Spontaneous shape transformation of free-floating lipid membrane nanotubes

Soft Matter ◽  
2013 ◽  
Vol 9 (21) ◽  
pp. 5155 ◽  
Author(s):  
Natalia Stepanyants ◽  
Haijiang Zhang ◽  
Tatsiana Lobovkina ◽  
Paul Dommersnes ◽  
Gavin D. M. Jeffries ◽  
...  
Keyword(s):  
Lipid Membrane ◽  
Shape Transformation ◽  
Membrane Nanotubes

scholarly journals Microfluidic chip with pillar arrays for controlled production and observation of lipid membrane nanotubes

Lab on a Chip ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 2748-2755 ◽  
Author(s):  
Juan Manuel Martinez Galvez ◽  
Maite Garcia-Hernando ◽  
Fernando Benito-Lopez ◽  
Lourdes Basabe-Desmonts ◽  
Anna V. Shnyrova
Keyword(s):  
Surface Chemistry ◽  
Microfluidic Chip ◽  
Lipid Membrane ◽  
Membrane Nanotubes ◽  
Microfluidic Chamber ◽  
Pillar Arrays

Microarray surface chemistry and design set the geometry of lipid membrane nanotubes easily formed and observed in a microfluidic chamber.

Formation and Stability of Lipid Membrane Nanotubes

ACS Nano ◽  
2017 ◽  
Vol 11 (9) ◽  
pp. 9558-9565 ◽  
Author(s):  
Amir Houshang Bahrami ◽  
Gerhard Hummer
Keyword(s):  
Lipid Membrane ◽  
Membrane Nanotubes

Size-dependent formation of membrane nanotubes: continuum modeling and molecular dynamics simulations

2018 ◽  
Vol 20 (5) ◽  
pp. 3474-3483 ◽  
Author(s):  
Falin Tian ◽  
Tongtao Yue ◽  
Wei Dong ◽  
Xin Yi ◽  
Xianren Zhang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Lipid Membrane ◽  
Continuum Theory ◽  
Mechanical Behaviors ◽  
Continuum Modeling ◽  
Membrane Nanotubes ◽  
Size Dependent ◽  
Structural Lipid ◽  
Dynamics Simulations

With continuum theory and molecular dynamics simulations we demonstrated that the lipid membrane upon extraction exhibits size- and tension-dependent mechanical behaviors, and different structural lipid rearrangements in different leaflets.

scholarly journals Straining soft colloids in aqueous nematic liquid crystals

2016 ◽  
Vol 113 (20) ◽  
pp. 5564-5569 ◽  
Author(s):  
Peter C. Mushenheim ◽  
Joel S. Pendery ◽  
Douglas B. Weibel ◽  
Saverio E. Spagnolie ◽  
Nicholas L. Abbott
Keyword(s):  
Liquid Crystals ◽  
Lipid Membrane ◽  
Membrane Surface ◽  
Mechanical Strain ◽  
Thermal Quenching ◽  
Soft Materials ◽  
Shape Transformation ◽  
Membrane Pore ◽  
Aspect Ratios ◽  
Soft Colloids

Liquid crystals (LCs), because of their long-range molecular ordering, are anisotropic, elastic fluids. Herein, we report that elastic stresses imparted by nematic LCs can dynamically shape soft colloids and tune their physical properties. Specifically, we use giant unilamellar vesicles (GUVs) as soft colloids and explore the interplay of mechanical strain when the GUVs are confined within aqueous chromonic LC phases. Accompanying thermal quenching from isotropic to LC phases, we observe the elasticity of the LC phases to transform initially spherical GUVs (diameters of 2–50 µm) into two distinct populations of GUVs with spindle-like shapes and aspect ratios as large as 10. Large GUVs are strained to a small extent (R/r < 1.54, where R and r are the major and minor radii, respectively), consistent with an LC elasticity-induced expansion of lipid membrane surface area of up to 3% and conservation of the internal GUV volume. Small GUVs, in contrast, form highly elongated spindles (1.54 < R/r < 10) that arise from an efflux of LCs from the GUVs during the shape transformation, consistent with LC-induced straining of the membrane leading to transient membrane pore formation. A thermodynamic analysis of both populations of GUVs reveals that the final shapes adopted by these soft colloids are dominated by a competition between the LC elasticity and an energy (∼0.01 mN/m) associated with the GUV–LC interface. Overall, these results provide insight into the coupling of strain in soft materials and suggest previously unidentified designs of LC-based responsive and reconfigurable materials.

Chapter 2b: The molecular antigenic structure of the TBEV

2020 ◽  
Keyword(s):  
Conformational Changes ◽  
Neutralizing Antibodies ◽  
Lipid Membrane ◽  
Cell Entry ◽  
Antigenic Structure ◽  
E Proteins ◽  
Amino Acid Sequence Level ◽  
Endosomal Membrane ◽  
E Protein ◽  
Golgi Network

TBEV-particles are assembled in an immature, noninfectious form in the endoplasmic reticulum by the envelopment of the viral core (containing the viral RNA) by a lipid membrane associated with two viral proteins, prM and E. Immature particles are transported through the cellular exocytic pathway and conformational changes induced by acidic pH in the trans-Golgi network allow the proteolytic cleavage of prM by furin, a cellular protease, resulting in the release of mature and infectious TBE-virions. The E protein controls cell entry by mediating attachment to as yet ill-defined receptors as well as by low-pH-triggered fusion of the viral and endosomal membrane after uptake by receptor-mediated endocytosis. Because of its key functions in cell entry, the E protein is the primary target of virus neutralizing antibodies, which inhibit these functions by different mechanisms. Although all flavivirus E proteins have a similar overall structure, divergence at the amino acid sequence level is up to 60 percent (e.g. between TBE and dengue viruses), and therefore cross-neutralization as well as (some degree of) cross-protection are limited to relatively closely related flaviviruses, such as those constituting the tick-borne encephalitis serocomplex.

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

Sign in / Sign up

Export Citation Format

Share Document