Mesoscale studies of ionic closed membranes with polyhedral geometries

Cruz, Mónica Olvera de la

doi:10.1063/1.4953570

Cited by 3 publications

(2 citation statements)

References 36 publications

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“…However, the canonical icosahedral shape of carboxysomes has been shown to sometimes become irregular or elongated in bacteria ( Iancu et al, 2010 ). Moreover, it has been suggested that pH variations and interactions with metallic cations may modify the shape of such compartments from spherical to faceted shapes ( Olvera de la Cruz, 2016 ). Finally, some proteins have been shown to stabilize ACC ( Rao et al, 2013 ) but this has never been tested on proteins composing the shell of bacterial microcompartments.…”

Section: Discussionmentioning

confidence: 99%

Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria

et al. 2018

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The recent discovery of cyanobacteria forming intracellular amorphous calcium carbonate (ACC) has challenged the former paradigm suggesting that cyanobacteria-mediated carbonatogenesis was exclusively extracellular. Yet, the mechanisms of intracellular biomineralization in cyanobacteria and in particular whether this takes place within an intracellular microcompartment, remain poorly understood. Here, we analyzed six cyanobacterial strains forming intracellular ACC by transmission electron microscopy. We tested two different approaches to preserve as well as possible the intracellular ACC inclusions: (i) freeze-substitution followed by epoxy embedding and room-temperature ultramicrotomy and (ii) high-pressure freezing followed by cryo-ultramicrotomy, usually referred to as cryo-electron microscopy of vitreous sections (CEMOVIS). We observed that the first method preserved ACC well in 500-nm-thick sections but not in 70-nm-thick sections. However, cell ultrastructures were difficult to clearly observe in the 500-nm-thick sections. In contrast, CEMOVIS provided a high preservation quality of bacterial ultrastructures, including the intracellular ACC inclusions in 50-nm-thick sections. ACC inclusions displayed different textures, suggesting varying brittleness, possibly resulting from different hydration levels. Moreover, an electron dense envelope of ∼2.5 nm was systematically observed around ACC granules in all studied cyanobacterial strains. This envelope may be composed of a protein shell or a lipid monolayer, but not a lipid bilayer as usually observed in other bacteria forming intracellular minerals. Overall, this study evidenced that ACC inclusions formed and were stabilized within a previously unidentified bacterial microcompartment in some species of cyanobacteria.

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Section: Discussionmentioning

confidence: 99%

Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria

et al. 2018

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“…This would be entropically unfavorable if Tween 40 molecules gathered at the side of Type A vesicles and were reorientated into new rims on Type B vesicles (i.e., the transition of Type A to Type B vesicles), although the energetical study should be examined. However, it has been shown that faceted structures can be low energy configurations of elastic spherical vesicles [23,[36][37][38]. If so, the faceted vesicles closer to the spherical vesicle (Type B) might be more stable than Type A vesicles.…”

Section: Discussionmentioning

confidence: 99%

Hydrothermal Preparation of Faceted Vesicles Made of Span 40 and Tween 40 and Their Characterization

et al. 2023

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The Span 40 (sorbitan monooleate)/Tween 40 (polyoxyethylene sorbitan monolaurate) system gives faceted vesicles with angular surfaces, rather than spherical vesicles. Herein, a continuous and facile preparation method, based on the subcritical water-assisted emulsification and solvent diffusion, was presented to yield faceted vesicles with two major and minor axes (Type A) and vesicles closer to a polyhedron (Type B). Type A, rather than Type B, vesicles were likely to be formed. From the measurements concerning ζ-potential, membrane fluidity, and the polarization environment of the membranes, faceted vesicles could be obtained at 0.25 wt% of the surfactant concentration. The phase-separated behavior of Span 40 and Tween 40 within vesicle membranes could explain the structural feature of faceted vesicles and calcein leakage behavior. The significant advantage is that Type A vesicles would be utilized as alternative drug carriers for others with low encapsulation efficiency, although the present technical limitations cause difficulty in the selective formation of Type A and B vesicles and the selection of adequate solvent to accelerate the solvent diffusion step.

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Preface: Special Topic on Materials Genome

Phillips

Littlewood

2016

APL Mater.

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Mesoscale studies of ionic closed membranes with polyhedral geometries

Abstract: High performance long wavelength infrared mega-pixel focal plane array based on type-II superlattices

Cited by 3 publications

References 36 publications

Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria

Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria

Hydrothermal Preparation of Faceted Vesicles Made of Span 40 and Tween 40 and Their Characterization

Preface: Special Topic on Materials Genome

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