Articles de revues : « Nanodomini »

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Okamoto, Yukihiro, Kaito Hamaguchi, Mayo Watanabe, Nozomi Watanabe et Hiroshi Umakoshi. « Characterization of Phase Separated Planar Lipid Bilayer Membrane by Fluorescence Ratio Imaging and Scanning Probe Microscope ». Membranes 12, n^o 8 (9 août 2022) : 770. http://dx.doi.org/10.3390/membranes12080770.

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The lipid membrane forms nanodomains (rafts) and shows heterogeneous properties. These nanodomains relate to significant roles in various cell functions, and thus the analysis of the nanodomains in phase-separated lipid membranes is important to clarify the function and role of the nanodomains. However, the lipid membrane possesses small-sized nanodomains and shows a small height difference between the nanodomains and their surroundings at certain lipid compositions. In addition, nanodomain analysis sometimes requires highly sensitive and expensive apparatus, such as a two-photon microscope. These have prevented the analysis by the conventional fluorescence microscope and by the topography of the scanning probe microscope (SPM), even though these are promising methods in macroscale and microscale analysis, respectively. Therefore, this study aimed to overcome these problems in nanodomain analysis. We successfully demonstrated that solvatochromic dye, LipiORDER, could analyze the phase state of the lipid membrane at the macroscale with low magnification lenses. Furthermore, we could prove that the phase mode of SPM was effective in the visualization of specific nanodomains by properties difference as well as topographic images of SPM. Hence, this combination method successfully gave much information on the phase state at the micro/macro scale, and thus this would be applied to the analysis of heterogeneous lipid membranes.

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Drab, Mitja, David Stopar, Veronika Kralj-Iglič et Aleš Iglič. « Inception Mechanisms of Tunneling Nanotubes ». Cells 8, n^o 6 (21 juin 2019) : 626. http://dx.doi.org/10.3390/cells8060626.

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Tunneling nanotubes (TNTs) are thin membranous tubes that interconnect cells, representing a novel route of cell-to-cell communication and spreading of pathogens. TNTs form between many cell types, yet their inception mechanisms remain elusive. We review in this study general concepts related to the formation and stability of membranous tubular structures with a focus on a deviatoric elasticity model of membrane nanodomains. We review experimental evidence that tubular structures initiate from local membrane bending facilitated by laterally distributed proteins or anisotropic membrane nanodomains. We further discuss the numerical results of several theoretical and simulation models of nanodomain segregation suggesting the mechanisms of TNT inception and stability. We discuss the coupling of nanodomain segregation with the action of protruding cytoskeletal forces, which are mostly provided in eukaryotic cells by the polymerization of f-actin, and review recent inception mechanisms of TNTs in relation to motor proteins.

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Liang, Pengbo, Thomas F. Stratil, Claudia Popp, Macarena Marín, Jessica Folgmann, Kirankumar S. Mysore, Jiangqi Wen et Thomas Ott. « Symbiotic root infections in Medicago truncatula require remorin-mediated receptor stabilization in membrane nanodomains ». Proceedings of the National Academy of Sciences 115, n^o 20 (30 avril 2018) : 5289–94. http://dx.doi.org/10.1073/pnas.1721868115.

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Plant cell infection is tightly controlled by cell surface receptor-like kinases (RLKs). Like other RLKs, the Medicago truncatula entry receptor LYK3 laterally segregates into membrane nanodomains in a stimulus-dependent manner. Although nanodomain localization arises as a generic feature of plant membrane proteins, the molecular mechanisms underlying such dynamic transitions and their functional relevance have remained poorly understood. Here we demonstrate that actin and the flotillin protein FLOT4 form the primary and indispensable core of a specific nanodomain. Infection-dependent induction of the remorin protein and secondary molecular scaffold SYMREM1 results in subsequent recruitment of ligand-activated LYK3 and its stabilization within these membrane subcompartments. Reciprocally, the majority of this LYK3 receptor pool is destabilized at the plasma membrane and undergoes rapid endocytosis in symrem1 mutants on rhizobial inoculation, resulting in premature abortion of host cell infections. These data reveal that receptor recruitment into nanodomains is indispensable for their function during host cell infection.

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Kim, Kyou-Hyun, et Jian-Min Zuo. « Convergent-beam electron-diffraction-pattern symmetry of nanodomains in complex lead-based perovskite crystals ». Acta Crystallographica Section A Foundations and Advances 70, n^o 6 (20 septembre 2014) : 583–90. http://dx.doi.org/10.1107/s2053273314013643.

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Convergent-beam electron diffraction (CBED) recorded using nanometre-sized probes, in principle, can detect the highest symmetry in a crystal. However, symmetry reduction may occur by overlapping crystal domains along the beam direction. Thus, delineating the relationship between the recorded and the crystal symmetry is important for studying crystals with complex nanodomains. This paper reports a study of the averaged local symmetry of 71°/109° rhombohedral (R), 90° tetragonal (T) and 180° monoclinic (M) nanodomain structures. The averaged symmetry of nanodomain structures is investigated by CBED simulations using the multislice method. The simulation results show that the 71°-R, 109°-R and 90°-T nanodomain structures partially mimic the monoclinic symmetries ofCmandPmthat have been proposed by the adaptive phase model. This study is also compared to the reported experimental CBED patterns recorded from PMN-31%PT.

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Lipke, Peter N., Caleen Ramsook, Melissa C. Garcia-Sherman, Desmond N. Jackson, Cho X. J. Chan, Michael Bois et Stephen A. Klotz. « Between Amyloids and Aggregation Lies a Connection with Strength and Adhesion ». New Journal of Science 2014 (2 février 2014) : 1–12. http://dx.doi.org/10.1155/2014/815102.

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We tell of a journey that led to discovery of amyloids formed by yeast cell adhesins and their importance in biofilms and host immunity. We begin with the identification of the adhesin functional amyloid-forming sequences that mediate fiber formation in vitro. Atomic force microscopy and confocal microscopy show 2-dimensional amyloid “nanodomains” on the surface of cells that are activated for adhesion. These nanodomains are arrays of adhesin molecules that bind multivalent ligands with high avidity. Nanodomains form when adhesin molecules are stretched in the AFM or under laminar flow. Treatment with anti-amyloid perturbants or mutation of the amyloid sequence prevents adhesion nanodomain formation and activation. We are now discovering biological consequences. Adhesin nanodomains promote formation and maintenance of biofilms, which are microbial communities. Also, in abscesses within candidiasis patients, we find adhesin amyloids on the surface of the fungi. In both human infection and a Caenorhabditis elegans infection model, the presence of fungal surface amyloids elicits anti-inflammatory responses. Thus, this is a story of how fungal adhesins respond to extension forces through formation of cell surface amyloid nanodomains, with key consequences for biofilm formation and host responses.

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Fukata, Yuko, Ariane Dimitrov, Gaelle Boncompain, Ole Vielemeyer, Franck Perez et Masaki Fukata. « Local palmitoylation cycles define activity-regulated postsynaptic subdomains ». Journal of Cell Biology 202, n^o 1 (8 juillet 2013) : 145–61. http://dx.doi.org/10.1083/jcb.201302071.

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Distinct PSD-95 clusters are primary landmarks of postsynaptic densities (PSDs), which are specialized membrane regions for synapses. However, the mechanism that defines the locations of PSD-95 clusters and whether or how they are reorganized inside individual dendritic spines remains controversial. Because palmitoylation regulates PSD-95 membrane targeting, we combined a conformation-specific recombinant antibody against palmitoylated PSD-95 with live-cell super-resolution imaging and discovered subsynaptic nanodomains composed of palmitoylated PSD-95 that serve as elementary units of the PSD. PSD-95 in nanodomains underwent continuous de/repalmitoylation cycles driven by local palmitoylating activity, ensuring the maintenance of compartmentalized PSD-95 clusters within individual spines. Plasma membrane targeting of DHHC2 palmitoyltransferase rapidly recruited PSD-95 to the plasma membrane and proved essential for postsynaptic nanodomain formation. Furthermore, changes in synaptic activity rapidly reorganized PSD-95 nano-architecture through plasma membrane–inserted DHHC2. Thus, the first genetically encoded antibody sensitive to palmitoylation reveals an instructive role of local palmitoylation machinery in creating activity-responsive PSD-95 nanodomains, contributing to the PSD (re)organization.

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Dai, Xunhu, Z. Xu, Jie-Fang Li et Dwight Viehland. « Effects of lanthanum modification on rhombohedral Pb(Zr1−xTix)O3 ceramics : Part II. Relaxor behavior versus enhanced antiferroelectric stability ». Journal of Materials Research 11, n^o 3 (mars 1996) : 626–38. http://dx.doi.org/10.1557/jmr.1996.0076.

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Lanthanum-modified lead zirconate titanate ceramics Pb1−3/2xLax(Zr1−yTiy)O3 [PLZT 100x/100(1 − y)/100y] with Zr/Ti ratios close to the antiferroelectric-ferroelectric (AFE-FE) phase boundary were investigated by dielectric spectroscopy, Sawyer–Tower polarization techniques, and electron microscopy. An incommensurate antiferroelectric (AFEIn) phase was found to be stabilized from the rhombohedral FE state in the compositional series 100x/90/10 for x ≥ 0.02. The La content required to induce the AFEIn state increased as the Ti content was increased. For 100x/85/15, a state with relaxor-like dielectric behavior and nanodomains was observed to develop with increasing La content; however, the double-loop-like P-E curves were suggestive of antiferroelectric behavior. Investigations for the composition 6/85/15 revealed the formation of nanodomains from the AFEIn modulation, where the size of the nanodomains equaled the value of the AFEIn modulation wavelength. For this composition, P-E studies revealed double hysteresis characteristics, whereas dielectric investigations revealed relaxor-like behavior. It is suggested that the order within the nanodomain state may be antipolar over a range of compositions in high La content rhombohedral PLZT ceramics.

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Stelate, Ayoub, Eva Tihlaříková, Kateřina Schwarzerová, Vilém Neděla et Jan Petrášek. « Correlative Light-Environmental Scanning Electron Microscopy of Plasma Membrane Efflux Carriers of Plant Hormone Auxin ». Biomolecules 11, n^o 10 (26 septembre 2021) : 1407. http://dx.doi.org/10.3390/biom11101407.

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Fluorescence light microscopy provided convincing evidence for the domain organization of plant plasma membrane (PM) proteins. Both peripheral and integral PM proteins show an inhomogeneous distribution within the PM. However, the size of PM nanodomains and protein clusters is too small to accurately determine their dimensions and nano-organization using routine confocal fluorescence microscopy and super-resolution methods. To overcome this limitation, we have developed a novel correlative light electron microscopy method (CLEM) using total internal reflection fluorescence microscopy (TIRFM) and advanced environmental scanning electron microscopy (A-ESEM). Using this technique, we determined the number of auxin efflux carriers from the PINFORMED (PIN) family (NtPIN3b-GFP) within PM nanodomains of tobacco cell PM ghosts. Protoplasts were attached to coverslips and immunostained with anti-GFP primary antibody and secondary antibody conjugated to fluorochrome and gold nanoparticles. After imaging the nanodomains within the PM with TIRFM, the samples were imaged with A-ESEM without further processing, and quantification of the average number of molecules within the nanodomain was performed. Without requiring any post-fixation and coating procedures, this method allows to study details of the organization of auxin carriers and other plant PM proteins.

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Huang, Dingquan, Yanbiao Sun, Zhiming Ma, Meiyu Ke, Yong Cui, Zichen Chen, Chaofan Chen et al. « Salicylic acid-mediated plasmodesmal closure via Remorin-dependent lipid organization ». Proceedings of the National Academy of Sciences 116, n^o 42 (1 octobre 2019) : 21274–84. http://dx.doi.org/10.1073/pnas.1911892116.

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Plasmodesmata (PD) are plant-specific membrane-lined channels that create cytoplasmic and membrane continuities between adjacent cells, thereby facilitating cell–cell communication and virus movement. Plant cells have evolved diverse mechanisms to regulate PD plasticity in response to numerous environmental stimuli. In particular, during defense against plant pathogens, the defense hormone, salicylic acid (SA), plays a crucial role in the regulation of PD permeability in a callose-dependent manner. Here, we uncover a mechanism by which plants restrict the spreading of virus and PD cargoes using SA signaling by increasing lipid order and closure of PD. We showed that exogenous SA application triggered the compartmentalization of lipid raft nanodomains through a modulation of the lipid raft-regulatory protein, Remorin (REM). Genetic studies, superresolution imaging, and transmission electron microscopy observation together demonstrated that Arabidopsis REM1.2 and REM1.3 are crucial for plasma membrane nanodomain assembly to control PD aperture and functionality. In addition, we also found that a 14-3-3 epsilon protein modulates REM clustering and membrane nanodomain compartmentalization through its direct interaction with REM proteins. This study unveils a molecular mechanism by which the key plant defense hormone, SA, triggers membrane lipid nanodomain reorganization, thereby regulating PD closure to impede virus spreading.

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Traeger, Jeremiah, Dehong Hu, Mengran Yang, Gary Stacey et Galya Orr. « Super-Resolution Imaging of Plant Receptor-Like Kinases Uncovers Their Colocalization and Coordination with Nanometer Resolution ». Membranes 13, n^o 2 (21 janvier 2023) : 142. http://dx.doi.org/10.3390/membranes13020142.

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Plant cell signaling often relies on the cellular organization of receptor-like kinases (RLKs) within membrane nanodomains to enhance signaling specificity and efficiency. Thus, nanometer-scale quantitative analysis of spatial organizations of RLKs could provide new understanding of mechanisms underlying plant responses to environmental stress. Here, we used stochastic optical reconstruction fluorescence microscopy (STORM) to quantify the colocalization of the flagellin-sensitive-2 (FLS2) receptor and the nanodomain marker, remorin, within Arabidopsis thaliana root hair cells. We found that recovery of FLS2 and remorin in the plasma membrane, following ligand-induced internalization by bacterial-flagellin-peptide (flg22), reached ~85% of their original membrane density after ~90 min. The pairs colocalized at the membrane at greater frequencies, compared with simulated randomly distributed pairs, except for directly after recovery, suggesting initial uncoordinated recovery followed by remorin and FLS2 pairing in the membrane. The purinergic receptor, P2K1, colocalized with remorin at similar frequencies as FLS2, while FLS2 and P2K1 colocalization occurred at significantly lower frequencies, suggesting that these RLKs mostly occupy distinct nanodomains. The chitin elicitor receptor, CERK1, colocalized with FLS2 and remorin at much lower frequencies, suggesting little coordination between CERK1 and FLS2. These findings emphasize STORM’s capacity to observe distinct nanodomains and degrees of coordination between plant cell receptors, and their respective immune pathways.

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Kure, Jakob L., Thommie Karlsson, Camilla B. Andersen, B. Christoffer Lagerholm, Vesa Loitto, Karl-Eric Magnusson et Eva C. Arnspang. « Using kICS to Reveal Changed Membrane Diffusion of AQP-9 Treated with Drugs ». Membranes 11, n^o 8 (28 juillet 2021) : 568. http://dx.doi.org/10.3390/membranes11080568.

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The formation of nanodomains in the plasma membrane are thought to be part of membrane proteins regulation and signaling. Plasma membrane proteins are often investigated by analyzing the lateral mobility. k-space ICS (kICS) is a powerful image correlation spectroscopy (ICS) technique and a valuable supplement to fluorescence correlation spectroscopy (FCS). Here, we study the diffusion of aquaporin-9 (AQP9) in the plasma membrane, and the effect of different membrane and cytoskeleton affecting drugs, and therefore nanodomain perturbing, using kICS. We measured the diffusion coefficient of AQP9 after addition of these drugs using live cell Total Internal Reflection Fluorescence imaging on HEK-293 cells. The actin polymerization inhibitors Cytochalasin D and Latrunculin A do not affect the diffusion coefficient of AQP9. Methyl-β-Cyclodextrin decreases GFP-AQP9 diffusion coefficient in the plasma membrane. Human epidermal growth factor led to an increase in the diffusion coefficient of AQP9. These findings led to the conclusion that kICS can be used to measure diffusion AQP9, and suggests that the AQP9 is not part of nanodomains.

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Ashrafzadeh, Parham, et Ingela Parmryd. « Methods applicable to membrane nanodomain studies ? » Essays in Biochemistry 57 (6 février 2015) : 57–68. http://dx.doi.org/10.1042/bse0570057.

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Membrane nanodomains are dynamic liquid entities surrounded by another type of dynamic liquid. Diffusion can take place inside, around and in and out of the domains, and membrane components therefore continuously shift between domains and their surroundings. In the plasma membrane, there is the further complexity of links between membrane lipids and proteins both to the extracellular matrix and to intracellular proteins such as actin filaments. In addition, new membrane components are continuously delivered and old ones removed. On top of this, cells move. Taking all of this into account imposes great methodological challenges, and in the present chapter we discuss some methods that are currently used for membrane nanodomain studies, what information they can provide and their weaknesses.

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Atifi, Abderrahman, et Michael D. Ryan. « Voltammetry and Spectroelectrochemistry of TCNQ in Acetonitrile/RTIL Mixtures ». Molecules 25, n^o 2 (12 janvier 2020) : 303. http://dx.doi.org/10.3390/molecules25020303.

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Understanding the solvation and ion-pairing interactions of anionic substrates in room-temperature ionic liquids (RTIL) is key for the electrochemical applications of these new classes of solvents. In this work, cyclic voltammetry and visible and infrared spectroelectrochemistry of tetracyanoquinodimethane (TCNQ) was examined in molecular (acetonitrile) and RTIL solvents, as well as mixtures of these solvents. The overall results were consistent with the formation of RTIL/acetonitrile nanodomains. The voltammetry indicated that the first electrogenerated product, TCNQ−, was not incorporated into the RTIL nanodomain, while the second electrogenerated product, TCNQ2−, was strongly attracted to the RTIL nanodomain. The visible spectroelectrochemistry was also consistent with these observations. Infrared spectroelectrochemistry showed no discrete ion pairing between the cation and TCNQ− in either the acetonitrile or RTIL solutions. Discrete ion pairing was, however, observed in the acetonitrile domain between the tetrabutylammonium ion and TCNQ2−. On the other hand, no discrete ion pairing was observed in BMImPF6 or BMImBF4 solutions with TCNQ2−. In BMImNTf2, however, discrete ion pairs were formed with BMIm+ and TCNQ2−. Density function theory (DFT) calculations showed that the cations paired above and below the aromatic ring. The results of this work support the understanding of the redox chemistry in RTIL solutions.

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Ouyang, Jun, Xianke Wang, Changtao Shao, Hongbo Cheng, Hanfei Zhu et Yuhang Ren. « Microstructural Origin of the High-Energy Storage Performance in Epitaxial Lead-Free Ba(Zr0.2Ti0.8)O3 Thick Films ». Materials 15, n^o 19 (30 septembre 2022) : 6778. http://dx.doi.org/10.3390/ma15196778.

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In our previous work, epitaxial Ba(Zr0.2Ti0.8)O3 thick films (~1–2 μm) showed an excellent energy storage performance with a large recyclable energy density (~58 J/cc) and a high energy efficiency (~92%), which was attributed to a nanoscale entangled heterophase polydomain structure. Here, we propose a detailed analysis of the structure–property relationship in these film materials, using an annealing process to illustrate the effect of nanodomain entanglement on the energy storage performance. It is revealed that an annealing-induced stress relaxation led to the segregation of the nanodomains (via detailed XRD analyses), and a degraded energy storage performance (via polarization-electric field analysis). These results confirm that a nanophase entanglement is an origin of the high-energy storage performance in the Ba(Zr0.2Ti0.8)O3 thick films.

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Vallés, Ana Sofía, et Francisco J. Barrantes. « Nanoscale Sub-Compartmentalization of the Dendritic Spine Compartment ». Biomolecules 11, n^o 11 (15 novembre 2021) : 1697. http://dx.doi.org/10.3390/biom11111697.

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Compartmentalization of the membrane is essential for cells to perform highly specific tasks and spatially constrained biochemical functions in topographically defined areas. These membrane lateral heterogeneities range from nanoscopic dimensions, often involving only a few molecular constituents, to micron-sized mesoscopic domains resulting from the coalescence of nanodomains. Short-lived domains lasting for a few milliseconds coexist with more stable platforms lasting from minutes to days. This panoply of lateral domains subserves the great variety of demands of cell physiology, particularly high for those implicated in signaling. The dendritic spine, a subcellular structure of neurons at the receiving (postsynaptic) end of central nervous system excitatory synapses, exploits this compartmentalization principle. In its most frequent adult morphology, the mushroom-shaped spine harbors neurotransmitter receptors, enzymes, and scaffolding proteins tightly packed in a volume of a few femtoliters. In addition to constituting a mesoscopic lateral heterogeneity of the dendritic arborization, the dendritic spine postsynaptic membrane is further compartmentalized into spatially delimited nanodomains that execute separate functions in the synapse. This review discusses the functional relevance of compartmentalization and nanodomain organization in synaptic transmission and plasticity and exemplifies the importance of this parcelization in various neurotransmitter signaling systems operating at dendritic spines, using two fast ligand-gated ionotropic receptors, the nicotinic acetylcholine receptor and the glutamatergic receptor, and a second-messenger G-protein coupled receptor, the cannabinoid receptor, as paradigmatic examples.

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Welberry, T. R., et D. J. Goossens. « Different models for the polar nanodomain structure of PZN and other relaxor ferroelectrics ». Journal of Applied Crystallography 41, n^o 3 (14 mai 2008) : 606–14. http://dx.doi.org/10.1107/s0021889808012491.

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Computer simulations have been carried out to test the recently proposed model for the nanodomain structure of relaxor ferroelectrics such as lead zinc niobate (PZN). In this recent model it was supposed that the polar nanodomains are three-dimensional, that the observed diffuse rods of scattering originate from the boundaries between domains and that the Pb displacements may be directed along \langle {100} \rangle, \langle {111} \rangle or \langle {110} \rangle. This is in marked contrast to a previously published model, which described the polar domains as thin plates with Pb displacements confined to the \langle {110} \rangle directions within the essentially two-dimensional domains. The present results confirm that \langle {100} \rangle and \langle {111} \rangle types of Pb displacement are viable possibilities, but the number of domain boundaries required to produce sufficiently strong diffuse rods of scattering means that individual domains cannot be described as three-dimensional and must still be relatively thin. The current work has been carried out with no direct involvement of theB-site cation ordering, which many workers assume is necessary to understand the formation of the polar nanodomains. While it may be true that theB-site cation distribution could provide an underlying perturbation field that might ultimately limit the extent of any polar domain, it is certainly not necessary to produce the observed scattering effects.

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Ingrole, Rohan S., Wenqian Tao, Jatindra N. Tripathy et Harvinder S. Gill. « Synthesis and Immunogenicity Assessment of Elastin-Like Polypeptide-M2e Construct as an Influenza Antigen ». Nano LIFE 04, n^o 02 (juin 2014) : 1450004. http://dx.doi.org/10.1142/s1793984414500044.

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The 23 amino acid-long extracellular domain of the influenza virus transmembrane protein M2 (M2e) has remained highly conserved since the 1918 pandemic, and is thus considered a good candidate for development of a universal influenza A vaccine. However, M2e is poorly immunogenic. In this study we assessed the potential of increasing immunogenicity of M2e by constructing a nanoscale-designed protein polymer containing the M2e sequence and an elastin-like polypeptide (ELP) nanodomain consisting of alanine and tyrosine guest residues (ELP(A2YA2)24). The ELP nanodomain was included to increase antigen size, and to exploit the inherent thermal inverse phase transition behavior of ELPs to purify the protein polymer. The ELP(A2YA2)24 + M2e nanodomained molecule was recombinantly synthesized. Characterization of its inverse phase transition behavior demonstrated that attachment of M2e to ELP(A2YA2)24 increased its transition temperature compared to ELP(A2YA2)24. Using a dot blot test we determined that M2e conjugated to ELP is recognizable by M2e-specific antibodies, suggesting that the conjugation process does not adversely affect the immunogenic property of M2e. Further, upon vaccinating mice with ELP(A2YA2)24 + M2e it was found that indeed the nanodomained protein enhanced M2e-specific antibodies in mouse serum compared to free M2e peptide and ELP(A2YA2)24. The immune serum could also recognize M2 expressed on influenza virions. Overall, this data suggests the potential of using molecules containing M2e-ELP nanodomains to develop a universal influenza vaccine.

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Glöckner, Nina, Sven zur Oven-Krockhaus, Leander Rohr, Frank Wackenhut, Moritz Burmeister, Friederike Wanke, Eleonore Holzwart, Alfred J. Meixner, Sebastian Wolf et Klaus Harter. « Three-Fluorophore FRET Enables the Analysis of Ternary Protein Association in Living Plant Cells ». Plants 11, n^o 19 (6 octobre 2022) : 2630. http://dx.doi.org/10.3390/plants11192630.

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Protein-protein interaction studies provide valuable insights into cellular signaling. Brassinosteroid (BR) signaling is initiated by the hormone-binding receptor Brassinosteroid Insensitive 1 (BRI1) and its co-receptor BRI1 Associated Kinase 1 (BAK1). BRI1 and BAK1 were shown to interact independently with the Receptor-Like Protein 44 (RLP44), which is implicated in BRI1/BAK1-dependent cell wall integrity perception. To demonstrate the proposed complex formation of BRI1, BAK1 and RLP44, we established three-fluorophore intensity-based spectral Förster resonance energy transfer (FRET) and FRET-fluorescence lifetime imaging microscopy (FLIM) for living plant cells. Our evidence indicates that RLP44, BRI1 and BAK1 form a ternary complex in a distinct plasma membrane nanodomain. In contrast, although the immune receptor Flagellin Sensing 2 (FLS2) also forms a heteromer with BAK1, the FLS2/BAK1 complexes are localized to other nanodomains. In conclusion, both three-fluorophore FRET approaches provide a feasible basis for studying the in vivo interaction and sub-compartmentalization of proteins in great detail.

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Schneider, Falk, Dominic Waithe, Mathias P. Clausen, Silvia Galiani, Thomas Koller, Gunes Ozhan, Christian Eggeling et Erdinc Sezgin. « Diffusion of lipids and GPI-anchored proteins in actin-free plasma membrane vesicles measured by STED-FCS ». Molecular Biology of the Cell 28, n^o 11 (juin 2017) : 1507–18. http://dx.doi.org/10.1091/mbc.e16-07-0536.

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Diffusion and interaction dynamics of molecules at the plasma membrane play an important role in cellular signaling and are suggested to be strongly associated with the actin cytoskeleton. Here we use superresolution STED microscopy combined with fluorescence correlation spectroscopy (STED-FCS) to access and compare the diffusion characteristics of fluorescent lipid analogues and GPI-anchored proteins (GPI-APs) in the live-cell plasma membrane and in actin cytoskeleton–free, cell-derived giant plasma membrane vesicles (GPMVs). Hindered diffusion of phospholipids and sphingolipids is abolished in the GPMVs, whereas transient nanodomain incorporation of ganglioside lipid GM1 is apparent in both the live-cell membrane and GPMVs. For GPI-APs, we detect two molecular pools in living cells; one pool shows high mobility with transient incorporation into nanodomains, and the other pool forms immobile clusters, both of which disappear in GPMVs. Our data underline the crucial role of the actin cortex in maintaining hindered diffusion modes of many but not all of the membrane molecules and highlight a powerful experimental approach to decipher specific influences on molecular plasma membrane dynamics.

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Nakagawa, Shintaro, Yuki Yoneguchi, Takashi Ishizone, Shuichi Nojima, Kazuo Yamaguchi et Seiichi Nakahama. « Crystal orientation of poly(ε-caprolactone) chains confined in lamellar nanodomains : Effects of chain-ends tethering to nanodomain interfaces ». Polymer 112 (mars 2017) : 116–24. http://dx.doi.org/10.1016/j.polymer.2017.01.075.

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Chao, Ying-Chi, Nicoletta C. Surdo, Sergio Pantano et Manuela Zaccolo. « Imaging cAMP nanodomains in the heart ». Biochemical Society Transactions 47, n^o 5 (31 octobre 2019) : 1383–92. http://dx.doi.org/10.1042/bst20190245.

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Abstract 3′-5′-cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that modulates multiple cellular functions. It is now well established that cAMP can mediate a plethora of functional effects via a complex system of local regulatory mechanisms that result in compartmentalized signalling. The use of fluorescent probes to monitor cAMP in intact, living cells have been instrumental in furthering our appreciation of this ancestral and ubiquitous pathway and unexpected details of the nano-architecture of the cAMP signalling network are starting to emerge. Recent evidence shows that sympathetic control of cardiac contraction and relaxation is achieved via generation of multiple, distinct pools of cAMP that lead to differential phosphorylation of target proteins localized only tens of nanometres apart. The specific local control at these nanodomains is enabled by a distinct signalosome where effectors, targets, and regulators of the cAMP signal are clustered. In this review, we focus on recent advances using targeted fluorescent reporters for cAMP and how they have contributed to our current understanding of nanodomain cAMP signalling in the heart. We briefly discuss how this information can be exploited to design novel therapies and we highlight some of the questions that remain unanswered.

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Zhong, Liyun, Zhun Zhang, Xiaoxu Lu, Shengde Liu, Crystal Y. Chen et Zheng W. Chen. « NSOM/QD-Based Visualization of GM1 Serving as Platforms for TCR/CD3 Mediated T-Cell Activation ». BioMed Research International 2013 (2013) : 1–9. http://dx.doi.org/10.1155/2013/276498.

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Direct molecular imaging of nanoscale relationship between T-cell receptor complexes (TCR/CD3) and gangliosidosis GM1 before and after T-cell activation has not been reported. In this study, we made use of our expertise of near-field scanning optical microscopy(NSOM)/immune-labeling quantum dots- (QD-)based dual-color imaging system to visualize nanoscale profiles for distribution and organization of TCR/CD3, GM1, as well as their nanospatial relationship and their correlation with PKCθsignaling cascade during T-cell activation. Interestingly, after anti-CD3/anti-CD28 Ab co-stimulation, both TCR/CD3 and GM1 were clustered to form nanodomains; moreover, all of TCR/CD3 nanodomains were colocalized with GM1 nanodomains, indicating that the formation of GM1 nanodomains was greatly correlated with TCR/CD3 mediated signaling. Specially, while T-cells were pretreated with PKCθsignaling inhibitor rottlerin to suppress IL-2 cytokine production, no visible TCR/CD3 nanodomains appeared while a lot of GM1 nanodomains were still observed. However, while T-cells are pretreated with PKCαβsignaling inhibitor GÖ6976 to suppress calcium-dependent manner, all of TCR/CD3 nanodomains were still colocalized with GM1 nanodomains. These findings possibly support the notion that the formation of GM1 nanodomains indeed serves as platforms for the recruitment of TCR/CD3 nanodomains, and TCR/CD3 nanodomains are required for PKCθsignaling cascades and T-cell activation

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Silvius, John R. « Membrane Nanodomains ». Colloquium Series on Building Blocks of the Cell : Cell Structure and Function 1, n^o 1 (28 février 2013) : 1–103. http://dx.doi.org/10.4199/c00076ed1v01y201303bbc001.

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Kar, Pulak, Yu-Ping Lin, Rajesh Bhardwaj, Charles J. Tucker, Gary S. Bird, Matthias A. Hediger, Carina Monico, Nader Amin et Anant B. Parekh. « The N terminus of Orai1 couples to the AKAP79 signaling complex to drive NFAT1 activation by local Ca2+ entry ». Proceedings of the National Academy of Sciences 118, n^o 19 (3 mai 2021) : e2012908118. http://dx.doi.org/10.1073/pnas.2012908118.

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To avoid conflicting and deleterious outcomes, eukaryotic cells often confine second messengers to spatially restricted subcompartments. The smallest signaling unit is the Ca2+ nanodomain, which forms when Ca2+ channels open. Ca2+ nanodomains arising from store-operated Orai1 Ca2+ channels stimulate the protein phosphatase calcineurin to activate the transcription factor nuclear factor of activated T cells (NFAT). Here, we show that NFAT1 tethered directly to the scaffolding protein AKAP79 (A-kinase anchoring protein 79) is activated by local Ca2+ entry, providing a mechanism to selectively recruit a transcription factor. We identify the region on the N terminus of Orai1 that interacts with AKAP79 and demonstrate that this site is essential for physiological excitation–transcription coupling. NMR structural analysis of the AKAP binding domain reveals a compact shape with several proline-driven turns. Orai2 and Orai3, isoforms of Orai1, lack this region and therefore are less able to engage AKAP79 and activate NFAT. A shorter, naturally occurring Orai1 protein that arises from alternative translation initiation also lacks the AKAP79-interaction site and fails to activate NFAT1. Interfering with Orai1–AKAP79 interaction suppresses cytokine production, leaving other Ca2+ channel functions intact. Our results reveal the mechanistic basis for how a subtype of a widely expressed Ca2+ channel is able to activate a vital transcription pathway and identify an approach for generation of immunosuppressant drugs.

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Koklič, Tilen, Alenka Hrovat, Ramon Guixà-González, Ismael Rodríguez-Espigares, Damaris Navio, Robert Frangež, Matjaž Uršič et al. « Electron Paramagnetic Resonance Gives Evidence for the Presence of Type 1 Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Subdomains of Lipid Rafts ». Molecules 26, n^o 4 (12 février 2021) : 973. http://dx.doi.org/10.3390/molecules26040973.

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This study investigated the effect of type 1 gonadotropin releasing hormone receptor (GnRH-R) localization within lipid rafts on the properties of plasma membrane (PM) nanodomain structure. Confocal microscopy revealed colocalization of PM-localized GnRH-R with GM1-enriched raft-like PM subdomains. Electron paramagnetic resonance spectroscopy (EPR) of a membrane-partitioned spin probe was then used to study PM fluidity of immortalized pituitary gonadotrope cell line αT3-1 and HEK-293 cells stably expressing GnRH-R and compared it with their corresponding controls (αT4 and HEK-293 cells). Computer-assisted interpretation of EPR spectra revealed three modes of spin probe movement reflecting the properties of three types of PM nanodomains. Domains with an intermediate order parameter (domain 2) were the most affected by the presence of the GnRH-Rs, which increased PM ordering (order parameter (S)) and rotational mobility of PM lipids (decreased rotational correlation time (τc)). Depletion of cholesterol by methyl-β-cyclodextrin (methyl-β-CD) inhibited agonist-induced GnRH-R internalization and intracellular Ca2+ activity and resulted in an overall reduction in PM order; an observation further supported by molecular dynamics (MD) simulations of model membrane systems. This study provides evidence that GnRH-R PM localization may be related to a subdomain of lipid rafts that has lower PM ordering, suggesting lateral heterogeneity within lipid raft domains.

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Kang, Xinchen, Xiaoxue Ma, Jianling Zhang, Xueqing Xing, Guang Mo, Zhonghua Wu, Zhihong Li et Buxing Han. « Formation of large nanodomains in liquid solutions near the phase boundary ». Chemical Communications 52, n^o 99 (2016) : 14286–89. http://dx.doi.org/10.1039/c6cc08015d.

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Mesarec, Luka, Mitja Drab, Samo Penič, Veronika Kralj-Iglič et Aleš Iglič. « On the Role of Curved Membrane Nanodomains and Passive and Active Skeleton Forces in the Determination of Cell Shape and Membrane Budding ». International Journal of Molecular Sciences 22, n^o 5 (26 février 2021) : 2348. http://dx.doi.org/10.3390/ijms22052348.

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Biological membranes are composed of isotropic and anisotropic curved nanodomains. Anisotropic membrane components, such as Bin/Amphiphysin/Rvs (BAR) superfamily protein domains, could trigger/facilitate the growth of membrane tubular protrusions, while isotropic curved nanodomains may induce undulated (necklace-like) membrane protrusions. We review the role of isotropic and anisotropic membrane nanodomains in stability of tubular and undulated membrane structures generated or stabilized by cyto- or membrane-skeleton. We also describe the theory of spontaneous self-assembly of isotropic curved membrane nanodomains and derive the critical concentration above which the spontaneous necklace-like membrane protrusion growth is favorable. We show that the actin cytoskeleton growth inside the vesicle or cell can change its equilibrium shape, induce higher degree of segregation of membrane nanodomains or even alter the average orientation angle of anisotropic nanodomains such as BAR domains. These effects may indicate whether the actin cytoskeleton role is only to stabilize membrane protrusions or to generate them by stretching the vesicle membrane. Furthermore, we demonstrate that by taking into account the in-plane orientational ordering of anisotropic membrane nanodomains, direct interactions between them and the extrinsic (deviatoric) curvature elasticity, it is possible to explain the experimentally observed stability of oblate (discocyte) shapes of red blood cells in a broad interval of cell reduced volume. Finally, we present results of numerical calculations and Monte-Carlo simulations which indicate that the active forces of membrane skeleton and cytoskeleton applied to plasma membrane may considerably influence cell shape and membrane budding.

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Timofeeva, Ekaterina E., Elena Yu Panchenko, Maria V. Zherdeva, Aida B. Tokhmetova, Nikita Yu Surikov, Yuriy I. Chumlyakov et Ibrahim Karaman. « The Effect of Thermal Treatment on Microstructure and Thermal-Induced Martensitic Transformations in Ni44Fe19Ga27Co10 Single Crystals ». Metals 12, n^o 11 (16 novembre 2022) : 1960. http://dx.doi.org/10.3390/met12111960.

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Heat treatments of single crystals of Ni44Fe19Ga27Co10 (at.%) shape memory alloys cause various microstructures of the high-temperature phase. The nanodomain structure, consisting of regions of the L21- and B2-phases, and nanosized particles are the main parameters that change during heat treatments and determine the mechanism of nucleation and growth of martensite crystals, the size of thermal-induced martensite lamellae, the temperature Ms, and the temperature intervals of the martensitic transformation. In the as-grown single crystals, the high-temperature phase has only the L21-structure and the MT occurs at low (Ms = 125 K) temperatures due to the motion of the practically single interphase boundary in narrow temperature ranges of 3–7 K. The reduction in the volume fraction of the L21-phase to 40% and the formation of nanodomains (20–50 nm) of the L21-and B2-phases due to annealing at 1448 K for 1 h with quenching causes an increase in the MT temperatures by 80 K. The MT occurs in wide temperature ranges of 40–45 K because of multiple nucleation of individual large (300–500 µm) martensite lamellae and their growth. After aging at 773 K for 1 h, the precipitation of nanosized particles of the ω-phase in such a structure additionally increases the MT temperatures by 45 K. The MT occurs due to the multiple nucleation of packets of small (20–50 μm) martensite lamellae.

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Cebecauer, Marek, Mariana Amaro, Piotr Jurkiewicz, Maria João Sarmento, Radek Šachl, Lukasz Cwiklik et Martin Hof. « Membrane Lipid Nanodomains ». Chemical Reviews 118, n^o 23 (26 octobre 2018) : 11259–97. http://dx.doi.org/10.1021/acs.chemrev.8b00322.

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Kedia, Shekhar, Pratyush Ramakrishna, Pallavi Rao Netrakanti, Mini Jose, Jean-Baptiste Sibarita, Suhita Nadkarni et Deepak Nair. « Real-time nanoscale organization of amyloid precursor protein ». Nanoscale 12, n^o 15 (2020) : 8200–8215. http://dx.doi.org/10.1039/d0nr00052c.

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Regulatory nanodomains modulated by lateral diffusion control transient equilibrium between pools of APP within an excitatory synapse. Molecular fingerprints of these nanodomains are altered in variants of APP implicated in Alzheimer's Disease.

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Kundu, Asish K., Oleg I. Lebedev, Nadezhda E. Volkova, Md Motin Seikh, Vincent Caignaert, Vladimir A. Cherepanov et Bernard Raveau. « Quintuple perovskites Ln2Ba3Fe5−xCoxO15−δ(Ln = Sm, Eu) : nanoscale ordering and unconventional magnetism ». Journal of Materials Chemistry C 3, n^o 21 (2015) : 5398–405. http://dx.doi.org/10.1039/c5tc00494b.

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Perovskite Sm₂Ba₃Fe₃Co₂O_14.07consists of 90° chemically twinned nanodomains with five-fold periodicity and exhibits short range AFM interactions within the nanodomains.

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Kudryashov, Sergey, Alexey Rupasov, Mikhail Kosobokov, Andrey Akhmatkhanov, George Krasin, Pavel Danilov, Boris Lisjikh et al. « Ferroelectric Nanodomain Engineering in Bulk Lithium Niobate Crystals in Ultrashort-Pulse Laser Nanopatterning Regime ». Nanomaterials 12, n^o 23 (23 novembre 2022) : 4147. http://dx.doi.org/10.3390/nano12234147.

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Ferroelectric nanodomains were formed in bulk lithium niobate single crystals near nanostructured microtracks laser-inscribed by 1030-nm 0.3-ps ultrashort laser pulses at variable pulse energies in sub- and weakly filamentary laser nanopatterning regimes. The microtracks and related nanodomains were characterized by optical, scanning probe and confocal second-harmonic generation microscopy methods. The nanoscale material sub-structure in the microtracks was visualized in the sample cross-sections by atomic force microscopy (AFM), appearing weakly birefringent in polarimetric microscope images. The piezoresponce force microscopy (PFM) revealed sub-100 nm ferroelectric domains formed in the vicinity of the embedded microtrack seeds, indicating a promising opportunity to arrange nanodomains in the bulk ferroelectric crystal in on-demand positions. These findings open a new modality in direct laser writing technology, which is related to nanoscale writing of ferroelectric nanodomains and prospective three-dimensional micro-electrooptical and nanophotonic devices in nonlinear-optical ferroelectrics.

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Li, Guangtao, Qing Wang, Shinako Kakuda et Erwin London. « Nanodomains can persist at physiologic temperature in plasma membrane vesicles and be modulated by altering cell lipids ». Journal of Lipid Research 61, n^o 5 (21 janvier 2020) : 758–66. http://dx.doi.org/10.1194/jlr.ra119000565.

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The formation and properties of liquid-ordered (Lo) lipid domains (rafts) in the plasma membrane are still poorly understood. This limits our ability to manipulate ordered lipid domain-dependent biological functions. Giant plasma membrane vesicles (GPMVs) undergo large-scale phase separations into coexisting Lo and liquid-disordered lipid domains. However, large-scale phase separation in GPMVs detected by light microscopy is observed only at low temperatures. Comparing Förster resonance energy transfer-detected versus light microscopy-detected domain formation, we found that nanodomains, domains of nanometer size, persist at temperatures up to 20°C higher than large-scale phases, up to physiologic temperature. The persistence of nanodomains at higher temperatures is consistent with previously reported theoretical calculations. To investigate the sensitivity of nanodomains to lipid composition, GPMVs were prepared from mammalian cells in which sterol, phospholipid, or sphingolipid composition in the plasma membrane outer leaflet had been altered by cyclodextrin-catalyzed lipid exchange. Lipid substitutions that stabilize or destabilize ordered domain formation in artificial lipid vesicles had a similar effect on the thermal stability of nanodomains and large-scale phase separation in GPMVs, with nanodomains persisting at higher temperatures than large-scale phases for a wide range of lipid compositions. This indicates that it is likely that plasma membrane nanodomains can form under physiologic conditions more readily than large-scale phase separation. We also conclude that membrane lipid substitutions carried out in intact cells are able to modulate the propensity of plasma membranes to form ordered domains. This implies lipid substitutions can be used to alter biological processes dependent upon ordered domains.

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Shur, V. Ya, V. A. Shikhova, P. S. Zelenovskiy, D. V. Pelegov, L. I. Ivleva et J. Dec. « Formation of self-assembled nanodomain structures in single crystals of uniaxial ferroelectrics lithium niobate, lithium tantalate and strontium–barium niobate ». Journal of Advanced Dielectrics 04, n^o 01 (janvier 2014) : 1450006. http://dx.doi.org/10.1142/s2010135x14500064.

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The formation and evolution of the self-assembled nanodomain structures during polarization reversal have been comparatively analyzed in single crystals of various uniaxial ferroelectrics: LiNbO 3 (LN), LiTaO 3 (LT) and Sr x Ba 1-x Nb 2 O 6 (SBN). Several experimental methods have been used for visualization of the micro- and nanodomain patterns. The static domain images have been obtained by optical microscopy and piezoresponse force microscopy. The Raman confocal microscopy allowed us to obtain the domain images in the bulk. The equilibrium slow switching with effective screening resulted in growth of polygon-shaped micro-domains: hexagons in LN, triangles in LT and squares in SBN, which corresponds to crystal symmetry. Switching in nonequilibrium conditions (noneffective screening of depolarization field) brings to appearance of similar nanodomain structures in all studied crystals as a result of different processes: (1) formation of nanodomain ensembles, (2) discrete switching, (3) incomplete merging and (4) spontaneous backswitching.

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Gan, Kefu, et Zhiming Li. « Unveiling the role of glassy nanodomains in strength and plasticity of crystal–glass nanocomposites via atomistic simulation ». Journal of Applied Physics 131, n^o 8 (28 février 2022) : 085109. http://dx.doi.org/10.1063/5.0080746.

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Crystalline metals and alloys are usually ductile owing to lattice dislocations and various slip systems, while bulk metallic glasses show ultrahigh yield strength with very limited plasticity. Combining the crystalline and glassy phases in one alloy has recently been shown to be promising for achieving both ultrahigh strength and good deformability. Yet, it is challenging to capture the dynamic dislocation behavior through the deformation process and elucidate the role of glassy domains on the excellent mechanical performance of the nanocomposites. Here, we unveil and visualize the atomic-scale interactions among dislocations, glassy nanodomains, and crystal–glass interfaces in a specially designed configuration via molecular dynamics simulation. The glassy nanodomains occupying the triple junctions of grain boundaries are found to optimize the dynamic partitioning of shear strains between the two phases, thus manipulating the production of both dislocations in the crystalline matrix and shear transformation zones in the glassy nanodomains. The crystal–glass interfaces where strain concentration can occur function as both dislocation sources and sinks for plasticity, which in turn alter the strain distributions in the two phases. Systematic observations further suggest that the glassy nanodomains can dynamically tune the dislocation content and configuration in the crystalline matrix throughout the deformation. The unveiled mechanisms thus open a pathway for the development of novel ultrahigh-strength and ductile materials by tuning dislocation behavior in the crystalline matrix via glassy nanodomains.

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Hajnoczky, György. « Cellular hydrogen peroxide nanodomains ». Free Radical Biology and Medicine 165 (mars 2021) : 14. http://dx.doi.org/10.1016/j.freeradbiomed.2020.12.282.

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Ma, Yuanqing, Elizabeth Hinde et Katharina Gaus. « Nanodomains in biological membranes ». Essays in Biochemistry 57 (6 février 2015) : 93–107. http://dx.doi.org/10.1042/bse0570093.

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Lipid rafts are defined as cholesterol- and sphingomyelin-enriched membrane domains in the plasma membrane of cells that are highly dynamic and cannot be resolved with conventional light microscopy. Membrane proteins that are embedded in the phospholipid matrix can be grouped into raft and non-raft proteins based on their association with detergent-resistant membranes in biochemical assays. Selective lipid–protein interactions not only produce heterogeneity in the membrane, but also cause the spatial compartmentalization of membrane reactions. It has been proposed that lipid rafts function as platforms during cell signalling transduction processes such as T-cell activation (see Chapter 13 (pages 165–175)). It has been proposed that raft association co-localizes specific signalling proteins that may yield the formation of the observed signalling microclusters at the immunological synapses. However, because of the nanometre size and high dynamics of lipid rafts, direct observations have been technically challenging, leading to an ongoing discussion of the lipid raft model and its alternatives. Recent developments in fluorescence imaging techniques have provided new opportunities to investigate the organization of cell membranes with unprecedented spatial resolution. In this chapter, we describe the concept of the lipid raft and alternative models and how new imaging technologies have advanced these concepts.

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Jackson, Peter K. « cAMP Signaling in Nanodomains ». Cell 182, n^o 6 (septembre 2020) : 1379–81. http://dx.doi.org/10.1016/j.cell.2020.08.041.

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Scott, J. F., A. Gruverman, D. Wu, I. Vrejoiu et M. Alexe. « Nanodomain faceting in ferroelectrics ». Journal of Physics : Condensed Matter 20, n^o 42 (30 septembre 2008) : 425222. http://dx.doi.org/10.1088/0953-8984/20/42/425222.

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Zhao, Zunqiang, Shu Deng, Zhongwei Lv et Jianshe Yang. « Cellular Innate Biological Nano Confinements Control Cancer Metastasis Through Materials Seizing and Signaling Regulating ». Technology in Cancer Research & ; Treatment 22 (janvier 2023) : 153303382311589. http://dx.doi.org/10.1177/15330338231158917.

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Cancer is a debilitating disease, causing millions of deaths annually throughout the world. Due to their adaptive ability to meet nutritional demands, cancer cells often utilize more energy than normal cells. In order to develop new strategies to treat cancer, it is necessary to understand the underlying mechanisms of energy metabolism, which is yet largely unknown. Recent studies have shown that cellular innate nanodomains are involved in cellular energy metabolism and anabolism and GPCRs signaling regulation, which have a direct effect on cell fate and functions. Therefore, harnessing cellular innate nanodomains may evoke significant therapeutic impact and shift the research focus from exogenous nanomaterials to cellular innate nanodomains, which will have great potential to develop a new treatment modality for cancer. Keeping these points in view, we briefly discuss the impact of cellular innate nanodomains and their potential for advancing cancer therapeutics, and propose the concept of innate biological nano confinements, which include any innate structural and functional nano domains both in extracellular and intracellular with spatial heterogeneity.

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Castells-Garcia, Alvaro, Ilyas Ed-daoui, Esther González-Almela, Chiara Vicario, Jason Ottestrom, Melike Lakadamyali, Maria Victoria Neguembor et Maria Pia Cosma. « Super resolution microscopy reveals how elongating RNA polymerase II and nascent RNA interact with nucleosome clutches ». Nucleic Acids Research 50, n^o 1 (21 décembre 2021) : 175–90. http://dx.doi.org/10.1093/nar/gkab1215.

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Abstract Transcription and genome architecture are interdependent, but it is still unclear how nucleosomes in the chromatin fiber interact with nascent RNA, and which is the relative nuclear distribution of these RNAs and elongating RNA polymerase II (RNAP II). Using super-resolution (SR) microscopy, we visualized the nascent transcriptome, in both nucleoplasm and nucleolus, with nanoscale resolution. We found that nascent RNAs organize in structures we termed RNA nanodomains, whose characteristics are independent of the number of transcripts produced over time. Dual-color SR imaging of nascent RNAs, together with elongating RNAP II and H2B, shows the physical relation between nucleosome clutches, RNAP II, and RNA nanodomains. The distance between nucleosome clutches and RNA nanodomains is larger than the distance measured between elongating RNAP II and RNA nanodomains. Elongating RNAP II stands between nascent RNAs and the small, transcriptionally active, nucleosome clutches. Moreover, RNA factories are small and largely formed by few RNAP II. Finally, we describe a novel approach to quantify the transcriptional activity at an individual gene locus. By measuring local nascent RNA accumulation upon transcriptional activation at single alleles, we confirm the measurements made at the global nuclear level.

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Arcos Casarrubias, JA, A. Reyes-Mayer, R. Guardian-Tapia, P. Castillo-Ocampo et A. Romo-Uribe. « Rubber Nanodomains Reinforced Epoxy Resin ». MRS Advances 1, n^o 21 (2016) : 1571–76. http://dx.doi.org/10.1557/adv.2016.297.

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ABSTRACTIt has been reported that the addition of liquid rubbers, like poly(dimethylsiloxane) (PDMS), to epoxy resins alter the final morphology, increase the toughness and influence the curing kinetics. Due to immiscibility, there is phase separation of the elastomeric phase during curing giving rise to microdomains embedded in the epoxic matrix. The resultant heterogeneous morphology obtained after the reaction controls to an important extent the properties of the epoxy composite. Here we report a method to obtain well-dispersed rubber nanodomains of silyl-diglycidyl ether terminated polydimethyl siloxane (PDMS-DGE) in diglycidyl ether of bisphenol-A (DGEBA) epoxy by using a prepolymerization step. Light scattering and optical microscopy showed that initial mixing of pre-polymerized rubber produced phase separation with micron-scale droplet formation. However, as the curing reaction proceeded, the rubber domains decreased below optical resolution, light scattering intensity reached a maximum and then decreased. Finally, rubber nanodomains of about 100 nm size were formed at the end of curing reaction, as revealed by transmission electron microscopy (TEM). The pre-polymerization step induced a two-fold increase in gel time, tgel, due to lesser active groups available for reaction. Strikingly, tensile modulus and toughness increased, suggesting rubber-epoxy interaction. The final nanocomposite also exhibited higher thermal stability and char formation.

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Chen, Hong, Giuseppe R. Palmese et Yossef A. Elabd. « Membranes with Oriented Polyelectrolyte Nanodomains ». Chemistry of Materials 18, n^o 20 (octobre 2006) : 4875–81. http://dx.doi.org/10.1021/cm061422w.

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Ivanova, S. V. « Nanodomain structures in nonlinear crystal ». Ferroelectrics 539, n^o 1 (25 janvier 2019) : 9–15. http://dx.doi.org/10.1080/00150193.2019.1570005.

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Berger, Mareike, Manoel Manghi et Nicolas Destainville. « Nanodomains in Biomembranes with Recycling ». Journal of Physical Chemistry B 120, n^o 40 (30 septembre 2016) : 10588–602. http://dx.doi.org/10.1021/acs.jpcb.6b07631.

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Iwaji, Naoki, Chiharu Sakaki, Nobuyuki Wada, Hiroshi Takagi et Shigeo Mori. « Ferroelectric Domain Structures and Piezoelectric Properties of Pb(Zr,Ti)O₃ Ceramics ». Key Engineering Materials 485 (juillet 2011) : 3–6. http://dx.doi.org/10.4028/www.scientific.net/kem.485.3.

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We investigated domain structures in Pb(Zr,Ti)O3(PZT) ceramics whose composition lies on the morphotropic phase boundary (MPB) using transmission electron microscopy (TEM) and evaluated the piezoelectric properties of PZT. We found that monoclinic nanosized domains (nanodomains), which form in tetragonal domains, strongly correlated with the piezoelectric properties of PZT. The degree of formation of nanodomains depends on the grain composition. Thus, controlling the homogeneity of grain composition in the ceramics is crucial for optimizing the piezoelectric properties of PZT.

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Montefusco, Francesco, et Morten Pedersen. « From Local to Global Modeling for Characterizing Calcium Dynamics and Their Effects on Electrical Activity and Exocytosis in Excitable Cells ». International Journal of Molecular Sciences 20, n^o 23 (30 novembre 2019) : 6057. http://dx.doi.org/10.3390/ijms20236057.

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Electrical activity in neurons and other excitable cells is a result of complex interactions between the system of ion channels, involving both global coupling (e.g., via voltage or bulk cytosolic Ca2+ concentration) of the channels, and local coupling in ion channel complexes (e.g., via local Ca2+ concentration surrounding Ca2+ channels (CaVs), the so-called Ca2+ nanodomains). We recently devised a model of large-conductance BKCa potassium currents, and hence BKCa–CaV complexes controlled locally by CaVs via Ca2+ nanodomains. We showed how different CaV types and BKCa–CaV stoichiometries affect whole-cell electrical behavior. Ca2+ nanodomains are also important for triggering exocytosis of hormone-containing granules, and in this regard, we implemented a strategy to characterize the local interactions between granules and CaVs. In this study, we coupled electrical and exocytosis models respecting the local effects via Ca2+ nanodomains. By simulating scenarios with BKCa–CaV complexes with different stoichiometries in pituitary cells, we achieved two main electrophysiological responses (continuous spiking or bursting) and investigated their effects on the downstream exocytosis process. By varying the number and distance of CaVs coupled with the granules, we found that bursting promotes exocytosis with faster rates than spiking. However, by normalizing to Ca2+ influx, we found that bursting is only slightly more efficient than spiking when CaVs are far away from granules, whereas no difference in efficiency between bursting and spiking is observed with close granule-CaV coupling.

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Nagashima, Teruyoshi, et Shogo Uematsu. « Water-Binding Phospholipid Nanodomains and Phase-Separated Diacylglycerol Nanodomains Regulate Enzyme Reactions in Lipid Monolayers ». Langmuir 31, n^o 4 (22 janvier 2015) : 1479–88. http://dx.doi.org/10.1021/la503906m.

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Hankel, Robert F., Paula E. Rojas, Mary Cano-Sarabia, Santi Sala, Jaume Veciana, Andreas Braeuer et Nora Ventosa. « Surfactant-free CO2-based microemulsion-like systems ». Chem. Commun. 50, n^o 60 (2014) : 8215–18. http://dx.doi.org/10.1039/c4cc01804d.

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Farinha, J. P. S., et J. M. G. Martinho. « Resonance Energy Transfer in Polymer Nanodomains ». Journal of Physical Chemistry C 112, n^o 29 (juillet 2008) : 10591–601. http://dx.doi.org/10.1021/jp8016437.

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