Citrate is critical to the flavor of horticultural fruit and governed by ACO.However,the specific ACO and its upstream regulators involved in citrate metabolism during pear(Pyrus spp.)fruit development remained unchar...Citrate is critical to the flavor of horticultural fruit and governed by ACO.However,the specific ACO and its upstream regulators involved in citrate metabolism during pear(Pyrus spp.)fruit development remained uncharacterized.This study identified and characterized six PbrACOs from the Pyrus bretschneideri Rehd.genome.Comprehensive analyses of citrate levels,cyt/mitACO activities,and PbrACOs expression profiles in the pericarp and cortex tissues of developing’Yali’and’Dangshansuli’fruits revealed PbrACO2 as a candidate gene.Subsequently,PbrACO2 was confirmed as a mitochondrial aconitase catalyzing citrate-to-isocitrate conversion in vitro and in vivo.Analysis of differentially expressed transcription factors(TFs)and cis-acting elements in the PbrACO2 promoter identified nuclear PbrMYB3 and PbrMYB65,derived from whole genome duplication/segmental duplication,as candidate upstream regulators.These MYB TFs,without direct relationship,bound,as monomers,to the same two MYB-binding sites in the PbrACO2 promoter to activate its transcription,thereby promoting citrate isomerization in pear and tomato.Further investigation revealed that PbrMYB3 and PbrMYB65 are transcriptionally regulated by PbrNAC34a.Given their tissue-dependent expression profiles,the PbrNAC34a-PbrMYB3/65-PbrACO2 cascade partially accounts for citrate differences between pear fruit pericarp and cortex tissues.These findings enhance understanding of citrate accumulation in Rosaceae fruit and provide genetic resources for pear breeding.展开更多
Design and synthesis of efficient photocatalysts for hydrogen production via water splitting are of great importance from both theoretical and practical viewpoints. Many metal-based semiconductors have been explored f...Design and synthesis of efficient photocatalysts for hydrogen production via water splitting are of great importance from both theoretical and practical viewpoints. Many metal-based semiconductors have been explored for this purpose in recent decades. Here, for the first time, an entirely carbon-based material, bulk three-dimensionally cross-linked graphene （3DG）, has been developed as a photocatalyst for hydrogen production. It exhibits a remarkable hydrogen production rate of 270 μmol-h-l.g-t under full-spectrum light via a hot/free electron emission mechanism. Furthermore, when combined with the widely used semiconductor TiO2 to form a TiO2/3DG composite, it appears to become a more efficient hydrogen production photocatalyst. The composite achieves a production rate of 1,205 bimol-h μg-t under ultraviolet-visible （UV-vis） light and a 7.2% apparent quantum efficiency at 350 nm due to the strong synergetic effects between TiO2 and 3DG.展开更多
It has been shown that analog-to-information conversion(AIC) is an efficient scheme to perform sub-Nyquist sampling of pulsed radar echoes. However, it is often impractical, if not infeasible, to reconstruct full-rang...It has been shown that analog-to-information conversion(AIC) is an efficient scheme to perform sub-Nyquist sampling of pulsed radar echoes. However, it is often impractical, if not infeasible, to reconstruct full-range Nyquist samples because of huge storage and computational load requirements. Based on the analyses of AIC measurement system, this paper develops a novel segment-sliding reconstruction(Seg SR) scheme to effectively reconstruct the Nyquist samples. The Seg SR performs segment-by-segment reconstruction in a sliding mode and can be implemented in real time. An important characteristic that distinguishes the proposed Seg SR from existing methods is that the measurement matrix in each segment satisfies the restricted isometry property(RIP) condition. Partial support in the previous segment can be incorporated into the estimation of the Nyquist samples in the current segment. The effect of interference introduced from adjacent segments is theoretically analyzed, and it is revealed that the interference consists of two interference levels with different impacts to the signal reconstruction performance. With these observations, a two-step orthogonal matching pursuit(OMP)procedure is proposed for segment reconstruction, which takes into account different interference levels and partially known support of the previous segment. The proposed Seg SR scheme achieves near-optimal reconstruction performance with a significant reduction of computational loads and storage requirements. Theoretical analyses and simulations verify its effectiveness.展开更多
基金supported by the Natural Science Foundation of Guangxi(2023GXNSFAA026479)the Municipal Science and Technology Project of Alar(Xinjiang)(2022XX5)+5 种基金the National Natural Science Foundation of China(32302615,31872070,31830081&31701868)the Fundamental Research Funds for the Central Universities(JCQY201901)the Seed Industry Promotion Project of Jiangsu(JBGS(2021)022)the Guidance Foundation of the Hainan Institute of Nanjing Agricultural University(NAUSYMS08)the Jiangsu Agriculture Science and Technology Innovation Fund(CX(22)2025)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Earmarked Fund for China Agriculture Research System(CARS-28).
文摘Citrate is critical to the flavor of horticultural fruit and governed by ACO.However,the specific ACO and its upstream regulators involved in citrate metabolism during pear(Pyrus spp.)fruit development remained uncharacterized.This study identified and characterized six PbrACOs from the Pyrus bretschneideri Rehd.genome.Comprehensive analyses of citrate levels,cyt/mitACO activities,and PbrACOs expression profiles in the pericarp and cortex tissues of developing’Yali’and’Dangshansuli’fruits revealed PbrACO2 as a candidate gene.Subsequently,PbrACO2 was confirmed as a mitochondrial aconitase catalyzing citrate-to-isocitrate conversion in vitro and in vivo.Analysis of differentially expressed transcription factors(TFs)and cis-acting elements in the PbrACO2 promoter identified nuclear PbrMYB3 and PbrMYB65,derived from whole genome duplication/segmental duplication,as candidate upstream regulators.These MYB TFs,without direct relationship,bound,as monomers,to the same two MYB-binding sites in the PbrACO2 promoter to activate its transcription,thereby promoting citrate isomerization in pear and tomato.Further investigation revealed that PbrMYB3 and PbrMYB65 are transcriptionally regulated by PbrNAC34a.Given their tissue-dependent expression profiles,the PbrNAC34a-PbrMYB3/65-PbrACO2 cascade partially accounts for citrate differences between pear fruit pericarp and cortex tissues.These findings enhance understanding of citrate accumulation in Rosaceae fruit and provide genetic resources for pear breeding.
文摘Design and synthesis of efficient photocatalysts for hydrogen production via water splitting are of great importance from both theoretical and practical viewpoints. Many metal-based semiconductors have been explored for this purpose in recent decades. Here, for the first time, an entirely carbon-based material, bulk three-dimensionally cross-linked graphene （3DG）, has been developed as a photocatalyst for hydrogen production. It exhibits a remarkable hydrogen production rate of 270 μmol-h-l.g-t under full-spectrum light via a hot/free electron emission mechanism. Furthermore, when combined with the widely used semiconductor TiO2 to form a TiO2/3DG composite, it appears to become a more efficient hydrogen production photocatalyst. The composite achieves a production rate of 1,205 bimol-h μg-t under ultraviolet-visible （UV-vis） light and a 7.2% apparent quantum efficiency at 350 nm due to the strong synergetic effects between TiO2 and 3DG.
基金supported by National Natural Science Foundation of China (Grant Nos. 61171166, 61401210, 61571228)China Postdoctoral Science Foundation (Grant No. 2014M551597)
文摘It has been shown that analog-to-information conversion(AIC) is an efficient scheme to perform sub-Nyquist sampling of pulsed radar echoes. However, it is often impractical, if not infeasible, to reconstruct full-range Nyquist samples because of huge storage and computational load requirements. Based on the analyses of AIC measurement system, this paper develops a novel segment-sliding reconstruction(Seg SR) scheme to effectively reconstruct the Nyquist samples. The Seg SR performs segment-by-segment reconstruction in a sliding mode and can be implemented in real time. An important characteristic that distinguishes the proposed Seg SR from existing methods is that the measurement matrix in each segment satisfies the restricted isometry property(RIP) condition. Partial support in the previous segment can be incorporated into the estimation of the Nyquist samples in the current segment. The effect of interference introduced from adjacent segments is theoretically analyzed, and it is revealed that the interference consists of two interference levels with different impacts to the signal reconstruction performance. With these observations, a two-step orthogonal matching pursuit(OMP)procedure is proposed for segment reconstruction, which takes into account different interference levels and partially known support of the previous segment. The proposed Seg SR scheme achieves near-optimal reconstruction performance with a significant reduction of computational loads and storage requirements. Theoretical analyses and simulations verify its effectiveness.
