scholarly journals Reversible membrane deformations by straight DNA origami filaments

Soft Matter ◽  
2021 ◽  
Author(s):  
Henri G. Franquelim ◽  
Hendrik Dietz ◽  
Petra Schwille
Keyword(s):  
Lipid Membranes ◽  
Dna Origami ◽  
Membrane Bound ◽  
Membrane Deformations

Reversible MgCl2-induced blunt-end polymerization of membrane-bound straight DNA origami monomers into filaments leads to protruding deformations on freestanding lipid membranes.

Monolayerwise application of linear elasticity theory well describes strongly deformed lipid membranes and the effect of solvent

Soft Matter ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1179-1189 ◽  
Author(s):  
Timur R. Galimzyanov ◽  
Pavel V. Bashkirov ◽  
Paul S. Blank ◽  
Joshua Zimmerberg ◽  
Oleg V. Batishchev ◽  
...  
Keyword(s):  
Elasticity Theory ◽  
Linear Theory ◽  
Linear Elasticity ◽  
Lipid Membranes ◽  
Bilayer Membrane ◽  
Theory Of Elasticity ◽  
Linear Elasticity Theory ◽  
Effect Of Solvent ◽  
Model Based ◽  
Membrane Deformations

The linear theory of elasticity can be expanded through the range from weak to strong bilayer membrane deformations using a generalized Helfrich model based on monolayer membrane additivity.

scholarly journals Diffusion and Freezing Transition of Rod-Like DNA Origami on Freestanding Lipid Membranes

2014 ◽  
Vol 106 (2) ◽  
pp. 701a
Author(s):  
Eugene P. Petrov ◽  
Aleksander Czogalla ◽  
Dominik J. Kauert ◽  
Ralf Seidel ◽  
Petra Schwille
Keyword(s):  
Lipid Membranes ◽  
Dna Origami ◽  
Freezing Transition

scholarly journals Electrodes modified with lipid membranes to study quinone oxidoreductases

2009 ◽  
Vol 37 (4) ◽  
pp. 707-712 ◽  
Author(s):  
Sophie A. Weiss ◽  
Lars J.C. Jeuken
Keyword(s):  
Lipid Membranes ◽  
Biochemical Properties ◽  
Model Membranes ◽  
Water Soluble ◽  
Enzyme Assays ◽  
Membrane Enzymes ◽  
Membrane Bound ◽  
Hydrophobic Nature

Quinone oxidoreductases are a class of membrane enzymes that catalyse the oxidation or reduction of membrane-bound quinols/quinones. The conversion of quinone/quinol by these enzymes is difficult to study because of the hydrophobic nature of the enzymes and their substrates. We describe some biochemical properties of quinones and quinone oxidoreductases and then look in more detail at two model membranes that can be used to study quinone oxidoreductases in a native-like membrane environment with their native lipophilic quinone substrates. The results obtained with these model membranes are compared with classical enzyme assays that use water-soluble quinone analogues.

scholarly journals Construction of membrane-bound artificial cells using microfluidics: a new frontier in bottom-up synthetic biology

2016 ◽  
Vol 44 (3) ◽  
pp. 723-730 ◽  
Author(s):  
Yuval Elani
Keyword(s):  
Synthetic Biology ◽  
High Throughput ◽  
Lipid Membranes ◽  
Spatial Organization ◽  
Building Blocks ◽  
Artificial Cells ◽  
Bottom Up ◽  
Grand Challenges ◽  
New Frontier ◽  
Membrane Bound

The quest to construct artificial cells from the bottom-up using simple building blocks has received much attention over recent decades and is one of the grand challenges in synthetic biology. Cell mimics that are encapsulated by lipid membranes are a particularly powerful class of artificial cells due to their biocompatibility and the ability to reconstitute biological machinery within them. One of the key obstacles in the field centres on the following: how can membrane-based artificial cells be generated in a controlled way and in high-throughput? In particular, how can they be constructed to have precisely defined parameters including size, biomolecular composition and spatial organization? Microfluidic generation strategies have proved instrumental in addressing these questions. This article will outline some of the major principles underpinning membrane-based artificial cells and their construction using microfluidics, and will detail some recent landmarks that have been achieved.

scholarly journals The Effect of Amphotericin B on the Water and Nonelectrolyte Permeability of Thin Lipid Membranes

1969 ◽  
Vol 53 (2) ◽  
pp. 133-156 ◽  
Author(s):  
Thomas E. Andreoli ◽  
Vincent W. Dennis ◽  
Ann M. Weigl
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Permeability Coefficient ◽  
Circular Cylinders ◽  
Osmotic Water Permeability ◽  
Polyene Antibiotic ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
Membrane Bound ◽  
Nonelectrolyte Permeability

This paper reports the effects of amphotericin B, a polyene antibiotic, on the water and nonelectrolyte permeability of optically black, thin lipid membranes formed from sheep red blood cell lipids dissolved in decane. The permeability coefficients for the diffusion of water and nonelectrolytes (PDDi) were estimated from unidirectional tracer fluxes when net water flow (Jw) was zero. Alternatively, an osmotic water permeability coefficient (Pf) was computed from Jw when the two aqueous phases contained unequal solute concentrations. In the absence of amphotericin B, when the membrane solutions contained equimolar amounts of cholesterol and phospholipid, Pf was 22.9 ± 4.6 µsec-1 and PDDHDH2O was 10.8 ± 2.4 µsec-1. Furthermore, PDDi was < 0.05 µsec-1 for urea, glycerol, ribose, arabinose, glucose, and sucrose, and σi, the reflection coefficient of each of these solutes was one. When amphotericin B (10-6 M) was present in the aqueous phases and the membrane solutions contained equimolar amounts of cholesterol and phospholipid, PDDHDH2O was 18.1 ± 2.4 µsec-1; Pf was 549 ± 143 µsec-1 when glucose, sucrose, and raffinose were the aqueous solutes. Concomitantly, PDDi varied inversely, and σi directly, with the effective hydrodynamic radii of the solutes tested. These polyene-dependent phenomena required the presence of cholesterol in the membrane solutions. These data were analyzed in terms of restricted diffusion and filtration through uniform right circular cylinders, and were compatible with the hypothesis that the interactions of amphotericin B with membrane-bound cholesterol result in the formation of pores whose equivalent radii are in the range 7 to 10.5 A.

DNA Origami Nanoneedles on Freestanding Lipid Membranes as a Tool To Observe Isotropic–Nematic Transition in Two Dimensions

Nano Letters ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 649-655 ◽  
Author(s):  
Aleksander Czogalla ◽  
Dominik J. Kauert ◽  
Ralf Seidel ◽  
Petra Schwille ◽  
Eugene P. Petrov
Keyword(s):  
Lipid Membranes ◽  
Two Dimensions ◽  
Dna Origami

scholarly journals The Interaction of Polyene Antibiotics with Thin Lipid Membranes

1968 ◽  
Vol 52 (2) ◽  
pp. 300-325 ◽  
Author(s):  
Thomas E. Andreoli ◽  
Marcia Monahan
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Sheep Erythrocyte ◽  
Cholesterol Content ◽  
Transference Numbers ◽  
Ionic Selectivity ◽  
Antibiotic Concentration ◽  
Polyene Antibiotics ◽  
Cyclic Polyene ◽  
Membrane Bound

Optically black, thin lipid membranes prepared from sheep erythrocyte lipids have a high dc resistance (Rm ≅ 108 ohm-cm2) when the bathing solutions contain NaCl or KCl. The ionic transference numbers (Ti) indicate that these membranes are cation-selective (TNa ≅ 0.85; TCl ≅ 0.15). These electrical properties are independent of the cholesterol content of the lipid solutions from which the membranes are formed. Nystatin, and probably amphotericin B, are cyclic polyene antibiotics containing ≈36 ring atoms and a free amino and carboxyl group. When the lipid solutions used to form membranes contained equimolar amounts of cholesterol and phospholipid, these antibiotics reduced Rm to ≈102 ohm-cm2; concomitantly, TCl became ≅0.92. The slope of the line relating log Rm and log antibiotic concentration was ≅4.5. Neither nystatin (2 x 10-5 M) nor amphotericin B (2 x 10-7 M) had any effect on membrane stability. The antibiotics had no effect on Rm or membrane permselectivity when the lipids used to form membranes were cholesterol-depleted. Filipin (10-5 M), an uncharged polyene with 28 ring atoms, produced striking membrane instability, but did not affect Rm or membrane ionic selectivity. These data suggest that amphotericin B or nystatin may interact with membrane-bound sterols to produce multimolecular complexes which greatly enhance the permeability of such membranes for anions (Cl-, acetate), and, to a lesser degree, cations (Na+, K+, Li+).

How To Tackle the Issues in Free Energy Simulations of Long Amphiphiles Interacting with Lipid Membranes: Convergence and Local Membrane Deformations

2014 ◽  
Vol 118 (13) ◽  
pp. 3572-3581 ◽  
Author(s):  
Hugo A. L. Filipe ◽  
Maria João Moreno ◽  
Tomasz Róg ◽  
Ilpo Vattulainen ◽  
Luís M. S. Loura
Keyword(s):  
Free Energy ◽  
Lipid Membranes ◽  
Energy Simulations ◽  
Membrane Deformations

scholarly journals Enzyme Catalysis Enhances Lateral Lipid Motility and Directional Particle Transport on Membranes

2021 ◽  
Author(s):  
Ambika Somasundar ◽  
Niladri Sekhar Mandal ◽  
Ayusman Sen
Keyword(s):  
Lipid Membranes ◽  
Enzyme Catalysis ◽  
Lateral Diffusion ◽  
Cholesterol Content ◽  
Supported Bilayers ◽  
Membrane Fluctuations ◽  
Diffusion Enhancement ◽  
Membrane Bound ◽  
Passive Tracers ◽  
Membrane Bound Enzymes

The dynamic interplay between the composition of lipid membranes and the behavior of membrane-bound enzymes is critical to the understanding of cellular function and viability, and the design of membrane-based biosensing platforms. While there is a significant body of knowledge on how lipid composition and dynamics affect membrane-bound enzymes, little is known about how enzyme catalysis influences the motility and lateral transport in lipid membranes. Using enzymes-attached lipids in supported bilayers (SLB), we show catalysis-induced enhanced lateral diffusion of lipids in the bilayer. Enhancing the membrane viscosity by increasing the cholesterol content in the bilayer suppresses the overall diffusion but not the relative diffusion enhancement of the enzyme-attached lipids. We also provide direct evidence of catalysis-induced membrane fluctuations leading to the enhanced diffusion of passive tracers resting on the SLB. Additionally, by using active enzyme patches, we demonstrate the directional transport of tracers on SLBs. These are first steps in understanding diffusion and transport in lipid membranes due to active, out-of-equilibrium processes that are the hallmark of living systems. In general, our study demonstrates how active enzymes can be used to control diffusion and transport in confined 2-D environments.

Sign in / Sign up

Export Citation Format

Share Document