Membrane Transport in Biology. Volume I (Concepts and Models).D. C. TostesonMembrane Transport in Biology. Volume II (Transport Across Single Biological Membranes).D. C. TostesonMembrane Transport in Biology. Volume III (Transport Across Multi-Membrane Systems).G. Giebisch

1980 ◽  
Vol 55 (1) ◽  
pp. 67-68
Author(s):  
Paul G. LeFevre
Keyword(s):  
Membrane Transport ◽  
Biological Membranes ◽  
Membrane Systems

scholarly journals Localization of trehalose in partially hydrated DOPC bilayers: insights into cryoprotective mechanisms

2014 ◽  
Vol 11 (95) ◽  
pp. 20140069 ◽  
Author(s):  
Ben Kent ◽  
Taavi Hunt ◽  
Tamim A. Darwish ◽  
Thomas Hauß ◽  
Christopher J. Garvey ◽  
...  
Keyword(s):  
Experimental Data ◽  
Lipid Bilayer ◽  
Molecular Mechanisms ◽  
Biological Membranes ◽  
Water Layer ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Membrane Systems ◽  
Gaussian Profile

Trehalose, a natural disaccharide with bioprotective properties, is widely recognized for its ability to preserve biological membranes during freezing and dehydration events. Despite debate over the molecular mechanisms by which this is achieved, and that different mechanisms imply quite different distributions of trehalose molecules with respect to the bilayer, there are no direct experimental data describing the location of trehalose within lipid bilayer membrane systems during dehydration. Here, we use neutron membrane diffraction to conclusively show that the trehalose distribution in a dioleoylphosphatidylcholine (DOPC) system follows a Gaussian profile centred in the water layer between bilayers. The absence of any preference for localizing near the lipid headgroups of the bilayers indicates that the bioprotective effects of trehalose at physiologically relevant concentrations are the result of non-specific mechanisms that do not rely on direct interactions with the lipid headgroups.

scholarly journals An equation for the biological transmembrane potential from basic biophysical principles

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 676
Author(s):  
Marco Arieli Herrera-Valdez
Keyword(s):  
Membrane Potential ◽  
Transmembrane Potential ◽  
Biological Membrane ◽  
Classical Model ◽  
Biological Membranes ◽  
Biochemical Properties ◽  
Electrical Circuit ◽  
Basic Knowledge ◽  
Membrane Systems ◽  
Ion Movement

Biological membranes mediate different physiological processes necessary for life, many of which depend on ion movement. In turn, the difference between the electrical potentials around a biological membrane, called transmembrane potential, or membrane potential for short, is one of the key biophysical variables affecting ion movement. Most of the existing equations that describe the change in membrane potential are based on analogies with resistive-capacitive electrical circuits. These equivalent circuit models assume resistance and capacitance as measures of the permeable and the impermeable properties of the membrane, respectively. These models have increased our understanding of bioelectricity, and were particularly useful at times when the basic structure, biochemistry, and biophysics of biological membrane systems were not well known. However, the parts in the ohmic circuits from which equations are derived, are not quite like the biological elements present in the spaces around and within biological membranes. Using current, basic knowledge about the structure, biophysics, and biochemical properties of biological membrane systems, it is shown here that it is possible to derive a simple equation for the transmembrane potential. Of note, the resulting equation is not based on electrical circuit analogies. Nevertheless, the classical model for the membrane potential based on an equivalent RC-circuit is recovered as a particular case, thus providing a mathematical justification for the classical models. Examples are presented showing the effects of the voltage dependence of charge aggregation around the membrane, on the timing and shape of neuronal action potentials.

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