Transcription factors(TFs)play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens.OsSPL10(SQUAMOSA promoter binding protein-like10)is an important TF regulating t...Transcription factors(TFs)play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens.OsSPL10(SQUAMOSA promoter binding protein-like10)is an important TF regulating trichome development and salt tolerance in rice.Here we report that knockout of OsSPL10 reduces whereas its overexpression enhances rice resistance to blast disease.OsSPL10 positively regulates chitin-induced immune responses including reactive oxygen species(ROS)burst and callose deposition.We show that OsSPL10 physically associates with OsJAmyb,an important TF involved in jasmonic acid(JA)signaling,and positively regulates its protein stability.We then prove that OsJAmyb positively regulates resistance to blast.Our results reveal a molecular module consisting of OsSPL10 and OsJAmyb that positively regulates blast resistance.展开更多
Plant trichomes are a specialized cellular tissue that functions in resistance to biotic and abiotic stresses.In rice,three transcription-factor genes:OsWOX3B,HL6,and OsSPL10,have been found to control trichome develo...Plant trichomes are a specialized cellular tissue that functions in resistance to biotic and abiotic stresses.In rice,three transcription-factor genes:OsWOX3B,HL6,and OsSPL10,have been found to control trichome development.Although studies have shown interactions between the three genes,their full relationship in trichome development is unclear.We found that the expression levels of OsWOX3B and HL6 were both reduced in OsSPL10-knockout plants but increased in OsSPL10-overexpression plants,suggesting that OsSPL10 positively regulates their expression.Physical interaction between OsSPL10 and OsWOX3B was found both in vivo and in vitro and attenuated their abilities to bind to the promoter of HL6 to activate its transcription.This mechanism may regulate trichome length by adjusting the expression of HL6.A rice gene network regulating trichome development is proposed.展开更多
The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Dao...The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.展开更多
In plant immunity, pathogen-activated intracellular nucleotide binding/leucine rich repeat (NLR) receptors mobilize disease resistance pathways, but the downstream signaling mechanisms remain obscure. Enhanced disea...In plant immunity, pathogen-activated intracellular nucleotide binding/leucine rich repeat (NLR) receptors mobilize disease resistance pathways, but the downstream signaling mechanisms remain obscure. Enhanced disease susceptibility 1 (EDS1) controls transcriptional reprogramming in resistance triggered by Toll-lnterleukinl-Receptor domain (TIR)-family NLRs (TNLs). Transcriptional induction of the salicylic acid (SA) hormone defense sector provides one crucial barrier against biotrophic pathogens. Here, we present genetic and molecular evidence that in Arabidopsis an EDS1 complex with its partner PAD4 inhibits MYC2, a master regulator of SA-antagonizing jasmonic acid (JA) hormone pathways. In the TNL immune response, EDSl/PAD4 interference with MYC2 boosts the SA defense sector independently of EDS1-induced SA synthesis, thereby effectively blocking actions of a potent bacterial JA mimic, coronatine (COR). We show that antagonism of MYC2 occurs after COR has been sensed inside the nucleus but before or coincident with MYC2 binding to a target promoter, pANAC019. The stable interaction of PAD4 with MYC2 in planta is competed by EDS1-PAD4 complexes. However, suppression of MYC2-promoted genes requires EDS1 together with PAD4, pointing to an essential EDS1-PAD4 heterodimer activity in MYC2 inhibition. Taken together, these results uncover an immune receptor signaling circuit that intersects with hormone pathway crosstalk to reduce bacterial pathogen growth.展开更多
Four-dimensional (4D) printing is an emerging and highly innovative additive manufacturing process by which to fabricate pre-designed,self-assembly structures with the ability to transform over time.However,one of the...Four-dimensional (4D) printing is an emerging and highly innovative additive manufacturing process by which to fabricate pre-designed,self-assembly structures with the ability to transform over time.However,one of the critical challenges of 4D printing is the lack of advanced 4D printing systems that not only meet all the essential requirements of shape change but also possess smart,dynamic capabilities to spatiotemporally and instantly control the shape-transformation process.Here,we present a facile 4D printing platform which incorporates nanomaterials into the conventional stimuli-responsive polymer,allowing the 4D printed object to achieve a dynamic and remote controlled,on-time and position shape transformation.A proof-of-concept 4D printed brain model was created using near-infrared light (NIR) responsive nanocomposite to evaluate the capacity for controllable 4D transformation,and the feasibility of photothermal stimulation for modulating neural stem cell behaviors.This novel 4D printing strategy can not only be used to create dynamic 3D patterned biological structures that can spatiotemporally control their shapes or behaviors of transformation under a human benign stimulus (NIR),but can also provide a potential method for building complex self-morphing objects for widespread applications.展开更多
As one of the new structural layout in the family of woven composites, 2.5D Woven Composites(2.5D-WC) have recently attracted an increasing interest owing to its excellent properties, i.e. high specific strength and...As one of the new structural layout in the family of woven composites, 2.5D Woven Composites(2.5D-WC) have recently attracted an increasing interest owing to its excellent properties, i.e. high specific strength and fatigue resistance, in the aerospace and automobile industry. Indepth understanding of the fatigue behavior of this material at un-ambient temperatures is critical for the engineering applications, especially in aero-engine field. Here, fatigue behavior of 2.5D-WC at different temperatures was numerically investigated based on the unit cell approach. Firstly, the unit cell model of 2.5D-WC was established using ANSYS software. Subsequently, the temperature-dependent fatigue life prediction model was built up. Finally, the fatigue lives alongside the damage evolution processes of 2.5D-WC at ambient temperature(20 ℃) and unambient temperature(180 ℃) were analyzed. The results show that numerical results are in good agreement with the relevant experimental results at 20 and 180 ℃. Fatigue behavior of 2.5D-WC is also sensitive to temperature, which is partially attributed to the mechanical properties of resin and the change of inclination angle of warp yarns. We hope that the proposed fatigue life prediction model and the findings could further promote the engineering application of 2.5D-WC, especially in aero-engine field.展开更多
The friction properties of wet clutches are highly dependent on the surface tribofilms formed by automatic transmission fluids (ATFs). Here, four commercial ATFs were evaluated with a disc-on-disc tribometer to study ...The friction properties of wet clutches are highly dependent on the surface tribofilms formed by automatic transmission fluids (ATFs). Here, four commercial ATFs were evaluated with a disc-on-disc tribometer to study tribofilm formation on steel surfaces and the effects of tribofilms on the friction properties. The chemical composition, stoichiometry, structure, and thickness of the tribofilms were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS). Calcium phosphate (CaP) tribofilms form on the friction surface with all ATFs, which contributes to their antishudder characteristics. The thickness and surface coverage of CaP tribofilms are positively correlated with their antishudder properties.展开更多
In this paper fretting fatigue crack behavior in 1045 steel is studied by in-situ observation and finite element analysis.in-situ fretting fatigue experiments are conducted to capture real-time fretting fatigue crack ...In this paper fretting fatigue crack behavior in 1045 steel is studied by in-situ observation and finite element analysis.in-situ fretting fatigue experiments are conducted to capture real-time fretting fatigue crack formation and propagation process.The fretting fatigue tests under different load conditions are carried out,then the lifetime and fracture surface are obtained.The crack propagation rates under different loading conditions are measured by in-situ observations.With in-situ observation,crack initiation location and direction are analyzed.Finite element model is used to calculate J-integral which then is applied to fitting with experimental crack growth rate,and establishing crack growth rate model.From fitted S-N curve,it turns out that smaller load ratio leads to higher lifetime.Crack initiates slightly below the point equivalent to line contact of the contact surface in different test conditions,and crack direction shows no obvious relationship with load parameters.The established crack growth rate model well agrees with the test results.展开更多
Although the process by which the cortical tissues of the brain fold has been the subject of considerable study and debate over the past few decades,a single mechanistic description of the phenomenon has yet to be ful...Although the process by which the cortical tissues of the brain fold has been the subject of considerable study and debate over the past few decades,a single mechanistic description of the phenomenon has yet to be fully accepted.Rather,two competing explanations of cortical folding have arisen in recent years;known as the axonal tension and the differential tangential expansion models.In the present review,these two models are introduced by analyzing the computational,theoretical,materials-based,and cell studies which have yielded them.Then Four-dimensional bioprinting is presented as a powerful technology which can not only be used to test both models of cortical folding de novo,but can also be used to explore the reciprocal effects that folding associated mechanical stresses may have on neural development.Therein,the fabrication of‘smart’tissue models which can accurately simulate the in vivo folding process and recapitulate physiologically relevant stresses are introduced.We also provide a general description of both cortical neurobiology as well as the cellular basis of cortical folding.Our discussion also entails an overview of both 3D and 4D bioprinting technologies,as well as a brief commentary on recent advancements in printed central nervous system tissue engineering.展开更多
基金supported by grants from Natural Science Foundation Key Program of Fujian Province(2023J02011)National Natural Science Foundation of China(31970281,31671668)+1 种基金a Sino-German Mobility Program funded jointly by National Natural Science Foundation of ChinaGerman Research Foundation(M-0275).
文摘Transcription factors(TFs)play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens.OsSPL10(SQUAMOSA promoter binding protein-like10)is an important TF regulating trichome development and salt tolerance in rice.Here we report that knockout of OsSPL10 reduces whereas its overexpression enhances rice resistance to blast disease.OsSPL10 positively regulates chitin-induced immune responses including reactive oxygen species(ROS)burst and callose deposition.We show that OsSPL10 physically associates with OsJAmyb,an important TF involved in jasmonic acid(JA)signaling,and positively regulates its protein stability.We then prove that OsJAmyb positively regulates resistance to blast.Our results reveal a molecular module consisting of OsSPL10 and OsJAmyb that positively regulates blast resistance.
基金the National Natural Science Foundation of China(31671668)Natural Science Foundation of Fujian Province(2021J01076)+1 种基金International Atomic Energy Agency Coordinated Research Project(D23031-22287)Key Program of Science and Technology in Fujian Province(2020NZ08016).
文摘Plant trichomes are a specialized cellular tissue that functions in resistance to biotic and abiotic stresses.In rice,three transcription-factor genes:OsWOX3B,HL6,and OsSPL10,have been found to control trichome development.Although studies have shown interactions between the three genes,their full relationship in trichome development is unclear.We found that the expression levels of OsWOX3B and HL6 were both reduced in OsSPL10-knockout plants but increased in OsSPL10-overexpression plants,suggesting that OsSPL10 positively regulates their expression.Physical interaction between OsSPL10 and OsWOX3B was found both in vivo and in vitro and attenuated their abilities to bind to the promoter of HL6 to activate its transcription.This mechanism may regulate trichome length by adjusting the expression of HL6.A rice gene network regulating trichome development is proposed.
基金supported by the National Natural Science Foundation of China(Grant Nos.41971009&41503054)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2000300)。
文摘The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.
基金This work was funded by The Max Planck Society, an Alexander von Hum-boldt Foundation postdoctoral fellowship, and the National Nature Science Foundation of China (Grant 31770277) (HC), a Chinese Scholarship Council PhD fellowship (CSC) (JQ) and Deutsche Forschungsgemein- schaft SFB 670 grant (JEP, DB).
文摘In plant immunity, pathogen-activated intracellular nucleotide binding/leucine rich repeat (NLR) receptors mobilize disease resistance pathways, but the downstream signaling mechanisms remain obscure. Enhanced disease susceptibility 1 (EDS1) controls transcriptional reprogramming in resistance triggered by Toll-lnterleukinl-Receptor domain (TIR)-family NLRs (TNLs). Transcriptional induction of the salicylic acid (SA) hormone defense sector provides one crucial barrier against biotrophic pathogens. Here, we present genetic and molecular evidence that in Arabidopsis an EDS1 complex with its partner PAD4 inhibits MYC2, a master regulator of SA-antagonizing jasmonic acid (JA) hormone pathways. In the TNL immune response, EDSl/PAD4 interference with MYC2 boosts the SA defense sector independently of EDS1-induced SA synthesis, thereby effectively blocking actions of a potent bacterial JA mimic, coronatine (COR). We show that antagonism of MYC2 occurs after COR has been sensed inside the nucleus but before or coincident with MYC2 binding to a target promoter, pANAC019. The stable interaction of PAD4 with MYC2 in planta is competed by EDS1-PAD4 complexes. However, suppression of MYC2-promoted genes requires EDS1 together with PAD4, pointing to an essential EDS1-PAD4 heterodimer activity in MYC2 inhibition. Taken together, these results uncover an immune receptor signaling circuit that intersects with hormone pathway crosstalk to reduce bacterial pathogen growth.
文摘Four-dimensional (4D) printing is an emerging and highly innovative additive manufacturing process by which to fabricate pre-designed,self-assembly structures with the ability to transform over time.However,one of the critical challenges of 4D printing is the lack of advanced 4D printing systems that not only meet all the essential requirements of shape change but also possess smart,dynamic capabilities to spatiotemporally and instantly control the shape-transformation process.Here,we present a facile 4D printing platform which incorporates nanomaterials into the conventional stimuli-responsive polymer,allowing the 4D printed object to achieve a dynamic and remote controlled,on-time and position shape transformation.A proof-of-concept 4D printed brain model was created using near-infrared light (NIR) responsive nanocomposite to evaluate the capacity for controllable 4D transformation,and the feasibility of photothermal stimulation for modulating neural stem cell behaviors.This novel 4D printing strategy can not only be used to create dynamic 3D patterned biological structures that can spatiotemporally control their shapes or behaviors of transformation under a human benign stimulus (NIR),but can also provide a potential method for building complex self-morphing objects for widespread applications.
基金supported by Jiangsu Innovation Program fo Graduate Education (No. KYLX_0237)
文摘As one of the new structural layout in the family of woven composites, 2.5D Woven Composites(2.5D-WC) have recently attracted an increasing interest owing to its excellent properties, i.e. high specific strength and fatigue resistance, in the aerospace and automobile industry. Indepth understanding of the fatigue behavior of this material at un-ambient temperatures is critical for the engineering applications, especially in aero-engine field. Here, fatigue behavior of 2.5D-WC at different temperatures was numerically investigated based on the unit cell approach. Firstly, the unit cell model of 2.5D-WC was established using ANSYS software. Subsequently, the temperature-dependent fatigue life prediction model was built up. Finally, the fatigue lives alongside the damage evolution processes of 2.5D-WC at ambient temperature(20 ℃) and unambient temperature(180 ℃) were analyzed. The results show that numerical results are in good agreement with the relevant experimental results at 20 and 180 ℃. Fatigue behavior of 2.5D-WC is also sensitive to temperature, which is partially attributed to the mechanical properties of resin and the change of inclination angle of warp yarns. We hope that the proposed fatigue life prediction model and the findings could further promote the engineering application of 2.5D-WC, especially in aero-engine field.
文摘The friction properties of wet clutches are highly dependent on the surface tribofilms formed by automatic transmission fluids (ATFs). Here, four commercial ATFs were evaluated with a disc-on-disc tribometer to study tribofilm formation on steel surfaces and the effects of tribofilms on the friction properties. The chemical composition, stoichiometry, structure, and thickness of the tribofilms were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS). Calcium phosphate (CaP) tribofilms form on the friction surface with all ATFs, which contributes to their antishudder characteristics. The thickness and surface coverage of CaP tribofilms are positively correlated with their antishudder properties.
基金financially supported by the National Natural Science Foundation of China(Nos.91860101,11632010,11902370 and 11572171)National Major Science and Technology Projects of China(No.2017-VI-0003-0073)。
文摘In this paper fretting fatigue crack behavior in 1045 steel is studied by in-situ observation and finite element analysis.in-situ fretting fatigue experiments are conducted to capture real-time fretting fatigue crack formation and propagation process.The fretting fatigue tests under different load conditions are carried out,then the lifetime and fracture surface are obtained.The crack propagation rates under different loading conditions are measured by in-situ observations.With in-situ observation,crack initiation location and direction are analyzed.Finite element model is used to calculate J-integral which then is applied to fitting with experimental crack growth rate,and establishing crack growth rate model.From fitted S-N curve,it turns out that smaller load ratio leads to higher lifetime.Crack initiates slightly below the point equivalent to line contact of the contact surface in different test conditions,and crack direction shows no obvious relationship with load parameters.The established crack growth rate model well agrees with the test results.
基金supported by NSF MME program grant#1642186March of Dimes Foundation’s Gene Discovery and Translational Research Grant and NIH Director’s New Innovator Award 1DP2EB020549-01.
文摘Although the process by which the cortical tissues of the brain fold has been the subject of considerable study and debate over the past few decades,a single mechanistic description of the phenomenon has yet to be fully accepted.Rather,two competing explanations of cortical folding have arisen in recent years;known as the axonal tension and the differential tangential expansion models.In the present review,these two models are introduced by analyzing the computational,theoretical,materials-based,and cell studies which have yielded them.Then Four-dimensional bioprinting is presented as a powerful technology which can not only be used to test both models of cortical folding de novo,but can also be used to explore the reciprocal effects that folding associated mechanical stresses may have on neural development.Therein,the fabrication of‘smart’tissue models which can accurately simulate the in vivo folding process and recapitulate physiologically relevant stresses are introduced.We also provide a general description of both cortical neurobiology as well as the cellular basis of cortical folding.Our discussion also entails an overview of both 3D and 4D bioprinting technologies,as well as a brief commentary on recent advancements in printed central nervous system tissue engineering.