced hepatotoxicity.Afterward,the mechanism of RB-induced hepatotoxicity was confirmed.The results showed that saikosaponin A and saikosaponin D could inhibit GSH synthase(GSS)activity in the liver,and further cause liver injury through oxidative stress and nuclear factor kappa B(NF-kB)/NOD-like receptor thermal protein domain associated protein 3(NLRP3)pathway.Furthermore,the mechanisms by which RPA attenuates RBinduced hepatotoxicity were investigated.The results demonstrated that RPA increased the abundance of intestinal bacteria with glycosidase activity,thereby promoting the conversion of saikosaponins to saikogenins in vivo.Different from saikosaponin A and saikosaponin D,which are directly combined with GSS as an inhibitor,their deglycosylation conversion products saikogenin F and saikogenin G exhibited no GSS binding activity.Based on this,RPA can alleviate the inhibitory effect of saikosaponins on GSS activity to reshape the liver redox balance and further reverse the RB-induced liver inflammatory response by the NFkB/NLRP3 pathway.In conclusion,the present study suggests that promoting the conversion of saikosaponins by modulating gut microbiota to attenuate the inhibition of GSS is the potential mechanism by which RPA prevents RB-induced hepatotoxicity.展开更多
Immunotherapy has become a promising research“hotspot”in cancer treatment.“Soldier”immune cells are not uniform throughout the body;they accumulate mostly in the immune organs such as the spleen and lymph nodes(LN...Immunotherapy has become a promising research“hotspot”in cancer treatment.“Soldier”immune cells are not uniform throughout the body;they accumulate mostly in the immune organs such as the spleen and lymph nodes(LNs),etc.The unique structure of LNs provides the microenvironment suitable for the survival,activation,and proliferation of multiple types of immune cells.LNs play an important role in both the initiation of adaptive immunity and the generation of durable anti-tumor responses.Antigens taken up by antigen-presenting cells in peripheral tissues need to migrate with lymphatic fluid to LNs to activate the lymphocytes therein.Meanwhile,the accumulation and retaining of many immune functional compounds in LNs enhance their efficacy significantly.Therefore,LNs have become a key target for tumor immunotherapy.Unfortunately,the nonspecific distribution of the immune drugs in vivo greatly limits the activation and proliferation of immune cells,which leads to unsatisfactory anti-tumor effects.The efficient nano-delivery system to LNs is an effective strategy to maximize the efficacy of immune drugs.Nano-delivery systems have shown beneficial in improving biodistribution and enhancing accumulation in lymphoid tissues,exhibiting powerful and promising prospects for achieving effective delivery to LNs.Herein,the physiological structure and the delivery barriers of LNs were summarized and the factors affecting LNs accumulation were discussed thoroughly.Moreover,developments in nano-delivery systems were reviewed and the transformation prospects of LNs targeting nanocarriers were summarized and discussed.展开更多
Objective:Research the chemical constituents of Paeonia suffruticosa that are responsible for its anti-infective properties.Methods:Several column chromatographic methods were used to purify the chemical constituents ...Objective:Research the chemical constituents of Paeonia suffruticosa that are responsible for its anti-infective properties.Methods:Several column chromatographic methods were used to purify the chemical constituents from P.suffruticosa,including medium pressure liquid chromatography,Sephadex LH-20,and normal silica gel.A disc diffusion method was used to screen for antibacterial activity,and their anti-virulence activity was assessed on the type III secretion system(T3SS)of Salmonella pathogenicity island 1(SPI-1)in Salmonella enterica serovar Typhimurium UK-1 g 8956 by SDS-PAGE and western blots.Results:Twenty-one compounds were identified.Compounds 7,8 and 17 showed moderate activity against S.aureus ATCC25923,compounds 8,9 and 10 showed weak activities against B.subtilis ACCC11060.Meanwhile,phenols(14-18)and flavonoids(20 and 21)inhibited T3SS protein secretion of S.typhimurium without affecting bacterial growth.Furthermore,a strong inhibitory effect was observed for 17 and 20 on SPI-1 mediated invasion of HeLa cells.Additionally,no toxicity was observed for these compounds.Conclusion:P.suffruticosa has anti-infective properties due in part to the fact that phenols and flavonoids can block the secretion of T3SS-associated protein effectors.展开更多
Chaigui granules(CG)are a compound composed of six herbal medicines with significant antidepressant effects.However,the antidepressant mechanism of CG remains unclear.In the present study,we attempted to elucidate the...Chaigui granules(CG)are a compound composed of six herbal medicines with significant antidepressant effects.However,the antidepressant mechanism of CG remains unclear.In the present study,we attempted to elucidate the antidepressant mechanism of CG by regulating purine metabolism and purinergic signaling.First,the regulatory effect of CG on purine metabolites in the prefrontal cortex(PFC)of chronic unpredictable mild stress(CUMS)rats was analyzed by ultra high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)targeted quantitative analysis.Meanwhile,purinergic receptors(P2X7 receptor(P2X7R),A1 receptor(A1R)and A2A receptor(A2AR))and signaling pathways(nod-like receptor protein 3(NLRP3)inflammasome pathway and cyclic adenosine monophosphate(cAMP)-protein kinase A(PKA)pathway)associated with purine metabolism were analyzed by western blotting and enzyme-linked immunosorbent assay(ELISA).Besides,antidepressant mechanism of CG by modulating purine metabolites to activate purinergic receptors and related signaling pathways was dissected by exogenous supplementation of purine metabolites and antagonism of purinergic receptors in vitro.An in vivo study showed that the decrease in xanthine and the increase in four purine nucleosides were closely related to the antidepressant effects of CG.Additionally,purinergic receptors(P2X7R,A1R and A2AR)and related signaling pathways(NLRP3 inflammasome pathway and cAMP-PKA pathway)were also significantly regulated by CG.The results of exogenous supplementation of purine metabolites and antagonism of purinergic receptors showed that excessive accumulation of xanthine led to activation of the P2X7R-NLRP3 inflammasome pathway,and the reduction of adenosine and inosine inhibited the A1R-cAMP-PKA pathway,which was significantly ameliorated by CG.Overall,CG could promote neuroprotection and ultimately play an antidepressant role by inhibiting the xanthine-P2X7R-NLRP3 inflammasome pathway and activating the adenosine/inosine-A1R-cAMP-PKA pathway.展开更多
Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–...Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–property correlation is essential for the development and application of advanced supercapacitors.Herein,we adopt the crystal field theory and density functional simulation to reveal the structural dependence of the pseudocapacitive property of M_(x)MnO_(2).Attributing to the Jahn–Teller effect of Mn^(3+),the bandgap of Kx MnO_(2)can be tuned by changing the x value(i.e.,the Mn(III)/Mn(IV)ratio).Then,we design a narrow-bandgap K 0.25 MnO_(2)(0.84 eV),which affords a high capacitance of 415 F g^(-1)at 1 A g^(-1)and a desirable rate capability of 293 F g^(-1)at 20 A g^(-1).Operando Raman spectroscopy confirms that the Jahn–Teller induced structure evolution of[MnO_(6)]octahedron accounts for the superior pseudocapacitive behavior of K_(0.25)MnO_(2).This finding offers theoretical guidance to the design and application of birnessite materials for pseudocapacitors.展开更多
The solute carrier family 12(SLC12)of cation-chloride cotransporters(CCCs)comprises potassium chloride cotransporters(KCCs,e.g.KCC1,KCC2,KCC3,and KCC4)-mediated Cl^(-)extrusion,and sodium potassium chloride cotranspor...The solute carrier family 12(SLC12)of cation-chloride cotransporters(CCCs)comprises potassium chloride cotransporters(KCCs,e.g.KCC1,KCC2,KCC3,and KCC4)-mediated Cl^(-)extrusion,and sodium potassium chloride cotransporters(N[K]CCs,NKCC1,NKCC2,and NCC)-mediated Cl^(-)loading.The CCCs play vital roles in cell volume regulation and ion homeostasis.Gain-of-function or loss-of-function of these ion transporters can cause diseases in many tissues.In recent years,there have been considerable advances in our understanding of CCCs'control mechanisms in cell volume regulations,with many techniques developed in studying the functions and activities of CCCs.Classic approaches to directly measure CCC activity involve assays that measure the transport of potassium substitutes through the CCCs.These techniques include the ammonium pulse technique,radioactive or nonradioactive rubidium ion uptakeassay,and thallium ion-uptake assay.CCCs'activity can also be indirectly observed by measuring gaminobutyric acid(GABA)activity with patch-clamp electrophysiology and intracellular chloride concentration with sensitive microelectrodes,radiotracer^(36)Cl^(-),and fluorescent dyes.Other techniques include directly looking at kinase regulatory sites phosphorylation,flame photometry,22Nat uptake assay,structural biology,molecular modeling,and high-throughput drug screening.This review summarizes the role of CCCs in genetic disorders and cell volume regulation,current methods applied in studying CCCs biology,and compounds developed that directly or indirectly target the CCCs for disease treatments.展开更多
To investigate the structure-activity relationship of polysaccharide and obtain a better antidepressant polysaccharide,the antidepressant-like activity of a carboxymethyl polysaccharide(C-MEPS2)subjected to submerged ...To investigate the structure-activity relationship of polysaccharide and obtain a better antidepressant polysaccharide,the antidepressant-like activity of a carboxymethyl polysaccharide(C-MEPS2)subjected to submerged fermentation was systematically studied.PC12-H cell and Kunming mice were used to investigate the differences and their mechanism in the antidepressant effects of C-MEPS2 and MEPS2.Cell experiments have showed that C-MEPS2 has a better antidepressant effect than MEPS2.C-MEPS2 could exert antidepressant effects related to catecholamine synthesis with specifi c sites of TH,D2DR,and P-CAMKII.In addition,C-MEPS2 could repair the Res-induced damage in PC12-H cell,stabilize the mitochondrial membrane potential and regulate intracellular Ca^(2+) concentration,thus reducing cell apoptosis caused by RES.Antagonists common dosing experiments on animals further proved that CMEPS2 could signifi cantly improve the antidepressant effect of derivatives without affecting the antidepressant mechanism of MEPS2.It is speculated that it may be related to carboxymethylated modifi cation.展开更多
Cell-free expression systems have emerged as a versatile and powerful platform for metabolic engineering,biosynthesis and synthetic biology studies.Nevertheless,successful examples of the synthesis of complex natural ...Cell-free expression systems have emerged as a versatile and powerful platform for metabolic engineering,biosynthesis and synthetic biology studies.Nevertheless,successful examples of the synthesis of complex natural products using this system are still limited.Bicyclomycin,a structurally unique and complex diketopiperazine alkaloid,is a clinically promising antibiotic that selectively inhibits the transcription termination factor Rho.Here,we established a modular cell-free expression system with cascade catalysis for the biosynthesis of bicyclomycin from a chemically synthesized cyclodipeptide.The six cell-free expressed biosynthetic enzymes,including five iron-andα-ketoglutarate-dependent dioxygenases and one cytochrome P450 monooxygenase,were active in converting their substrates to the corresponding products.The co-expressed enzymes in the cell-free module were able to complete the related partial pathway.In vitro biosynthesis of bicyclomycin was also achieved by reconstituting the entire biosynthetic pathways(i.e.,six enzymes)using the modular cell-free expression system.This study demonstrates that the modular cell-free expression system can be used as a robust and promising platformforthe biosynthesis of complex antibiotics.展开更多
Metabolic syndrome(Met S)is a chronic disease associated with the disturbance of gut microbiota homeostasis.Metabolites derived from gut microbes play essential roles in Met S prevention and therapy.Here,we focused on...Metabolic syndrome(Met S)is a chronic disease associated with the disturbance of gut microbiota homeostasis.Metabolites derived from gut microbes play essential roles in Met S prevention and therapy.Here,we focused on the inhibitory effect of the extract of millet bran protein(EMBP)on a high-fat diet(HFD)-induced Met S,aiming to identify gut microbiota and their metabolites that involve in the anti-Met S activity of EMBP.The obesity,chronic inflammation,insulin resistance in Met S mouse models were abolished after EMBP treatment.The protective mechanism of EMBP against HFD-induced Met S may depend on improved gut barrier function.Using microbiome analysis,we found that EMBP supplementation improved gut microbiome dysbiosis in Met S mice,specifically upregulating Bacteroides acidifaciens.The fecal microbiota transplantation(FMT)also demonstrated this phenomenon.In addition,metabolomic analysis showed that EMBP mediates metabolic profiling reprogramming in Met S mice.Notably,a microbiota-derived metabolite,gamma-aminobutyric acid(GABA),is enriched by EMBP.In addition,exogenous GABA treatment produced a similar protective effect to EMBP by improving NRF2-dependent gut barrier function to protect HFDinduced Met S.The results suggest that EMBP suppress host Met S by remodeling of gut microbiota as an effective candidate for next-generation medicine food dual purpose dietary supplement to intervene in MetS.展开更多
A novel compound, diethyl puerarin-7-yl phosphate, was synthesized through a simplified Atheron-Todd reaction for the first time. The structure of this compound was elucidated by IR, ESI-MS and NMR. Two conformations ...A novel compound, diethyl puerarin-7-yl phosphate, was synthesized through a simplified Atheron-Todd reaction for the first time. The structure of this compound was elucidated by IR, ESI-MS and NMR. Two conformations of the compound were testified by 2D NMR (HSQC and HMBC) and dynamic NMR. Furthermore, we carried out the conformational analysis using chemical calculation by the Gaussian 03. Finally, we obtained two preferred conformations and energy values.展开更多
Two DNA fragments encoding PDZ domain (21-110 residues) and BAR domain ( 150-360 residues) from PICK1 (1-416 residues) were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to...Two DNA fragments encoding PDZ domain (21-110 residues) and BAR domain ( 150-360 residues) from PICK1 (1-416 residues) were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to generate recombinant plasmids, pE-pdz and pM-bar. Having been separately transferred into the hosts E. coli BL21 and E. coli JM109, these two strains can express fusion proteins: His-tagged PDZ(PDZ domain) and maltose binding protein-BAR( MBP-BAR domain) respectively, as confirmed by both SDS-PAGE and Wostem blotting. The interaction between these two domains is dose-dependence, as identified by a pull-down test. Moreover, it has been shown from the ELISA analysis that the actual amount of PDZ bound to MBP-BAR-amylose beads reaches ( 16 ± 0. 5)%, as calculated by the molar ratio of PDZ to MBP-BAR. In addition, the interaction between BAR(bait) and PDZ(prey) in vivo was also examined with a yeast two-hybrid system.展开更多
Vascular endothelial growth factor receptor 2(VEGFR-2)and neuropilin-1(NRP-1)are two prominent antiangiogenic targets.They are highly expressed on vascular endothelial cells and some tumor cells.Therefore,targeting VE...Vascular endothelial growth factor receptor 2(VEGFR-2)and neuropilin-1(NRP-1)are two prominent antiangiogenic targets.They are highly expressed on vascular endothelial cells and some tumor cells.Therefore,targeting VEGFR-2 and NRP-1 may be a potential antiangiogenic and antitumor strategy.A7R,a peptide with sequence of Ala-Thr-Trp-Leu-Pro-Pro-Arg that was found by phage display of peptide libraries,can preferentially target VEGFR-2 and NRP-1 and destroy the binding between vascular endothelial growth factor 165(VEGF165)and VEGFR-2 or NRP-1.This peptide is a new potent inhibitor of tumor angiogenesis and a targeting ligand for cancer therapy.This review describes the discovery,function and mechanism of the action of A7R,and further introduces the applications of A7R in antitumor angiogenic treatments,tumor angiogenesis imaging and targeted drug delivery systems.In this review,strategies to deliver different drugs by A7R-modified liposomes and nanoparticles are highlighted.A7R,a new dual targeting ligand of VEGFR-2 and NRP-1,is expected to have efficient therapeutic or targeting roles in tumor drug delivery.展开更多
Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 : Pr3 + , Na^+ (CZTOPN) was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glyc...Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 : Pr3 + , Na^+ (CZTOPN) was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glycol solvent and then react with Ti(OC4H9)4 to form sol and gel. The decomposition process of the precursor, and crystallization and particle size of CZTOPN were examined by thermal analysis (TG-DSC), powder X-ray diffraction (XRD), and scan election microscopy (SEM). Results of TG-DSC and XRD reveal that the composition of Ca0.8 Zn0.2 TiO3 : Pr3 + , Na^+ changes with the sintering temperature. SEM data indicate that the diameter of particles is under 50 nm even if the sintering temperature increases to 1000 ℃. In contrast to a solid state reaction, the excitation spectra of samples synthesized by the sol-gel method shift blue about 10 nm and the emission intensity at 617 nm increases significantly.展开更多
New functionalized ionic liquids, 1-carboxylmethyl-3-methylimimidazolium hexafluorophosphate or fluoborate and 1-aminoethyl-3-methylimimidazolium hexafluorophosphate or fluoborate have been synthesized and investigate...New functionalized ionic liquids, 1-carboxylmethyl-3-methylimimidazolium hexafluorophosphate or fluoborate and 1-aminoethyl-3-methylimimidazolium hexafluorophosphate or fluoborate have been synthesized and investigated. The obtained amino or carboxyl-functionalized ionic liquids were all characterized by FT-IR, ^1H NMR and MS (ESI) and their properties such as freezing point, viscosity, solubility, specific gravity, surface tension, and interfacial tension were also determined.展开更多
Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) h...Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) have been synthesized hydrothermally, and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic space group P2/c, while 2 crystallizes in triclinic, space group P1. Crystal data for 1: C_(16)H_(14)MnN_4O_7, Mr = 429.25, a = 10.684(2), b = 9.338(1), c = 9.896(2) ?, β = 113.89(3)o, V = 902.7(3) ?~3, Z = 2, T = 153(2) K, Dc = 1.579 g/cm^3, μ = 0.780 mm-1, F(000) = 438, R = 0.1084, wR = 0.3507, and GOF = 1.069; For 2: C44 H30 MnN6 O5, Mr = 777.68, a = 11.255(2), b = 11.554(2), c = 15.417(3) ?, α = 107.28(3), β = 101.07(3), γ = 107.23(3)o, V = 1740.2(6) ?~3, Z = 2, T = 293(2) K, Dc = 1.484 g/cm3, μ = 0.440 mm^(-1), F(000) = 802, R = 0.0471, wR = 0.1050, and GOF = 0.948. In both compounds, the central Mn(Ⅱ) ions adopt the same distorted pentagonal-bipyramid geometry [MnN_3O_4] with different secondary structure units. L1 ligand adopts the μ_2-1κ~3N,N?,N??:2κ~2O,O? mode to coordinate with mononuclear manganese to build a single chainlike compound 1, while L2 employs μ_3-1κ~3N,N?,N??:2κ~2O,O?:3κ~1O and 1κ~1O modes to link dimeric Mn_2O_2 to exhibit a double chainlike 2. Both compounds display weak antiferromagnetic coupling interactions.展开更多
Graphitic carbon nitride(g-C_(3)N_(4)) is a fascinating photocatalyst for solar energy utilization in photo-catalysis.Nevertheless,it often suffers from moderate photo-catalytic activity due to its low specific surfac...Graphitic carbon nitride(g-C_(3)N_(4)) is a fascinating photocatalyst for solar energy utilization in photo-catalysis.Nevertheless,it often suffers from moderate photo-catalytic activity due to its low specific surface area and fast recombination rate of photogenerated electrons upon photo-excitation.Herein,we overcome the bottlenecks by constructing a porous g-C_(3)N_(4) nanosheet(PCNS)through a simple thermal oxidation etching method.Benefited from its porous layer structure,the obtained PCNS exhibits large specific surface area,efficient separation of photogenerated charge carriers,as well as high exposure of active sites.As a result,it is robust and universal in visible light-driven dehydrogenation of alcohols in water under oxidant-free condition.Almost quantitative yields(>99%)of various valuable carbonyl compounds were obtained over PCNS,while bulk g-C_(3)N_(4) was far less efficient.Moreover,the photo-catalyst was highly stable and could be facilely recovered from the aqueous system for efficient reuse.The easy preparation and excellent performance made PCNS a promising and competitive photocatalyst for the solar applications.展开更多
Transferrin(TF) and its isoforms have been widely reported via various analytical techniques, including a noticeable increased number of isoforms with low content of sialic acid(asialo-, monosialo-, and disialo-tra...Transferrin(TF) and its isoforms have been widely reported via various analytical techniques, including a noticeable increased number of isoforms with low content of sialic acid(asialo-, monosialo-, and disialo-transferrin) and asialo-TF as well as disialo-TF, with one or several oligosaccharides released in human serum transferrin(hTf). Here, hTf has been purified by native gradient polyacrylamide gel electrophoresis(PAGEso) before use. The hTf extracted with the electron-transfer approach showed a single subunit band(77.1 Da) in the SDS-PAGE gel, but it exhibited two bands in the native and denatured isoelectric focusing(IEF) gels, namely, hTf-2Fe^3+ and apo-hTf, without finding any other transferrin isoforms. A reversed phase HPLC(RP-HPLC) equipped with a C18 column effectively separated hTf and its polymers and combined off-line techniques, including peptide mass fingerprinting(PMF), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) and database search, and identified the high homology among hTf, apo-hTf, and their isoforms. Moreover, the elution solution consisting of acetonitrile and formic acid could easily denature both hTf and apo-hTf to form various isoforms during separation with HPLC, indicating that chemical factors lead to the formation of various isoforms in transferrin, artificially, during extraction and separation. The authors claimed that only two transferrin isoforms existed in the NHS, namely, hTf-2Fe^3+ and apo-hTf, which could be employed in biomarkers, to distinguish the healthy population from many disease sufferers, such as, carbohydrate-deficient transferrin(CDT)展开更多
Two artificial minic polypeptides which are synthetic analogues of natural products with DNA affinity were synthesized, and theirs cleavage activity with DNA were examined. The structures of these compounds was confir...Two artificial minic polypeptides which are synthetic analogues of natural products with DNA affinity were synthesized, and theirs cleavage activity with DNA were examined. The structures of these compounds was confirmed by ^1H NMR, MS and IR.展开更多
The ciliate Tetrahymena is a valuable model organism in the studies of ecotoxicology. Changes in intracellular metabolism are caused by exogenous chemicals in the environment. Intracellular metabolite changes signify ...The ciliate Tetrahymena is a valuable model organism in the studies of ecotoxicology. Changes in intracellular metabolism are caused by exogenous chemicals in the environment. Intracellular metabolite changes signify toxic effects and can be monitored by metabolomics analysis. In this work, a protocol for the GC-MS-based metabolomic analysis of Tetrahymena was established. Different extraction solvents showed divergent effects on the metabolomic analysis of Tetrahymena thermophila. The peak intensity of metabolites detected in the samples of extraction solvent Formula 1(F1) was the strongest and stable, while 61 metabolites were identified. Formula 1 showed an excellent extraction performance for carbohydrates. In the samples of extraction solvent Formula 2(F2), 66 metabolites were characterized, and fatty acid metabolites were extracted. Meanwhile, 57 and 58 metabolites were characterized in the extraction with Formula 3(F3) and Formula 4(F4), respectively. However, the peak intensity of the metabolites was low, and the metabolites were unstable. These results indicated that different extraction solvents substantially affected the detected coverage and peak intensity of intracellular metabolites. A total of 74 metabolites(19 amino acids, 11 organic acids, 2 inorganic acids, 11 fatty acids, 11 carbohydrates, 3 glycosides, 4 alcohols, 6 amines, and 7 other compounds) were identified in all experimental groups. Among these metabolites, amino acids, glycerol, myoinositol, and unsaturated fatty acids may become potential biomarkers of metabolite set enrichment analysis for detecting the ability of T. thermophila against environmental stresses.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 20171031)
文摘For the uracil-BX3 (X = F, Cl) systems, geometries and binding energies have been calculated by using the Lee-Young-Parr correlation functionals (B3LYP) method of density functional theory (DFT) and the second-order Moller-Plesset (MP2) method of ab initio at the 6- 311 +G^* or 6-311 ++G^* basis set. Four isomers were found for each system, and then the single-point energy evaluations were performed using the larger basis sets of (6-311 +G(2df, p) and aug-cc-pVDZ with DFF method. In the most stable isomer of uracil-BF3 or uracil-BCl3, the boron atom of BX3 (X = F, Cl) connects to the carbonyl oxygen O7 of uracil with a stabilization energy of -46.56 or -31.10 kJ/mol at the B3LYP/6-31 1+G^* level (BSSE corrected). The analyses for combining interaction between BX3 and uracil with the atom-in-molecule theory (AIM) and natural bond orbital method (NBO) have been performed. The results indicate that all isomers were formed with σ-p type interactions between uracil and BX3, in which the carbonyl oxygen offers its lone pair electrons to the empty p orbital of boron atom and the concomitances of charge transfer from uracil to BX3 occur. Moreover, there exists one or two hydrogen bonds in most isomers of uracil-BX3 system and these hydrogen bonds contribute to the stability of the complex systems. Frequency analysis suggests that the stretching vibration of BX3 undergoes a red shift in complexes. Uracil-BF3 complex is more stable than uracil-BCl3 although the distance of B-O is shorter in the latter. Besides, the conversion mechanisms between different isomers of uracil-BF3 have been obtained.
基金This study is funded by the National Nature Science Foundation of China(Grant Nos.:82074323,and 81673572)Key Research and Development Program of Shanxi Province(Program No.:202102130501010)+2 种基金The major science and technology project for“Significant New Drugs Creation”(Project No.:2017ZX09301047)Research Project Supported by Shanxi Scholarship Council of China(Project No.:2020019)The special fund for Science and Technology Innovation Teams of Shanxi Province(Grant No.:202204051002011).
文摘Radix Bupleuri(RB)is commonly used to treat depression,but it can also lead to hepatotoxicity after longterm use.In many anti-depression prescriptions,RB is often used in combination with Radix Paeoniae Alba(RPA)as an herb pair.However,whether RPA can alleviate RB-induced hepatotoxicity remain unclear.In this work,the results confirmed that RB had a dose-dependent antidepressant effect,but the optimal antidepressant dose caused hepatotoxicity.Notably,RPA effectively reversed RB-induced hepatotoxicity.Afterward,the mechanism of RB-induced hepatotoxicity was confirmed.The results showed that saikosaponin A and saikosaponin D could inhibit GSH synthase(GSS)activity in the liver,and further cause liver injury through oxidative stress and nuclear factor kappa B(NF-kB)/NOD-like receptor thermal protein domain associated protein 3(NLRP3)pathway.Furthermore,the mechanisms by which RPA attenuates RBinduced hepatotoxicity were investigated.The results demonstrated that RPA increased the abundance of intestinal bacteria with glycosidase activity,thereby promoting the conversion of saikosaponins to saikogenins in vivo.Different from saikosaponin A and saikosaponin D,which are directly combined with GSS as an inhibitor,their deglycosylation conversion products saikogenin F and saikogenin G exhibited no GSS binding activity.Based on this,RPA can alleviate the inhibitory effect of saikosaponins on GSS activity to reshape the liver redox balance and further reverse the RB-induced liver inflammatory response by the NFkB/NLRP3 pathway.In conclusion,the present study suggests that promoting the conversion of saikosaponins by modulating gut microbiota to attenuate the inhibition of GSS is the potential mechanism by which RPA prevents RB-induced hepatotoxicity.
基金supported by National Natural Science Foundation of China(No.82173757,No.82173756)Scientists Fund of National Natural Science Foundation of China(82003682)+1 种基金Medical Science and Technolpgy Program of Henan Province(Joint construction project,LHGJ20200026)Shandong Excellent Youth Fund(ZR2022YQ76).
文摘Immunotherapy has become a promising research“hotspot”in cancer treatment.“Soldier”immune cells are not uniform throughout the body;they accumulate mostly in the immune organs such as the spleen and lymph nodes(LNs),etc.The unique structure of LNs provides the microenvironment suitable for the survival,activation,and proliferation of multiple types of immune cells.LNs play an important role in both the initiation of adaptive immunity and the generation of durable anti-tumor responses.Antigens taken up by antigen-presenting cells in peripheral tissues need to migrate with lymphatic fluid to LNs to activate the lymphocytes therein.Meanwhile,the accumulation and retaining of many immune functional compounds in LNs enhance their efficacy significantly.Therefore,LNs have become a key target for tumor immunotherapy.Unfortunately,the nonspecific distribution of the immune drugs in vivo greatly limits the activation and proliferation of immune cells,which leads to unsatisfactory anti-tumor effects.The efficient nano-delivery system to LNs is an effective strategy to maximize the efficacy of immune drugs.Nano-delivery systems have shown beneficial in improving biodistribution and enhancing accumulation in lymphoid tissues,exhibiting powerful and promising prospects for achieving effective delivery to LNs.Herein,the physiological structure and the delivery barriers of LNs were summarized and the factors affecting LNs accumulation were discussed thoroughly.Moreover,developments in nano-delivery systems were reviewed and the transformation prospects of LNs targeting nanocarriers were summarized and discussed.
基金National Natural Science Foundation of China(2217070336,81673317)the Program for Changjiang Scholars andInnovative Research Team in University(IRT_17R68)。
文摘Objective:Research the chemical constituents of Paeonia suffruticosa that are responsible for its anti-infective properties.Methods:Several column chromatographic methods were used to purify the chemical constituents from P.suffruticosa,including medium pressure liquid chromatography,Sephadex LH-20,and normal silica gel.A disc diffusion method was used to screen for antibacterial activity,and their anti-virulence activity was assessed on the type III secretion system(T3SS)of Salmonella pathogenicity island 1(SPI-1)in Salmonella enterica serovar Typhimurium UK-1 g 8956 by SDS-PAGE and western blots.Results:Twenty-one compounds were identified.Compounds 7,8 and 17 showed moderate activity against S.aureus ATCC25923,compounds 8,9 and 10 showed weak activities against B.subtilis ACCC11060.Meanwhile,phenols(14-18)and flavonoids(20 and 21)inhibited T3SS protein secretion of S.typhimurium without affecting bacterial growth.Furthermore,a strong inhibitory effect was observed for 17 and 20 on SPI-1 mediated invasion of HeLa cells.Additionally,no toxicity was observed for these compounds.Conclusion:P.suffruticosa has anti-infective properties due in part to the fact that phenols and flavonoids can block the secretion of T3SS-associated protein effectors.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.:82074323 and 81673572)Key Research and Development Program of Shanxi Province(Grant No.:202102130501010)+2 种基金Innovation Project for Graduate Students in Shanxi Province(Grant No.:2022Y162)the Major Science and Technology Project for“Significant New Drugs Creation”(Grant No.:2017ZX09301047)Research Project Supported by Shanxi Scholarship Council of China(Grant No.:2020019).
文摘Chaigui granules(CG)are a compound composed of six herbal medicines with significant antidepressant effects.However,the antidepressant mechanism of CG remains unclear.In the present study,we attempted to elucidate the antidepressant mechanism of CG by regulating purine metabolism and purinergic signaling.First,the regulatory effect of CG on purine metabolites in the prefrontal cortex(PFC)of chronic unpredictable mild stress(CUMS)rats was analyzed by ultra high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)targeted quantitative analysis.Meanwhile,purinergic receptors(P2X7 receptor(P2X7R),A1 receptor(A1R)and A2A receptor(A2AR))and signaling pathways(nod-like receptor protein 3(NLRP3)inflammasome pathway and cyclic adenosine monophosphate(cAMP)-protein kinase A(PKA)pathway)associated with purine metabolism were analyzed by western blotting and enzyme-linked immunosorbent assay(ELISA).Besides,antidepressant mechanism of CG by modulating purine metabolites to activate purinergic receptors and related signaling pathways was dissected by exogenous supplementation of purine metabolites and antagonism of purinergic receptors in vitro.An in vivo study showed that the decrease in xanthine and the increase in four purine nucleosides were closely related to the antidepressant effects of CG.Additionally,purinergic receptors(P2X7R,A1R and A2AR)and related signaling pathways(NLRP3 inflammasome pathway and cAMP-PKA pathway)were also significantly regulated by CG.The results of exogenous supplementation of purine metabolites and antagonism of purinergic receptors showed that excessive accumulation of xanthine led to activation of the P2X7R-NLRP3 inflammasome pathway,and the reduction of adenosine and inosine inhibited the A1R-cAMP-PKA pathway,which was significantly ameliorated by CG.Overall,CG could promote neuroprotection and ultimately play an antidepressant role by inhibiting the xanthine-P2X7R-NLRP3 inflammasome pathway and activating the adenosine/inosine-A1R-cAMP-PKA pathway.
基金supported by Ministry of Science and Technology of China(2016YFA0201904)National Natural Science Foundation of China(21631002,52172219,51872192)+3 种基金Projects of International Cooperation and Exchanges NSFC(22120102004)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD-202001)the Jiangsu Natural Science Foundation(No.BK20180002)Fundamental Research Program of Shanxi Province(202103021223019).
文摘Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–property correlation is essential for the development and application of advanced supercapacitors.Herein,we adopt the crystal field theory and density functional simulation to reveal the structural dependence of the pseudocapacitive property of M_(x)MnO_(2).Attributing to the Jahn–Teller effect of Mn^(3+),the bandgap of Kx MnO_(2)can be tuned by changing the x value(i.e.,the Mn(III)/Mn(IV)ratio).Then,we design a narrow-bandgap K 0.25 MnO_(2)(0.84 eV),which affords a high capacitance of 415 F g^(-1)at 1 A g^(-1)and a desirable rate capability of 293 F g^(-1)at 20 A g^(-1).Operando Raman spectroscopy confirms that the Jahn–Teller induced structure evolution of[MnO_(6)]octahedron accounts for the superior pseudocapacitive behavior of K_(0.25)MnO_(2).This finding offers theoretical guidance to the design and application of birnessite materials for pseudocapacitors.
基金We are very grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.:82170406,81970238,and 32111530119)Shanghai Municipal Science and Technology Major Project,China(Grant No.:2018SHZDZX01)+1 种基金The Royal Society UK(Grant No.:IEC\NSFC\201094)the Commonwealth Scholarship Commission UK(Grant No.:NGCA-2020-43).
文摘The solute carrier family 12(SLC12)of cation-chloride cotransporters(CCCs)comprises potassium chloride cotransporters(KCCs,e.g.KCC1,KCC2,KCC3,and KCC4)-mediated Cl^(-)extrusion,and sodium potassium chloride cotransporters(N[K]CCs,NKCC1,NKCC2,and NCC)-mediated Cl^(-)loading.The CCCs play vital roles in cell volume regulation and ion homeostasis.Gain-of-function or loss-of-function of these ion transporters can cause diseases in many tissues.In recent years,there have been considerable advances in our understanding of CCCs'control mechanisms in cell volume regulations,with many techniques developed in studying the functions and activities of CCCs.Classic approaches to directly measure CCC activity involve assays that measure the transport of potassium substitutes through the CCCs.These techniques include the ammonium pulse technique,radioactive or nonradioactive rubidium ion uptakeassay,and thallium ion-uptake assay.CCCs'activity can also be indirectly observed by measuring gaminobutyric acid(GABA)activity with patch-clamp electrophysiology and intracellular chloride concentration with sensitive microelectrodes,radiotracer^(36)Cl^(-),and fluorescent dyes.Other techniques include directly looking at kinase regulatory sites phosphorylation,flame photometry,22Nat uptake assay,structural biology,molecular modeling,and high-throughput drug screening.This review summarizes the role of CCCs in genetic disorders and cell volume regulation,current methods applied in studying CCCs biology,and compounds developed that directly or indirectly target the CCCs for disease treatments.
基金funded by the Natural Science Foundation of China(32072203)the Tianjin Municipal Education Commission(TD13-5013)+4 种基金the Open Project of State Key Laboratory of Food Nutrition and Safety,Tianjin University of Science&Technology(SKLFNS-KF-202102)Natural Science Foundation of Shanxi(201901D211130)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2017105)Tianjin synthetic biotechnology innovation capacity improvement project(TSBICIP-KJGG-016)Tianjin Science and Technology Plan Project(21ZYJDJC00030).
文摘To investigate the structure-activity relationship of polysaccharide and obtain a better antidepressant polysaccharide,the antidepressant-like activity of a carboxymethyl polysaccharide(C-MEPS2)subjected to submerged fermentation was systematically studied.PC12-H cell and Kunming mice were used to investigate the differences and their mechanism in the antidepressant effects of C-MEPS2 and MEPS2.Cell experiments have showed that C-MEPS2 has a better antidepressant effect than MEPS2.C-MEPS2 could exert antidepressant effects related to catecholamine synthesis with specifi c sites of TH,D2DR,and P-CAMKII.In addition,C-MEPS2 could repair the Res-induced damage in PC12-H cell,stabilize the mitochondrial membrane potential and regulate intracellular Ca^(2+) concentration,thus reducing cell apoptosis caused by RES.Antagonists common dosing experiments on animals further proved that CMEPS2 could signifi cantly improve the antidepressant effect of derivatives without affecting the antidepressant mechanism of MEPS2.It is speculated that it may be related to carboxymethylated modifi cation.
基金supported in part by grants from the National Key Research and Development Program of China(2022YFC2303100)the National Natural Science Foundation of China(22207117).
文摘Cell-free expression systems have emerged as a versatile and powerful platform for metabolic engineering,biosynthesis and synthetic biology studies.Nevertheless,successful examples of the synthesis of complex natural products using this system are still limited.Bicyclomycin,a structurally unique and complex diketopiperazine alkaloid,is a clinically promising antibiotic that selectively inhibits the transcription termination factor Rho.Here,we established a modular cell-free expression system with cascade catalysis for the biosynthesis of bicyclomycin from a chemically synthesized cyclodipeptide.The six cell-free expressed biosynthetic enzymes,including five iron-andα-ketoglutarate-dependent dioxygenases and one cytochrome P450 monooxygenase,were active in converting their substrates to the corresponding products.The co-expressed enzymes in the cell-free module were able to complete the related partial pathway.In vitro biosynthesis of bicyclomycin was also achieved by reconstituting the entire biosynthetic pathways(i.e.,six enzymes)using the modular cell-free expression system.This study demonstrates that the modular cell-free expression system can be used as a robust and promising platformforthe biosynthesis of complex antibiotics.
基金supported by National Natural Science Foundation of China(32270420,32072220)National Key Research and Development Project(2020YFD1001405)+2 种基金Shanxi Province Science Foundation(202103021224011)Shanxi Key Laboratory for Research and Development of Regional PlantsShanxi Province“136”Revitalization Medical Project Construction Funds。
文摘Metabolic syndrome(Met S)is a chronic disease associated with the disturbance of gut microbiota homeostasis.Metabolites derived from gut microbes play essential roles in Met S prevention and therapy.Here,we focused on the inhibitory effect of the extract of millet bran protein(EMBP)on a high-fat diet(HFD)-induced Met S,aiming to identify gut microbiota and their metabolites that involve in the anti-Met S activity of EMBP.The obesity,chronic inflammation,insulin resistance in Met S mouse models were abolished after EMBP treatment.The protective mechanism of EMBP against HFD-induced Met S may depend on improved gut barrier function.Using microbiome analysis,we found that EMBP supplementation improved gut microbiome dysbiosis in Met S mice,specifically upregulating Bacteroides acidifaciens.The fecal microbiota transplantation(FMT)also demonstrated this phenomenon.In addition,metabolomic analysis showed that EMBP mediates metabolic profiling reprogramming in Met S mice.Notably,a microbiota-derived metabolite,gamma-aminobutyric acid(GABA),is enriched by EMBP.In addition,exogenous GABA treatment produced a similar protective effect to EMBP by improving NRF2-dependent gut barrier function to protect HFDinduced Met S.The results suggest that EMBP suppress host Met S by remodeling of gut microbiota as an effective candidate for next-generation medicine food dual purpose dietary supplement to intervene in MetS.
文摘A novel compound, diethyl puerarin-7-yl phosphate, was synthesized through a simplified Atheron-Todd reaction for the first time. The structure of this compound was elucidated by IR, ESI-MS and NMR. Two conformations of the compound were testified by 2D NMR (HSQC and HMBC) and dynamic NMR. Furthermore, we carried out the conformational analysis using chemical calculation by the Gaussian 03. Finally, we obtained two preferred conformations and energy values.
基金the National Natural Science Foundation of China(No 30400065)
文摘Two DNA fragments encoding PDZ domain (21-110 residues) and BAR domain ( 150-360 residues) from PICK1 (1-416 residues) were amplified by PCR and then introduced into vectors, pET-32M and pMAL-e2X respectively to generate recombinant plasmids, pE-pdz and pM-bar. Having been separately transferred into the hosts E. coli BL21 and E. coli JM109, these two strains can express fusion proteins: His-tagged PDZ(PDZ domain) and maltose binding protein-BAR( MBP-BAR domain) respectively, as confirmed by both SDS-PAGE and Wostem blotting. The interaction between these two domains is dose-dependence, as identified by a pull-down test. Moreover, it has been shown from the ELISA analysis that the actual amount of PDZ bound to MBP-BAR-amylose beads reaches ( 16 ± 0. 5)%, as calculated by the molar ratio of PDZ to MBP-BAR. In addition, the interaction between BAR(bait) and PDZ(prey) in vivo was also examined with a yeast two-hybrid system.
基金funded by National Natural Science Foundation of China(No.81302686)Primary Research&Developement Plan of Shandong Province(No.2016GSF201083)
文摘Vascular endothelial growth factor receptor 2(VEGFR-2)and neuropilin-1(NRP-1)are two prominent antiangiogenic targets.They are highly expressed on vascular endothelial cells and some tumor cells.Therefore,targeting VEGFR-2 and NRP-1 may be a potential antiangiogenic and antitumor strategy.A7R,a peptide with sequence of Ala-Thr-Trp-Leu-Pro-Pro-Arg that was found by phage display of peptide libraries,can preferentially target VEGFR-2 and NRP-1 and destroy the binding between vascular endothelial growth factor 165(VEGF165)and VEGFR-2 or NRP-1.This peptide is a new potent inhibitor of tumor angiogenesis and a targeting ligand for cancer therapy.This review describes the discovery,function and mechanism of the action of A7R,and further introduces the applications of A7R in antitumor angiogenic treatments,tumor angiogenesis imaging and targeted drug delivery systems.In this review,strategies to deliver different drugs by A7R-modified liposomes and nanoparticles are highlighted.A7R,a new dual targeting ligand of VEGFR-2 and NRP-1,is expected to have efficient therapeutic or targeting roles in tumor drug delivery.
文摘Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 : Pr3 + , Na^+ (CZTOPN) was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glycol solvent and then react with Ti(OC4H9)4 to form sol and gel. The decomposition process of the precursor, and crystallization and particle size of CZTOPN were examined by thermal analysis (TG-DSC), powder X-ray diffraction (XRD), and scan election microscopy (SEM). Results of TG-DSC and XRD reveal that the composition of Ca0.8 Zn0.2 TiO3 : Pr3 + , Na^+ changes with the sintering temperature. SEM data indicate that the diameter of particles is under 50 nm even if the sintering temperature increases to 1000 ℃. In contrast to a solid state reaction, the excitation spectra of samples synthesized by the sol-gel method shift blue about 10 nm and the emission intensity at 617 nm increases significantly.
文摘New functionalized ionic liquids, 1-carboxylmethyl-3-methylimimidazolium hexafluorophosphate or fluoborate and 1-aminoethyl-3-methylimimidazolium hexafluorophosphate or fluoborate have been synthesized and investigated. The obtained amino or carboxyl-functionalized ionic liquids were all characterized by FT-IR, ^1H NMR and MS (ESI) and their properties such as freezing point, viscosity, solubility, specific gravity, surface tension, and interfacial tension were also determined.
基金supported by the Scientific Research Fund of Hunan Provincial Education Department(15C0818,17C0948)the Opening Fund of Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research(Ministry of Education of China)Hunan Normal University(KLCBTCMR201808)
文摘Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) have been synthesized hydrothermally, and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic space group P2/c, while 2 crystallizes in triclinic, space group P1. Crystal data for 1: C_(16)H_(14)MnN_4O_7, Mr = 429.25, a = 10.684(2), b = 9.338(1), c = 9.896(2) ?, β = 113.89(3)o, V = 902.7(3) ?~3, Z = 2, T = 153(2) K, Dc = 1.579 g/cm^3, μ = 0.780 mm-1, F(000) = 438, R = 0.1084, wR = 0.3507, and GOF = 1.069; For 2: C44 H30 MnN6 O5, Mr = 777.68, a = 11.255(2), b = 11.554(2), c = 15.417(3) ?, α = 107.28(3), β = 101.07(3), γ = 107.23(3)o, V = 1740.2(6) ?~3, Z = 2, T = 293(2) K, Dc = 1.484 g/cm3, μ = 0.440 mm^(-1), F(000) = 802, R = 0.0471, wR = 0.1050, and GOF = 0.948. In both compounds, the central Mn(Ⅱ) ions adopt the same distorted pentagonal-bipyramid geometry [MnN_3O_4] with different secondary structure units. L1 ligand adopts the μ_2-1κ~3N,N?,N??:2κ~2O,O? mode to coordinate with mononuclear manganese to build a single chainlike compound 1, while L2 employs μ_3-1κ~3N,N?,N??:2κ~2O,O?:3κ~1O and 1κ~1O modes to link dimeric Mn_2O_2 to exhibit a double chainlike 2. Both compounds display weak antiferromagnetic coupling interactions.
基金financial support provided by the National Natural Science Foundation of China(21676078)the Natural Science Foundation of Hunan Province for Distinguished Young Scholar(2016JJ1013)+1 种基金Scientific Research Fund of Hunan Provincial Education Department(19A323)Science and Technology Planning Project of Hunan Province(2018TP1017)。
文摘Graphitic carbon nitride(g-C_(3)N_(4)) is a fascinating photocatalyst for solar energy utilization in photo-catalysis.Nevertheless,it often suffers from moderate photo-catalytic activity due to its low specific surface area and fast recombination rate of photogenerated electrons upon photo-excitation.Herein,we overcome the bottlenecks by constructing a porous g-C_(3)N_(4) nanosheet(PCNS)through a simple thermal oxidation etching method.Benefited from its porous layer structure,the obtained PCNS exhibits large specific surface area,efficient separation of photogenerated charge carriers,as well as high exposure of active sites.As a result,it is robust and universal in visible light-driven dehydrogenation of alcohols in water under oxidant-free condition.Almost quantitative yields(>99%)of various valuable carbonyl compounds were obtained over PCNS,while bulk g-C_(3)N_(4) was far less efficient.Moreover,the photo-catalyst was highly stable and could be facilely recovered from the aqueous system for efficient reuse.The easy preparation and excellent performance made PCNS a promising and competitive photocatalyst for the solar applications.
基金National Natural Science Foundation of China(No.30470372Foundation of Xiamen Natural Science of China(No.3502Z2001262)Program for Innovative Research Team in Science and Technology in Fujian Province University
文摘Transferrin(TF) and its isoforms have been widely reported via various analytical techniques, including a noticeable increased number of isoforms with low content of sialic acid(asialo-, monosialo-, and disialo-transferrin) and asialo-TF as well as disialo-TF, with one or several oligosaccharides released in human serum transferrin(hTf). Here, hTf has been purified by native gradient polyacrylamide gel electrophoresis(PAGEso) before use. The hTf extracted with the electron-transfer approach showed a single subunit band(77.1 Da) in the SDS-PAGE gel, but it exhibited two bands in the native and denatured isoelectric focusing(IEF) gels, namely, hTf-2Fe^3+ and apo-hTf, without finding any other transferrin isoforms. A reversed phase HPLC(RP-HPLC) equipped with a C18 column effectively separated hTf and its polymers and combined off-line techniques, including peptide mass fingerprinting(PMF), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) and database search, and identified the high homology among hTf, apo-hTf, and their isoforms. Moreover, the elution solution consisting of acetonitrile and formic acid could easily denature both hTf and apo-hTf to form various isoforms during separation with HPLC, indicating that chemical factors lead to the formation of various isoforms in transferrin, artificially, during extraction and separation. The authors claimed that only two transferrin isoforms existed in the NHS, namely, hTf-2Fe^3+ and apo-hTf, which could be employed in biomarkers, to distinguish the healthy population from many disease sufferers, such as, carbohydrate-deficient transferrin(CDT)
文摘Two artificial minic polypeptides which are synthetic analogues of natural products with DNA affinity were synthesized, and theirs cleavage activity with DNA were examined. The structures of these compounds was confirmed by ^1H NMR, MS and IR.
基金supported by the National Natural Science Foundation of China (Nos. 31572253, 31601857, 31702009)the Science Foundation for Youths of Shanxi Province (No. 201801D221241)the Postdoctoral Science Foundation of China (No. 2014M551961)
文摘The ciliate Tetrahymena is a valuable model organism in the studies of ecotoxicology. Changes in intracellular metabolism are caused by exogenous chemicals in the environment. Intracellular metabolite changes signify toxic effects and can be monitored by metabolomics analysis. In this work, a protocol for the GC-MS-based metabolomic analysis of Tetrahymena was established. Different extraction solvents showed divergent effects on the metabolomic analysis of Tetrahymena thermophila. The peak intensity of metabolites detected in the samples of extraction solvent Formula 1(F1) was the strongest and stable, while 61 metabolites were identified. Formula 1 showed an excellent extraction performance for carbohydrates. In the samples of extraction solvent Formula 2(F2), 66 metabolites were characterized, and fatty acid metabolites were extracted. Meanwhile, 57 and 58 metabolites were characterized in the extraction with Formula 3(F3) and Formula 4(F4), respectively. However, the peak intensity of the metabolites was low, and the metabolites were unstable. These results indicated that different extraction solvents substantially affected the detected coverage and peak intensity of intracellular metabolites. A total of 74 metabolites(19 amino acids, 11 organic acids, 2 inorganic acids, 11 fatty acids, 11 carbohydrates, 3 glycosides, 4 alcohols, 6 amines, and 7 other compounds) were identified in all experimental groups. Among these metabolites, amino acids, glycerol, myoinositol, and unsaturated fatty acids may become potential biomarkers of metabolite set enrichment analysis for detecting the ability of T. thermophila against environmental stresses.