An ESR characterization of micelles and vesicles formed in aqueous decanoic acid/sodium decanoate systems using different spin labels

Dejanović, Branka; Mirosavljević, Krunoslav; Noethig-Laslo, Vesna; Pečar, Slavko; Šentjurc, Marjeta; Walde, Peter

doi:10.1016/j.chemphyslip.2008.08.003

Cited by 12 publications

(11 citation statements)

References 34 publications

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“…Since the TEMPO-spin labels report the dynamic properties at the surface of the oleic acid/oleate system, spectral fitting with only one type of spin label motion suggests similar surface properties of micelles and vesicles, known to coexist in the pH range 9.8 > pH > 8.0 (Hargreaves and Deamer, 1978;Morigaki and Walde, 2007;Fukuda et al, 2001). When TEMPO-spin labels (TEMPOoctanoate and TEMPO-decanoate) were applied to aqueous decanoic acid/sodium decanoate system, in the range 7.9 > pH > 6.8 for the best fit of the experimental spectra two different spin label environments had to be supposed, suggesting different surface properties of vesicles and micelles in that system (Dejanović et al, 2008). Similar surface properties of micelles and vesicles in the oleic acid/oleate system in the pH range 9.8 > pH > 8.0 are probably due to longer and unsaturated aliphatic chains, as compared to the decanoic acid/decanote system.…”

Section: Resultsmentioning

confidence: 98%

On the surface properties of oleate micelles and oleic acid/oleate vesicles studied by spin labeling

Dejanović

Noethig-Laslo

Šentjurc

et al. 2011

Chemistry and Physics of Lipids

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Section: Resultsmentioning

confidence: 98%

On the surface properties of oleate micelles and oleic acid/oleate vesicles studied by spin labeling

Dejanović

Noethig-Laslo

Šentjurc

et al. 2011

Chemistry and Physics of Lipids

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“…3,4 While the high working concentrations of such species precluded the quantitative fluorescence-based analysis introduced here, previous ESR experiments have shown similar micelle–vesicle coexistence in a decanoic acid (C10) system. 15 …”

Section: Discussionmentioning

confidence: 99%

Concentration-Driven Growth of Model Protocell Membranes

2012

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The first protocell membranes may have assembled from fatty acids and related single-chain lipids available in the prebiotic environment. Prior to the evolution of complex cellular machinery, spontaneous protocell membrane growth and division had to result from the intrinsic physicochemical properties of these molecules, in the context of specific environmental conditions. Depending on the nature of the chemical and physical environment, fatty acids can partition between several different phases, including soluble monomers, micelles, and lamellar vesicles. Here we address the concentration dependence of fatty acid aggregation, which is dominated by entropic considerations. We quantitatively distinguish between fatty acid phases using a combination of physical and spectroscopic techniques, including the use of the fluorescent fatty acid analogue Laurdan, whose emission spectrum is sensitive to structural differences between micellar and lamellar aggregates. We find that the monomer–aggregate transition largely follows a characteristic pseudophase model of molecular aggregation but that the composition of the aggregate phase is also concentration dependent. At low amphiphile concentrations above the critical aggregate concentration, vesicles coexist with a significant proportion of micelles, while more concentrated solutions favor the lamellar vesicle phase. We subsequently show that the micelle–vesicle equilibrium can be used to drive the growth of pre-existing vesicles upon an increase in amphiphile concentration either through solvent evaporation or following the addition of excess lipids. We propose a simple model for a primitive environmentally driven cell cycle, in which protocell membrane growth results from evaporative concentration, followed by shear force or photochemically induced division.

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“… Atomic force micrographs show that dehydrated micelles assemble into ribbons. Decanoic acid vesicles are always in equilibrium with micelles, [28] so dried dispersions of 50 mM decanoic acid vesicles produce ribbons (A) in addition to membrane stacks (Figure 2A). Control dispersions of 50 mM heptanoic acid, which form micelles and not vesicles, produce only ribbons (B).…”

Section: Figurementioning

confidence: 99%

“…In Step 3, the dimers were rehydrated, and then treated with NaOH, which cleaved ethyl-esters and linearized cyclic dipeptides. Isotope-labeled internal standards were added prior to analysis by LC-MS-MS. [28] so dried dispersions of 50 mM decanoic acid vesicles produce ribbons (A) in addition to membrane stacks (Figure 2A). Control dispersions of 50 mM heptanoic acid, which form micelles and not vesicles, produce only ribbons (B).…”

mentioning

confidence: 99%

Prebiotic Membranes and Micelles Do Not Inhibit Peptide Formation During Dehydration

et al. 2021

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Cycles of dehydration and rehydration could have enabled formation of peptides and RNA in otherwise unfavorable conditions on the early Earth. Development of the first protocells would have hinged upon colocalization of these biopolymers with fatty acid membranes. Using atomic force microscopy, we find that a prebiotic fatty acid (decanoic acid) forms stacks of membranes after dehydration. Using LC‐MS‐MS (liquid chromatography‐tandem mass spectrometry) with isotope internal standards, we measure the rate of formation of serine dipeptides. We find that dipeptides form during dehydration at moderate temperatures (55 °C) at least as fast in the presence of decanoic acid membranes as in the absence of membranes. Our results are consistent with the hypothesis that protocells could have formed within evaporating environments on the early Earth.

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An ESR characterization of micelles and vesicles formed in aqueous decanoic acid/sodium decanoate systems using different spin labels

Cited by 12 publications

References 34 publications

On the surface properties of oleate micelles and oleic acid/oleate vesicles studied by spin labeling

On the surface properties of oleate micelles and oleic acid/oleate vesicles studied by spin labeling

Concentration-Driven Growth of Model Protocell Membranes

Prebiotic Membranes and Micelles Do Not Inhibit Peptide Formation During Dehydration

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