Objective Detection and quantification of RNA synthesis in cells is a widely used technique for monitoring cell viability,health,and metabolic rate.After exposure to environmental stimuli,both the internal reference g...Objective Detection and quantification of RNA synthesis in cells is a widely used technique for monitoring cell viability,health,and metabolic rate.After exposure to environmental stimuli,both the internal reference gene and target gene would be degraded.As a result,it is imperative to consider the accurate capture of nascent RNA and the detection of transcriptional levels of RNA following environmental stimulation.This study aims to create a Click Chemistry method that utilizes its property to capture nascent RNA from total RNA that was stimulated by the environment.Methods The new RNA was labeled with 5-ethyluridine(5-EU)instead of uracil,and the azido-biotin medium ligand was connected to the magnetic sphere using a combination of“Click Chemistry”and magnetic bead screening.Then the new RNA was captured and the transcription rate of 16S rRNA was detected by fluorescence molecular beacon(M.B.)and quantitative reverse transcription PCR(qRT-PCR).Results The bacterial nascent RNA captured by“Click Chemistry”screening can be used as a reverse transcription template to form cDNA.Combined with the fluorescent molecular beacon M.B.1,the synthesis rate of rRNA at 37℃is 1.2 times higher than that at 15℃.The 16S rRNA gene and cspI gene can be detected by fluorescent quantitative PCR,it was found that the measured relative gene expression changes were significantly enhanced at 25℃and 16℃when analyzed with nascent RNA rather than total RNA,enabling accurate detection of RNA transcription rates.Conclusion Compared to other article reported experimental methods that utilize screening magnetic columns,the technical scheme employed in this study is more suitable for bacteria,and the operation steps are simple and easy to implement,making it an effective RNA capture method for researchers.展开更多
Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippin...Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources （input） and arc or back-arc magmas （output） in the Philippine Sea Plate-Ryukyu Arc-Okinawa Trough system （PROS）. The results obtained showed that several components were variably involved in the petrogenesis of the Oki-nawa Trough lavas：sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt （MORB）-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and sub-continental lithospheric mantle （SCLM） beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the＂seafloor spreading＂process in the southwest segment,＂rift propagation＂process in the middle seg-ment, and＂crustal extension＂process in the northeast segment, and a nascent ocean basin occurs in the southwest segment.展开更多
The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile （PAN） wet-spinning and the effect of coagulation bath conditions on the structure and properties ...The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile （PAN） wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers gradually increases with the increasing of coagulation time. Too large spinning tension leads to grooves occurring on surface of fibers. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ℃, 65% （concentration） and 0.9 （draw ratio）.展开更多
In an effort to find the effect of mass transfer, surface tension and drag forces on the velocity distribution, the mathematical model of the velocity profile of a nascent hollow fiber during membrane formation in the...In an effort to find the effect of mass transfer, surface tension and drag forces on the velocity distribution, the mathematical model of the velocity profile of a nascent hollow fiber during membrane formation in the air gap region was numerically simulated by using the Runge-Kutta method (fourth-order method). The effect of mass transfer on velocity distribution based on the complicated function (G(Cs h)) was presented and the effects of a complicated function were studied in two cases: in the first case, G(Cs h) was constant; in the second, G(Cs h) was variable. The latter was done by varying with the concentration of solvent in a nascent hollow fiber through the air-gap region. One empirical equation was used to describe this change and the predicted values had a better agreement with the experimental values. To verify the model hypotheses, hollow fiber membranes were spun from 20∶80 polybenzimidazole/polyetherimide dopes with 25.6 wt% solid in N, N-dimethylacetamide (DMAc) using water as the external and internal coagulants. Based on the experimental results of dry-jet wet-spinning process for the fabrication of hollow fiber membranes, it is found that the model calculated values were in a good agreement with the experimental values.展开更多
The region between the preexisting and nascentmembranes of a cleaving Rana egg is a dense protrusionregion of nearly 40μm wide at 180°stage.Later,thisregion differentiate,into an upper part,a strip withlong, bra...The region between the preexisting and nascentmembranes of a cleaving Rana egg is a dense protrusionregion of nearly 40μm wide at 180°stage.Later,thisregion differentiate,into an upper part,a strip withlong, branched and randomly distributed protrusionswhich are derived largely from the preexistingmembrane,and a lower part,a band with microvilli.During 4-and 8-cel1 stages,the strip is almost vanishedand microvilli in the band is shortened.The nascentmembrane is smooth at the 180°stage,then a rough areaappears below the smooth region and quickly expands.Wheat germ agglutinin which can bind to preexistingmembrane interrupts the development of the regionbetween the preexisting and nascent membranes.Detergent,Brij,having the property to increase the areaof nascent membrane,does not interrupt the developmentof the region between the preexisting and nascentmembranes.展开更多
Reliable knowledge on pathogenic agents contributes to effective plant protection.For most plant pathogens,maintaining protein homeostasis(proteostasis)is essential for unfolding the cellular functions to survive and ...Reliable knowledge on pathogenic agents contributes to effective plant protection.For most plant pathogens,maintaining protein homeostasis(proteostasis)is essential for unfolding the cellular functions to survive and thrive.However,the fungal proteins involved in proteostasis remain poorly characterized in the process of pathogenesis.In this study,we characterized the function of the nascent polypeptideassociated complex(NAC)in Fusarium graminearum(F.graminearum)(FgNAC),one of the top 10 fungal pathogens with predominant scientific/economic importance.We found that FgNACa,a subunit of FgNAC,manifests high structural and functional similarity to its homologous counterparts in yeast and other species.The mutants of F.graminearum lacking NACa are viable but suffer significant defects in vegetative growth,conidial production,and pathogenesis.In addition,we show here that FgNACa can interact with another subunit of NAC(FgNACb)in a yeast-two-hybrid assay.The subcellular localization results show that FgNACa and FgNACb are predominantly localized in the cytoplasm.Future studies should focus on deciphering the mechanism by which NAC orchestrates protein biogenesis and consequentially modulates development and pathogenesis.展开更多
Asparagine-linked glycosylation protein 1 homolog(ALG1)participates in the initial stage of protein N-glycosylation and N-glycosylation has been implicated in the process of hepatocellular carcinoma(HCC)progression.Ho...Asparagine-linked glycosylation protein 1 homolog(ALG1)participates in the initial stage of protein N-glycosylation and N-glycosylation has been implicated in the process of hepatocellular carcinoma(HCC)progression.However,whether ALG1 plays a role in human HCC remains unknown.In this study,the expression profile of ALG1 in tumorous and corresponding adjacent non-tumor tissues was analyzed.The relationship of ALG1 expression with clinical features and prognosis of HCC patients was also evaluated using immuno-histochemical method.Here we found ALG1 decreased in HCC tissues compared with adjacent normal liver tissues,which predicted an unfavorable prognosis.Combined with RNA interference,nascent proteome and glycoproteome were determined systematically in Huh7 cell line.Bioinformatics analysis indicated that the differentially expressed proteins participating in the response of ALG1 knockdown were most significantly associated with cell-cell adhesion.Functional studies confirmed that knockdown of ALG1 reduced cell adhesion capacity,and promoted cell migration.Furthermore,down-regulation of H8N2(on N-glycosite N651)and H5N4S2F1(on N-glycosite N692)from N-cadherin was identified as a feature of ALG1 knockdown.Our findings revealed that ALG1 controlled the expression of glycosylated N-cadherin and played a role in HCC migration,with implications for prognosis.展开更多
Alternative splicing of eukaryotic precursor(messenger)RNAs in the nucleus not only increases transcriptomic complexity,but also expands proteomic and functional diversity.In addition to basic types of alternative spl...Alternative splicing of eukaryotic precursor(messenger)RNAs in the nucleus not only increases transcriptomic complexity,but also expands proteomic and functional diversity.In addition to basic types of alternative splicing,recent transcriptome-wide analyses have also suggested other new types of non-canonical splicing,such as back splicing and recursive splicing,and their widespread expression across species.Increasing lines of evidence have suggested mechanisms for back splicing,including insights from analyses of nascent RNA sequencing.In this review,we discuss our current understanding of back splicing regulation,and highlight its distinct characteristics in processing during nascent RNA synthesis by taking advantage of metabolic tagging nascent RNA sequencing.Features of recursive splicing are also discussed in the perspective of nascent RNA sequencing.展开更多
Nascent polypeptide associated complex(NAC)and its two isolated subunits,αNAC and βNAC,play important roles in nascent peptide targeting.We determined a 1.9Åresolution crystal structure of the interaction core ...Nascent polypeptide associated complex(NAC)and its two isolated subunits,αNAC and βNAC,play important roles in nascent peptide targeting.We determined a 1.9Åresolution crystal structure of the interaction core of NAC heterodimer and a 2.4Åresolution crystal structure ofαNAC NAC domain homodimer.These structures provide detailed information of NAC heterodimerization and αNAC homodimerization.We found that the NAC domains of αNAC and βNAC share very similar folding despite of their relative low identity of amino acid sequences.Furthermore,different electric charge distributions of the two subunits at the NAC interface provide an explanation to the observation that the heterodimer of NAC complex is more stable than the single subunit homodimer.In addition,we successfully built a βNAC NAC domain homodimer model based on homologous modeling,suggesting that NAC domain dimerization is a general property of the NAC family.These 3D structures allow further studies on structurefunction relationship of NAC.展开更多
Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open syste...Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen source.Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the cathode.Furthermore,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,respectively.The results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/C.This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.展开更多
文摘Objective Detection and quantification of RNA synthesis in cells is a widely used technique for monitoring cell viability,health,and metabolic rate.After exposure to environmental stimuli,both the internal reference gene and target gene would be degraded.As a result,it is imperative to consider the accurate capture of nascent RNA and the detection of transcriptional levels of RNA following environmental stimulation.This study aims to create a Click Chemistry method that utilizes its property to capture nascent RNA from total RNA that was stimulated by the environment.Methods The new RNA was labeled with 5-ethyluridine(5-EU)instead of uracil,and the azido-biotin medium ligand was connected to the magnetic sphere using a combination of“Click Chemistry”and magnetic bead screening.Then the new RNA was captured and the transcription rate of 16S rRNA was detected by fluorescence molecular beacon(M.B.)and quantitative reverse transcription PCR(qRT-PCR).Results The bacterial nascent RNA captured by“Click Chemistry”screening can be used as a reverse transcription template to form cDNA.Combined with the fluorescent molecular beacon M.B.1,the synthesis rate of rRNA at 37℃is 1.2 times higher than that at 15℃.The 16S rRNA gene and cspI gene can be detected by fluorescent quantitative PCR,it was found that the measured relative gene expression changes were significantly enhanced at 25℃and 16℃when analyzed with nascent RNA rather than total RNA,enabling accurate detection of RNA transcription rates.Conclusion Compared to other article reported experimental methods that utilize screening magnetic columns,the technical scheme employed in this study is more suitable for bacteria,and the operation steps are simple and easy to implement,making it an effective RNA capture method for researchers.
基金The National Natural Science Foundation of China under contract Nos 41322036,41230960,40906034,41276003 and 41176058China Ocean Mineral Resources R&D Association(COMRA)under contract No.DY125-12-R-05
文摘Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources （input） and arc or back-arc magmas （output） in the Philippine Sea Plate-Ryukyu Arc-Okinawa Trough system （PROS）. The results obtained showed that several components were variably involved in the petrogenesis of the Oki-nawa Trough lavas：sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt （MORB）-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and sub-continental lithospheric mantle （SCLM） beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the＂seafloor spreading＂process in the southwest segment,＂rift propagation＂process in the middle seg-ment, and＂crustal extension＂process in the northeast segment, and a nascent ocean basin occurs in the southwest segment.
基金Funded by the Science and Technology Program of the Higher Education Institutions of Shandong Province (No. J09LD06)the Doctoral Fund of University of Jinan (No. XBS0813)
文摘The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile （PAN） wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers gradually increases with the increasing of coagulation time. Too large spinning tension leads to grooves occurring on surface of fibers. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ℃, 65% （concentration） and 0.9 （draw ratio）.
文摘In an effort to find the effect of mass transfer, surface tension and drag forces on the velocity distribution, the mathematical model of the velocity profile of a nascent hollow fiber during membrane formation in the air gap region was numerically simulated by using the Runge-Kutta method (fourth-order method). The effect of mass transfer on velocity distribution based on the complicated function (G(Cs h)) was presented and the effects of a complicated function were studied in two cases: in the first case, G(Cs h) was constant; in the second, G(Cs h) was variable. The latter was done by varying with the concentration of solvent in a nascent hollow fiber through the air-gap region. One empirical equation was used to describe this change and the predicted values had a better agreement with the experimental values. To verify the model hypotheses, hollow fiber membranes were spun from 20∶80 polybenzimidazole/polyetherimide dopes with 25.6 wt% solid in N, N-dimethylacetamide (DMAc) using water as the external and internal coagulants. Based on the experimental results of dry-jet wet-spinning process for the fabrication of hollow fiber membranes, it is found that the model calculated values were in a good agreement with the experimental values.
文摘The region between the preexisting and nascentmembranes of a cleaving Rana egg is a dense protrusionregion of nearly 40μm wide at 180°stage.Later,thisregion differentiate,into an upper part,a strip withlong, branched and randomly distributed protrusionswhich are derived largely from the preexistingmembrane,and a lower part,a band with microvilli.During 4-and 8-cel1 stages,the strip is almost vanishedand microvilli in the band is shortened.The nascentmembrane is smooth at the 180°stage,then a rough areaappears below the smooth region and quickly expands.Wheat germ agglutinin which can bind to preexistingmembrane interrupts the development of the regionbetween the preexisting and nascent membranes.Detergent,Brij,having the property to increase the areaof nascent membrane,does not interrupt the developmentof the region between the preexisting and nascentmembranes.
基金This work was supported by the National Natural Science Foundation of China(31471737,31671984,and 31801691)the Advanced Programs of Guizhou Province for the Returned Overseas Scholars([2018]02).
文摘Reliable knowledge on pathogenic agents contributes to effective plant protection.For most plant pathogens,maintaining protein homeostasis(proteostasis)is essential for unfolding the cellular functions to survive and thrive.However,the fungal proteins involved in proteostasis remain poorly characterized in the process of pathogenesis.In this study,we characterized the function of the nascent polypeptideassociated complex(NAC)in Fusarium graminearum(F.graminearum)(FgNAC),one of the top 10 fungal pathogens with predominant scientific/economic importance.We found that FgNACa,a subunit of FgNAC,manifests high structural and functional similarity to its homologous counterparts in yeast and other species.The mutants of F.graminearum lacking NACa are viable but suffer significant defects in vegetative growth,conidial production,and pathogenesis.In addition,we show here that FgNACa can interact with another subunit of NAC(FgNACb)in a yeast-two-hybrid assay.The subcellular localization results show that FgNACa and FgNACb are predominantly localized in the cytoplasm.Future studies should focus on deciphering the mechanism by which NAC orchestrates protein biogenesis and consequentially modulates development and pathogenesis.
基金the financial support of the National Key Research and Development Program of China(2017YFA0505100)NSF of China(Grants 21974025 and 82121004)for this work.
文摘Asparagine-linked glycosylation protein 1 homolog(ALG1)participates in the initial stage of protein N-glycosylation and N-glycosylation has been implicated in the process of hepatocellular carcinoma(HCC)progression.However,whether ALG1 plays a role in human HCC remains unknown.In this study,the expression profile of ALG1 in tumorous and corresponding adjacent non-tumor tissues was analyzed.The relationship of ALG1 expression with clinical features and prognosis of HCC patients was also evaluated using immuno-histochemical method.Here we found ALG1 decreased in HCC tissues compared with adjacent normal liver tissues,which predicted an unfavorable prognosis.Combined with RNA interference,nascent proteome and glycoproteome were determined systematically in Huh7 cell line.Bioinformatics analysis indicated that the differentially expressed proteins participating in the response of ALG1 knockdown were most significantly associated with cell-cell adhesion.Functional studies confirmed that knockdown of ALG1 reduced cell adhesion capacity,and promoted cell migration.Furthermore,down-regulation of H8N2(on N-glycosite N651)and H5N4S2F1(on N-glycosite N692)from N-cadherin was identified as a feature of ALG1 knockdown.Our findings revealed that ALG1 controlled the expression of glycosylated N-cadherin and played a role in HCC migration,with implications for prognosis.
基金supported by the National Natural Science Foundation of China(31730111 to L.Y.,31925011 to L.Y.,91940306 to L.Y.,31801073 to W.X.)the Youth Innovation Promotion Association(to W.X.)from Chinese Academy of Sciences。
文摘Alternative splicing of eukaryotic precursor(messenger)RNAs in the nucleus not only increases transcriptomic complexity,but also expands proteomic and functional diversity.In addition to basic types of alternative splicing,recent transcriptome-wide analyses have also suggested other new types of non-canonical splicing,such as back splicing and recursive splicing,and their widespread expression across species.Increasing lines of evidence have suggested mechanisms for back splicing,including insights from analyses of nascent RNA sequencing.In this review,we discuss our current understanding of back splicing regulation,and highlight its distinct characteristics in processing during nascent RNA synthesis by taking advantage of metabolic tagging nascent RNA sequencing.Features of recursive splicing are also discussed in the perspective of nascent RNA sequencing.
基金This work was supported by the National Natural Science Foundation of China(grant No.30730022)the National Basic Research Program(973 Program)(grant Nos.2006CB806503 and 2007CB914304)+1 种基金the National Programs for High Technology Research and Development Program(863 Program)(grant Nos.2006AA02A322 and 2006AA020502)the CAS(China)grant KSCX2-YW-R-05 to Z.R.
文摘Nascent polypeptide associated complex(NAC)and its two isolated subunits,αNAC and βNAC,play important roles in nascent peptide targeting.We determined a 1.9Åresolution crystal structure of the interaction core of NAC heterodimer and a 2.4Åresolution crystal structure ofαNAC NAC domain homodimer.These structures provide detailed information of NAC heterodimerization and αNAC homodimerization.We found that the NAC domains of αNAC and βNAC share very similar folding despite of their relative low identity of amino acid sequences.Furthermore,different electric charge distributions of the two subunits at the NAC interface provide an explanation to the observation that the heterodimer of NAC complex is more stable than the single subunit homodimer.In addition,we successfully built a βNAC NAC domain homodimer model based on homologous modeling,suggesting that NAC domain dimerization is a general property of the NAC family.These 3D structures allow further studies on structurefunction relationship of NAC.
基金supported by the National Natural Science Foundation of China(No.51878169)the Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)+1 种基金Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110497)。
文摘Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen source.Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the cathode.Furthermore,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,respectively.The results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/C.This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.
