Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag(NH3)2]+ to Ag0 in the solution into which some amount of ...Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag(NH3)2]+ to Ag0 in the solution into which some amount of OH- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solu-tion. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.展开更多
Cells employ proteins to perform metabolic functions and maintain active physiological state through charge transfer and energy conversion.These processes are carried out in a narrow space precisely and rapidly,which,...Cells employ proteins to perform metabolic functions and maintain active physiological state through charge transfer and energy conversion.These processes are carried out in a narrow space precisely and rapidly,which,no doubt,bring great difficulty for their detection and dissection.Fortunately,in recent years,the development and expansion of single-molecule technique in protein research make monitoring the dynamical changes of protein at single-molecule level a reality,which also provides a powerful tool for the further exploration of new phenomena and new mechanisms of life activities.This paper aims to summarize the working principle and essential achievements of single-molecule technique in protein research in recent five years.We focus on not only dissecting the difference of nanopores,atomic force microscope,scanning tunneling microscope,and optical tweezers technique,but also discussing the great significance of these single-molecule techniques in investigating intramolecular and intermolecular interactions,electron transport,and conformational changes.Finally,the opportunities and challenges of the single-molecule technique in protein research are discussed,which provide a new door for single-molecule protein research.展开更多
Two new a-aminophosphonate derivatives containing thieno[2,3-d]pyrimidine, diethyl(((6-ethyl-2-methyl-4-oxothieno[2,3-d]pyrimidin-3 (4H)-yl)amino)(4-methoxyphenyl)methyl) phosphonate (1) and diethyl((4-b...Two new a-aminophosphonate derivatives containing thieno[2,3-d]pyrimidine, diethyl(((6-ethyl-2-methyl-4-oxothieno[2,3-d]pyrimidin-3 (4H)-yl)amino)(4-methoxyphenyl)methyl) phosphonate (1) and diethyl((4-bromophenyl)((6-ethyl-2-methyl-4-oxothieno[2,3-d]pyrimidin-3 (4//)-yl)amino)methyl)phosphonate (2), have been synthesized by a facial phosphorylated reaction, and their structures were characterized by NMR, IR, HRMS and X-ray single-crystal diffraction. Compound 1 (C21H28N3O5PS, Mr = 465.49) belongs to the orthorhombic system, space group P212121, with a = 10.83653(16), b = 12.04906(19), c = 18.0061(3) A, V= 2351.06(6) A3, Z= 4, Dc= 1.315 g/cm3, p = 2.177 mm-1, F(000) = 984.0, the final R = 0.0389 and wR = 0.0985 for all data. Compound 2 (C20H25BrN304PS, Mr = 514.37) belongs to the orthorhombic system, space group P212121, with a = 10.9187(5), b = 11.9522(4), c = 17.7667(7) A, V= 2318.60(16) A3, Z = 4, Dc= 1.474 g/cm3,μ = 4.175 mm^-1, F(000) = 1056.0, the final R = 0.0367 and wR = 0.0946 for all data.展开更多
Objective:To investigate the effect of fusion proteins expressed by the fused gene of porcineα1,3 galactosyltransierase(α1,3 GT) and enhanced green fluorescent protein(EGFP) on the green fluorescence intensity of EG...Objective:To investigate the effect of fusion proteins expressed by the fused gene of porcineα1,3 galactosyltransierase(α1,3 GT) and enhanced green fluorescent protein(EGFP) on the green fluorescence intensity of EGFP.Methods:The fragment containingα1.3GT was firstly recovered after the pcDNA3.1-α1.3GT recombinant vector were digested with BamHl and EcoRI,and then,the resultant fragment was ligated to the pEGFP-N1 vector which was also digested with the same enzymes.The new recombinant eukaryotic expression pEGFP/a 1,3GT vector was obtained and sequenced.The pEGFP/α1,3GT was used to transfect human lung carcinoma cells A549 and HEKC 293FT,and the expression of EGFP was quantitatively analyzed by fluorescent microscope and flow cytometry.Results:The positive percentage of A549 was 80.5%,and that of 293 FT was 86.5%48 hours after the two cell lines both were transfected by pEGFP-N1.The positive percentage of A549 was 75.8%,and that of 293 FT was 81.2%48 hours after the two cell lines were transfected by pEGFP/α1.3GT.The mean fluorescence intensities of A549 transfected with pEGFP-N1 and pEGFP/α1.3GT were 1.21 and 0.956,respectively when compared with that of A549 without transfection.Meanwhile,the those of the 293FT that were transfected with pEGFP-N1 and pEGFP/αl,3GT were 7.66 and 1.00.respectively when compared with that of 293FT cells without transfection.Conclusions:These results suggested that the expression of EGFP gene fused with porcineα1,3GT gene was partly inhibited.展开更多
P450 fatty acid decarboxylase Ole T from Staphylococcus aureus(Ole TSA)is a novel cytochrome P450 enzyme that catalyzes the oxidative decarboxylation of fatty acids to yield primarily terminal alkenes and CO_(2) or mi...P450 fatty acid decarboxylase Ole T from Staphylococcus aureus(Ole TSA)is a novel cytochrome P450 enzyme that catalyzes the oxidative decarboxylation of fatty acids to yield primarily terminal alkenes and CO_(2) or minor a-andβ-hydroxylated fatty acids as side-products.In this work,the interactions between a series of cycloalkyl phosphorus heterocycles(CPHs)and Ole TSAwere investigated in detail by fluorescence titration experiment,ultraviolet-visible(UV-vis)and31 P NMR spectroscopies.Fluorescence titration experiment results clearly showed that a dynamic quenching occurred when CPH-6,a representative CPHs,interacted with Ole TSAwith a binding constant value of 15.2×104 M-1 at 293 K.The thermodynamic parameters(ΔH,ΔS andΔG)showed that the hydrogen bond and van der Waals force played major roles in the interaction between Ole TSAand CPHs.The UV-vis and31 P NMR studies indicated the penetration of CPH-6 into the interior environment of Ole TSA,which greatly affects the enzymatic activity of Ole TSA.Therefore,our study revealed an effective way to use phosphorus heterocyclic compounds to modulate the activity of cytochrome P450 enzymes.展开更多
Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation...Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation pathways were investigated, and it was observed that most fragment ions contained the phosphoryl group. It was interesting to observe that the fragmentation pathways of the protonated molecule show some differences when compared with those of the sodium ion adduct. The methoxy group of amino acid methyl ester can migrate from the carbonyl group to the phosphoryl group in the sodium ion adduct.展开更多
Cathelicidin Pc-CATH1 is a cathelicidin-derived myeloid antimicrobial peptide identified from Phasianus colchicus with strong antimicrobial activity against most of bacteria and fungi tested,including the clinically i...Cathelicidin Pc-CATH1 is a cathelicidin-derived myeloid antimicrobial peptide identified from Phasianus colchicus with strong antimicrobial activity against most of bacteria and fungi tested,including the clinically isolated(IS)drug-resistant strains.Considering the uniform distribution of net positive charge in both C-and N-terminus sequence of cathelicidin Pc-CATH1 and most of hydrophobic amino acid(aa)residues positioned in middle of the sequence,the antimicrobial peptide was used to investigate the structure-function relationship by truncating gradually N-or C-terminus amino acid residue.More than 10 modified peptide homo-logues(20-26 aa length)of cathelicidin Pc-CATH1 were found to keep strong antimicrobial abilities.The possible relationships between bioactivities including antimicrobial and hemolytic abilities,components of secondary structure,hydrophobicity,amphipathicity,net charge,and sequence length were investigated.The current work provided suggestions for structural and functional modification of linear,α-helical antimicrobial peptides containing no disulfided bridges.展开更多
Here, we report an observation that illustrate the potential of polyelectrolyte microgels in salt-free solutions to display a high ionic conductivity. Laser light scattering and ionic conductivity tests on very dilute...Here, we report an observation that illustrate the potential of polyelectrolyte microgels in salt-free solutions to display a high ionic conductivity. Laser light scattering and ionic conductivity tests on very dilute aqueous dispersions of the microgels indicate that both small size and swollen state of gel particles play vital roles, which should favor the counterions to freely penetrate and leave gel particles, and thus can contribute to the ion-conducting property. Upon discovering this on microgels that are composed of imidazolium-based poly(ionic liquid), we also illustrate the generality of the finding to single lithium-ion polyelectrolyte microgels that are of more technically relevant features for applications, for instance, as injectable liquid “microgel-in-solution” electrolytes of high conductivity(ca. 8.2 × 10^(-2)S/m at 25.0 ℃ for1.0 × 10^(-2)g/m L of microgels in a LiNO_(3)-free 1:1 v/v mixture of 1,2-dioxolane and dimethoxymethane) and high lithium-ion transference number(0.87) for use in the rechargeable lithium-sulfur battery.展开更多
Developing practical strategies for the synthesis of organophosphorus compounds(OPCs)from white phosphorus(P_(4))without the use of Cl_(2) and PCl_(3) remains a significant challenge.The first multicomponent oxidative...Developing practical strategies for the synthesis of organophosphorus compounds(OPCs)from white phosphorus(P_(4))without the use of Cl_(2) and PCl_(3) remains a significant challenge.The first multicomponent oxidative α-phosphonylation of amines with P_(4) and alcohols has been developed.With the use of copper(Ⅱ)as the catalyst and air as the safe oxidant,structurally sophisticated α-aminophosphonates have been prepared in high yields.Furthermore,this method is also suitable for selective construction of P-O-P compounds.The reaction is characterized by a complete conversion of P_(4).The activation of P_(4) with transition metals often leads to formation of complexes[M_(x)P_(y)]_(n) associated with the deactivation of transition metals.This breakthrough showcases the potential of transition-metal-catalyzed reactions in elemental phosphorus chemistry.展开更多
The authors regret that the original version of this article unfortunately contained a mistake[1].It is stated that:“Based on TIRF,another strategy for resolution increase…However,this technique requires the chemica...The authors regret that the original version of this article unfortunately contained a mistake[1].It is stated that:“Based on TIRF,another strategy for resolution increase…However,this technique requires the chemical modification to immobilize an individual particle,which may in turn alter their physical and biochemical properties.”on page 494-495.This is incorrect and should be replaced by:“Another strategy for resolution increase…This technique doesn’t require the chemical modification to immobilize an individual particle,which avoids altering their physical and biochemical properties.”展开更多
Post-translational modification of proteins by N-phosphorylation of the basic amino acid residues plays important roles in biological processes. The high-energy P–N bond might have contributed to the evolution of pre...Post-translational modification of proteins by N-phosphorylation of the basic amino acid residues plays important roles in biological processes. The high-energy P–N bond might have contributed to the evolution of prebiotic chemistry. N-phosphoryl amino acids(PAAs) can serve as interesting small molecular models for the study of P–N bonds in prebiotic chemical evolution. PAAs are capable of simultaneously producing several important biomolecules such as polypeptides and oligonucleotides under mild reaction conditions. In this review, we describe the chemistry of PAAs, discusse their likely prebiotic origins and their reactivity and how they relate to biological P–N bond species. We also depict a possible prebiotic scenario mediated by PAAs in which PAAs may have acted as one of the essential forces driving prebiotic biomolecules to the first protocell.展开更多
Gold-catalyzed nucleophilic addition to terminal alkynes has received considerable interest in the past decade, as this chemistry offers a highly efficient and regioselective way for CAC, CAH and CAX bond formation. H...Gold-catalyzed nucleophilic addition to terminal alkynes has received considerable interest in the past decade, as this chemistry offers a highly efficient and regioselective way for CAC, CAH and CAX bond formation. However, such a nucleophilic addition mainly involves a Markovnikov addition. In this short review, the recent progress of the gold-catalyzed 5-endo-dig cycloisomerization-initiated tandem reactions by utilizing the steric strain in ring formation to achieve an anti-Markovnikov regioselectivity was reviewed, including the scope of reactions, mechanism and synthetic applications.展开更多
Circulating tumor cells(CTCs),as important liquid biopsy target,can provide valuable information for cancer progress monitoring and individualized treatment.However,current isolation platforms incapable of balancing c...Circulating tumor cells(CTCs),as important liquid biopsy target,can provide valuable information for cancer progress monitoring and individualized treatment.However,current isolation platforms incapable of balancing capture efficiency,specificity,cell viability,and gentle release have restricted the clinical applications of CTCs.Herein,inspired by the structure and functional merits of natural membrane interfaces,we established an antibody-engineered red blood cell(RBC-Ab)affinity interface on microfluidic chip for high-performance isolation and release of CTCs.The lateral fluidity,pliability,and anti-adhesion property of the RBC microfluidic interface enabled efficient CTCs capture(96.5%),high CTCs viability(96.1%),and high CTCs purity(average 4.2-log depletion of leukocytes).More importantly,selective lysis of RBCs by simply changing the salt concentration was utilized to destroy the affinity interface for efficient and gentle release of CTCs without nucleic acid contamination.Using this chip,CTCs were successfully detected in colon cancer samples with 90%sensitivity and 100%specificity(20 patients and 10 healthy individuals).After the release process,KRAS gene mutations of CTCs were identified from all the 5 cancer samples,which was consistent with the results of tissue biopsy.We expect this RBC interface strategy will inspire further biomimetic interface construction for rare cell analysis.展开更多
Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal convers...Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal conversion.Also,their anti-bacterial and antifouling performances are crucial for the practical application.Herein,we introduce reduced graphene oxide(RGO)with broadband absorbance across the entire solar spectrum,and polypyrrole(PPy),an antibacterial polymer with efficient solar absorption and low thermal conductivity,to develop integrated RGO/PPy aerogel as both the solar absorber and evaporator for highly efficient solar-driven steam generation.As a result,the RGO/PPy aerogel shows strong absorption and good photothermal performance,leading to an evaporation rate of 1.44 kg·m^(−2)·h^(−1)and high salt rejection(up to 99.99%)for real seawater,with photothermal conversion efficiency>90%under one sun irradiation.The result is attributed to the localized heat at the air-water interface by the RGO/PPy and its porous nature with functional groups that facilitates the water evaporation.Moreover,the RGO/PPy demonstrates excellent durability and antibacterial efficiency close to 100%for 12 h,crucial characteristics for longterm application.Our well-designed RGO/PPy aerogel with efficient water desalination performance and antibacterial property provides a straightforward approach to improve the solar-driven evaporation performance by multifunctional materials integration,and offers a viable route towards practical seawater desalination.展开更多
Lipid-based nanomedicines(LBNMs),including liposomes,lipid nanoparticles(LNPs)and extracellular vesicles(EVs),are recognized as one of the most clinically acceptable nano-formulations.However,the bench-to-bedside tran...Lipid-based nanomedicines(LBNMs),including liposomes,lipid nanoparticles(LNPs)and extracellular vesicles(EVs),are recognized as one of the most clinically acceptable nano-formulations.However,the bench-to-bedside translation efficiency is far from satisfactory,mainly due to the lack of in-depth understanding of their physical and biochemical attributes at the single-particle level.In this review,we first give a brief introduction of LBNMs,highlighting some milestones and related scientific and clinical achievements in the past several decades,as well as the grand challenges in the characterization of LBNMs.Next,we present an overview of each category of LB-NMs as well as the core properties that largely dictate their biological characteristics and clinical performance,such as size distribution,particle concentration,morphology,drug encapsulation and surface properties.Then,the recent applications of several analytical techniques including electron microscopy,atomic force microscopy,fluorescence microscopy,Raman microscopy,nanoparticle tracking analysis,tunable resistive pulse sensing and flow cytometry on the single-particle characterization of LBNMs are thoroughly discussed.Particularly,the com-parative advantages of the newly developed nano-flow cytometry that enables quantitative analysis of both the physical and biochemical characteristics of LBNMs smaller than 40 nm with high throughput and statistical ro-bustness are emphasized.The overall aim of this review article is to illustrate the importance,challenges and achievements associated with single-particle characterization of LBNMs.展开更多
Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.C...Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.Current methods for trace lanthanides detection mainly rely on sophisticated instruments.In this article,a Ln^(3+)dependent DNAzyme was incorporated into a hydrogel to generate Ln^(3+)sensitive DNAzyme hydrogel for portable colorimetric detection.The enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles(AuNPs)as the indicator of hydrogel stability.Any ions in the Ln^(3+)series can trigger the cleavage of substrate strand by activating the enzyme strand,thereby decreasing the crosslink ratio and leading to collapse of the hydrogel.The release of the encapsulated AuNPs turns the supernatant wine red.Using this colorimetric method,Ln^(3+)can be detected with high sensitivity,with a limit of detection(LOD)of 20 nM for Ce^(3+).The hydrogel responds specifically to any Ln^(3+)ion and works well with the spiked lake sample without the need of instruments and skilled operators.Our results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln^(3+)contamination in the field.展开更多
Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2....Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2.0]compounds in generally good to excellent yields with broad substrate scope under mild reaction conditions.Importantly,this protocol not only constitutes a rare example of non-noble metal-catalyzed alkyne carbocyclization,but also represents a rare cyclization on the B-position ofπu-tethered ynamides.The possibility of asymmetric carbocyclization via kinetic resolution also emerges.展开更多
Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral ...Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Br■nsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities.展开更多
Catalytic asymmetric transformations of ynamides have attracted considerable attention in recent years.However,most of them were limited to intramolecular reactions or required metal catalysts.Herein,a chiral Br?nsted...Catalytic asymmetric transformations of ynamides have attracted considerable attention in recent years.However,most of them were limited to intramolecular reactions or required metal catalysts.Herein,a chiral Br?nsted acid-catalyzed asymmetric intermolecular[4+2]annulation of ynamides with para-quinone methides(p-QMs)is disclosed,which not only represents the first metal-free protocol for catalytic asymmetric nucleophilic addition of ynamides to electrophiles,but also constitutes the first enantioselective annulation between p-QMs and alkynes.This methodology leads to the practical synthesis of biologically important chiral 4-aryl-3,4-dihydrocoumarins and 4-aryl-coumarins.Preliminary control experiments indicate that the orthohydroxyphenyl substituted p-QMs could isomerize into ortho-quinone methides(o-QMs)in the presence of chiral catalyst,which further react with ynamides via enantioselective[4+2]annulation,to generate the chiral product.展开更多
Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the singl...Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.展开更多
基金Supported by the National Natural Science Foundation of China (No.20376076).
文摘Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag(NH3)2]+ to Ag0 in the solution into which some amount of OH- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solu-tion. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.
基金This work was financially supported by the National Natural Science Foundation of China(No.21978245)National Postdoctoral Program for Innovative Talents(No.BX20200197).
文摘Cells employ proteins to perform metabolic functions and maintain active physiological state through charge transfer and energy conversion.These processes are carried out in a narrow space precisely and rapidly,which,no doubt,bring great difficulty for their detection and dissection.Fortunately,in recent years,the development and expansion of single-molecule technique in protein research make monitoring the dynamical changes of protein at single-molecule level a reality,which also provides a powerful tool for the further exploration of new phenomena and new mechanisms of life activities.This paper aims to summarize the working principle and essential achievements of single-molecule technique in protein research in recent five years.We focus on not only dissecting the difference of nanopores,atomic force microscope,scanning tunneling microscope,and optical tweezers technique,but also discussing the great significance of these single-molecule techniques in investigating intramolecular and intermolecular interactions,electron transport,and conformational changes.Finally,the opportunities and challenges of the single-molecule technique in protein research are discussed,which provide a new door for single-molecule protein research.
基金supported by the National Natural Science Foundation of China(Nos.21105091 and 21171149)
文摘Two new a-aminophosphonate derivatives containing thieno[2,3-d]pyrimidine, diethyl(((6-ethyl-2-methyl-4-oxothieno[2,3-d]pyrimidin-3 (4H)-yl)amino)(4-methoxyphenyl)methyl) phosphonate (1) and diethyl((4-bromophenyl)((6-ethyl-2-methyl-4-oxothieno[2,3-d]pyrimidin-3 (4//)-yl)amino)methyl)phosphonate (2), have been synthesized by a facial phosphorylated reaction, and their structures were characterized by NMR, IR, HRMS and X-ray single-crystal diffraction. Compound 1 (C21H28N3O5PS, Mr = 465.49) belongs to the orthorhombic system, space group P212121, with a = 10.83653(16), b = 12.04906(19), c = 18.0061(3) A, V= 2351.06(6) A3, Z= 4, Dc= 1.315 g/cm3, p = 2.177 mm-1, F(000) = 984.0, the final R = 0.0389 and wR = 0.0985 for all data. Compound 2 (C20H25BrN304PS, Mr = 514.37) belongs to the orthorhombic system, space group P212121, with a = 10.9187(5), b = 11.9522(4), c = 17.7667(7) A, V= 2318.60(16) A3, Z = 4, Dc= 1.474 g/cm3,μ = 4.175 mm^-1, F(000) = 1056.0, the final R = 0.0367 and wR = 0.0946 for all data.
基金supported in part by National Natural Scientific Foundation of China(8l072148,30760248,30660185,30000203)Program for New Century Excellent Talents in University of China(NCET-06-0761)+6 种基金International Cooperation Project of The Ministry of Science and Technology of the People's Republic of China(2008DFA31380)Project of Scentific Activity of Ministry of Personnel for Returnee (2007-170)Program of Science and Technology of Hunan Province(06SK4060)Program of Science and Technology of Hainan Province(070210)Program of Science and Technology of Fujian Province(2008-59-08)Project of Medical Innovation of Fujian Province(2007CX18)Program of Science and Technology of Xiamen (3502Z20084012)
文摘Objective:To investigate the effect of fusion proteins expressed by the fused gene of porcineα1,3 galactosyltransierase(α1,3 GT) and enhanced green fluorescent protein(EGFP) on the green fluorescence intensity of EGFP.Methods:The fragment containingα1.3GT was firstly recovered after the pcDNA3.1-α1.3GT recombinant vector were digested with BamHl and EcoRI,and then,the resultant fragment was ligated to the pEGFP-N1 vector which was also digested with the same enzymes.The new recombinant eukaryotic expression pEGFP/a 1,3GT vector was obtained and sequenced.The pEGFP/α1,3GT was used to transfect human lung carcinoma cells A549 and HEKC 293FT,and the expression of EGFP was quantitatively analyzed by fluorescent microscope and flow cytometry.Results:The positive percentage of A549 was 80.5%,and that of 293 FT was 86.5%48 hours after the two cell lines both were transfected by pEGFP-N1.The positive percentage of A549 was 75.8%,and that of 293 FT was 81.2%48 hours after the two cell lines were transfected by pEGFP/α1.3GT.The mean fluorescence intensities of A549 transfected with pEGFP-N1 and pEGFP/α1.3GT were 1.21 and 0.956,respectively when compared with that of A549 without transfection.Meanwhile,the those of the 293FT that were transfected with pEGFP-N1 and pEGFP/αl,3GT were 7.66 and 1.00.respectively when compared with that of 293FT cells without transfection.Conclusions:These results suggested that the expression of EGFP gene fused with porcineα1,3GT gene was partly inhibited.
基金supported by the China Scholarship Council and Fujian University-Industry Research Cooperation Project(Project No.:2018N5013)。
文摘P450 fatty acid decarboxylase Ole T from Staphylococcus aureus(Ole TSA)is a novel cytochrome P450 enzyme that catalyzes the oxidative decarboxylation of fatty acids to yield primarily terminal alkenes and CO_(2) or minor a-andβ-hydroxylated fatty acids as side-products.In this work,the interactions between a series of cycloalkyl phosphorus heterocycles(CPHs)and Ole TSAwere investigated in detail by fluorescence titration experiment,ultraviolet-visible(UV-vis)and31 P NMR spectroscopies.Fluorescence titration experiment results clearly showed that a dynamic quenching occurred when CPH-6,a representative CPHs,interacted with Ole TSAwith a binding constant value of 15.2×104 M-1 at 293 K.The thermodynamic parameters(ΔH,ΔS andΔG)showed that the hydrogen bond and van der Waals force played major roles in the interaction between Ole TSAand CPHs.The UV-vis and31 P NMR studies indicated the penetration of CPH-6 into the interior environment of Ole TSA,which greatly affects the enzymatic activity of Ole TSA.Therefore,our study revealed an effective way to use phosphorus heterocyclic compounds to modulate the activity of cytochrome P450 enzymes.
基金Supported by the National Natural Science Foundation of China(No.20572061).
文摘Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation pathways were investigated, and it was observed that most fragment ions contained the phosphoryl group. It was interesting to observe that the fragmentation pathways of the protonated molecule show some differences when compared with those of the sodium ion adduct. The methoxy group of amino acid methyl ester can migrate from the carbonyl group to the phosphoryl group in the sodium ion adduct.
基金supported by Chinese National Natural Science Foundation(31070701,31000962,31025025,30730026)the Program of Shanghai Subject Chief Scientist(NO.09XD1405100)+1 种基金the Ministry of Science and Technology(2010CB529800,2009ZX09103-1/091,2011ZX09102-002-10)the Ministry of Agriculture(2009ZX08009-159B).
文摘Cathelicidin Pc-CATH1 is a cathelicidin-derived myeloid antimicrobial peptide identified from Phasianus colchicus with strong antimicrobial activity against most of bacteria and fungi tested,including the clinically isolated(IS)drug-resistant strains.Considering the uniform distribution of net positive charge in both C-and N-terminus sequence of cathelicidin Pc-CATH1 and most of hydrophobic amino acid(aa)residues positioned in middle of the sequence,the antimicrobial peptide was used to investigate the structure-function relationship by truncating gradually N-or C-terminus amino acid residue.More than 10 modified peptide homo-logues(20-26 aa length)of cathelicidin Pc-CATH1 were found to keep strong antimicrobial abilities.The possible relationships between bioactivities including antimicrobial and hemolytic abilities,components of secondary structure,hydrophobicity,amphipathicity,net charge,and sequence length were investigated.The current work provided suggestions for structural and functional modification of linear,α-helical antimicrobial peptides containing no disulfided bridges.
基金supported by National Natural Science Foundation of China (Nos.21774105 and 20923004)Chuying Plan Youth Topnotch Talents of Fujian Province,National Fund for Fostering Talents of Basic Science (No.J1310024)。
文摘Here, we report an observation that illustrate the potential of polyelectrolyte microgels in salt-free solutions to display a high ionic conductivity. Laser light scattering and ionic conductivity tests on very dilute aqueous dispersions of the microgels indicate that both small size and swollen state of gel particles play vital roles, which should favor the counterions to freely penetrate and leave gel particles, and thus can contribute to the ion-conducting property. Upon discovering this on microgels that are composed of imidazolium-based poly(ionic liquid), we also illustrate the generality of the finding to single lithium-ion polyelectrolyte microgels that are of more technically relevant features for applications, for instance, as injectable liquid “microgel-in-solution” electrolytes of high conductivity(ca. 8.2 × 10^(-2)S/m at 25.0 ℃ for1.0 × 10^(-2)g/m L of microgels in a LiNO_(3)-free 1:1 v/v mixture of 1,2-dioxolane and dimethoxymethane) and high lithium-ion transference number(0.87) for use in the rechargeable lithium-sulfur battery.
基金the National Key Research and Development Program of China(grant no.2020YFA0608300)the Space Application System of China Manned Space Program(grant no.KJZ-YY-WSM01)National Natural Science Foundation of China(grant nos.21772163,21778042,and 41876072).
文摘Developing practical strategies for the synthesis of organophosphorus compounds(OPCs)from white phosphorus(P_(4))without the use of Cl_(2) and PCl_(3) remains a significant challenge.The first multicomponent oxidative α-phosphonylation of amines with P_(4) and alcohols has been developed.With the use of copper(Ⅱ)as the catalyst and air as the safe oxidant,structurally sophisticated α-aminophosphonates have been prepared in high yields.Furthermore,this method is also suitable for selective construction of P-O-P compounds.The reaction is characterized by a complete conversion of P_(4).The activation of P_(4) with transition metals often leads to formation of complexes[M_(x)P_(y)]_(n) associated with the deactivation of transition metals.This breakthrough showcases the potential of transition-metal-catalyzed reactions in elemental phosphorus chemistry.
文摘The authors regret that the original version of this article unfortunately contained a mistake[1].It is stated that:“Based on TIRF,another strategy for resolution increase…However,this technique requires the chemical modification to immobilize an individual particle,which may in turn alter their physical and biochemical properties.”on page 494-495.This is incorrect and should be replaced by:“Another strategy for resolution increase…This technique doesn’t require the chemical modification to immobilize an individual particle,which avoids altering their physical and biochemical properties.”
基金supported by the National Basic Research Program of China(2013CB910700,2012CB821600)the National Natural Science Foundation of China(21232005,21375113,21305115)the Program of Chinese Ministry of Education for Changjiang Scholars and Innovative Research Team in University
文摘Post-translational modification of proteins by N-phosphorylation of the basic amino acid residues plays important roles in biological processes. The high-energy P–N bond might have contributed to the evolution of prebiotic chemistry. N-phosphoryl amino acids(PAAs) can serve as interesting small molecular models for the study of P–N bonds in prebiotic chemical evolution. PAAs are capable of simultaneously producing several important biomolecules such as polypeptides and oligonucleotides under mild reaction conditions. In this review, we describe the chemistry of PAAs, discusse their likely prebiotic origins and their reactivity and how they relate to biological P–N bond species. We also depict a possible prebiotic scenario mediated by PAAs in which PAAs may have acted as one of the essential forces driving prebiotic biomolecules to the first protocell.
基金supported by the National Natural Science Foundation of China(21272191,21572186 and 21622204)the Natural Science Foundation of Fujian Province for Distinguished Young Scholars(2015J06003)+1 种基金the President Research Funds from Xiamen University(20720150045)NFFTBS(J1310024)
文摘Gold-catalyzed nucleophilic addition to terminal alkynes has received considerable interest in the past decade, as this chemistry offers a highly efficient and regioselective way for CAC, CAH and CAX bond formation. However, such a nucleophilic addition mainly involves a Markovnikov addition. In this short review, the recent progress of the gold-catalyzed 5-endo-dig cycloisomerization-initiated tandem reactions by utilizing the steric strain in ring formation to achieve an anti-Markovnikov regioselectivity was reviewed, including the scope of reactions, mechanism and synthetic applications.
基金the National Natural Science Foundation of China(21775128,21974113,21735004,21974112,and 21874089)National Key R&D Program of China(2019YFA0905800)+2 种基金Program for Chang Jiang Scholars and Innovative Research Teams in University(IRT13036)Medical and Health Program of Xiamen(3502Z20189005)the National Science Fund for Fostering Talents in Basic Science(NFFTBS,J1310024)for their financial support.
文摘Circulating tumor cells(CTCs),as important liquid biopsy target,can provide valuable information for cancer progress monitoring and individualized treatment.However,current isolation platforms incapable of balancing capture efficiency,specificity,cell viability,and gentle release have restricted the clinical applications of CTCs.Herein,inspired by the structure and functional merits of natural membrane interfaces,we established an antibody-engineered red blood cell(RBC-Ab)affinity interface on microfluidic chip for high-performance isolation and release of CTCs.The lateral fluidity,pliability,and anti-adhesion property of the RBC microfluidic interface enabled efficient CTCs capture(96.5%),high CTCs viability(96.1%),and high CTCs purity(average 4.2-log depletion of leukocytes).More importantly,selective lysis of RBCs by simply changing the salt concentration was utilized to destroy the affinity interface for efficient and gentle release of CTCs without nucleic acid contamination.Using this chip,CTCs were successfully detected in colon cancer samples with 90%sensitivity and 100%specificity(20 patients and 10 healthy individuals).After the release process,KRAS gene mutations of CTCs were identified from all the 5 cancer samples,which was consistent with the results of tissue biopsy.We expect this RBC interface strategy will inspire further biomimetic interface construction for rare cell analysis.
基金supported by the National Key R&D Program of China(Nos.2018YFA0209500 and 2018YFA0306900)the National Natural Science Foundation of China(Nos.21872114 and 21627811).
文摘Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal conversion.Also,their anti-bacterial and antifouling performances are crucial for the practical application.Herein,we introduce reduced graphene oxide(RGO)with broadband absorbance across the entire solar spectrum,and polypyrrole(PPy),an antibacterial polymer with efficient solar absorption and low thermal conductivity,to develop integrated RGO/PPy aerogel as both the solar absorber and evaporator for highly efficient solar-driven steam generation.As a result,the RGO/PPy aerogel shows strong absorption and good photothermal performance,leading to an evaporation rate of 1.44 kg·m^(−2)·h^(−1)and high salt rejection(up to 99.99%)for real seawater,with photothermal conversion efficiency>90%under one sun irradiation.The result is attributed to the localized heat at the air-water interface by the RGO/PPy and its porous nature with functional groups that facilitates the water evaporation.Moreover,the RGO/PPy demonstrates excellent durability and antibacterial efficiency close to 100%for 12 h,crucial characteristics for longterm application.Our well-designed RGO/PPy aerogel with efficient water desalination performance and antibacterial property provides a straightforward approach to improve the solar-driven evaporation performance by multifunctional materials integration,and offers a viable route towards practical seawater desalination.
基金We are grateful to the National Natural Science Foundation of China(21934004,21627811)the National Key R&D Program of China(2021YFA0909400)the Natural Science Foundation of Fujian Province(2022J01329)for financial support.
文摘Lipid-based nanomedicines(LBNMs),including liposomes,lipid nanoparticles(LNPs)and extracellular vesicles(EVs),are recognized as one of the most clinically acceptable nano-formulations.However,the bench-to-bedside translation efficiency is far from satisfactory,mainly due to the lack of in-depth understanding of their physical and biochemical attributes at the single-particle level.In this review,we first give a brief introduction of LBNMs,highlighting some milestones and related scientific and clinical achievements in the past several decades,as well as the grand challenges in the characterization of LBNMs.Next,we present an overview of each category of LB-NMs as well as the core properties that largely dictate their biological characteristics and clinical performance,such as size distribution,particle concentration,morphology,drug encapsulation and surface properties.Then,the recent applications of several analytical techniques including electron microscopy,atomic force microscopy,fluorescence microscopy,Raman microscopy,nanoparticle tracking analysis,tunable resistive pulse sensing and flow cytometry on the single-particle characterization of LBNMs are thoroughly discussed.Particularly,the com-parative advantages of the newly developed nano-flow cytometry that enables quantitative analysis of both the physical and biochemical characteristics of LBNMs smaller than 40 nm with high throughput and statistical ro-bustness are emphasized.The overall aim of this review article is to illustrate the importance,challenges and achievements associated with single-particle characterization of LBNMs.
基金supported by the National Basic Research Program of China(2013CB933703)the National Natural Science Foundation of China(91313302,21205100,21275122,21075104)+2 种基金the National Instrumentation Program(2011YQ03012412)the National Found for Fostering Talents of Basic Science(J1310024)the National Science Foundation for Distinguished Young Scholars(21325522)
文摘Lanthanide elements(Ln)play an important role in industry and agriculture.As a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and fauna.Current methods for trace lanthanides detection mainly rely on sophisticated instruments.In this article,a Ln^(3+)dependent DNAzyme was incorporated into a hydrogel to generate Ln^(3+)sensitive DNAzyme hydrogel for portable colorimetric detection.The enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles(AuNPs)as the indicator of hydrogel stability.Any ions in the Ln^(3+)series can trigger the cleavage of substrate strand by activating the enzyme strand,thereby decreasing the crosslink ratio and leading to collapse of the hydrogel.The release of the encapsulated AuNPs turns the supernatant wine red.Using this colorimetric method,Ln^(3+)can be detected with high sensitivity,with a limit of detection(LOD)of 20 nM for Ce^(3+).The hydrogel responds specifically to any Ln^(3+)ion and works well with the spiked lake sample without the need of instruments and skilled operators.Our results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln^(3+)contamination in the field.
基金We are grateful for financial support from the National Natural Science Foundation of China(Nos.21772161 and 21622204)the Natural Science Foundation of Fujian Province of China(No.2019J02001)+1 种基金the President Research Funds from Xiamen University(No.20720180036)NFFTBS(No.J1310024),PCSIRT,and Science&Technology Cooperation Program of Xiamen(No.3502Z20183015).
文摘Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2.0]compounds in generally good to excellent yields with broad substrate scope under mild reaction conditions.Importantly,this protocol not only constitutes a rare example of non-noble metal-catalyzed alkyne carbocyclization,but also represents a rare cyclization on the B-position ofπu-tethered ynamides.The possibility of asymmetric carbocyclization via kinetic resolution also emerges.
基金financial support from the National Natural Science Foundation of China(Nos.22125108,22101238,92056104 and 21772161)the China Postdoctoral Science Foundation(No.2020M680087)+3 种基金the Natural Science Foundation of Fujian Province of China(No.2019J02001)the President Research Funds from Xiamen University(No.20720210002)the Fundamental Research Funds for the Central Universities(No.20720202008)NFFTBS(No.J1310024)。
文摘Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Br■nsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities.
基金supported by the Ministry of Science and Technology(MOST)(2021YFC2100100)the National Natural Science Foundation of China(22125108,22121001,92056104)+3 种基金the President Research Funds from Xiamen University(20720210002)the Natural Science Foundation of Jiangsu Province(BK20211059)the Project of Science and Technology of Xuzhou Government(KC22080)the National Fund for Fostering Talents of Basic Science(NFFTBS)(J1310024)。
文摘Catalytic asymmetric transformations of ynamides have attracted considerable attention in recent years.However,most of them were limited to intramolecular reactions or required metal catalysts.Herein,a chiral Br?nsted acid-catalyzed asymmetric intermolecular[4+2]annulation of ynamides with para-quinone methides(p-QMs)is disclosed,which not only represents the first metal-free protocol for catalytic asymmetric nucleophilic addition of ynamides to electrophiles,but also constitutes the first enantioselective annulation between p-QMs and alkynes.This methodology leads to the practical synthesis of biologically important chiral 4-aryl-3,4-dihydrocoumarins and 4-aryl-coumarins.Preliminary control experiments indicate that the orthohydroxyphenyl substituted p-QMs could isomerize into ortho-quinone methides(o-QMs)in the presence of chiral catalyst,which further react with ynamides via enantioselective[4+2]annulation,to generate the chiral product.
基金the National Key Basic Research Program of China(2013CB933703)the National Natural Science Foundation of China(91313302,21105082,21225523,21472158,21027010,21521004)the Program for Changjiang Scholars and Innovative Research Team in University(IRT13036)
文摘Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.