Characterization of the fluorophore 4-heptadecyl-7-hydroxycoumarin: a probe for the head-group region of lipid bilayers and biological membranes

Biochemistry ◽  
1985 ◽  
Vol 24 (3) ◽  
pp. 573-581 ◽  
Author(s):  
Ranajit Pal ◽  
William A. Petri ◽  
Vered Ben-Yashar ◽  
Robert R. Wagner ◽  
Yechezkel Barenholz
Keyword(s):  
Lipid Bilayers ◽  
Biological Membranes ◽  
Head Group

Observation of Concanavalin-A receptors on hydrated planar erythrocyte membrane film by in situ electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 608-609
Author(s):  
Neng-Bo He ◽  
S.W. Hui
Keyword(s):  
Lipid Bilayers ◽  
Erythrocyte Membrane ◽  
Lipid Membranes ◽  
Surface Film ◽  
Biological Membranes ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Black Lipid Membranes ◽  
Fine Mesh ◽  
Planar Films

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).

scholarly journals Fracture faces of frozen membranes: 50th anniversary

2016 ◽  
Vol 27 (3) ◽  
pp. 421-423
Author(s):  
Daniel Branton
Keyword(s):  
Electron Microscopy ◽  
Lipid Bilayers ◽  
Fracture Process ◽  
Relative Proportion ◽  
50Th Anniversary ◽  
Biological Membranes ◽  
Bilayer Membrane ◽  
Biological Cells ◽  
Membrane Surfaces ◽  
Freeze Etching

In 1961, the development of an improved freeze-etching (FE) procedure to prepare rapidly frozen biological cells or tissues for electron microscopy raised two important questions. How does a frozen cell membrane fracture? What do the extensive face views of the cell’s membranes exposed by the fracture process of FE tell us about the overall structure of biological membranes? I discovered that all frozen membranes tend to split along weakly bonded lipid bilayers. Consequently, the fracture process exposes internal membrane faces rather than either of the membrane’s two external surfaces. During etching, when ice is allowed to sublime after fracturing, limited regions of the actual membrane surfaces are revealed. Examination of the fractured faces and etched surfaces provided strong evidence that biological membranes are organized as lipid bilayers with some proteins on the surface and other proteins extending through the bilayer. Membrane splitting made it possible for electron microscopy to show the relative proportion of a membrane’s area that exists in either of these two organizational modes.

scholarly journals Preparation and Characterization of Solid-Supported Lipid Bilayers Formed by Langmuir–Blodgett Deposition: A Tutorial

Langmuir ◽  
2018 ◽  
Vol 34 (51) ◽  
pp. 15622-15639 ◽  
Author(s):  
James Kurniawan ◽  
João Francisco Ventrici de Souza ◽  
Amanda T. Dang ◽  
Gang-yu Liu ◽  
Tonya L. Kuhl
Keyword(s):  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Langmuir Blodgett

scholarly journals Structural Characterization of Natural Yeast Phosphatidylcholine and Bacterial Phosphatidylglycerol Lipid Multilayers by Neutron Diffraction

2021 ◽  
Vol 9 ◽  
Author(s):  
Alessandra Luchini ◽  
Giacomo Corucci ◽  
Krishna Chaithanya Batchu ◽  
Valerie Laux ◽  
Michael Haertlein ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Acyl Chain ◽  
Model Systems ◽  
Head Group ◽  
Single Class ◽  
Lipid Mixtures ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
The Impact

Eukaryotic and prokaryotic cell membranes are difficult to characterize directly with biophysical methods. Membrane model systems, that include fewer molecular species, are therefore often used to reproduce their fundamental chemical and physical properties. In this context, natural lipid mixtures directly extracted from cells are a valuable resource to produce advanced models of biological membranes for biophysical investigations and for the development of drug testing platforms. In this study we focused on single phospholipid classes, i.e. Pichia pastoris phosphatidylcholine (PC) and Escherichia coli phosphatidylglycerol (PG) lipids. These lipids were characterized by a different distribution of their respective acyl chain lengths and number of unsaturations. We produced both hydrogenous and deuterated lipid mixtures. Neutron diffraction experiments at different relative humidities were performed to characterize multilayers from these lipids and investigate the impact of the acyl chain composition on the structural organization. The novelty of this work resides in the use of natural extracts with a single class head-group and a mixture of chain compositions coming from yeast or bacterial cells. The characterization of the PC and PG multilayers showed that, as a consequence of the heterogeneity of their acyl chain composition, different lamellar phases are formed.

scholarly journals Non-axisymmetric shapes of biological membranes from locally induced curvature

2019 ◽  
Author(s):  
Yannick A. D. Omar ◽  
Amaresh Sahu ◽  
Roger A. Sauer ◽  
Kranthi K. Mandadapu
Keyword(s):  
Phase Separation ◽  
Cell Membrane ◽  
Viscous Flow ◽  
Lipid Bilayers ◽  
Biological Membranes ◽  
Rate Of Change ◽  
Computational Studies ◽  
Biological Processes ◽  
Resting Tension ◽  
Physical Phenomena

In various biological processes such as endocytosis and caveolae formation, the cell membrane is locally deformed into curved configurations. Previous theoretical and computational studies to understand membrane morphologies resulting from locally induced curvature are often limited to axisymmetric shapes, which severely restricts the physically admissible morphologies. Under the restriction of axisymmetry, past efforts predict that the cell membrane buds at low resting tensions and stalls at a flat pit at high resting tensions. In this work, we lift the restriction of axisymmetry by employing recent theoretical and numerical advances to understand arbitrarily curved and deforming lipid bilayers. Our non-axisymmetric morphologies reveal membrane morphologies which agree well with axisymmetric studies—however only if the resting tension of the membrane is low. When the resting tension is moderate to high, we show that (i) axisymmetric invaginations are unstable; and (ii) non-axisymmetric ridge-shaped structures are energetically favorable. We further study the dynamical effects resulting from the interplay between intramembrane viscous flow and induced curvature, and find the rate at which the locally induced curvature increases is a key determinant in the formation of ridges. In particular, we show that axisymmetric buds are favored when the induced curvature is rapidly increased, while non-axisymmetric ridges are favored when the curvature is slowly increased: The rate of change of induced curvature affects the intramembrane viscous flow of lipids, which can impede the membrane’s ability to transition into ridges. We conclude that the appearance of non-axisymmetric ridges indicates that axisymmetry cannot be generally assumed when understanding processes involving locally induced curvature. Our results hold potentially relevant implications for biological processes such as endocytosis, and physical phenomena like phase separation in lipid bilayers.

Formation and Nanoscale Characterization of Asymmetric Supported Lipid Bilayers Containing Raft-Like Domains

2021 ◽  
pp. 243-256
Author(s):  
Romina F. Vázquez ◽  
Erasmo Ovalle-García ◽  
Armando Antillón ◽  
Iván Ortega-Blake ◽  
Carlos Muñoz-Garay ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Nanoscale Characterization

scholarly journals Characterization of the Extra-Membrane Domains of CrgA in Lipid Bilayers using Solid State NMR

2019 ◽  
Vol 116 (3) ◽  
pp. 57a
Author(s):  
Yiseul Shin ◽  
Riqiang Fu ◽  
Huajune Qin ◽  
Timothy A. Cross
Keyword(s):  
Solid State ◽  
Lipid Bilayers ◽  
Solid State Nmr ◽  
Membrane Domains
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