The interactions of squalene, alkanes and other mineral oils with model membranes; effects on membrane heterogeneity and function

Richens, Joanna L.; Lane, Jordan; Mather, Melissa L.; O’Shea, Paul

doi:10.1016/j.jcis.2015.06.052

Cited by 12 publications

(10 citation statements)

References 42 publications

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“…This fluorescence assay has previously been used in model membrane systems to show adsorption of Ca 2+ ions, study membrane-peptide interactions and insertion and to quantify the effects of mineral oils on the binding of oleic acid. 2,3 In this study, we use these techniques to characterise the adsorption of lanthanide ions onto a DMPC bilayer. Lanthanide ions have applications in clinical research including the treatment of burns, anticoagulants, anti-tumour therapy and imaging studies as well as acting as a tool for fundamental studies on model membrane systems.…”

Section: Introductionmentioning

confidence: 99%

How does ytterbium chloride interact with DMPC bilayers? A computational and experimental study

Gonzalez

Barriga

Richens

et al. 2017

Phys. Chem. Chem. Phys.

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Lanthanide salts have been studied for many years, primarily in Nuclear Magnetic Resonance (NMR) experiments of mixed lipid-protein systems and more recently to study lipid flip-flop in model membrane systems. It is well recognised that lanthanide salts can influence the behaviour of both lipid and protein systems, however a full molecular level description of lipid-lanthanide interactions is still outstanding. Here we present a study of lanthanide-bilayer interactions, using molecular dynamics computer simulations, fluorescence electrostatic potential experiments and nuclear magnetic resonance. Computer simulations reveal the microscopic structure of DMPC lipid bilayers in the presence of Yb, and a surprising ability of the membranes to adsorb significant concentrations of Yb without disrupting the overall membrane structure. At concentrations commonly used in NMR experiments, Yb ions bind strongly to 5 lipids, inducing a small decrease of the area per lipid and a slight increase of the ordering of the aliphatic chains and the bilayer thickness. The area compressibility modulus increases by a factor of two, with respect to the free-salt case, showing that Yb ions make the bilayer more rigid. These modifications of the bilayer properties should be taken into account in the interpretation of NMR experiments.

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Section: Introductionmentioning

confidence: 99%

How does ytterbium chloride interact with DMPC bilayers? A computational and experimental study

Gonzalez

Barriga

Richens

et al. 2017

Phys. Chem. Chem. Phys.

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“…Squalene (C 30 H 50 ), a natural isoprenoid compound, could be conjugated to phospholipids in the formation of liposomes with the intention of improving the membrane lipophilicity and consequently, the affinity towards the environment of lipid bilayers. As reported by Richens et al [20], oily natural substances such as squalene can modify the membrane dipole potential. The adhesion capability of squalene could be affected by its lipophilic character and its tendency to integrate with the ML membrane bilayer.…”

Section: Introductionmentioning

confidence: 69%

Impact of Quercetin Encapsulation with Added Phytosterols on Bilayer Membrane and Photothermal-Alteration of Novel Mixed Soy Lecithin-Based Liposome

et al. 2020

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This study used highly lipophilic agents with an aim to increase the oxidant inhibitory activity and enhance photothermal stability of a novel mixed soy lecithin (ML)-based liposome by changing the composition of formulation within the membrane. Specifically, the development and optimization of the liposome intended for improving Trolox equivalent antioxidant capacity (TEAC) value and %TEAC loss was carried out by incorporating a natural antioxidant, quercetin (QU). In this context, a focus was set on QU encapsulation in ML-based liposomes and the concentration-dependent solubility of QU was investigated and calculated as encapsulation efficiency (EE). To explore the combined effects of the incorporation of plant sterols on the integrity and entrapment capacity of mixed phospholipid vesicles, conjugation of two types of phytosterols (PSs), namely β-sitosterol (βS) and stigmasterol (ST), to mixed membranes at different ratios was also performed. The EE measurement revealed that QU could be efficiently encapsulated in the stable ML-based liposome using 0.15 and 0.1 g/100 mL of βS and ST, respectively. The aforementioned liposome complex exhibited a considerable TEAC (197.23%) and enhanced TEAC loss (30.81%) when exposed to ultraviolet (UV) light (280–320 nm) over a 6 h duration. It appeared that the presence and type of PSs affect the membrane-integration characteristics as well as photodamage transformation of the ML-based liposome. The association of QU with either βS or ST in the formulation was justified by their synergistic effects on the enhancement of the EE of liposomes. Parallel to this, it was demonstrated that synergistic PS effects could be in effect in the maintenance of membrane order of the ML-based liposome. The findings presented in this study provided useful information for the development and production of stable QU-loaded ML-based liposomes for food and nutraceutical applications and could serve as a potential mixed lipids-based delivery system in the disease management using antioxidant therapy.

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“…Previous research revealed that squalene reduces H + and cation permeability in artificial membranes (Richens et al, ) or in the membranes of alkaliphilic bacteria (Gilmore et al, ). Observed sensitization of terbinafine‐treated QM cells to the protonophore CCCP (Figure d) indicated that maintenance of transmembrane potential could be affected by squalene accumulation in LD‐less cells.…”

Section: Resultsmentioning

confidence: 98%

“…In the coiled form, squalene can be incorporated between phospholipid acyl chains analogously to sterol molecules (Spanova & Daum, ). Several studies have shown that squalene present in artificial lipid bilayers significantly affects membrane characteristics such as lipid molecular packing (Gilmore et al, ) proton permeability (Haines, ), H II phase induction and stabilization (Lohner, Degovics, Laggner, Gnamusch, & Paltauf, ; Siegel, Banschbach, & Yeagle, ), predisposition to membrane fusion (Basáñez, Goñi, & Alonso, ), or formation of membrane microdomains (Richens, Lane, Mather, & O'Shea, ). On the other hand, the study of Spanova et al () indicated that squalene accumulating in yeast LD‐less hem1Δ QM cells had only marginal effect on the fluidity of isolated microsomes and plasma membranes.…”

Section: Introductionmentioning

confidence: 99%

Squalene lipotoxicity in a lipid droplet‐less yeast mutant is linked to plasma membrane dysfunction

Csáky

Garaiová

Kodedová

et al. 2020

Yeast

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Squalene is a naturally occurring triterpene with wide industrial applications. Due to limited natural resources, production of this valuable lipid in yeast is of high commercial relevance. Typically low levels of squalene in yeast can be significantly increased by specific cultivation conditions or genetic modifications. Under normal conditions, excess squalene is stored in lipid droplets (LD), while in a Saccharomyces cerevisiae mutant unable to form LD it is distributed to cellular membranes. We present here

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The interactions of squalene, alkanes and other mineral oils with model membranes; effects on membrane heterogeneity and function

Cited by 12 publications

References 42 publications

How does ytterbium chloride interact with DMPC bilayers? A computational and experimental study

How does ytterbium chloride interact with DMPC bilayers? A computational and experimental study

Impact of Quercetin Encapsulation with Added Phytosterols on Bilayer Membrane and Photothermal-Alteration of Novel Mixed Soy Lecithin-Based Liposome

Squalene lipotoxicity in a lipid droplet‐less yeast mutant is linked to plasma membrane dysfunction

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