We investigate the electronic structure of NbGeSb with non-symmorphic symmetry.We employ angle-resolved photoemission spectroscopy(ARPES)to observe and identify the bulk and surface states over the Brillouin zone.By u...We investigate the electronic structure of NbGeSb with non-symmorphic symmetry.We employ angle-resolved photoemission spectroscopy(ARPES)to observe and identify the bulk and surface states over the Brillouin zone.By utilizing high-energy photons,we identify the bulk Fermi surface and bulk nodal line along the direction X–R,while the Fermi surface of the surface state is observed by using low-energy photons.We observe the splitting of surface bands away from the high-symmetry point X.The density functional theory calculations on bulk and 1 to 5-layer slab models,as well as spin textures of NbGeSb,verify that the band splitting could be attributed to the Rashba-like spin–orbit coupling caused by space-inversion-symmetry breaking at the surface.These splitted surface bands cross with each other,forming two-dimensional Weyl-like crossings that are protected by mirror symmetry.Our findings provide insights into the two-dimensional topological and symmetry-protected band inversion of surface states.展开更多
The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,suc...The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,such as surface deformation,groundwater storage changes,and mass migration before and after earthquakes.Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region(SYR)from 2015 to 2017,we determine a time series of degree 120 gravity fields using the localized spherical harmonic(Slepian)basis functions.Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR.The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features.The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site.展开更多
Computational tool-assisted primer design for real-time reverse transcription(RT)PCR(qPCR)analysis largely ignores the sequence similarities between sequences of homologous genes in a plant genome.It can lead to false...Computational tool-assisted primer design for real-time reverse transcription(RT)PCR(qPCR)analysis largely ignores the sequence similarities between sequences of homologous genes in a plant genome.It can lead to false confidence in the quality of the designed primers,which sometimes results in skipping the optimization steps for qPCR.However,the optimization of qPCR parameters plays an essential role in the efficiency,specificity,and sensitivity of each gene’s primers.Here,we proposed an optimized approach to sequentially optimizing primer sequences,annealing temperatures,primer concentrations,and cDNA concentration range for each reference(and target)gene.Our approach started with a sequence-specific primer design that should be based on the single-nucleotide polymorphisms(SNPs)present in all the homologous sequences for each of the reference(and target)genes under study.By combining the efficiency calibrated and standard curve methods with the 2−ΔΔCt method,the standard cDNA concentration curve with a logarithmic scale was obtained for each primer pair for each gene.As a result,an R 2≥0.9999 and the efficiency(E)=100±5% should be achieved for the best primer pair of each gene,which serve as the prerequisite for using the 2^(−ΔΔCt) method for data analysis.We applied our newly developed approach to identify the best reference genes in different tissues and at various inflorescence developmental stages of Tripidium ravennae,an ornamental and biomass grass,and validated their utility under varying abiotic stress conditions.We also applied this approach to test the expression stability of six reference genes in soybean under biotic stress treatment with Xanthomonas axonopodis pv.glycines(Xag).Thus,these case studies demonstrated the effectiveness of our optimized protocol for qPCR analysis.展开更多
Camelina sativa is a self-pollinating and facultative outcrossing oilseed crop.Genetic engineering has been used to improve camelina yield potential for altered fatty acid composition,modified protein profiles,improve...Camelina sativa is a self-pollinating and facultative outcrossing oilseed crop.Genetic engineering has been used to improve camelina yield potential for altered fatty acid composition,modified protein profiles,improved seed and oil yield,and enhanced drought resistance.The deployment of transgenic camelina in the field posits high risks related to the introgression of transgenes into nontransgenic camelina and wild relatives.Thus,effective bioconfinement strategies need to be developed to prevent pollen-mediated gene f low(PMGF)from transgenic camelina.In the present study,we overexpressed the cleistogamy(i.e.f loral petal non-openness)-inducing PpJAZ1 gene from peach in transgenic camelina.Transgenic camelina overexpressing PpJAZ1 showed three levels of cleistogamy,affected pollen germination rates after anthesis but not during anthesis,and caused a minor silicle abortion only on the main branches.We also conducted field trials to examine the effects of the overexpressed PpJAZ1 on PMGF in the field,and found that the overexpressed PpJAZ1 dramatically inhibited PMGF from transgenic camelina to non-transgenic camelina under the field conditions.Thus,the engineered cleistogamy using the overexpressed PpJAZ1 is a highly effective bioconfinement strategy to limit PMGF from transgenic camelina,and could be used for bioconfinement in other dicot species.展开更多
Background:A keloid is a disease of excessive fibrosis that is characterized by the aberrant prolifer-ation of fibroblasts.However,the molecular mechanisms of fibroblasts during the development of keloids remain uncle...Background:A keloid is a disease of excessive fibrosis that is characterized by the aberrant prolifer-ation of fibroblasts.However,the molecular mechanisms of fibroblasts during the development of keloids remain unclear.This study aims to identify new molecular targets that promote the proliferation and migration of keloid fibroblasts,providing new ideas for the prevention and treatment of keloids.Methods:We utilized bioinformatics tools to analyze data from keloid fibroblasts(KFs)available in the Gene Expression Omnibus(GEO)database to identify the key genes involved in keloid development.Homeobox C6(HOXC6)emerged as a hub gene in KFs from the GEO database was verified in keloid tissue samples and KFs using reverse transcription-quantitative polymerase chain reaction,western blot(WB)and immunohistochemistry.Subsequently,the effects of down-regulated HOXC6 expression on the cellular behaviors of KFs were examined by performing Cell Counting Kit-8,flow cytometry,transwell migration and WB assays.Meanwhile,we performed transcriptome sequencing and gene set enrichment analysis(GSEA)to further explore HOXC6-related mechanisms and validated the signaling pathways by performing a series of experiments.Results:HOXC6 was the top-ranking hub gene of KFs in microarray datasets from GEO and was upregulated in keloid tissue samples and KFs.Downregulation of HOXC6 inhibited proliferation,migration and extracellular matrix(ECM)accumulation and promoted KF apoptosis.GSEA pre-dicted that the hypoxia signaling pathway was associated with HOXC6 in KFs.Transcriptome sequencing suggested that the extracellular regulated protein kinase(ERK)pathway was one of the downstream pathways of HOXC6 in KFs.Our experiments confirmed that hypoxia-inducible factor-1α(HIF-1α)upregulates HOXC6,contributing to KFs proliferation,migration,apoptosis inhibition and collagen accumulation through the ERK signaling pathway.Conclusions:Our findings first revealed that HOXC6 acts as an oncogenic driver in the molec-ular mechanisms of fibroblasts in keloids.The HIF-1α/HOXC6/ERK axis promotes proliferation,migration and ECM production by KFs,contributing to the progression of keloids.Taken together,HOXC6 may serve as a promising novel therapeutic target and new focus for research designed to understand the pathogenesis of keloids.展开更多
Diarrhea is the third leading cause of death in developing countries in children under the age of five.About half a million children die of diarrhea every year,most of which in developing countries.Viruses are the mai...Diarrhea is the third leading cause of death in developing countries in children under the age of five.About half a million children die of diarrhea every year,most of which in developing countries.Viruses are the main pathogen of diarrhea.In China,the fecal virome of children with diarrhea has been rarely studied.Using an unbiased viral metagenomics approach,we analyzed the fecal virome in children with diarrhea.Many DNA or RNA viruses associated with diarrhea identified in those fecal samples were mainly from six families of Adenoviridae,Astroviridae,Caliciviridae,Parvoviridae,Picornaviridae,and Reoviridae.Among them,the family of Caliciviridae accounts for the largest proportion of 78.42%,following with Adenoviridae(8.94%)and Picornaviridae(8.36%).In addition to those diarrhea-related viruses that have already been confirmed to cause human diarrhea,the viruses not associated with diarrhea were also identified including anellovirus and picobirnavirus.This study increased our understanding of diarrheic children fecal virome and provided valuable information for the prevention and treatment of viral diarrhea in this area.展开更多
In the last decade and a half, a number of earthquakes of magnitude 4-5 have occurred in the Beijing_Tianjin_Tangshan_Zhangjiakou (BTTZ) region. On the basis of the analysis of the temporally continuous gravity variat...In the last decade and a half, a number of earthquakes of magnitude 4-5 have occurred in the Beijing_Tianjin_Tangshan_Zhangjiakou (BTTZ) region. On the basis of the analysis of the temporally continuous gravity variation data principally from the Baijiatuan (BJTN) semi_permanent gravity base station, a general picture of gravity variation related to the seismogenesis and occurrence of earthquakes has emerged.\;As gravity variation is generally observed on the earth’s surface, the predominant influence is that of the near_surface groundwater. The subsurface fluids are distributed throughout all depths in the crust and respond to the seismogenic processes of earthquakes as well. The influence of the subsurface fluid on gravity variation is, therefore, of equal importance. The fluids, which include the near_surface groundwater and the subsurface fluids distributed throughout all depths in the crust, play a more important role in the gravity variations in terms of the seismogenesis and occurrence of earthquakes than previously realized.\;The abundance of accumulated data shows that the dilatancy instability (IPE) model seems not applicable at least to the seismogenesis and occurrence of earthquakes in the BTTZ region. In order to reflect the physical reality, the earlier proposed combined dilatancy model requires modification. The seismogenic area in the BTTZ region may be modelled as a large pre_stressed volume of a fluid_filled poroelastic medium, including not only the pre_stressed volume surrounding the impending rupture zone but also the volume containing the rupture of the fault zone itself. The pre_stressed volume outside the impending rupture zone is under a state of relatively small change of the pre_existing regional tectonic stress, while the volume containing the impending rupture zone is an induced region of very high local stress concentration, and/or pore over_pressure.\;The calculated gravity variations based on the modified combined dilatancy model (MCDM) with the known physical parameters of the region resemble the observed residual gravity variations. Apparently the residual gravity variations, in addition to responding to the deep_seated seismogenesis and occurrence of earthquakes, predominantly respond to the near_surface groundwater, and the subsurface fluids, which themselves also respond to the seismogenesis and occurrence of earthquakes. On the basis of comparison between the calculated MCDM gravity variations and the observed residual gravity variations, the change of the regional tectonic stress field for the earthquakes of magnitude 4-5 in the BTTZ region could be approximately estimated to be in the neighbourhood of 5%-7%.\;It is apparent that simultaneously monitoring the temporally continuous variations of the near_surface groundwater, subsurface fluids, and gravity coupled with modelling would provide vital information on the history and evolution of the seismogenic processes about 10 months to 1 year prior to the occurrence of an earthquake of magnitude 4-5 and tens of years prior to that of an earthquake of magnitude 7-8 such as the Haicheng earthquake in 1975 and the Tangshan earthquake in 1976 in the BTTZ region. These earthquakes of magnitude 4-5, which so far have occurred in the BTTZ region, may well be the precursory events to a larger earthquake.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1403803)H.M.is supported by the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China(Grant No.22XNH099)+7 种基金The results of DFT calculations described in this paper are supported by HPC Cluster of ITP-CAS.M.L.is supported by the National Natural Science Foundation of China(Grant No.12204536)the Fundamental Research Funds for the Central Universities,and the Research Funds of People’s Public Security University of China(PPSUC)(Grant No.2023JKF02ZK09)T.L.X.is supported by the National Key R&D Program of China(Grant No.2019YFA0308602)the National Natural Science Foundation of China(Grant Nos.12074425 and 11874422)Y.Y.W.is supported by the National Natural Science Foundation of China(Grant No.12104011)H.Y.L.is supported by the National Natural Science Foundation of China(Grant No.12074213)the Major Basic Program of Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province.
文摘We investigate the electronic structure of NbGeSb with non-symmorphic symmetry.We employ angle-resolved photoemission spectroscopy(ARPES)to observe and identify the bulk and surface states over the Brillouin zone.By utilizing high-energy photons,we identify the bulk Fermi surface and bulk nodal line along the direction X–R,while the Fermi surface of the surface state is observed by using low-energy photons.We observe the splitting of surface bands away from the high-symmetry point X.The density functional theory calculations on bulk and 1 to 5-layer slab models,as well as spin textures of NbGeSb,verify that the band splitting could be attributed to the Rashba-like spin–orbit coupling caused by space-inversion-symmetry breaking at the surface.These splitted surface bands cross with each other,forming two-dimensional Weyl-like crossings that are protected by mirror symmetry.Our findings provide insights into the two-dimensional topological and symmetry-protected band inversion of surface states.
基金the National Natural Science Foundation of China(Nos.41974095,41774090,and U1939205)the Special Fund of the Institute of Geophysics,China Earthquake Administration(Nos.DQJB20X09,and DQJB21R30)The first author acknowledges support from the China Postdoctoral Science Foundation(No.2018M641424)。
文摘The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,such as surface deformation,groundwater storage changes,and mass migration before and after earthquakes.Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region(SYR)from 2015 to 2017,we determine a time series of degree 120 gravity fields using the localized spherical harmonic(Slepian)basis functions.Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR.The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features.The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site.
基金The authors thank the USDA National Institute of Food and Agriculture Hatch project 02685 and North Carolina State University for the startup funds to the Liu laboratorythe NSFC fund 31871646 to the Zhao laboratory。
文摘Computational tool-assisted primer design for real-time reverse transcription(RT)PCR(qPCR)analysis largely ignores the sequence similarities between sequences of homologous genes in a plant genome.It can lead to false confidence in the quality of the designed primers,which sometimes results in skipping the optimization steps for qPCR.However,the optimization of qPCR parameters plays an essential role in the efficiency,specificity,and sensitivity of each gene’s primers.Here,we proposed an optimized approach to sequentially optimizing primer sequences,annealing temperatures,primer concentrations,and cDNA concentration range for each reference(and target)gene.Our approach started with a sequence-specific primer design that should be based on the single-nucleotide polymorphisms(SNPs)present in all the homologous sequences for each of the reference(and target)genes under study.By combining the efficiency calibrated and standard curve methods with the 2−ΔΔCt method,the standard cDNA concentration curve with a logarithmic scale was obtained for each primer pair for each gene.As a result,an R 2≥0.9999 and the efficiency(E)=100±5% should be achieved for the best primer pair of each gene,which serve as the prerequisite for using the 2^(−ΔΔCt) method for data analysis.We applied our newly developed approach to identify the best reference genes in different tissues and at various inflorescence developmental stages of Tripidium ravennae,an ornamental and biomass grass,and validated their utility under varying abiotic stress conditions.We also applied this approach to test the expression stability of six reference genes in soybean under biotic stress treatment with Xanthomonas axonopodis pv.glycines(Xag).Thus,these case studies demonstrated the effectiveness of our optimized protocol for qPCR analysis.
基金supported by Biotechnology Risk Assessment Grant Program competitive grant no.2016-33522-25627 from the U.S.Department of Agriculture,the Hatch project 02685 from the U.S.Department of Agriculture National Institute of Food and Agriculture,and the startup funding to the Liu laboratory from North Carolina State University.
文摘Camelina sativa is a self-pollinating and facultative outcrossing oilseed crop.Genetic engineering has been used to improve camelina yield potential for altered fatty acid composition,modified protein profiles,improved seed and oil yield,and enhanced drought resistance.The deployment of transgenic camelina in the field posits high risks related to the introgression of transgenes into nontransgenic camelina and wild relatives.Thus,effective bioconfinement strategies need to be developed to prevent pollen-mediated gene f low(PMGF)from transgenic camelina.In the present study,we overexpressed the cleistogamy(i.e.f loral petal non-openness)-inducing PpJAZ1 gene from peach in transgenic camelina.Transgenic camelina overexpressing PpJAZ1 showed three levels of cleistogamy,affected pollen germination rates after anthesis but not during anthesis,and caused a minor silicle abortion only on the main branches.We also conducted field trials to examine the effects of the overexpressed PpJAZ1 on PMGF in the field,and found that the overexpressed PpJAZ1 dramatically inhibited PMGF from transgenic camelina to non-transgenic camelina under the field conditions.Thus,the engineered cleistogamy using the overexpressed PpJAZ1 is a highly effective bioconfinement strategy to limit PMGF from transgenic camelina,and could be used for bioconfinement in other dicot species.
基金supported by the National Natural Science Foundation of China(grant numbers 81703098 and 82073464)the President Foundation of Nanfang Hospital,Southern Medical University(grant numbers 2021B004 and 2021L002).
文摘Background:A keloid is a disease of excessive fibrosis that is characterized by the aberrant prolifer-ation of fibroblasts.However,the molecular mechanisms of fibroblasts during the development of keloids remain unclear.This study aims to identify new molecular targets that promote the proliferation and migration of keloid fibroblasts,providing new ideas for the prevention and treatment of keloids.Methods:We utilized bioinformatics tools to analyze data from keloid fibroblasts(KFs)available in the Gene Expression Omnibus(GEO)database to identify the key genes involved in keloid development.Homeobox C6(HOXC6)emerged as a hub gene in KFs from the GEO database was verified in keloid tissue samples and KFs using reverse transcription-quantitative polymerase chain reaction,western blot(WB)and immunohistochemistry.Subsequently,the effects of down-regulated HOXC6 expression on the cellular behaviors of KFs were examined by performing Cell Counting Kit-8,flow cytometry,transwell migration and WB assays.Meanwhile,we performed transcriptome sequencing and gene set enrichment analysis(GSEA)to further explore HOXC6-related mechanisms and validated the signaling pathways by performing a series of experiments.Results:HOXC6 was the top-ranking hub gene of KFs in microarray datasets from GEO and was upregulated in keloid tissue samples and KFs.Downregulation of HOXC6 inhibited proliferation,migration and extracellular matrix(ECM)accumulation and promoted KF apoptosis.GSEA pre-dicted that the hypoxia signaling pathway was associated with HOXC6 in KFs.Transcriptome sequencing suggested that the extracellular regulated protein kinase(ERK)pathway was one of the downstream pathways of HOXC6 in KFs.Our experiments confirmed that hypoxia-inducible factor-1α(HIF-1α)upregulates HOXC6,contributing to KFs proliferation,migration,apoptosis inhibition and collagen accumulation through the ERK signaling pathway.Conclusions:Our findings first revealed that HOXC6 acts as an oncogenic driver in the molec-ular mechanisms of fibroblasts in keloids.The HIF-1α/HOXC6/ERK axis promotes proliferation,migration and ECM production by KFs,contributing to the progression of keloids.Taken together,HOXC6 may serve as a promising novel therapeutic target and new focus for research designed to understand the pathogenesis of keloids.
基金supported by Jiangsu Provincial Key Research and Development Projects No.BE2017693National Natural Science Foundation of China No.81741062
文摘Diarrhea is the third leading cause of death in developing countries in children under the age of five.About half a million children die of diarrhea every year,most of which in developing countries.Viruses are the main pathogen of diarrhea.In China,the fecal virome of children with diarrhea has been rarely studied.Using an unbiased viral metagenomics approach,we analyzed the fecal virome in children with diarrhea.Many DNA or RNA viruses associated with diarrhea identified in those fecal samples were mainly from six families of Adenoviridae,Astroviridae,Caliciviridae,Parvoviridae,Picornaviridae,and Reoviridae.Among them,the family of Caliciviridae accounts for the largest proportion of 78.42%,following with Adenoviridae(8.94%)and Picornaviridae(8.36%).In addition to those diarrhea-related viruses that have already been confirmed to cause human diarrhea,the viruses not associated with diarrhea were also identified including anellovirus and picobirnavirus.This study increased our understanding of diarrheic children fecal virome and provided valuable information for the prevention and treatment of viral diarrhea in this area.
文摘In the last decade and a half, a number of earthquakes of magnitude 4-5 have occurred in the Beijing_Tianjin_Tangshan_Zhangjiakou (BTTZ) region. On the basis of the analysis of the temporally continuous gravity variation data principally from the Baijiatuan (BJTN) semi_permanent gravity base station, a general picture of gravity variation related to the seismogenesis and occurrence of earthquakes has emerged.\;As gravity variation is generally observed on the earth’s surface, the predominant influence is that of the near_surface groundwater. The subsurface fluids are distributed throughout all depths in the crust and respond to the seismogenic processes of earthquakes as well. The influence of the subsurface fluid on gravity variation is, therefore, of equal importance. The fluids, which include the near_surface groundwater and the subsurface fluids distributed throughout all depths in the crust, play a more important role in the gravity variations in terms of the seismogenesis and occurrence of earthquakes than previously realized.\;The abundance of accumulated data shows that the dilatancy instability (IPE) model seems not applicable at least to the seismogenesis and occurrence of earthquakes in the BTTZ region. In order to reflect the physical reality, the earlier proposed combined dilatancy model requires modification. The seismogenic area in the BTTZ region may be modelled as a large pre_stressed volume of a fluid_filled poroelastic medium, including not only the pre_stressed volume surrounding the impending rupture zone but also the volume containing the rupture of the fault zone itself. The pre_stressed volume outside the impending rupture zone is under a state of relatively small change of the pre_existing regional tectonic stress, while the volume containing the impending rupture zone is an induced region of very high local stress concentration, and/or pore over_pressure.\;The calculated gravity variations based on the modified combined dilatancy model (MCDM) with the known physical parameters of the region resemble the observed residual gravity variations. Apparently the residual gravity variations, in addition to responding to the deep_seated seismogenesis and occurrence of earthquakes, predominantly respond to the near_surface groundwater, and the subsurface fluids, which themselves also respond to the seismogenesis and occurrence of earthquakes. On the basis of comparison between the calculated MCDM gravity variations and the observed residual gravity variations, the change of the regional tectonic stress field for the earthquakes of magnitude 4-5 in the BTTZ region could be approximately estimated to be in the neighbourhood of 5%-7%.\;It is apparent that simultaneously monitoring the temporally continuous variations of the near_surface groundwater, subsurface fluids, and gravity coupled with modelling would provide vital information on the history and evolution of the seismogenic processes about 10 months to 1 year prior to the occurrence of an earthquake of magnitude 4-5 and tens of years prior to that of an earthquake of magnitude 7-8 such as the Haicheng earthquake in 1975 and the Tangshan earthquake in 1976 in the BTTZ region. These earthquakes of magnitude 4-5, which so far have occurred in the BTTZ region, may well be the precursory events to a larger earthquake.
