scholarly journals Interleaflet coupling of n-alkane incorporated bilayers

2020 ◽  
Vol 22 (10) ◽  
pp. 5418-5426 ◽  
Author(s):  
Hatsuho Usuda ◽  
Mafumi Hishida ◽  
Elizabeth G. Kelley ◽  
Yasuhisa Yamamura ◽  
Michihiro Nagao ◽  
...  
Keyword(s):  
Bending Modulus ◽  
Membrane Bending ◽  
The Relationship

The relationship between the membrane bending modulus (κ) and compressibility modulus (KA) depends on the extent of coupling between the two monolayers (leaflets).

scholarly journals Estimation of membrane bending modulus of stiffness tuned human red blood cells from micropore filtration studies

PLoS ONE ◽  
2019 ◽  
Vol 14 (12) ◽  
pp. e0226640 ◽  
Author(s):  
Rekha Selvan ◽  
Praveen Parthasarathi ◽  
Shruthi S. Iyengar ◽  
Sharath Ananthamurthy ◽  
Sarbari Bhattacharya
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Human Red Blood Cells ◽  
Bending Modulus ◽  
Membrane Bending

Investigation of Free Volume Size and Mechanical Properties for PolymethylMethacrylate/Organic Rectorite Composites by PALS

2011 ◽  
Vol 233-235 ◽  
pp. 1868-1871
Author(s):  
Wei Zhou ◽  
Yan Sheng Gong
Keyword(s):  
Mechanical Properties ◽  
Free Volume ◽  
Atomic Scale ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Scale Free ◽  
Bending Modulus ◽  
Weight Content ◽  
The Relationship ◽  
Volume Size

PolymethylMethacrylate (PMMA) composites with different weight content of organic rectorite (OREC) are prepared via melt blending. The results of X-ray diffraction (XRD) show that the layer distance of OREC is much larger than that of the pristine rectorite. SEM images reveal that the OREC filler has been well dispersed in matrix. With the addition of OREC, Bending modulus increased obviously. Ortho-positronium (o-Ps) lifetimes show that the free volume sizes of PMMA/OREC composites are larger than those of the PMMA matrix. The relationship between the atomic-scale free volume size and mechanical properties is preliminarily discussed in this work.

scholarly journals Membrane bending begins at any stage of clathrin-coat assembly and defines endocytic dynamics

2017 ◽  
Author(s):  
Brandon L. Scott ◽  
Kem A. Sochacki ◽  
Shalini T. Low-Nam ◽  
Elizabeth M. Bailey ◽  
QuocAhn Luu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Total Internal Reflection ◽  
Super Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fundamental Biological Process ◽  
Resolution Imaging ◽  
Membrane Bending ◽  
The Relationship ◽  
Spherical Vesicles

Summary ParagraphClathrin-mediated endocytosis internalizes membrane from the cell surface by reshaping flat regions of membrane into spherical vesicles(1, 2). The relationship between membrane bending and clathrin coatomer assembly has been inferred from electron microscopy and structural biology, without directly visualization of membrane bending dynamics (3–6). This has resulted in two distinct and opposing models for how clathrin bends membrane (7–10). Here, polarized Total Internal Reflection Fluorescence microscopy was improved and combined with electron microscopy, atomic force microscopy, and super-resolution imaging to measure membrane bending during endogenous clathrin and dynamin assembly in living cells. Surprisingly, and not predicted by either model, the timing of membrane bending was variable relative to clathrin assembly. Approximately half of the time, membrane bending occurs at the start of clathrin assembly, in the other half, the onset of membrane bending lags clathrin arrival, and occasionally completely assembled flat clathrin transitions into a pit. Importantly, once the membrane bends, the process proceeds to scission with similar timing. We conclude that the pathway of coatomer formation is versatile and can bend the membrane during or after the assembly of the clathrin lattice. These results highlight the heterogeneity in this fundamental biological process, and provide a more complete nanoscale view of membrane bending dynamics during endocytosis.

scholarly journals Physical Characterization of Triolein and Implications for Its Role in Lipid Droplet Biogenesis

2021 ◽  
Author(s):  
Siyoung Kim ◽  
Gregory A. Voth
Keyword(s):  
Negative Curvature ◽  
Critical Concentration ◽  
Bilayer Membrane ◽  
The Other ◽  
Coarse Grained ◽  
Membrane Properties ◽  
Bending Modulus ◽  
Cytosolic Side ◽  
Membrane Bending ◽  
Free Energy Sampling

Lipid droplets (LDs) are neutral lipid storing organelles surrounded by a phospholipid (PL) monolayer. At present, how LDs are formed in the endoplasmic reticulum (ER) bilayer is poorly understood. In this study, we present a revised triolein (TG) model, the main constituent of the LD core, and characterize its properties in a bilayer membrane to demonstrate the implications of its behavior in LD biogenesis. In all-atom (AA) bilayer simulations, TG resides at the surface, adopting PL-like conformations (denoted in this work as SURF-TG). Free energy sampling simulation results estimate the barrier for TG relocating from the bilayer surface to the bilayer center to be ~2 kcal/mol in the absence of an oil lens. Conical SURF-TG is able to modulate membrane properties by increasing PL ordering, decreasing bending modulus, and creating local negative curvature. The other conical lipid, dioleoyl-glycerol (DAG), also reduces the membrane bending modulus and populates the negative curvature regions. A phenomenological coarse-grained (CG) model is also developed to observe larger scale SURF-TG-mediated membrane deformation. The CG simulations confirm that TG nucleates between the bilayer leaflets at a critical concentration when SURF-TG is evenly distributed. However, when one monolayer contains more SURF-TG, the membrane bends toward the other leaflet. The central conclusion of this study is that SURF-TG is a negative curvature inducer, as well as a membrane modulator. To this end, a model has proposed in which the accumulation of SURF-TG in the luminal leaflet bends the ER bilayer toward the cytosolic side, followed by TG nucleation.

scholarly journals Correction: Estimation of membrane bending modulus of stiffness tuned human red blood cells from micropore filtration studies

PLoS ONE ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. e0228125
Author(s):  
Rekha Selvan ◽  
Praveen Parthasarathi ◽  
Shruthi S. Iyengar ◽  
Sharath Ananthamurthy ◽  
Sarbari Bhattacharya
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Human Red Blood Cells ◽  
Bending Modulus ◽  
Membrane Bending

scholarly journals Response and Recovery Times of Elastic and Viscoelastic Capsules in Shear Flow

2015 ◽  
Vol 17 (5) ◽  
pp. 1151-1168 ◽  
Author(s):  
John Gounley ◽  
Yan Peng
Keyword(s):  
Shear Flow ◽  
Fluid Viscosity ◽  
Membrane Viscosity ◽  
Recovery Times ◽  
Shear Elasticity ◽  
Response And Recovery ◽  
Membrane Bending ◽  
The Relationship ◽  
Spherical Capsule

AbstractAmid the recent interest in the role of membrane viscosity in the deformation of a fluid-filled capsule, we consider the role of various capsule properties (shear elasticity, membrane bending stiffness and viscosity) in determining the response and recovery times of a spherical capsule in shear flow. These times are determined by fitting exponential functions to results for the Taylor deformation parameter Dxy. We focus on the relationship between the membrane and fluid viscosity ratios, as suggested by Diaz et al, and whether adjustments to the fluid viscosity ratio may be used to approximate the effects of membrane viscosity. Based on its ability to reproduce response and recovery times, our results suggest that such an approach holds promise.

scholarly journals Membrane Bending Modulus and Adhesion Energy of Wild-Type and Mutant Cells of Dictyostelium Lacking Talin or Cortexillins

1998 ◽  
Vol 74 (1) ◽  
pp. 514-522 ◽  
Author(s):  
Rudolf Simson ◽  
Eva Wallraff ◽  
Jan Faix ◽  
Jens Niewöhner ◽  
Günther Gerisch ◽  
...  
Keyword(s):  
Adhesion Energy ◽  
Wild Type ◽  
Bending Modulus ◽  
Membrane Bending ◽  
Mutant Cells

scholarly journals Stiffness of Fluid and Gel Phase Lipid Nanovesicles: Weighting the Contributions of Membrane Bending Modulus and Luminal Pressurization

Langmuir ◽  
2021 ◽  
Author(s):  
Andrea Ridolfi ◽  
Lucrezia Caselli ◽  
Matteo Baldoni ◽  
Costanza Montis ◽  
Francesco Mercuri ◽  
...  
Keyword(s):  
Bending Modulus ◽  
Gel Phase ◽  
Membrane Bending

Living cell motility

2007 ◽  
Vol 366 (1864) ◽  
pp. 319-328 ◽  
Author(s):  
José Coelho Neto ◽  
Oscar Nassif Mesquita
Keyword(s):  
Membrane Surface ◽  
Optical Microscope ◽  
Living Cells ◽  
Physical Models ◽  
Microscopy Technique ◽  
Bending Modulus ◽  
Membrane Fluctuations ◽  
Complex Process ◽  
Dynamical Parameters ◽  
Membrane Bending

The motility of living eukaryotic cells is a complex process driven mainly by polymerization and depolymerization of actin filaments underneath the plasmatic membrane (actin cytoskeleton). However, the exact mechanisms through which cells are able to control and employ ‘actin-generated’ mechanical forces, in order to change shape and move in a well-organized and coordinated way, are not quite established. Here, we summarize the experimental results obtained by our research group during recent years in studying the motion of living cells, such as macrophages and erythrocytes. By using our recently developed defocusing microscopy technique, which allows quantitative analysis of membrane surface dynamics of living cells using a simple bright-field optical microscope, we were able to analyse morphological and dynamical parameters of membrane ruffles and small membrane fluctuations, study the process of phagocytosis and also measure values for cell refractive index, membrane bending modulus and cell viscosity. Although many questions still remain unanswered, our data seem to corroborate some aspects of recent physical models of cell membranes and motility.

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