scholarly journals Electron tomography of the nucleoid of Gemmata obscuriglobus reveals complex liquid crystalline cholesteric structure

2012 ◽  
Vol 3 ◽  
Author(s):  
Benjamin Yee ◽  
Evgeny Sagulenko ◽  
Garry P. Morgan ◽  
Richard I. Webb ◽  
John A. Fuerst
Keyword(s):  
Liquid Crystalline ◽  
Electron Tomography ◽  
Gemmata Obscuriglobus ◽  
Complex Liquid

scholarly journals Nanoarchitecture and dynamics of the mouse enteric glycocalyx examined by freeze-etching electron tomography and intravital microscopy

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Willy W. Sun ◽  
Evan S. Krystofiak ◽  
Alejandra Leo-Macias ◽  
Runjia Cui ◽  
Antonio Sesso ◽  
...  
Keyword(s):  
Intravital Microscopy ◽  
Network Architecture ◽  
Liquid Crystalline ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Gastrointestinal Diseases ◽  
Size Exclusion ◽  
Primary Host ◽  
Single Plane ◽  
Freeze Etching

AbstractThe glycocalyx is a highly hydrated, glycoprotein-rich coat shrouding many eukaryotic and prokaryotic cells. The intestinal epithelial glycocalyx, comprising glycosylated transmembrane mucins, is part of the primary host-microbe interface and is essential for nutrient absorption. Its disruption has been implicated in numerous gastrointestinal diseases. Yet, due to challenges in preserving and visualizing its native organization, glycocalyx structure-function relationships remain unclear. Here, we characterize the nanoarchitecture of the murine enteric glycocalyx using freeze-etching and electron tomography. Micrometer-long mucin filaments emerge from microvillar-tips and, through zigzagged lateral interactions form a three-dimensional columnar network with a 30 nm mesh. Filament-termini converge into globular structures ~30 nm apart that are liquid-crystalline packed within a single plane. Finally, we assess glycocalyx deformability and porosity using intravital microscopy. We argue that the columnar network architecture and the liquid-crystalline packing of the filament termini allow the glycocalyx to function as a deformable size-exclusion filter of luminal contents.

Complex Liquid-Crystalline Superstructure of a π-Conjugated Oligothiophene

2007 ◽  
Vol 119 (41) ◽  
pp. 8002-8005 ◽  
Author(s):  
Marko Prehm ◽  
Günther Götz ◽  
Peter Bäuerle ◽  
Feng Liu ◽  
Xiangbing Zeng ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Complex Liquid

[5-(p-alkoxy)phenyl-10, 15, 20-tri-phenyl] porphyrin and their rare earth complex liquid crystalline

2007 ◽  
Vol 20 (4) ◽  
pp. 229-235 ◽  
Author(s):  
Miao Yu ◽  
Wen-yang Zhang ◽  
Yong Fan ◽  
Wen-ping Jian ◽  
Guo-fa Liu
Keyword(s):  
Rare Earth ◽  
Liquid Crystalline ◽  
Rare Earth Complex ◽  
Complex Liquid

scholarly journals Morphological peculiarities of DNA-protein complexes in dormant Escherichia coli cells, subjected to prolonged starvation Condensation of DNA in dormant cells of Escherichia coli

2020 ◽  
Author(s):  
Natalia Loiko ◽  
Yana Danilova ◽  
Andrey Moiseenko ◽  
Vladislav Kovalenko ◽  
Ksenia Tereshkina ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Liquid Crystalline ◽  
Environmental Changes ◽  
Electron Tomography ◽  
Protein Complexes ◽  
Bacterial Cells ◽  
Ordered Structures ◽  
Extreme Stress ◽  
Different Types ◽  
Dps Protein

AbstractOne of the adaptive strategies for the constantly changing conditions of the environment utilized in bacterial cells involves the condensation of DNA in complex with the DNA-binding protein, Dps. With the use of electron microscopy and electron tomography, we observed several morphologically different types of DNA condensation in dormant Escherichia coli cells, namely: nanocrystalline, liquid crystalline, and the folded nucleosome-like. We confirmed the presence of both Dps and DNA in all of the ordered structures using EDX analysis. The comparison of EDX spectra obtained for the three different ordered structures revealed that in nanocrystalline formation the majority of Dps protein is tightly bound to nucleoid DNA. We demonstrated that the population of the dormant cell is structurally heterogeneous, which allows cells to respond flexibly to environmental changes. It increases the ability of the whole bacterial population to survive under extreme stress conditions.

scholarly journals Liquid-crystalline lipid phase transitions in lipid droplets selectively remodel the LD proteome

2021 ◽  
Author(s):  
Sean Rogers ◽  
Long Gui ◽  
Anastasiia Kovalenko ◽  
Evan Reetz ◽  
Daniela Nicastro ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Lipid Droplets ◽  
Liquid Crystalline ◽  
Electron Tomography ◽  
Organelle Transport ◽  
Lipid Phase ◽  
Sterol Esters ◽  
Lipid Phase Transitions ◽  
Liquid Crystalline Phases ◽  
Glucose Restriction

Lipid droplets (LDs) are reservoirs for triglycerides (TGs) and sterol-esters (SEs). How lipids are organized within LDs and influence the LD proteome remains unclear. Using in situ cryo-electron tomography, we show that glucose restriction triggers lipid phase transitions within LDs generating liquid-crystalline lattices inside them. Mechanistically, this requires TG lipolysis, which alters LD neutral lipid composition and promotes SE transition to a liquid-crystalline phase. Fluorescence imaging and proteomics further reveal that LD liquid-crystalline lattices selectively remodel the LD proteome. Some canonical LD proteins including Erg6 re-localize to the ER network, whereas others remain on LDs. Model peptide LiveDrop also redistributes from LDs to the ER, suggesting liquid-crystalline-phases influence ER-LD inter-organelle transport. Proteomics also indicates glucose restriction elevates peroxisome lipid oxidation, suggesting TG mobilization provides fatty acids for cellular energetics. This suggests glucose restriction drives TG mobilization, which alters the phase properties of LD lipids and selectively remodels the LD proteome.

Complex Liquid-Crystalline Superstructure of a π-Conjugated Oligothiophene

2007 ◽  
Vol 46 (41) ◽  
pp. 7856-7859 ◽  
Author(s):  
Marko Prehm ◽  
Günther Götz ◽  
Peter Bäuerle ◽  
Feng Liu ◽  
Xiangbing Zeng ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Complex Liquid

scholarly journals Multi‐Photon 4D Printing of Complex Liquid Crystalline Microstructures by In Situ Alignment Using Electric Fields

2021 ◽  
pp. 2100944
Author(s):  
Alexander Münchinger ◽  
Vincent Hahn ◽  
Dominik Beutel ◽  
Simon Woska ◽  
Joël Monti ◽  
...  
Keyword(s):  
Electric Fields ◽  
Liquid Crystalline ◽  
4D Printing ◽  
Complex Liquid

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

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