The expanded outer seed coat and the rigid inner seed coat of pomegranate seeds,both affect the sensory qualities of the fruit and its acceptability to consumers.Pomegranate seeds are also an appealing model for the s...The expanded outer seed coat and the rigid inner seed coat of pomegranate seeds,both affect the sensory qualities of the fruit and its acceptability to consumers.Pomegranate seeds are also an appealing model for the study of seed coat differentiation and development.We conducted nontarget metabolic profiling to detect metabolites that contribute to the morphological differentiation of the seed coats along with transcriptomic profiling to unravel the genetic mechanisms underlying this process.Comparisons of metabolites in the lignin biosynthetic pathway accumulating in seed coat layers at different developmental stages revealed that monolignols,including coniferyl alcohol and sinapyl alcohol,greatly accumulated in inner seed coats and monolignol glucosides greatly accumulated in outer seed coats.Strong expression of genes involved in monolignol biosynthesis and transport might explain the spatial patterns of biosynthesis and accumulation of these metabolites.Hemicellulose constituents and flavonoids in particular accumulated in the inner seed coat,and candidate genes that might be involved in their accumulation were also identified.Genes encoding transcription factors regulating monolignol,cellulose,and hemicellulose metabolism were chosen by coexpression analysis.These results provide insights into metabolic factors influencing seed coat differentiation and a reference for studying seed coat developmental biology and pomegranate genetic improvement.展开更多
叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和...叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。展开更多
Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC electromotility and its associated nonlinear...Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC electromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cuticular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface cisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.展开更多
Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engi...Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engineering applications.In this work,longitudinal compression,bending,longitudinal shear,longitudinal tensile,transverse compression and transverse tensile tests of bamboo materials are conducted,considering the influence of the bamboo nodes.The mechanical properties of the whole bamboo stalk with the wall thickness and outer circumference are explored.Through univariate and multiple regression analysis,the relationship between mechanical properties and wall thickness and perimeter is fitted,and the conversion parameters between different mechanical properties are derived.The research results show that the transverse compressive strength of nodal specimen,and transverse tensile strength of nodal and inter-node specimens increase with the increase of wall thickness and outer circumference,but other mechanical properties decrease with the increase of wall thickness and outer circumference.The prediction formula and conversion parameters of bamboo mechanical properties proposed in this research have high applicability and accuracy.Moreover,this research can provide references for the evaluation of bamboo performance and saving test costs.展开更多
基金supported by the Natural Science Foundation of Anhui Province(1708085MC85).
文摘The expanded outer seed coat and the rigid inner seed coat of pomegranate seeds,both affect the sensory qualities of the fruit and its acceptability to consumers.Pomegranate seeds are also an appealing model for the study of seed coat differentiation and development.We conducted nontarget metabolic profiling to detect metabolites that contribute to the morphological differentiation of the seed coats along with transcriptomic profiling to unravel the genetic mechanisms underlying this process.Comparisons of metabolites in the lignin biosynthetic pathway accumulating in seed coat layers at different developmental stages revealed that monolignols,including coniferyl alcohol and sinapyl alcohol,greatly accumulated in inner seed coats and monolignol glucosides greatly accumulated in outer seed coats.Strong expression of genes involved in monolignol biosynthesis and transport might explain the spatial patterns of biosynthesis and accumulation of these metabolites.Hemicellulose constituents and flavonoids in particular accumulated in the inner seed coat,and candidate genes that might be involved in their accumulation were also identified.Genes encoding transcription factors regulating monolignol,cellulose,and hemicellulose metabolism were chosen by coexpression analysis.These results provide insights into metabolic factors influencing seed coat differentiation and a reference for studying seed coat developmental biology and pomegranate genetic improvement.
文摘叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。
基金supported by NIH (NIDCD DC 05989)NSFC (30600700, 30772413)
文摘Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC electromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cuticular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface cisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.
基金This research was funded by the National Key Research&Development Program(Grant No.2017YFC0703500).
文摘Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engineering applications.In this work,longitudinal compression,bending,longitudinal shear,longitudinal tensile,transverse compression and transverse tensile tests of bamboo materials are conducted,considering the influence of the bamboo nodes.The mechanical properties of the whole bamboo stalk with the wall thickness and outer circumference are explored.Through univariate and multiple regression analysis,the relationship between mechanical properties and wall thickness and perimeter is fitted,and the conversion parameters between different mechanical properties are derived.The research results show that the transverse compressive strength of nodal specimen,and transverse tensile strength of nodal and inter-node specimens increase with the increase of wall thickness and outer circumference,but other mechanical properties decrease with the increase of wall thickness and outer circumference.The prediction formula and conversion parameters of bamboo mechanical properties proposed in this research have high applicability and accuracy.Moreover,this research can provide references for the evaluation of bamboo performance and saving test costs.
文摘在计算域内生成密实圆形颗粒集合体是离散单元法模拟中的一个重要问题.颗粒生成算法中,波前法(包括closed型和open型)作为一种纯几何算法,由于其高效性得到了广泛应用.然而,波前法生成的颗粒集合体在域边界上存在较大的间隙,从而导致边界的非光滑性.为克服这一问题,将closed型波前法中处理外域边界方法拓展到open型波前法.该算法通过Netwon-Raphson迭代方法得到颗粒的中心坐标和半径,从而保证新生成的颗粒与域边界相切,最终消除了边界间隙和凹凸性.针对open型波前法在堆积过程中出现的右端抬升问题,给出了解决方法,消除了潜在的优势结构面,进一步提高了计算效率.结果表明:提出的closed型和open型算法对不同的内外域边界都有很好的适用性.相比其他颗粒生成算法,open型算法效率非常高,其效率分别是离散元模拟软件和closed型的20500倍和4.4倍.在考虑域边界情况下,open型波前法在2.3 GHz的笔记本电脑上生成410万密实圆形颗粒集合体只需0.9 s.
