The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highreso...The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highresolution AFM images of chromatin compaction at several levels can be demonstrated. An extended beads-on-astring (width of ～ 15-20nm, height of ～ 2-3nm for eachindividual nucleosome) can be consistently observed. Furthermore, superbeads (width of ～ 40nm, height of ～ 7nm)are demonstrated. Visualization of the solenoid conformation at the level of 30nm chromatin fiber is attained eitherby using AFM or by using electron microscopy. In addition, tightly coiled chromatin fibers (～ 50-60nm and ～90-110nm) can be revealed. Our data suggest that the chromatin in the interphase nucleus of chicken erythrocyte represents a high-order conformation and AFM provides useful high-resolution structural information concerning thefolding pattern of interphase chromatin fibers.展开更多
Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization...Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization in terms of storage volume and folding creases.In this paper,a flat foldable equiangular spiral folding pattern inspired by the sunflower disk is introduced.Then,a parametric design method for this equiangular spiral crease diagram is introduced in detail.Subsequently,a kinematic model of the equiangular spiral folding pattern is established based on the kinematic equivalence between rigid origami and spherical linkages.A simulation of the developed model demonstrates that the equiangular spiral folding pattern can be folded flat.Using the folded ratio as an evaluation index,the calculated results and experiments show that the equiangular spiral crease pattern can yield fewer creases and improve stowage efficiency in comparison to flasher origami pattern.Equiangular spiral folding pattern can save a considerable amount of space and provide a new approach to spatially deployable structures.展开更多
CONSPECTUS:Peptides and proteins,though both composed of amino acids,differ significantly in their structural and functional complexity.Peptides are generally shorter chains of amino acids and typically adopt simple s...CONSPECTUS:Peptides and proteins,though both composed of amino acids,differ significantly in their structural and functional complexity.Peptides are generally shorter chains of amino acids and typically adopt simple secondary structures,such asα-helices orβ-sheets.However,they rarely develop the intricate tertiary and quaternary structures that are characteristic of proteins.Proteins,which consist of longer polypeptide chains,exhibit complex folding patterns stabilized by various interactions,including hydrogen bonds,disulfide linkages,and hydrophobic interactions.This structural complexity allows proteins to perform highly specialized biological functions,such as enzymatic catalysis,signal transduction,and structural support.Both peptides and proteins have the ability to undergo self-assembly,forming higher-order structures through noncovalent interactions such as hydrogen bonding,electrostatic forces,and hydrophobic interactions.In particular,peptide functional assemblies also serve various roles,such as drug delivery,biosensors,intracellular modulation,and structural scaffolds.Depending on their sequence,they can exhibit antioxidant,antimicrobial,receptor-targeting,or enzyme-inhibitory properties.Peptides also play a crucial role in developing biomaterials like hydrogels and nanomaterials for various applications in both biomedical and engineering fields.Researchers have explored the design of peptide-based hydrogels,nanoparticles,and scaffolds that can mimic extracellular matrices,facilitating cell growth and tissue regeneration.The combination of peptides with other biomaterials has also led to innovative solutions for controlled drug release and antimicrobial coatings.In proteins,self-assembly is crucial for biological function,as exemplified by the formation of multiprotein complexes.These complexes are essential for many biological processes,including structural scaffolds,cellular signaling and immune responses.Among structural protein assemblies,silk has gained significant attention due to its exceptional mechanical properties,biocompatibility,and sustainability.Silk fibers adopt a hierarchical structure comprising crystallineβ-sheet domains interspersed with amorphous regions.This unique arrangement imparts superior strength,elasticity,and toughness,making silk a versatile material for a wide range of applications.Traditionally used in textiles,silk has recently emerged as a promising biomaterial building block in the medical field.Its ability to form various material formats,including fibers,films,and hydrogels,has enabled advancements in drug delivery,wound healing,and regenerative medicine.The expanding field of recombinant silk and peptide engineering holds tremendous promise for sustainable bioengineering and biomaterial development.Advances in synthetic biology and genetic engineering have enabled the mass production of silk-inspired proteins and functional peptides using microbial expression systems.This progress not only reduces reliance on traditional silk production but also expands the possibilities for engineering novel biomaterials with tailored properties.As research in this field continues,the potential applications of silk materials and functional peptides in healthcare,material science,and environmental sustainability are expected to grow,paving the way for groundbreaking innovations in biotechnology and medicine.展开更多
文摘The organization of the higher order structure of chromatin in chicken erythrocytes has been examined withtapping-mode scanning force microscopy under conditionsclose to their native environment. Reproducible highresolution AFM images of chromatin compaction at several levels can be demonstrated. An extended beads-on-astring (width of ～ 15-20nm, height of ～ 2-3nm for eachindividual nucleosome) can be consistently observed. Furthermore, superbeads (width of ～ 40nm, height of ～ 7nm)are demonstrated. Visualization of the solenoid conformation at the level of 30nm chromatin fiber is attained eitherby using AFM or by using electron microscopy. In addition, tightly coiled chromatin fibers (～ 50-60nm and ～90-110nm) can be revealed. Our data suggest that the chromatin in the interphase nucleus of chicken erythrocyte represents a high-order conformation and AFM provides useful high-resolution structural information concerning thefolding pattern of interphase chromatin fibers.
基金supported in part by National Key R&D Program of China(Grant No.2018YFB1304600)CAS Interdisciplinary Innovation Team(Grant No.JCTD-2018-11)the Natural Science Foundation of China(Grant No.51775541).
文摘Flasher origami pattern has been widely utilized to improve the stowage efficiency of deployable structures.Nevertheless,flasher origami cannot be folded fully flat,and they still have great potential for optimization in terms of storage volume and folding creases.In this paper,a flat foldable equiangular spiral folding pattern inspired by the sunflower disk is introduced.Then,a parametric design method for this equiangular spiral crease diagram is introduced in detail.Subsequently,a kinematic model of the equiangular spiral folding pattern is established based on the kinematic equivalence between rigid origami and spherical linkages.A simulation of the developed model demonstrates that the equiangular spiral folding pattern can be folded flat.Using the folded ratio as an evaluation index,the calculated results and experiments show that the equiangular spiral crease pattern can yield fewer creases and improve stowage efficiency in comparison to flasher origami pattern.Equiangular spiral folding pattern can save a considerable amount of space and provide a new approach to spatially deployable structures.
基金supported by the Cabinet Office,Impulsing Paradigm Change through Disrupt Technologies Program(ImPACT)(K.N.)Japan Science and Technology(JST)ERATO(Grant No.JPMJER1602)(K.N.)+3 种基金Grant-in-Aid for Transformative Research Areas(B)(Grant No.JP20H05735)(K.N.)JST COI-Next(Grant Number JPMJPF2114)(K.N.)the MEXT Program:Data Creation and Utilization-Type Material Research and Development Project(Grant Number JPMXP1122714694)(K.N.)JSPS KAKENHI(Grant Number 24K17831)(S.S.Y.L).
文摘CONSPECTUS:Peptides and proteins,though both composed of amino acids,differ significantly in their structural and functional complexity.Peptides are generally shorter chains of amino acids and typically adopt simple secondary structures,such asα-helices orβ-sheets.However,they rarely develop the intricate tertiary and quaternary structures that are characteristic of proteins.Proteins,which consist of longer polypeptide chains,exhibit complex folding patterns stabilized by various interactions,including hydrogen bonds,disulfide linkages,and hydrophobic interactions.This structural complexity allows proteins to perform highly specialized biological functions,such as enzymatic catalysis,signal transduction,and structural support.Both peptides and proteins have the ability to undergo self-assembly,forming higher-order structures through noncovalent interactions such as hydrogen bonding,electrostatic forces,and hydrophobic interactions.In particular,peptide functional assemblies also serve various roles,such as drug delivery,biosensors,intracellular modulation,and structural scaffolds.Depending on their sequence,they can exhibit antioxidant,antimicrobial,receptor-targeting,or enzyme-inhibitory properties.Peptides also play a crucial role in developing biomaterials like hydrogels and nanomaterials for various applications in both biomedical and engineering fields.Researchers have explored the design of peptide-based hydrogels,nanoparticles,and scaffolds that can mimic extracellular matrices,facilitating cell growth and tissue regeneration.The combination of peptides with other biomaterials has also led to innovative solutions for controlled drug release and antimicrobial coatings.In proteins,self-assembly is crucial for biological function,as exemplified by the formation of multiprotein complexes.These complexes are essential for many biological processes,including structural scaffolds,cellular signaling and immune responses.Among structural protein assemblies,silk has gained significant attention due to its exceptional mechanical properties,biocompatibility,and sustainability.Silk fibers adopt a hierarchical structure comprising crystallineβ-sheet domains interspersed with amorphous regions.This unique arrangement imparts superior strength,elasticity,and toughness,making silk a versatile material for a wide range of applications.Traditionally used in textiles,silk has recently emerged as a promising biomaterial building block in the medical field.Its ability to form various material formats,including fibers,films,and hydrogels,has enabled advancements in drug delivery,wound healing,and regenerative medicine.The expanding field of recombinant silk and peptide engineering holds tremendous promise for sustainable bioengineering and biomaterial development.Advances in synthetic biology and genetic engineering have enabled the mass production of silk-inspired proteins and functional peptides using microbial expression systems.This progress not only reduces reliance on traditional silk production but also expands the possibilities for engineering novel biomaterials with tailored properties.As research in this field continues,the potential applications of silk materials and functional peptides in healthcare,material science,and environmental sustainability are expected to grow,paving the way for groundbreaking innovations in biotechnology and medicine.
