scholarly journals Gaussian curvature directs the distribution of spontaneous curvature on bilayer membrane necks

Soft Matter ◽  
2018 ◽  
Vol 14 (12) ◽  
pp. 2281-2294 ◽  
Author(s):  
Morgan Chabanon ◽  
Padmini Rangamani
Keyword(s):  
Gaussian Curvature ◽  
Bilayer Membrane ◽  
Spontaneous Curvature

The energy to maintain a catenoid-shaped membrane neck with spontaneous curvature shows a barrier dependent on the neck asymmetry.

scholarly journals Gaussian curvature directs the distribution of spontaneous curvature on bilayer membrane necks

2017 ◽  
Author(s):  
Morgan Chabanon ◽  
Padmini Rangamani
Keyword(s):  
Lipid Bilayers ◽  
Gaussian Curvature ◽  
Source Term ◽  
Bilayer Membrane ◽  
Fundamental Question ◽  
Spontaneous Curvature ◽  
Shape Equation ◽  
Curvature Distribution ◽  
Membrane Protein Interaction ◽  
The Relationship

ABSTRACTFormation of membrane necks is crucial for fission and fusion in lipid bilayers. In this work, we seek to answer the following fundamental question: what is the relationship between protein-induced spontaneous mean curvature and the Gaussian curvature at a membrane neck? Using an augmented Helfrich model for lipid bilayers to include membrane-protein interaction, we solve the shape equation on catenoids to find the field of spontaneous curvature that satisfies mechanical equilibrium of membrane necks. In this case, the shape equation reduces to a variable coefficient Helmholtz equation for spontaneous curvature, where the source term is proportional to the Gaussian curvature. We show how this latter quantity is responsible for non-uniform distribution of spontaneous curvature in minimal surfaces. We then explore the energetics of catenoids with different spontaneous curvature boundary conditions and geometric asymmetries to show how heterogeneities in spontaneous curvature distribution can couple with Gaussian curvature to result in membrane necks of different geometries.

Measuring the Spontaneous Curvature of Bilayer Membranes by Molecular Dynamics Simulations

2013 ◽  
Vol 13 (4) ◽  
pp. 1093-1106 ◽  
Author(s):  
Han Wang ◽  
Dan Hu ◽  
Pingwen Zhang
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Molecular Mechanisms ◽  
Bilayer Membrane ◽  
Spontaneous Curvature ◽  
Bilayer Membranes ◽  
Bead Diameter ◽  
The Mean ◽  
Dynamics Simulations ◽  
Theoretical Results

AbstractWe propose a mathematically rigorous method to measure the spontaneous curvature of a bilayer membrane by molecular dynamics (MD) simulation, which provides description of the molecular mechanisms that cause the spontaneous curvature. As a main result, for the membrane setup investigated, the spontaneous curvature is proved to be a constant plus twice the mean curvature of the membrane in its tensionless ground state. The spontaneous curvature due to the built-in transbilayer asymmetry of the membrane in terms of lipid shape is studied by the proposed method. A linear dependence of the spontaneous curvature with respect to the head-bead diameter difference and the lipid mixing ratio is discovered. The consistency with the theoretical results provides evidence supporting the validity of our method.

scholarly journals Multi-stability of free spontaneously curved anisotropic strips

2011 ◽  
Vol 468 (2138) ◽  
pp. 511-530 ◽  
Author(s):  
L. Giomi ◽  
L. Mahadevan
Keyword(s):  
Gaussian Curvature ◽  
Elastic Moduli ◽  
Composite Plates ◽  
Spontaneous Curvature ◽  
Bending Rigidity ◽  
Stable Conformation ◽  
Elastic Composite ◽  
Measuring Tape ◽  
Zero Gaussian Curvature ◽  
The Common

Multi-stable structures are objects with more than one stable conformation, exemplified by the simple switch. Continuum versions are often elastic composite plates or shells, such as the common measuring tape or the slap bracelet, both of which exhibit two stable configurations: rolled and unrolled. Here, we consider the energy landscape of a general class of multi-stable anisotropic strips with spontaneous Gaussian curvature. We show that while strips with non-zero Gaussian curvature can be bistable, and strips with positive spontaneous curvature are always bistable, independent of the elastic moduli, strips of spontaneous negative curvature are bistable only in the presence of spontaneous twist and when certain conditions on the relative stiffness of the strip in tension and shear are satisfied. Furthermore, anisotropic strips can become tristable when their bending rigidity is small. Our study complements and extends the theory of multi-stability in anisotropic shells and suggests new design criteria for these structures.

scholarly journals Effects of Spontaneous Bilayer Curvature on Influenza Virus–mediated Fusion Pores

1998 ◽  
Vol 112 (4) ◽  
pp. 409-422 ◽  
Author(s):  
Vladimir I. Razinkov ◽  
Grigory B. Melikyan ◽  
Richard M. Epand ◽  
Raquel F. Epand ◽  
Fredric S. Cohen
Keyword(s):  
Influenza Virus ◽  
Negative Curvature ◽  
Hexagonal Phase ◽  
Three Dimensional ◽  
Bilayer Membrane ◽  
Spontaneous Curvature ◽  
Dependent Manner ◽  
Small Pore ◽  
In Trans ◽  
Fusion Pores

Cells expressing the hemagglutinin protein of influenza virus were fused to planar bilayer membranes containing the fluorescent lipid probes octadecylrhodamine (R18) or indocarbocyanine (DiI) to investigate whether spontaneous curvature of each monolayer of a target membrane affects the growth of fusion pores. R18 and DiI lowered the transition temperatures for formation of an inverted hexagonal phase, indicating that these probes facilitate the formation of negative curvature structures. The probes are known to translocate from one monolayer of a bilayer membrane to the other in a voltage-dependent manner. The spontaneous curvature of the cis monolayer (facing the cells) or the trans monolayer could therefore be made more negative through control of the polarity of voltage across the planar membrane. Electrical admittance measurements showed that the open times of flickering fusion pores were shorter when probes were in trans monolayers and longer when in cis monolayers compared with times when probe was symmetrically distributed. Open times were the same for probe symmetrically distributed as when probes were not present. Thus, open times were a function of the asymmetry of the spontaneous curvature between the trans and cis monolayers. Enriching the cis monolayer with a negative curvature probe reduced the probability that a small pore would fully enlarge, whereas enriching the trans monolayer promoted enlargement. Lysophosphatidylcholine has positive spontaneous curvature and does not translocate. When lysophosphatidylcholine was placed in trans leaflets of planar membranes, closing of fusion pores was rare. The effects of the negative and positive spontaneous curvature probes do not support the hypothesis that a flickering pore closes from an open state within a hemifusion diaphragm (essentially a “flat” structure). Rather, such effects support the hypothesis that the membrane surrounding the open pore forms a three-dimensional hourglass shape from which the pore flickers shut.

Recent Advances in Novasome Formulation Technology

2014 ◽  
Vol 7 (2) ◽  
pp. 2407-2411
Author(s):  
J M Shah ◽  
N.H Shah ◽  
Hadiya P D
Keyword(s):  
Drug Delivery ◽  
Effective Means ◽  
Entrapment Efficiency ◽  
Bilayer Membrane ◽  
Water Soluble ◽  
Delivery Methods ◽  
Liposomal Drug ◽  
Pharmaceutical Technology ◽  
Insoluble Drugs ◽  
Novel Drug

Pharmaceutical technology has developed various newer modes of novel drug delivery aspects. Modifications in the previously existing drug delivery methods have led to various newly innovated technologies serving as a safe and effective means of improvement over the existing ones. Novasome technology is one of the new innovations of liposomes which have solved many of the problems related to liposomal drug delivery system. It offers a seven bilayer membrane which has the ability to incorporate both water soluble and insoluble drugs. It has an excellent entrapment efficiency which provides better medication. Formulation of novasomes is achieved in a high shear device. Due to its numerous advantages, novasomes have been used extensively in various fields like cosmetics, chemical, personal care, foods, pharmaceuticals and agrochemicals.

Excitation of Bilayer Membrane

1969 ◽  
Vol 9 (2) ◽  
pp. 49-66
Author(s):  
Masayuki TAKAGI
Keyword(s):  
Bilayer Membrane

scholarly journals Transmembrane signal transduction by cofactor transport

2021 ◽  
Author(s):  
Istvan Kocsis ◽  
Yudi Ding ◽  
Nicholas H. Williams ◽  
Christopher A. Hunter
Keyword(s):  
Signal Transduction ◽  
Lipid Bilayer ◽  
Metal Ion ◽  
Bilayer Membrane ◽  
Ester Hydrolysis ◽  
Lipid Bilayer Membrane ◽  
Metal Ion Cofactors

Synthetic transducers transport externally added metal ion cofactors across the lipid bilayer membrane of vesicles to trigger catalysis of ester hydrolysis in the inner compartment. Signal transduction activity is modulated by hydrazone formation.

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