scholarly journals Dynamics of pearling instability in polymersomes: The role of shear membrane viscosity and spontaneous curvature

2021 ◽  
Vol 33 (12) ◽  
pp. 122016
Author(s):  
J. Lyu ◽  
K. Xie ◽  
R. Chachanidze ◽  
A. Kahli ◽  
G. Boëdec ◽  
...  
Keyword(s):  
Spontaneous Curvature ◽  
Membrane Viscosity

Blocked Lipid Exchange in Bilayers and its Possible Influence on the Shape of Vesicles

1974 ◽  
Vol 29 (9-10) ◽  
pp. 510-515 ◽  
Author(s):  
W Helfrich
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Spontaneous Curvature ◽  
Lipid Exchange ◽  
Lipid Distribution ◽  
Shape Transformations ◽  
Curvature Elasticity ◽  
Possible Cause

Abstract The role of lipid exchange in the curvature elasticity of bilayers is studied theoretically. Blocking of exchange between the monolayers may give rise to a nonequilibrium lipid distribution going hand in hand with a spontaneous curvature. Some possible consequences for vesicular deformations are discussed. Lipid nonequilibrium is tentatively suggest as one possible cause for certain shape transformations of red blood cells

Membrane Curvature Induced by Sugar and Polymer Solutions

1997 ◽  
Vol 489 ◽  
Author(s):  
H.-G. Döbereiner ◽  
A. Lehmann ◽  
W. Goedel ◽  
O. Selchow ◽  
R. Lipowsky
Keyword(s):  
Polymer Solutions ◽  
Lipid Vesicles ◽  
Membrane Curvature ◽  
Elastic Membrane ◽  
Spontaneous Curvature ◽  
Membrane Asymmetry ◽  
Bending Modulus ◽  
Bending Elasticity ◽  
Cellular Organelles

AbstractWe monitor the effect of transversal membrane asymmetry on the morphology of giant uni-lamellar vesicles in sugar and polymer solutions. The shapes of fluid lipid vesicles are governed by the bending elasticity of their membrane which is characterized by the bending modulus and the spontaneous curvature of the bilayer. We present a recently developed technique for the measurement of the spontaneous curvature using quantitative phase contrast microscopy. Different mechanisms for elastic membrane asymmetry and the role of the bending energy concept for the morphology of cellular organelles are discussed.

The role of calcium in membrane condensation and spontaneous curvature variations in model lipidic systems

2011 ◽  
Vol 13 (8) ◽  
pp. 3115-3125 ◽  
Author(s):  
Anan Yaghmur ◽  
Barbara Sartori ◽  
Michael Rappolt
Keyword(s):  
Spontaneous Curvature

scholarly journals A Biophysical Model for Plant Cell Plate Development

2020 ◽  
Author(s):  
Muhammad Zaki Jawaid ◽  
Rosalie Sinclair ◽  
Daniel Cox ◽  
Georgia Drakakaki
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Late Stage ◽  
Cell Plate ◽  
Biophysical Model ◽  
Synthesis Rate ◽  
Spontaneous Curvature ◽  
Two Dimensional ◽  
A Cell

AbstractPlant cytokinesis, a fundamental process of plant life, involves de novo formation of a ‘cell plate’ that partitions the cytoplasm of the dividing cell. Cell plate formation is directed by orchestrated delivery, fusion of cytokinetic vesicles, and membrane maturation to the form the nascent cell wall by the timely deposition of polysaccharides such as callose, cellulose, and crosslinking glycans. In contrast to the role of endomembrane protein regulators the role of polysaccharides, in cell plate development is poorly understood. Callose, a β-1-3 glucan polymer, is transiently accumulated during cell plate expansion to be replaced by cellulose in mature stages. Based on the severity of cytokinesis defects in the absence of callose, it has been proposed that it stabilizes this membrane network structure. However, there is currently no theory to understand its role in cytokinesis.Here we extend the Helfrich free energy model for membranes including a phenomenological spreading force as an “areal pressure” generated by callose and/or other polysaccharides. Regular cell plate development in the model is possible, with suitable bending modulus, for a two-dimensional late stage spreading force parameter of between 2–6pN/nm, an osmotic pressure difference of 2–10kPa, and spontaneous curvature between 0–0.04nm−1. With these conditions, stable membrane conformation sizes and morphologies emerge in concordance with stages of cell plate development. With no spreading force, the cell plate fails to mature properly, corroborating experimental observations of cytokinesis arrest in the absence of callose. To reach a nearly mature cell plate, our model requires the late stage onset that the spreading force coupled with a concurrent loss of spontaneous curvature. A simple model based upon production of callose as a quasi-two-dimensional self-avoiding polymer produces the correct phenomenological form of the spreading force, which will be further refined, since matching to our numbers requires an exceptionally high callose synthesis rate.Significance StatementPlant cell division features the development of a unique membrane network called the cell plate that matures to a cell wall which separates the two daughter cells. During cell plate development, callose, a β-1-3 glucan polymer, is transiently synthesized at the cell plate only to be replaced by cellulose in mature stages. The role for this transient callose accumulation at the cell plate is unknown. It has been suggested that callose provides mechanical stability, as well as a spreading force that widens and expands tubular and fenestrated cell plate structures to aid the maturation of the cell plate. Chemical inhibition of callose deposition results in the failure of cell plate development supporting this hypothesis. This publication establishes the need for a spreading force in cell plate development using a biophysical model that predicts cell plate development in the presence and the absence of this force. Such models can potentially be used to decipher for the transition/maturation of membrane networks upon the deposition of polysaccharide polymers.

Smectic‐Ato bilayer evolution in concentrated surfactant solutions: The role of spontaneous curvature

1994 ◽  
Vol 101 (5) ◽  
pp. 4331-4342 ◽  
Author(s):  
Rony Granek ◽  
William M. Gelbart ◽  
Yardena Bohbot ◽  
Avinoam Ben‐Shaul
Keyword(s):  
Spontaneous Curvature ◽  
Surfactant Solutions

scholarly journals The glycolipid GM1 reshapes asymmetric biomembranes and giant vesicles by curvature generation

2018 ◽  
Vol 115 (22) ◽  
pp. 5756-5761 ◽  
Author(s):  
Raktim Dasgupta ◽  
Markus S. Miettinen ◽  
Nico Fricke ◽  
Reinhard Lipowsky ◽  
Rumiana Dimova
Keyword(s):  
Spontaneous Curvature ◽  
Intensity Analysis ◽  
Ganglioside Gm1 ◽  
Local Curvature ◽  
Giant Vesicles ◽  
Neuron Morphology ◽  
Receptor Proteins ◽  
Neuronal Membranes ◽  
Dynamics Simulations

The ganglioside GM1 is present in neuronal membranes at elevated concentrations with an asymmetric spatial distribution. It is known to generate curvature and can be expected to strongly influence the neuron morphology. To elucidate these effects, we prepared giant vesicles with GM1 predominantly present in one leaflet of the membrane, mimicking the asymmetric GM1 distribution in neuronal membranes. Based on pulling inward and outward tubes, we developed a technique that allowed the direct measurement of the membrane spontaneous curvature. Using vesicle electroporation and fluorescence intensity analysis, we were able to quantify the GM1 asymmetry across the membrane and to subsequently estimate the local curvature generated by the molecule in the bilayer. Molecular-dynamics simulations confirm the experimentally determined dependence of the membrane spontaneous curvature as a function of GM1 asymmetry. GM1 plays a crucial role in connection with receptor proteins. Our results on curvature generation of GM1 point to an additional important role of this ganglioside, namely in shaping neuronal membranes.

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 The Role of Plasma Membrane Viscosity in the Response and Resistance of Cancer Cells to Oxaliplatin

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6165
Author(s):  
Liubov Shimolina ◽  
Alexander Gulin ◽  
Nadezhda Ignatova ◽  
Irina Druzhkova ◽  
Margarita Gubina ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasma Membrane ◽  
Lipid Profile ◽  
Cancer Cells ◽  
Fluorescence Lifetime Imaging ◽  
Molecular Rotor ◽  
Membrane Viscosity

Maintenance of the biophysical properties of membranes is essential for cell survival upon external perturbations. However, the links between a fluid membrane state and the drug resistance of cancer cells remain elusive. Here, we investigated the role of membrane viscosity and lipid composition in the responses of cancer cells to oxaliplatin and the development of chemoresistance. Plasma membrane viscosity was monitored in live colorectal cancer cells and tumor xenografts using two-photon excited fluorescence lifetime imaging microscopy (FLIM) using the fluorescent molecular rotor BODIPY 2. The lipid profile was analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that the plasma membrane viscosity increased upon oxaliplatin treatment, both in vitro and in vivo, and that this correlated with lower phosphatidylcholine and higher cholesterol content. The emergence of resistance to oxaliplatin was accompanied by homeostatic adaptation of the membrane lipidome, and the recovery of lower viscosity. These results suggest that maintaining a constant plasma membrane viscosity via remodeling of the lipid profile is crucial for drug resistance in cancer.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor
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