Mechanical properties of vesicles. II. A model for osmotic swelling and lysis

Hallett, F. R.; Marsh, Julian B.; Nickel, B. G.; Wood, Janet M.

doi:10.1016/s0006-3495(93)81384-5

Cited by 97 publications

(101 citation statements)

References 17 publications

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“…The P-induced increase of vesicle volume was used to investigate the elastic properties of lipid bilayers of large unilamellar vesicles (LUVs) by measuring the change of average diameters of the LUVs under P using dynamic light scattering (DLS) (7)(8)(9). The P-induced leakage of fluorescent probes was also measured and analyzed (5,10,11). However, all measurements to date of the effects of P on vesicles have focused only on the P-induced volume increase of vesicles (6)(7)(8)(9)(10)(11)(12)(13)(14) and the leakage of their internal contents.…”

Section: Introductionmentioning

confidence: 99%

“…The P-induced leakage of fluorescent probes was also measured and analyzed (5,10,11). However, all measurements to date of the effects of P on vesicles have focused only on the P-induced volume increase of vesicles (6)(7)(8)(9)(10)(11)(12)(13)(14) and the leakage of their internal contents. There have been no experimental estimations of the membrane tension of vesicles of lipid membranes upon exposure to P. Moreover, all previous experiments have been conducted using LUVs.…”

Section: Introductionmentioning

confidence: 99%

“…There have been no experimental estimations of the membrane tension of vesicles of lipid membranes upon exposure to P. Moreover, all previous experiments have been conducted using LUVs. The polydispersity of LUVs (i.e., large distribution in LUV diameters) affects analysis by DLS (11), and fluorescence intensity measurements of LUV suspensions provide an ensemble average of the fluorescence intensity of many LUVs (15). In contrast, giant unilamellar vesicles (GUVs) of lipid membranes with diameters >10 mm have the advantage that their structures and physical properties can be directly observed as a function of time using optical microscopy (16)(17)(18)(19).…”

Section: Introductionmentioning

confidence: 99%

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Experimental Estimation of Membrane Tension Induced by Osmotic Pressure

Shibly

Ghatak

Karal

et al. 2016

Biophysical Journal

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Osmotic pressure (P) induces the stretching of plasma membranes of cells or lipid membranes of vesicles, which plays various roles in physiological functions. However, there have been no experimental estimations of the membrane tension of vesicles upon exposure to P. In this report, we estimated experimentally the lateral tension of the membranes of giant unilamellar vesicles (GUVs) when they were transferred into a hypotonic solution. First, we investigated the effect of P on the rate constant, k p , of constant-tension (s ex )-induced rupture of dioleoylphosphatidylcholine (DOPC)-GUVs using the method developed by us recently. We obtained the s ex dependence of k p in GUVs under P and by comparing this result with that in the absence of P, we estimated the tension of the membrane due to P at the swelling equilibrium, s eq osm . Next, we measured the volume change of DOPC-GUVs under small P. The experimentally obtained values of s eq osm and the volume change agreed with their theoretical values within the limits of the experimental errors. Finally, we investigated the characteristics of the P-induced pore formation in GUVs. The s eq osm corresponding to the threshold P at which pore formation is induced is similar to the threshold tension of the s ex -induced rupture. The time course of the radius change of GUVs in the P-induced pore formation depends on the total membrane tension, s t ; for small s t , the radius increased with time to an equilibrium one, which remained constant for a long time until pore formation, but for large s t , the radius increased with time and pore formation occurred before the swelling equilibrium was reached. Based on these results, we discussed the s eq osm and the P-induced pore formation in lipid membranes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Estimation of Membrane Tension Induced by Osmotic Pressure

Shibly

Ghatak

Karal

et al. 2016

Biophysical Journal

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“…The term lysis usually implies a process of vesicle rupture, involving at least transient alterations in gross vesicle structure, with consequent loss of osmolytes from the vesicle lumen. Hallett et al (1993) developed a model for vesicle swelling and lysis, and of specific interest are the mechanical properties that characterize membrane tension and membrane permeability, both of which are influenced by vesicle size. Importantly, lysis is not an all-or-nothing event, but instead a residual osmotic differential (ΔΠ) remained after lysis and does not result in complete solute loss (Mui et al 1993(Mui et al , 1994.…”

Section: Biophysical Principles In the Origin Of Mechanosensation In mentioning

confidence: 99%

Toward Understanding Protocell Mechanosensation

Balleza

2010

Orig Life Evol Biosph

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Mechanosensitive (MS) channels can prevent bacterial bursting during hypo-osmotic shocks by responding to increases in lateral tension at the membrane level through an integrated and coordinated opening mechanism. Mechanical regulation in protocells could have been one of the first mechanisms to evolve in order to preserve their integrity against changing environmental conditions. How has the rich functional diversity found in present cells been created throughout evolution, and what did the primordial MS channels look like? This review has been written with the aim of identifying which factors may have been important for the appearance of the first osmotic valve in a prebiotic context, and what this valve may have been like. It highlights the mechanical properties of lipid bilayers, the association of peptides as aggregates in membranes, and the conservation of sequence motifs as central aspects to understand the evolution of proteins that gate below the tension required for spontaneous pore formation and membrane rupture. The arguments developed here apply to both MscL and MscS homologs, but could be valid to mechano-susceptible proteins in general.

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“…where R is the ideal gas constant, T the absolute temperature, and c the concentration The guiding principle of this assay is that the bilayer of a vesicle has a threshold tension, t thresh , the maximum tension that it can withstand, dependent on its composition [23]. Eqs.…”

Section: Theoretical Descriptions Of Downshocked Vesiclesmentioning

confidence: 99%

Mechanosensitive channel of large conductance

Kloda

Petrov

Meyer

et al. 2008

The International Journal of Biochemistry & Cell Biology

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The bacterial mechanosensitive channel of large conductance (MscL) is an ideal starting point for understanding the molecular basis of mechanosensation. However, current methods for the characterization of its mutants, patch clamp and bacterial growth analysis, are difficult and time consuming, so a higher throughput method for screening mutants is desired. We have attempted to develop a fluorescence assay for detecting MscL activity in synthetic vesicles. The assay involved the separation of two solutionsone inside and one outside the vesicles-that are separately nonfluorescent but fluorescent when mixed. It was hoped that MscL activity due to downshock of the vesicles would bring about mixing of the solutions, producing fluorescence. The development of the assay required the optimization of several variables: the method for producing a uniform vesicle population containing MscL, the fluorescence system, and the lipid and protein composition of the vesicles. However, no MscL activity was ever detected even after optimization, so the assay was not fully developed. The probable cause of the failure was the inability of current techniques to produce a sufficiently uniform vesicle population.

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Mechanical properties of vesicles. II. A model for osmotic swelling and lysis

Cited by 97 publications

References 17 publications

Experimental Estimation of Membrane Tension Induced by Osmotic Pressure

Experimental Estimation of Membrane Tension Induced by Osmotic Pressure

Toward Understanding Protocell Mechanosensation

Mechanosensitive channel of large conductance

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