This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed ...This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed using real-time quantitative polymerase chain reaction(RT-qPCR)within both the patient tissue specimens and glioblastoma cell lines.The relationship between lncRNA DPP10-AS1 expression in glioblastoma and patient prognosis was investigated.Cell Counting Kit-8(CCK-8),transwell,and clonogenic experiments were utilized to assess tumor cells’proliferation,invasiveness,and migratory potentials after lncRNA DPP10-AS1 expression was up or down-regulated.Using an online bioinformatics prediction tool,the intracellular localization of lncRNA DPP10-AS1 and its target miRNA were predicted,and RNA-FISH verified results.A dual-luciferase reporter experiment validated the relationship across miR-24-3p together with lncRNA DPP10-AS1.MiR-24-3p expression within glioblastoma was identified through RT-qPCR,and potential link across miR-24-3p and lncRNA DPP10-AS1 was assessed using Pearson correlation analysis.Moreover,influence from lncRNA DPP10-AS1/miR-24-3p axis upon glioblastoma cell progression was assessed in vivo via a subcutaneous xenograft tumor model.Results:The expression of lncRNA DPP10-AS1 was notably reduced in both surgical specimens of glioblastoma and the equivalent cell lines.Low level of lncRNA DPP10-AS1 in glioblastoma is following poor prognosis.The downregulation of lncRNA DPP10-AS1 in glioblastoma cells resulted in enhanced cellular proliferation,migration,and invasion capabilities,accompanied by downregulated E-cadherin and upregulated vimentin and N-cadherin.Additionally,the observed upregulation of lncRNA DPP10-AS1 demonstrated a substantial inhibitory function upon proliferation,invasion,and migratory capabilities of LN229 cells.Subcellular localization disclosed that lncRNA DPP10-AS1 had a binding site that interacted with miR-24-3p.Upregulated miR-24-3p was detected in glioblastomas,displaying an inverse correlation with lncRNA DPP10-AS1 expression.MiR-24-3p downstream target has been determined as chromodomain helicase DNA binding protein 5(CHD5).LncRNA DPP10-AS1 affected the invasion and proliferation of glioblastoma by controlling the miR-24-3p/CHD5 axis.Conclusion:The present study demonstrated that lncRNA DPP10-AS1 can inhibit the invasive,migratory,and proliferative properties of glioblastoma by regulating the miR-24-3p/CHD5 signaling pathway.Consequently,lncRNA DPP10-AS1 has potential as a tumor suppressor and might be utilized for accurate diagnosis and targeted treatments of glioblastomas.展开更多
The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monito...The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monitored directly with radiocarbon(14 C).In this research,annual plants[Setaria viridis(L.)Beauv.]were collected from 26 sites in 2013 and2014 in the central urban district of Xi’an City.The△14C content of the samples were analyzed using a 3 MV Accelerator Mass Spectrometer,and CO2ff concentrations were calculated based on mass balance equations.The results showed that the CO2ff mixing ratio ranged from 15.9 to 25.0 ppm(part per million,equivalent toμmol mol-1),with an average of 20.5 ppm in 2013.The range of measured values became larger in 2014,from 13.9 ppm to 33.1 ppm,with an average of 23.5 ppm.The differences among the average CO2ff concentrations between the central area and outer urban areas were not statistically significant.Although the year-to-year variation of the CO2ff concentration was significant(P<0.01),there was a distinctly low CO2 ff value observed in the northeast corner of the city.CO2 ff emiissions from vehicle exhaust and residential sources appeared to be more significant than two thermal power plants,according to our observed CO2 ff spatial distribution.The variation of pollution source transport recorded in our observations was likely controlled by southwesterly winds.These results could assist in the optimal placement of regional CO2 monitoring stations,and benefit the local government in the implementation of efficient carbon emission reduction measures.展开更多
Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be ...Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer.However,highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered.Here,we developed a noveSIRT6 allosteric inhibitor,compound 11e,with maximal inhibitory potency and an IC_(50) value of 0.98±0.13μmol/L.Moreover,compound 11e exhibited significant selectivity against other histone deacetylases(HADC1-11 and SIRT1-3)at concentrations up to 100μmol/L.The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses.Importantly,we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis.To our knowledge,this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer.It not only provides a promising lead compound for subsequent inhibitor developmentargeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.展开更多
By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economica...By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economically feasible on industrial scales,exploring and engineering cyanobacterial chassis and cell factories with fast growth rates and carbon fixation activities facing environmental stresses are of great significance.To simplify and accelerate the screening for fast-growing cyanobacteria strains,a method called Individual Cyanobacteria Vitality Tests and Screening(iCyanVS)was established.We show that the ^(13)C incorporation ratio of carotenoids can be used to measure differences in cell growth and carbon fixation rates in individual cyanobacterial cells of distinct genotypes that differ in growth rates in bulk cultivations,thus greatly accelerating the process screening for fastest-growing cells.The feasibility of this approach is further demonstrated by phenotypically and then genotypically identifying individual cyanobacterial cells with higher salt tolerance from an artificial mutant library via Raman-activated gravity-driven encapsulation and sequencing.Therefore,this method should find broad applications in growth rate or carbon intake rate based screening of cyanobacteria and other photosynthetic cell factories.展开更多
(Hetero)cycloarenes possessing rigid molecular skeletons and largeπ-systems are the potential active materials in various electronic devices.However,the development of their organic electronics still lags far behind ...(Hetero)cycloarenes possessing rigid molecular skeletons and largeπ-systems are the potential active materials in various electronic devices.However,the development of their organic electronics still lags far behind the synthetic chemistry.Herein,in order to bridge this gap,we reported the study of organic semiconductor materials based on heterocycloarenes in detail about the relationship between structure,properties,and device performance.Three varying straight alkyl chain substituted butterflyshaped heterocycloarenes PTZs were strategically synthesized.Compared with bulky aryl(mesityl)substituted PTZ1,PTZs show additional self-assembly behavior.Concentration-dependent^(1)H NMR spectra indicated that the self-assembly behavior can be modulated by the alkyl chain length.Medium alkyl chain length substituted heterocycloarene PTZ-C6 showed the strongest association constants of 490 M^(–1)in solution,and a similar trend was also observed in solid state by thin film absorption spectra.Remarkably,despite the nonplanar conjugated backbones,solution-processing thin film transistor based on PTZ-C6 exhibits hole mobility up to 0.13 cm^(2)V^(–1)s^(–1)and considerable current on/off ratio of 10^(5).Our study demonstrates that substituent engineering of heterocycloarenes is a powerful strategy for modulating self-assembling structures and promoting transistor device performance.展开更多
A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic ph...A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic photoresponsive behaviors and intriguing supramolecular assembling properties.The smallest macro-cycle AzoM-1-E with a rigid planar conjugated backbone structure is used to prepare the single crystal transistors,showing reversible optical tunability.The moderate size macrocycle AzoM-2-E assembles into a dimer in the form of interpenetration throughπ-πstacking between azobenzene units.The largest macrocycle AzoM-3-E with enhancedflexibility can adaptively assemble with various types of electron-deficient guests accompanied by distortion of azobenzene.Typically,AzoM-3-E assembles with the planar F4-TCNQ to form a tetragonal geometry by C-F⋅⋅⋅π and π-π interactions,while the assembly with ellipsoidal C70 viaπ-πinteractions induces AzoM-3-E to form a boat-shaped geometry.This work will shed new light on the development of functional conjugated macrocycles in organic electronics.展开更多
A bottom-up precise synthesis for single-walled carbon nanotubes(SWCNTs)can overcome the disadvantages of conventional methods,such as impurities and high structural defects.As potential seeds or templates for the SWC...A bottom-up precise synthesis for single-walled carbon nanotubes(SWCNTs)can overcome the disadvantages of conventional methods,such as impurities and high structural defects.As potential seeds or templates for the SWCNTs bottom-up precise synthesis,carbon nanorings(CNRs)and carbon nanobelts(CNBs)are promising precursors and great progress in their development has been made in recent years[1–9].These molecules are defined as columnar p-conjugated macrocycles,needing the cleavage of at least one CAC bond for CNRs and two CAC bonds for CNBs in order to open their cylindrical skeletons(a macrocyclic arene system connected by single bonds for CNRs,a fully fused macrocyclic arene system for CNBs[9]).In addition,depending on the chiral indices(n,m)of the corresponding carbon nanotubes(CNTs),CNBs are further divided into armchair,chiral,and zigzag types.In this perspective,we will report on recent progress in CNRs and CNBs with a focus on synthetic strategies and molecular structures,and provide a perspective for their future development.展开更多
Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are p...Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are photoautotrophic microorganisms that are the main sources of primary productivity in the biosphere.Cyanobacteria,the only prokaryotic microalgae,have also been considered as promising chassis for photosynthetic biosynthesis,directly converting solar energy and CO_(2)into various bio-based products.This technological route is called photosynthetic biomanufacturing,and is advantageous to simultaneous carbon fixation and clean production.This review focuses on development mode,application and suggests trends related to the further development of photosynthetic biomanufacturing.With regard to the link between photosynthetic CO_(2)fixation and the production of desired metabolites,we summarized and compared three widely adopted strategies.“Screening to find”,screening a large number of high-quality cyanobacterial resources and analyzing their intracellular metabolites are of significance for screening novel cyanobacterial species with high-value chemicals and properties of industrial relevance.“Engineering to modify”,the emergence and application of synthetic biological tools and metabolic engineering strategies have enhanced the ability to modify different cyanobacterial species to reshape more carbon to flow toward synthetic tailored chemicals.“Stressing to activate”,through special culture conditions and strategies,combined with omics analysis techniques,silent metabolic pathways and functional modules are activated to induce the accumulation of high-value chemicals.This review provides valid and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production,providing specific feasible solutions for net zero emissions.展开更多
Plasticizers are essential to reduce processing difficulties and improve plastic properties.However,petroleumbased phthalate plasticizers,which are mostly used at present,urgently require alternatives due to their con...Plasticizers are essential to reduce processing difficulties and improve plastic properties.However,petroleumbased phthalate plasticizers,which are mostly used at present,urgently require alternatives due to their con-firmed and serious health risks.In this study,the green mass production of trans-aconitic acid was achieved via synthetic biotechnology and microbial fermentation,which was further expanded to multiple application sce-narios using chemical esterification,resulting in trans-aconitate plasticizers that are biosafe and environmentally friendly and have high plasticizing efficiency and long-term stability.Different plasticizers with various core structures and alkyl chains were studied to determine their properties as polyvinyl chloride(PVC)plasticizers,and tributyl trans-aconitate displayed the best comprehensive performance with up to 1.24 plasticizing effi-ciency.The possible PVC plasticization mechanism with synergistic solvent,support,and shielding effects was discussed and summarized.Tributyl trans-aconitate has significant potential to replace traditional PVC plasti-cizers in general merchandise,food packaging,medicinal materials,and other products,further promoting the development of the high-quality plastic industry with greener technology and safer applications.展开更多
Carbon is an essential element for human survival and development.Humans,animals and plants,clothing,food,shelter,and transportation are all based on carbon.In the past hundred years,the exploitation of fossil fuels,s...Carbon is an essential element for human survival and development.Humans,animals and plants,clothing,food,shelter,and transportation are all based on carbon.In the past hundred years,the exploitation of fossil fuels,such as coal,petroleum,and natural gas,have greatly im-proved the efficiency of industrial processes and directly advanced the progress of human civilization.At the same time,the continuously in-creasing emissions of greenhouse gases such as CO_(2) have disrupted the carbon balance established on Earth for over more than four billion years.This has led to global warming and an energy crisis with cata-strophic consequences.During the 21st century,green and low-carbon production and lifestyle have become a universal aim and provoked action around the world.展开更多
Aims:Proton pump inhibitors(PPI)are widely used for gastroesophageal varices in patients with cirrhosis after endoscopic therapy,although the effect of PPI on these patients remains controversial.This study aimed to e...Aims:Proton pump inhibitors(PPI)are widely used for gastroesophageal varices in patients with cirrhosis after endoscopic therapy,although the effect of PPI on these patients remains controversial.This study aimed to evaluate the effect of PPI on gastroesophageal varices in patients with cirrhosis after endoscopic therapy,including variceal bleeding and adverse events.Methods:Cirrhotic patients with endoscopically confirmed gastroesophageal varices were enrolled in this study between May 2017 and June 2019.Eligible patients were randomized into two groups:one group received PPI for 14 days and the other group did not receive PPI treatment(n=53 in each group).All patients were followed for 8 weeks.Results:During the follow‐up period,three patients(5.66%)in the PPI group experienced variceal bleeding on days 9,16,and 25 after endoscopic therapy,including two patients with acute bleeding and one with primary prophylaxis.In the non‐PPI group,three patients(5.66%)experienced variceal bleeding on days 7,42,and 56 after endoscopic therapy,including one patient with acute bleeding and two with secondary prophylaxis(p=0.990).The incidence of adverse events was similar between the two groups(37.74%vs.28.30%,p=0.30).Conclusions:PPI did not appear to reduce variceal bleeding and adverse events in patients with cirrhosis after endoscopic therapy.展开更多
Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics...Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.展开更多
The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector pl...The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.展开更多
A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention...A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention and a better resistance to thermal shock fatigue because of its role of the pores as crack arresters.A dense and coherent surface oxide layer leads to a significant benefit in residual strength during thermal fatigue, however, an increased fatigue number to 30 th cycle cannot cause a further influence although a thicker oxide layer presents, which is attributed to holes defect and disappearance of part intergranular phase.展开更多
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as...As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.展开更多
The fatty alk(a/e)ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygena...The fatty alk(a/e)ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygenase (cADO), which catalyzes the conversion of Cn fatty aldehyde to its corresponding Cn-1 alk(ale)ne, is a key enzyme in that pathway. Due to its low activity, alk(a/e)ne production by cADO is an inefficient process. Previous biochemical and structural investi. gations of cADO have provided some information on its catalytic reaction. However, the details of its cata- lytic processes remain unclear. Here we report five crystal structures of cADO from the Synechococcus elongates strain PCC7942 in both its iron-free and iron-bound forms, representing different states during its catalytic process. Structural comparisons and functional enzyme assays indicate that Giu144, one of the iron-coordinating residues, plays a vital role in the catalytic reaction of cADO. Moreover, the helix where Glu144 resides exhibits two distinct conformations that correlates with the different binding states of the di-iron center in cADO structures. Therefore, our results provide a structural explanation for the highly labile feature of cADO di-iron center, which we pro- posed to be related to its low enzymatic activity. On the basis of our structural and biochemical data, a possible catalytic process of cADO was proposed, which could aid the design of cADO with improved activity.展开更多
Cyanobacteria are ancient photosynthetic prokareyotes that have adapted successfully to adverse environments including high-light irradiation. Although it is known that the repair of photodamaged photosystem Ⅱ(PSⅡ...Cyanobacteria are ancient photosynthetic prokareyotes that have adapted successfully to adverse environments including high-light irradiation. Although it is known that the repair of photodamaged photosystem Ⅱ(PSⅡ) in the organisms is a highly regulated process, our knowledge of the molecular components that regulate each step of the process is limited.We have previously identified a hypothetical protein Slr0151 in the membrane fractions of cyanobacterium Synechocystis sp.PCC 6803. Here, we report that Slr0151 is involved in PSⅡ repair of the organism. We generated a mutant strain(Dslr0151)lacking the protein Slr0151 and analyzed its characteristics under normal and high-light conditions. Targeted deletion of slr0151 resulted in decreased PSⅡ activity in Synechocystis. Moreover,the mutant exhibited increased photoinhibition due to impairment of PSⅡ repair under high-light condition. Further analysis using in vivo radioactive labeling and 2-D blue native/sodium dodecylsulfate polyacrylamide gel electrophoresis indicated that the PSⅡ repair cycle was hindered at the levels of D1 synthesis and disassembly and/or assembly of PSⅡ in the mutant. Protein interaction assays demonstrated that Slr0151 interacts with D1 and CP43 proteins. Taken together,these results indicate that Slr0151 plays an important role in regulating PSⅡ repair in the organism under high-light stress condition.展开更多
A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obta...A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obtained TTM radical derivatives are extremely stable during chromatography purification and long-term storage in the solid state.展开更多
Cycloarenes are an essential class of polycyclic aromatic hydrocarbons with unique electronic structure,but their synthesis is very challenging.Herein,we report a facile synthetic strategy primarily involving macrocyc...Cycloarenes are an essential class of polycyclic aromatic hydrocarbons with unique electronic structure,but their synthesis is very challenging.Herein,we report a facile synthetic strategy primarily involving macrocyclization by the Suzuki coupling reaction,followed by bismuth(III)triflate-catalyzed cyclization of vinyl ethers.By utilizing this approach,aryl-substituted soluble cycloarenes 7 and 8 with different sizes were obtained.X-ray crystallographic analysis revealed a slightly distorted backbone in the kekulene derivative 7 and a saddle-shaped skeleton in the octulene derivative 8.Bond length analysis suggested that both of the cycloarenes mainly complied with the Clar’s bonding model with dominant local aromaticity,which was also in accord with our NMR measurements and the theoretical calculations[nucleus-independent chemical shift[NICS],anisotropy of the induced current density(ACID),three-dimensional isochemical shielding surface(3D ICSS)].The optical properties were investigated by UV-Vis absorption and fluorescence spectral measurements.Our method opens opportunities to access various expanded and core-modified cycloarenes in the future.展开更多
基金supported through the Natural Science Foundation of Jiangsu Province(No.BK20201172)the Key Project of the Jiangsu Health Commission(No.ZDB2020016)the Jiangsu Province Key Research and Development Program:Social Development Project(No.BE2021653).
文摘This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed using real-time quantitative polymerase chain reaction(RT-qPCR)within both the patient tissue specimens and glioblastoma cell lines.The relationship between lncRNA DPP10-AS1 expression in glioblastoma and patient prognosis was investigated.Cell Counting Kit-8(CCK-8),transwell,and clonogenic experiments were utilized to assess tumor cells’proliferation,invasiveness,and migratory potentials after lncRNA DPP10-AS1 expression was up or down-regulated.Using an online bioinformatics prediction tool,the intracellular localization of lncRNA DPP10-AS1 and its target miRNA were predicted,and RNA-FISH verified results.A dual-luciferase reporter experiment validated the relationship across miR-24-3p together with lncRNA DPP10-AS1.MiR-24-3p expression within glioblastoma was identified through RT-qPCR,and potential link across miR-24-3p and lncRNA DPP10-AS1 was assessed using Pearson correlation analysis.Moreover,influence from lncRNA DPP10-AS1/miR-24-3p axis upon glioblastoma cell progression was assessed in vivo via a subcutaneous xenograft tumor model.Results:The expression of lncRNA DPP10-AS1 was notably reduced in both surgical specimens of glioblastoma and the equivalent cell lines.Low level of lncRNA DPP10-AS1 in glioblastoma is following poor prognosis.The downregulation of lncRNA DPP10-AS1 in glioblastoma cells resulted in enhanced cellular proliferation,migration,and invasion capabilities,accompanied by downregulated E-cadherin and upregulated vimentin and N-cadherin.Additionally,the observed upregulation of lncRNA DPP10-AS1 demonstrated a substantial inhibitory function upon proliferation,invasion,and migratory capabilities of LN229 cells.Subcellular localization disclosed that lncRNA DPP10-AS1 had a binding site that interacted with miR-24-3p.Upregulated miR-24-3p was detected in glioblastomas,displaying an inverse correlation with lncRNA DPP10-AS1 expression.MiR-24-3p downstream target has been determined as chromodomain helicase DNA binding protein 5(CHD5).LncRNA DPP10-AS1 affected the invasion and proliferation of glioblastoma by controlling the miR-24-3p/CHD5 axis.Conclusion:The present study demonstrated that lncRNA DPP10-AS1 can inhibit the invasive,migratory,and proliferative properties of glioblastoma by regulating the miR-24-3p/CHD5 signaling pathway.Consequently,lncRNA DPP10-AS1 has potential as a tumor suppressor and might be utilized for accurate diagnosis and targeted treatments of glioblastomas.
基金supported by the National Natural Science Foundation of China(Grant No.NSFC41730108,41773141,41573136,and 41991250)National Research Program for Key Issues in Air Pollution Control(Grant No.DQGG0105-02)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23010302)the Youth Innovation Promotion Association CAS(Grant No.2016360)the Natural Science Basic Research Program of Shaanxi(Program No.2019JCW-20)。
文摘The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monitored directly with radiocarbon(14 C).In this research,annual plants[Setaria viridis(L.)Beauv.]were collected from 26 sites in 2013 and2014 in the central urban district of Xi’an City.The△14C content of the samples were analyzed using a 3 MV Accelerator Mass Spectrometer,and CO2ff concentrations were calculated based on mass balance equations.The results showed that the CO2ff mixing ratio ranged from 15.9 to 25.0 ppm(part per million,equivalent toμmol mol-1),with an average of 20.5 ppm in 2013.The range of measured values became larger in 2014,from 13.9 ppm to 33.1 ppm,with an average of 23.5 ppm.The differences among the average CO2ff concentrations between the central area and outer urban areas were not statistically significant.Although the year-to-year variation of the CO2ff concentration was significant(P<0.01),there was a distinctly low CO2 ff value observed in the northeast corner of the city.CO2 ff emiissions from vehicle exhaust and residential sources appeared to be more significant than two thermal power plants,according to our observed CO2 ff spatial distribution.The variation of pollution source transport recorded in our observations was likely controlled by southwesterly winds.These results could assist in the optimal placement of regional CO2 monitoring stations,and benefit the local government in the implementation of efficient carbon emission reduction measures.
基金supported by the National Key R&D Program of China(grant no.2022YFF1203005)the National Natural Science Foundation of China(22237005,81903458,82273425)+1 种基金Innovative research team of high-level local universities in Shanghai(SHSMU-ZDCX20212700,China)China Postdoctoral Science Foundation(2019M660090)。
文摘Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer.However,highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered.Here,we developed a noveSIRT6 allosteric inhibitor,compound 11e,with maximal inhibitory potency and an IC_(50) value of 0.98±0.13μmol/L.Moreover,compound 11e exhibited significant selectivity against other histone deacetylases(HADC1-11 and SIRT1-3)at concentrations up to 100μmol/L.The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses.Importantly,we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis.To our knowledge,this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer.It not only provides a promising lead compound for subsequent inhibitor developmentargeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.
基金supported by the National Key Research and Development Program of China(Grant number 2021YFA0909700)the National Natural Science Foundation of China(Grant numbers 32070084,32270103,32271484,32300058)+3 种基金the Youth Innovation Promotion Association CAS(to Guodong Luan)Postdoctoral Innovation Project of Shandong Province(Grant number SDCX-ZG-202202036)Postdoctoral Science Foundation of China(Grant number 2021M703320)the Shandong Taishan Scholarship(to Xuefeng Lu,and to Guodong Luan).
文摘By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economically feasible on industrial scales,exploring and engineering cyanobacterial chassis and cell factories with fast growth rates and carbon fixation activities facing environmental stresses are of great significance.To simplify and accelerate the screening for fast-growing cyanobacteria strains,a method called Individual Cyanobacteria Vitality Tests and Screening(iCyanVS)was established.We show that the ^(13)C incorporation ratio of carotenoids can be used to measure differences in cell growth and carbon fixation rates in individual cyanobacterial cells of distinct genotypes that differ in growth rates in bulk cultivations,thus greatly accelerating the process screening for fastest-growing cells.The feasibility of this approach is further demonstrated by phenotypically and then genotypically identifying individual cyanobacterial cells with higher salt tolerance from an artificial mutant library via Raman-activated gravity-driven encapsulation and sequencing.Therefore,this method should find broad applications in growth rate or carbon intake rate based screening of cyanobacteria and other photosynthetic cell factories.
基金supported by the National Natural Science Foundation of China(52073063,61890940)the National Key R&D Program of China(2018YFA0703200)+1 种基金the Natural Science Foundation of Shanghai(22ZR1405800 and 23ZR1405100)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning。
文摘(Hetero)cycloarenes possessing rigid molecular skeletons and largeπ-systems are the potential active materials in various electronic devices.However,the development of their organic electronics still lags far behind the synthetic chemistry.Herein,in order to bridge this gap,we reported the study of organic semiconductor materials based on heterocycloarenes in detail about the relationship between structure,properties,and device performance.Three varying straight alkyl chain substituted butterflyshaped heterocycloarenes PTZs were strategically synthesized.Compared with bulky aryl(mesityl)substituted PTZ1,PTZs show additional self-assembly behavior.Concentration-dependent^(1)H NMR spectra indicated that the self-assembly behavior can be modulated by the alkyl chain length.Medium alkyl chain length substituted heterocycloarene PTZ-C6 showed the strongest association constants of 490 M^(–1)in solution,and a similar trend was also observed in solid state by thin film absorption spectra.Remarkably,despite the nonplanar conjugated backbones,solution-processing thin film transistor based on PTZ-C6 exhibits hole mobility up to 0.13 cm^(2)V^(–1)s^(–1)and considerable current on/off ratio of 10^(5).Our study demonstrates that substituent engineering of heterocycloarenes is a powerful strategy for modulating self-assembling structures and promoting transistor device performance.
基金National Key R&D Program of China,Grant/Award Number:2018YFA0703200National Natural Science Foundation of China,Grant/Award Numbers:61890940,52073063+1 种基金Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher LearningNatural Science Foundation of Shanghai,Grant/Award Numbers:22ZR1405800,23ZR1405100。
文摘A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic photoresponsive behaviors and intriguing supramolecular assembling properties.The smallest macro-cycle AzoM-1-E with a rigid planar conjugated backbone structure is used to prepare the single crystal transistors,showing reversible optical tunability.The moderate size macrocycle AzoM-2-E assembles into a dimer in the form of interpenetration throughπ-πstacking between azobenzene units.The largest macrocycle AzoM-3-E with enhancedflexibility can adaptively assemble with various types of electron-deficient guests accompanied by distortion of azobenzene.Typically,AzoM-3-E assembles with the planar F4-TCNQ to form a tetragonal geometry by C-F⋅⋅⋅π and π-π interactions,while the assembly with ellipsoidal C70 viaπ-πinteractions induces AzoM-3-E to form a boat-shaped geometry.This work will shed new light on the development of functional conjugated macrocycles in organic electronics.
基金supported by the National Natural Science Foundation of China(52073063,51903052,and 61890940)the Natural Science Foundation of Shanghai(22ZR1405800)+1 种基金the National Key R&D Program of China(2018YFA0703200)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning.
文摘A bottom-up precise synthesis for single-walled carbon nanotubes(SWCNTs)can overcome the disadvantages of conventional methods,such as impurities and high structural defects.As potential seeds or templates for the SWCNTs bottom-up precise synthesis,carbon nanorings(CNRs)and carbon nanobelts(CNBs)are promising precursors and great progress in their development has been made in recent years[1–9].These molecules are defined as columnar p-conjugated macrocycles,needing the cleavage of at least one CAC bond for CNRs and two CAC bonds for CNBs in order to open their cylindrical skeletons(a macrocyclic arene system connected by single bonds for CNRs,a fully fused macrocyclic arene system for CNBs[9]).In addition,depending on the chiral indices(n,m)of the corresponding carbon nanotubes(CNTs),CNBs are further divided into armchair,chiral,and zigzag types.In this perspective,we will report on recent progress in CNRs and CNBs with a focus on synthetic strategies and molecular structures,and provide a perspective for their future development.
基金supported by the National Key Research and Development Program of China(Grant number 2021YFA0909700,to X.L.and G.L.)the Youth Innovation Promotion Association CAS(to G.L.)+2 种基金the National Natural Science Foundation of China(Grant number 32070084 to G.L.,32270103 to G.L.,32271484 to X.L.,32300058 to J.C.)the DNL Cooperation Fund,CAS(DNL202014,to G.L.)the Shandong Taishan Scholarship(to X.L.and G.L.).
文摘Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are photoautotrophic microorganisms that are the main sources of primary productivity in the biosphere.Cyanobacteria,the only prokaryotic microalgae,have also been considered as promising chassis for photosynthetic biosynthesis,directly converting solar energy and CO_(2)into various bio-based products.This technological route is called photosynthetic biomanufacturing,and is advantageous to simultaneous carbon fixation and clean production.This review focuses on development mode,application and suggests trends related to the further development of photosynthetic biomanufacturing.With regard to the link between photosynthetic CO_(2)fixation and the production of desired metabolites,we summarized and compared three widely adopted strategies.“Screening to find”,screening a large number of high-quality cyanobacterial resources and analyzing their intracellular metabolites are of significance for screening novel cyanobacterial species with high-value chemicals and properties of industrial relevance.“Engineering to modify”,the emergence and application of synthetic biological tools and metabolic engineering strategies have enhanced the ability to modify different cyanobacterial species to reshape more carbon to flow toward synthetic tailored chemicals.“Stressing to activate”,through special culture conditions and strategies,combined with omics analysis techniques,silent metabolic pathways and functional modules are activated to induce the accumulation of high-value chemicals.This review provides valid and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production,providing specific feasible solutions for net zero emissions.
基金National Key R&D Program of China(Grant No.2022YFF1501300)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA 21000000).X.Lu,Q.Wang and X.Huang are supported by the Shandong Taishan Scholarship.
文摘Plasticizers are essential to reduce processing difficulties and improve plastic properties.However,petroleumbased phthalate plasticizers,which are mostly used at present,urgently require alternatives due to their con-firmed and serious health risks.In this study,the green mass production of trans-aconitic acid was achieved via synthetic biotechnology and microbial fermentation,which was further expanded to multiple application sce-narios using chemical esterification,resulting in trans-aconitate plasticizers that are biosafe and environmentally friendly and have high plasticizing efficiency and long-term stability.Different plasticizers with various core structures and alkyl chains were studied to determine their properties as polyvinyl chloride(PVC)plasticizers,and tributyl trans-aconitate displayed the best comprehensive performance with up to 1.24 plasticizing effi-ciency.The possible PVC plasticization mechanism with synergistic solvent,support,and shielding effects was discussed and summarized.Tributyl trans-aconitate has significant potential to replace traditional PVC plasti-cizers in general merchandise,food packaging,medicinal materials,and other products,further promoting the development of the high-quality plastic industry with greener technology and safer applications.
文摘Carbon is an essential element for human survival and development.Humans,animals and plants,clothing,food,shelter,and transportation are all based on carbon.In the past hundred years,the exploitation of fossil fuels,such as coal,petroleum,and natural gas,have greatly im-proved the efficiency of industrial processes and directly advanced the progress of human civilization.At the same time,the continuously in-creasing emissions of greenhouse gases such as CO_(2) have disrupted the carbon balance established on Earth for over more than four billion years.This has led to global warming and an energy crisis with cata-strophic consequences.During the 21st century,green and low-carbon production and lifestyle have become a universal aim and provoked action around the world.
基金supported by the Key Research and Development Program of Shandong Province(NO.2019GSF108254,China).
文摘Aims:Proton pump inhibitors(PPI)are widely used for gastroesophageal varices in patients with cirrhosis after endoscopic therapy,although the effect of PPI on these patients remains controversial.This study aimed to evaluate the effect of PPI on gastroesophageal varices in patients with cirrhosis after endoscopic therapy,including variceal bleeding and adverse events.Methods:Cirrhotic patients with endoscopically confirmed gastroesophageal varices were enrolled in this study between May 2017 and June 2019.Eligible patients were randomized into two groups:one group received PPI for 14 days and the other group did not receive PPI treatment(n=53 in each group).All patients were followed for 8 weeks.Results:During the follow‐up period,three patients(5.66%)in the PPI group experienced variceal bleeding on days 9,16,and 25 after endoscopic therapy,including two patients with acute bleeding and one with primary prophylaxis.In the non‐PPI group,three patients(5.66%)experienced variceal bleeding on days 7,42,and 56 after endoscopic therapy,including one patient with acute bleeding and two with secondary prophylaxis(p=0.990).The incidence of adverse events was similar between the two groups(37.74%vs.28.30%,p=0.30).Conclusions:PPI did not appear to reduce variceal bleeding and adverse events in patients with cirrhosis after endoscopic therapy.
基金supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400800)from the Ministry of Science and Technology of China(MOST)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040400)the Hundred Talent Program of Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant Nos.11233001,11503027,11403026,11473027,and11733009)
文摘Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
基金China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)the National Key Research and Development Program of China(Grant No.2016YFA0400800)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400).
文摘The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.
基金financial support of the project from the National Natural Science Foundation of China (Nos. 51272206 and 51472198)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1280)+2 种基金the National Key Laboratory Functional Composite (No. 9140C560109130C56201)the Fundamental Research Funds for the Central University (No. xkjc2014009)the State Key Laboratory for Mechanical Behavior of Materials (No. 20121207)
文摘A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention and a better resistance to thermal shock fatigue because of its role of the pores as crack arresters.A dense and coherent surface oxide layer leads to a significant benefit in residual strength during thermal fatigue, however, an increased fatigue number to 30 th cycle cannot cause a further influence although a thicker oxide layer presents, which is attributed to holes defect and disappearance of part intergranular phase.
基金project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)support from the National Key Research and Development Program of China(Grant No.2016YFA0400800)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400)the National Natural Science Foundation of China(Grant Nos.U1838201,and U1838102).
文摘As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
基金We would like to thank Yi Han and Shengquan Liu at the Institute of Biophysics, CAS and the staffs at Shanghai Synchrotron Radiation Facility and Photo Factory, Japan, respectively, for help during X-ray data collection. We also thank Wei Shao at Beijing Center for Physical and Chemical Analysis for help with the GC analysis, Zhen Xue at Institute of Botany, CAS for providing help for the GC-QqQ- MS/MS analysis, and Hongzhi Zhang at Institute of Geographic Sciences and Natural Resources Research, CAS for technical support with the metal content analysis by ICP-OES. This work was supported by the National Basic Research Program (973 Program) (Nos. 2011CBA00902 and 2011CBA00907), Strategic Priority Research Program of the Chinese Academy of Sciences (XDB08020302), National Natural Science Foundation of China(Grant Nos. 31021062 and 31170765), and CAS Cross and Coop- eration Team for Scientific Innovation (Y31102110A).
文摘The fatty alk(a/e)ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygenase (cADO), which catalyzes the conversion of Cn fatty aldehyde to its corresponding Cn-1 alk(ale)ne, is a key enzyme in that pathway. Due to its low activity, alk(a/e)ne production by cADO is an inefficient process. Previous biochemical and structural investi. gations of cADO have provided some information on its catalytic reaction. However, the details of its cata- lytic processes remain unclear. Here we report five crystal structures of cADO from the Synechococcus elongates strain PCC7942 in both its iron-free and iron-bound forms, representing different states during its catalytic process. Structural comparisons and functional enzyme assays indicate that Giu144, one of the iron-coordinating residues, plays a vital role in the catalytic reaction of cADO. Moreover, the helix where Glu144 resides exhibits two distinct conformations that correlates with the different binding states of the di-iron center in cADO structures. Therefore, our results provide a structural explanation for the highly labile feature of cADO di-iron center, which we pro- posed to be related to its low enzymatic activity. On the basis of our structural and biochemical data, a possible catalytic process of cADO was proposed, which could aid the design of cADO with improved activity.
基金supported by the National Natural Science Foundation of China (31000018 and 30770037)the Ministry of Science and Technology of China (2009CB220000)+1 种基金the Chinese Academy of Sciencesby grant (M408030) from NTU, Singapore (to B. N.)
文摘Cyanobacteria are ancient photosynthetic prokareyotes that have adapted successfully to adverse environments including high-light irradiation. Although it is known that the repair of photodamaged photosystem Ⅱ(PSⅡ) in the organisms is a highly regulated process, our knowledge of the molecular components that regulate each step of the process is limited.We have previously identified a hypothetical protein Slr0151 in the membrane fractions of cyanobacterium Synechocystis sp.PCC 6803. Here, we report that Slr0151 is involved in PSⅡ repair of the organism. We generated a mutant strain(Dslr0151)lacking the protein Slr0151 and analyzed its characteristics under normal and high-light conditions. Targeted deletion of slr0151 resulted in decreased PSⅡ activity in Synechocystis. Moreover,the mutant exhibited increased photoinhibition due to impairment of PSⅡ repair under high-light condition. Further analysis using in vivo radioactive labeling and 2-D blue native/sodium dodecylsulfate polyacrylamide gel electrophoresis indicated that the PSⅡ repair cycle was hindered at the levels of D1 synthesis and disassembly and/or assembly of PSⅡ in the mutant. Protein interaction assays demonstrated that Slr0151 interacts with D1 and CP43 proteins. Taken together,these results indicate that Slr0151 plays an important role in regulating PSⅡ repair in the organism under high-light stress condition.
基金supported by the National Key Research and Development Program of China(nos.2018YFA0703200 and 2018YFA0209401)the National Natural Science Foundation of China(nos.61890940,52073063,51903052,and 21733003)+1 种基金the Shanghai Pujiang Project(no.19PJ1400700),the Natural Science Foundation of Shanghai(no.21ZR1409600)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning.
文摘A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obtained TTM radical derivatives are extremely stable during chromatography purification and long-term storage in the solid state.
基金The authors acknowledge financial support from the MOE Tier 3 program(no.MOE2014-T3-1-004)Tier 2 grant(no.MOE2018-T2-2-094)NRF Investigatorship(no.NRF-NRFI05-2019-0005).
文摘Cycloarenes are an essential class of polycyclic aromatic hydrocarbons with unique electronic structure,but their synthesis is very challenging.Herein,we report a facile synthetic strategy primarily involving macrocyclization by the Suzuki coupling reaction,followed by bismuth(III)triflate-catalyzed cyclization of vinyl ethers.By utilizing this approach,aryl-substituted soluble cycloarenes 7 and 8 with different sizes were obtained.X-ray crystallographic analysis revealed a slightly distorted backbone in the kekulene derivative 7 and a saddle-shaped skeleton in the octulene derivative 8.Bond length analysis suggested that both of the cycloarenes mainly complied with the Clar’s bonding model with dominant local aromaticity,which was also in accord with our NMR measurements and the theoretical calculations[nucleus-independent chemical shift[NICS],anisotropy of the induced current density(ACID),three-dimensional isochemical shielding surface(3D ICSS)].The optical properties were investigated by UV-Vis absorption and fluorescence spectral measurements.Our method opens opportunities to access various expanded and core-modified cycloarenes in the future.