Unlike regenerative-competent species that possess a remarkable intrinsic capacity to replenish lost neurons and restore neurocircuits spontaneously,the central nervous system in adult mammals lacks the ability to com...Unlike regenerative-competent species that possess a remarkable intrinsic capacity to replenish lost neurons and restore neurocircuits spontaneously,the central nervous system in adult mammals lacks the ability to compensate for the neuronal loss caused by neurodegenerative diseases or traumatic injuries resulting in permanent loss of functionality.Inspired by earlier discoveries that radial glia or astrocytes isolated from the postnatal cortex can generate neurons.展开更多
Dilated cardiomyopathy（DCM）is characterized by the dilated heart chambers and reduced systolic function in the absence of specific aetiology[1].Approximately one third of DCM cases are hereditary.In recent years,DCM...Dilated cardiomyopathy（DCM）is characterized by the dilated heart chambers and reduced systolic function in the absence of specific aetiology[1].Approximately one third of DCM cases are hereditary.In recent years,DCM concomitant with arrhythmias and sudden death resulting from gene mutation has been widely展开更多
美国加息导致美债遭遇自1781年以来最严重抛售,作为“债券卫士”的金融机构或将力挽狂澜,美国银行(Bankof America Corp.)的策略师最近获得了可以追溯到美国建国以来的债券市场数据。他们说,这些数据表明,美国国债以前从未出现过像过去...美国加息导致美债遭遇自1781年以来最严重抛售,作为“债券卫士”的金融机构或将力挽狂澜,美国银行(Bankof America Corp.)的策略师最近获得了可以追溯到美国建国以来的债券市场数据。他们说,这些数据表明,美国国债以前从未出现过像过去三年那样长时间的下跌。展开更多
Anthocyanin accumulation is recognized as a visible biomarker of plants that have suffered from environmental stresses. However, the molecular mechanisms underlying stress-induced anthocyanin biosynthesis remain uncle...Anthocyanin accumulation is recognized as a visible biomarker of plants that have suffered from environmental stresses. However, the molecular mechanisms underlying stress-induced anthocyanin biosynthesis remain unclear. Expression of anthocyanin-specific genes is regulated by the conserved MBW complex, which is composed of the MYB, bHLH, and WD40 subunRs in higher plants. MBW activity is repressed by MYBL2 and the JAZ family proteins, which bind competitively to bHLH and MYB/bHLH, respectively. Here, we found that MYBL2 and JAZs mediate gibberellic acid-inhibRed anthocyanin biosynthesis in Arabidopsis. Competitive pull-down and dual-lucifarase assays showed that DELLA proteins directly sequester MYBL2 and JAZ repressors, leading to the release of bHLH/MYB subunits and subsequently to the formation of active MBW complex, which then activates the anthocyanin biosynthetic pathway. The JAZ-DELLA-MYBL2 module also plays an Important role in abiotic stress-induced anthocy- anin biosynthesis. Furthermore, we found that the DELLA protein RGA accumulates upon plant exposure to abiotic stresses. Altogether, our data reveal that DELLA-promoted anthocyanin biosynthesis is mediated at least in part by MYBL2 and JAZ regulatory proteins, providing new insights into the coordinated regulation of plant growth and defense through metabolic pathway regulation.展开更多
Anthocyanins, a group of L-phenylalanine （Phe）-derived flavonoids, have been demonstrated to play impor- tant roles in plant stress resistance and interactions between plants and insects. Although the anthocyanin bi...Anthocyanins, a group of L-phenylalanine （Phe）-derived flavonoids, have been demonstrated to play impor- tant roles in plant stress resistance and interactions between plants and insects. Although the anthocyanin biosynthetic pathway and its regulatory mechanisms have been extensively studied, it remains unclear whether the level of Phe supply affects anthocyanin biosynthesis. Here, we investigated the roles of arogenate dehydratases （ADTs）, the key enzymes that catalyze the conversion of arogenate into Phe, in sucrose-induced anthocyanin biosynthesis in Arabidopsis. Genetic analysis showed that all six ADT isoforms function redundantly in anthocyanin biosynthesis but have differential contributions. ADT2 contributes the most to anthocyanin accumulation, followed by ADT1 and ADT3, and ADT4-ADT6. We found that anthocyanin content is positively correlated with the levels of Phe and sucrose-induced ADT transcripts in seedlings. Consistently, addition of Phe to the medium could dramatically increase anthocyanin content in the wild-type plants and rescue the phenotype of the adtl adt3 double mutant regarding the anthocyanin accumulation. Moreover, transgenic plants overexpressing ADT4, which appears to be less sensitive to Phe than overexpression ofADT2, hyperaccumulate Phe and produce elevated level of antho- cyanins. Taken together, our results suggest that the level of Phe is an important regulatory factor for sus- taining anthocyanin biosynthesis.展开更多
Flavonols have been demonstrated to play many important roles in plant growth, development, and communication with other organisms. Flavonol biosynthesis is spatiotemporally regulated by the subgroup 7 R2R3-MYB (SG7 M...Flavonols have been demonstrated to play many important roles in plant growth, development, and communication with other organisms. Flavonol biosynthesis is spatiotemporally regulated by the subgroup 7 R2R3-MYB (SG7 MYB) transcription factors including MYB11/MYB12/MYB111. However, whether SG7- MYB activity is subject to post-translational regulation remains unclear. Here, we show that gibberellic acid (GA) inhibits flavonol biosynthesis via DELLA proteins in Arabidopsis. Protein-protein interaction analyses revealed that DELLAs (RGA and GAI) interacted with SG7 MYBs (MYB12 and MYB111) both in vitro and in vivo, leading to enhanced affinity of MYB binding to the promoter regions of key genes for flavonol biosynthesis and thus increasing their transcriptional levels. We observed that the level of auxin in the root tip was negatively correlated with root flavonol content. Furthermore, genetic assays showed that loss-of-function mutations in MYB 12, which is predominantly expressed in roots, partially rescued the short-root phenotype of the GA-deficient mutant ga1-3 by increasing root meristem size and mature cell size. Consistent with these observations, exogenous application of the flavonol quercetin restored the root meristem size of myb12 ga1-3 to that of ga1-3. Taken together, our data elucidate a molecular mechanism by which GA promotes root growth by directly reducing flavonol biosynthesis.展开更多
The paper overviews the state-of-art of aircraft powered by hybrid electric propulsion systems.The research status of the design and energy management of hybrid aircraft and hybrid propulsion systems are further revie...The paper overviews the state-of-art of aircraft powered by hybrid electric propulsion systems.The research status of the design and energy management of hybrid aircraft and hybrid propulsion systems are further reviewed.The first contribution of the review is to demonstrate that,in the context of relatively underdeveloped electrical storage technologies,the study of mid-scale hybrid aircraft can contribute the most to both theoretical and practical knowledge.Meanwhile,the profits and potential drawbacks of applying hybrid propulsion to mid-scale hybrid airplanes have not been thoroughly illustrated.Secondly,as summed in the overview of design methodologies,the multi-objective optimization transcends the single-objective one.The potential of the hybrid propulsion system can be thoroughly evaluated in only one optimization run,if several objectives optimized simultaneously.Yet there are few researches covering the conceptual design of hybrid aircraft using multi-objective optimization.The review of the most popular energy management strategies discloses the third research gap—current methodologies favoured in hybrid ground vehicles do not consider the aircraft safety.Additionally,both non-causal and causal energy management are needed for performing a complicated flight mission with several sub-tasks.展开更多
Mutants defective in chloroplast development or photosynthesis are liable to accumulate higher levels of anthocyanin in photo-oxidative stress.However,regulatory mechanisms of anthocyanin biosynthesis in the mutants r...Mutants defective in chloroplast development or photosynthesis are liable to accumulate higher levels of anthocyanin in photo-oxidative stress.However,regulatory mechanisms of anthocyanin biosynthesis in the mutants remain unclear.Here,we investigated the mechanism by which the deletion of thylakoid formation1（THF1） leads to an increased level of anthocyanin in Arabidopsis thaliana L.Physiological and genetic evidence showed that the increased level of anthocyanin in thf1 is dependent on coronatine-insensitive1（COM）signaling.Our data showed that thf1 had higher levels of basalα-linolenic acid（α-LeA）,and methyl jasmonate（JA）-induced α-LeA and 12-oxophytodienoic acid（OPDA） than the wild type（WT）.Consistently,expression levels of phospholipase genes including pPLAIIα and PLA-Iγ1 were elevated in thf1.Furthermore,inhibition of lipase activity by bromoenol lactone,a specific inhibitor of plant pPLA,led to producing identical levels of anthocyanins in WT and thf1 plants.Interestingly,OPDA biosynthesis was triggered by light illumination in isolated chloroplasts,indicating that new protein import into chloroplasts is not required for OPDA biosynthesis.Thus,we conclude that the elevated anthocyanin accumulation in thf1 is attributed to an increase in JA levels.This JA-mediated signaling to coordinate plant metabolism and growth in stress may be conserved in other photosensitive mutants.展开更多
Anthocyanin biosynthesis is regulated by a conserved transcriptional MBW complex composed of MYB,b HLH and WD40 subunits. However, molecular mechanisms underlying transcriptional regulation of these MBW subunits remai...Anthocyanin biosynthesis is regulated by a conserved transcriptional MBW complex composed of MYB,b HLH and WD40 subunits. However, molecular mechanisms underlying transcriptional regulation of these MBW subunits remain largely elusive. In this study, we isolated an Arabidopsis mutant that displays a constitutive red color in aboveground tissues with retarded growth phenotypes. In the presence of sucrose, the mutant accumulates more than 3-fold anthocyanins of the wild type(WT), but cannot produce anthocyanins as WT in the absence of sucrose. Map-based cloning results demonstrated that the mutation occurs in the locus At4 G01000, which encodes a conserved nuclear-localized ubiquitin-like(UBL) superfamily protein, silencing defective 2(SDE2), in eukaryotes. SDE2 is ubiquitously expressed in various tissues. In the sucrose-induced anthocyanin biosynthesis, SDE2 expression was not responded to sucrose treatment at the early stage but was enhanced at the late stage. SDE2 mutations result in upregulation of anthocyanin biosynthetic and regulatory genes. Yeast-two hybrid analysis indicated that SDE2 has no direct interaction with the MYB transcription factor PAP1 and b HLH factor TT8, indicating that SDE2 is a indirect factor to affect anthocyanin accumulation. Taking together, our data suggest that SDE2 may play a role in finely coordinating anthocyanin biosynthesis with other biological processes.展开更多
基金supported by National Institutes of Health grants R01 EY024986 and R01 EY028921,an unrestricted challenge grant from Research to Prevent Blindnessthe New York Eye and Ear Infirmary FoundationThe Harold W.McGraw,Jr.Family Foundation for Vision Research(to BC)。
文摘Unlike regenerative-competent species that possess a remarkable intrinsic capacity to replenish lost neurons and restore neurocircuits spontaneously,the central nervous system in adult mammals lacks the ability to compensate for the neuronal loss caused by neurodegenerative diseases or traumatic injuries resulting in permanent loss of functionality.Inspired by earlier discoveries that radial glia or astrocytes isolated from the postnatal cortex can generate neurons.
基金the funds of "the Youth Fund of Nantong Health Bureau 2015",ID:WQ2015009
文摘Dilated cardiomyopathy（DCM）is characterized by the dilated heart chambers and reduced systolic function in the absence of specific aetiology[1].Approximately one third of DCM cases are hereditary.In recent years,DCM concomitant with arrhythmias and sudden death resulting from gene mutation has been widely
文摘Anthocyanin accumulation is recognized as a visible biomarker of plants that have suffered from environmental stresses. However, the molecular mechanisms underlying stress-induced anthocyanin biosynthesis remain unclear. Expression of anthocyanin-specific genes is regulated by the conserved MBW complex, which is composed of the MYB, bHLH, and WD40 subunRs in higher plants. MBW activity is repressed by MYBL2 and the JAZ family proteins, which bind competitively to bHLH and MYB/bHLH, respectively. Here, we found that MYBL2 and JAZs mediate gibberellic acid-inhibRed anthocyanin biosynthesis in Arabidopsis. Competitive pull-down and dual-lucifarase assays showed that DELLA proteins directly sequester MYBL2 and JAZ repressors, leading to the release of bHLH/MYB subunits and subsequently to the formation of active MBW complex, which then activates the anthocyanin biosynthetic pathway. The JAZ-DELLA-MYBL2 module also plays an Important role in abiotic stress-induced anthocy- anin biosynthesis. Furthermore, we found that the DELLA protein RGA accumulates upon plant exposure to abiotic stresses. Altogether, our data reveal that DELLA-promoted anthocyanin biosynthesis is mediated at least in part by MYBL2 and JAZ regulatory proteins, providing new insights into the coordinated regulation of plant growth and defense through metabolic pathway regulation.
文摘Anthocyanins, a group of L-phenylalanine （Phe）-derived flavonoids, have been demonstrated to play impor- tant roles in plant stress resistance and interactions between plants and insects. Although the anthocyanin biosynthetic pathway and its regulatory mechanisms have been extensively studied, it remains unclear whether the level of Phe supply affects anthocyanin biosynthesis. Here, we investigated the roles of arogenate dehydratases （ADTs）, the key enzymes that catalyze the conversion of arogenate into Phe, in sucrose-induced anthocyanin biosynthesis in Arabidopsis. Genetic analysis showed that all six ADT isoforms function redundantly in anthocyanin biosynthesis but have differential contributions. ADT2 contributes the most to anthocyanin accumulation, followed by ADT1 and ADT3, and ADT4-ADT6. We found that anthocyanin content is positively correlated with the levels of Phe and sucrose-induced ADT transcripts in seedlings. Consistently, addition of Phe to the medium could dramatically increase anthocyanin content in the wild-type plants and rescue the phenotype of the adtl adt3 double mutant regarding the anthocyanin accumulation. Moreover, transgenic plants overexpressing ADT4, which appears to be less sensitive to Phe than overexpression ofADT2, hyperaccumulate Phe and produce elevated level of antho- cyanins. Taken together, our results suggest that the level of Phe is an important regulatory factor for sus- taining anthocyanin biosynthesis.
文摘Flavonols have been demonstrated to play many important roles in plant growth, development, and communication with other organisms. Flavonol biosynthesis is spatiotemporally regulated by the subgroup 7 R2R3-MYB (SG7 MYB) transcription factors including MYB11/MYB12/MYB111. However, whether SG7- MYB activity is subject to post-translational regulation remains unclear. Here, we show that gibberellic acid (GA) inhibits flavonol biosynthesis via DELLA proteins in Arabidopsis. Protein-protein interaction analyses revealed that DELLAs (RGA and GAI) interacted with SG7 MYBs (MYB12 and MYB111) both in vitro and in vivo, leading to enhanced affinity of MYB binding to the promoter regions of key genes for flavonol biosynthesis and thus increasing their transcriptional levels. We observed that the level of auxin in the root tip was negatively correlated with root flavonol content. Furthermore, genetic assays showed that loss-of-function mutations in MYB 12, which is predominantly expressed in roots, partially rescued the short-root phenotype of the GA-deficient mutant ga1-3 by increasing root meristem size and mature cell size. Consistent with these observations, exogenous application of the flavonol quercetin restored the root meristem size of myb12 ga1-3 to that of ga1-3. Taken together, our data elucidate a molecular mechanism by which GA promotes root growth by directly reducing flavonol biosynthesis.
基金the Innovate UK(No.102361)partly the Zhejiang Lab’s project“From Hybrid e VTOL Air Vehicle to Urban Air Mobility”(No.2018DF0ZX01),which aims to build the autonomous manned hybrid e VTOL aircraft for the future urban air transportpartly sponsored by Leading Innovation and Entrepreneurship Team of Zhejiang Province of China(No.2018R01006)。
文摘The paper overviews the state-of-art of aircraft powered by hybrid electric propulsion systems.The research status of the design and energy management of hybrid aircraft and hybrid propulsion systems are further reviewed.The first contribution of the review is to demonstrate that,in the context of relatively underdeveloped electrical storage technologies,the study of mid-scale hybrid aircraft can contribute the most to both theoretical and practical knowledge.Meanwhile,the profits and potential drawbacks of applying hybrid propulsion to mid-scale hybrid airplanes have not been thoroughly illustrated.Secondly,as summed in the overview of design methodologies,the multi-objective optimization transcends the single-objective one.The potential of the hybrid propulsion system can be thoroughly evaluated in only one optimization run,if several objectives optimized simultaneously.Yet there are few researches covering the conceptual design of hybrid aircraft using multi-objective optimization.The review of the most popular energy management strategies discloses the third research gap—current methodologies favoured in hybrid ground vehicles do not consider the aircraft safety.Additionally,both non-causal and causal energy management are needed for performing a complicated flight mission with several sub-tasks.
基金supported by grants to J.H.from the Ministry of Science and Technology of China(2013CB127000)the CAS/SAFEA International Partnership Program for Creative Research Teamsthe National Science Fund for Distinguished Young Scholars(30925005)
文摘Mutants defective in chloroplast development or photosynthesis are liable to accumulate higher levels of anthocyanin in photo-oxidative stress.However,regulatory mechanisms of anthocyanin biosynthesis in the mutants remain unclear.Here,we investigated the mechanism by which the deletion of thylakoid formation1（THF1） leads to an increased level of anthocyanin in Arabidopsis thaliana L.Physiological and genetic evidence showed that the increased level of anthocyanin in thf1 is dependent on coronatine-insensitive1（COM）signaling.Our data showed that thf1 had higher levels of basalα-linolenic acid（α-LeA）,and methyl jasmonate（JA）-induced α-LeA and 12-oxophytodienoic acid（OPDA） than the wild type（WT）.Consistently,expression levels of phospholipase genes including pPLAIIα and PLA-Iγ1 were elevated in thf1.Furthermore,inhibition of lipase activity by bromoenol lactone,a specific inhibitor of plant pPLA,led to producing identical levels of anthocyanins in WT and thf1 plants.Interestingly,OPDA biosynthesis was triggered by light illumination in isolated chloroplasts,indicating that new protein import into chloroplasts is not required for OPDA biosynthesis.Thus,we conclude that the elevated anthocyanin accumulation in thf1 is attributed to an increase in JA levels.This JA-mediated signaling to coordinate plant metabolism and growth in stress may be conserved in other photosensitive mutants.
基金supported by the National Basic Research Program of China (2013CB127000)the National Natural Science Foundation of China (31370326)
文摘Anthocyanin biosynthesis is regulated by a conserved transcriptional MBW complex composed of MYB,b HLH and WD40 subunits. However, molecular mechanisms underlying transcriptional regulation of these MBW subunits remain largely elusive. In this study, we isolated an Arabidopsis mutant that displays a constitutive red color in aboveground tissues with retarded growth phenotypes. In the presence of sucrose, the mutant accumulates more than 3-fold anthocyanins of the wild type(WT), but cannot produce anthocyanins as WT in the absence of sucrose. Map-based cloning results demonstrated that the mutation occurs in the locus At4 G01000, which encodes a conserved nuclear-localized ubiquitin-like(UBL) superfamily protein, silencing defective 2(SDE2), in eukaryotes. SDE2 is ubiquitously expressed in various tissues. In the sucrose-induced anthocyanin biosynthesis, SDE2 expression was not responded to sucrose treatment at the early stage but was enhanced at the late stage. SDE2 mutations result in upregulation of anthocyanin biosynthetic and regulatory genes. Yeast-two hybrid analysis indicated that SDE2 has no direct interaction with the MYB transcription factor PAP1 and b HLH factor TT8, indicating that SDE2 is a indirect factor to affect anthocyanin accumulation. Taking together, our data suggest that SDE2 may play a role in finely coordinating anthocyanin biosynthesis with other biological processes.
