scholarly journals Raman microscopy-based quantification of the physical properties of intracellular lipids

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Masaaki Uematsu ◽  
Takao Shimizu
Keyword(s):  
Physical Properties ◽  
Plasma Membranes ◽  
Raman Microscopy ◽  
Traditional Role ◽  
Intracellular Lipids ◽  
Treatment Conditions ◽  
Novel Approach ◽  
Lipid Species ◽  
Storage Organelle ◽  
Lipid Environment

AbstractThe physical properties of lipids, such as viscosity, are homeostatically maintained in cells and are intimately involved in physiological roles. Measurement of the physical properties of plasma membranes has been achieved primarily through chemical or genetically encoded fluorescent probes. However, since most probes target plasma membranes, physical properties of lipids in intracellular organelles, including lipid droplets (LDs) are yet to be analyzed. Here, we present a novel Raman microscopy-based approach for quantifying the physical properties of intracellular lipids under deuterium-labeled fatty acid treatment conditions. Focusing on the fact that Raman spectra of carbon-deuterium vibration are altered depending on the surrounding lipid species, we quantitatively represented the physical properties of lipids as the gauche/trans conformational ratio of the introduced labeled fatty acids, which can be used as an indicator of viscosity. Intracellular Raman imaging revealed that the gauche/trans ratio of cytosolic regions was robustly preserved against perturbations attempting to alter the lipid composition. This was likely due to LDs functioning as a buffer against excess gauche/trans ratio, beyond its traditional role as an energy storage organelle. Our novel approach enables the observation of the physical properties of organelle lipids, which is difficult to perform with conventional probes, and is useful for quantitative assessment of the subcellular lipid environment.

scholarly journals Raman microscopy-based quantification of the physical properties of intracellular lipids

2020 ◽  
Author(s):  
Masaaki Uematsu ◽  
Takao Shimizu ◽  
Hideo Shindou
Keyword(s):  
Physical Properties ◽  
Plasma Membranes ◽  
Raman Microscopy ◽  
The Novel ◽  
Intracellular Lipids ◽  
Treatment Conditions ◽  
Novel Approach ◽  
Lipid Species ◽  
Target Plasma ◽  
Intracellular Organelles

ABSTRACTThe physical properties of lipids, such as viscosity, are homeostatically maintained in cells, and are intimately involved in physiological roles. Measurement of the physical properties of plasma membranes has been achieved primarily through chemical or genetically encoded fluorescent probes, however, the effect of the probes themselves on these physical properties hampered accurate measurements. In addition, as most probes target plasma membranes, physical properties of lipids in intracellular organelles, including lipid droplets (LDs) are yet to be analyzed. Here, we present a novel Raman microscopy-based approach for quantifying the intracellular physical properties of lipids under deuterium-labeled fatty acid treatment conditions. Focusing on the fact that Raman spectra of carbon-deuterium vibration are altered depending on the surrounding lipid species, we quantitatively represented the physical properties of lipids as the gauche/trans conformational ratio of the introduced labeled fatty acids, which can be used as an indicator of viscosity. Intracellular Raman imaging revealed that the gauche/trans ratio of cytosolic regions was robustly preserved against stimuli attempting to alter the lipid composition. This was likely due to LDs functioning as a buffer against excess gauche/trans ratio. The novel approach, that is, using the target lipid itself as a probe, overcomes the issues presented by conventional probes, making it useful for the quantitative evaluation of biological functions and regulatory mechanisms associated with the physical state of intracellular lipid environments.

Magnetic-field-induced self-assembly of FeCo/CoFe2O4 core/shell nanoparticles with tunable collective magnetic properties

Nanoscale ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 4519-4529
Author(s):  
J. Mohapatra ◽  
J. Elkins ◽  
M. Xing ◽  
D. Guragain ◽  
Sanjay R. Mishra ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Physical Properties ◽  
Self Assembly ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Novel Approach ◽  
Core Shell Nanoparticles

Self-assembly of nanoparticles into ordered patterns is a novel approach to build up new consolidated materials with desired collective physical properties.

scholarly journals LION/web: a web-based ontology enrichment tool for lipidomic data analysis

GigaScience ◽  
2019 ◽  
Vol 8 (6) ◽  
Author(s):  
Martijn R Molenaar ◽  
Aike Jeucken ◽  
Tsjerk A Wassenaar ◽  
Chris H A van de Lest ◽  
Jos F Brouwers ◽  
...  
Keyword(s):  
Membrane Fluidity ◽  
Plasma Membranes ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Lateral Diffusion ◽  
Decanoic Acid ◽  
Web Based ◽  
Ovary Cells ◽  
Lipid Species ◽  
Significant Enrichment

Abstract Background A major challenge for lipidomic analyses is the handling of the large amounts of data and the translation of results to interpret the involvement of lipids in biological systems. Results We built a new lipid ontology (LION) that associates >50,000 lipid species to biophysical, chemical, and cell biological features. By making use of enrichment algorithms, we used LION to develop a web-based interface (LION/web, www.lipidontology.com) that allows identification of lipid-associated terms in lipidomes. LION/web was validated by analyzing a lipidomic dataset derived from well-characterized sub-cellular fractions of RAW 264.7 macrophages. Comparison of isolated plasma membranes with the microsomal fraction showed a significant enrichment of relevant LION-terms including “plasma membrane", “headgroup with negative charge", "glycerophosphoserines", “above average bilayer thickness", and “below average lateral diffusion". A second validation was performed by analyzing the membrane fluidity of Chinese hamster ovary cells incubated with arachidonic acid. An increase in membrane fluidity was observed both experimentally by using pyrene decanoic acid and by using LION/web, showing significant enrichment of terms associated with high membrane fluidity ("above average", "very high", and "high lateral diffusion" and "below average transition temperature"). Conclusions The results demonstrate the functionality of LION/web, which is freely accessible in a platform-independent way.

scholarly journals Lipid-protein interactions are unique fingerprints for membrane proteins

2017 ◽  
Author(s):  
Valentina Corradi ◽  
Eduardo Mendez-Villuendas ◽  
Helgi I. Ingólfsson ◽  
Ruo-Xu Gu ◽  
Iwona Siuda ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Protein Interactions ◽  
Cell Membranes ◽  
Spatiotemporal Resolution ◽  
Lipid Dynamics ◽  
Lipid Species ◽  
Lipid Environment ◽  
Lipid Protein Interactions ◽  
Dynamics Simulations ◽  
Asymmetrically Distributed

ABSTRACTCell membranes contain hundreds of different proteins and lipids in an asymmetric arrangement. Understanding the lateral organization principles of these complex mixtures is essential for life and health. However, our current understanding of the detailed organization of cell membranes remains rather elusive, owing to the lack of experimental methods suitable for studying these fluctuating nanoscale assemblies of lipids and proteins with the required spatiotemporal resolution. Here, we use molecular dynamics simulations to characterize the lipid environment of ten membrane proteins. To provide a realistic lipid environment, the proteins are embedded in a model plasma membrane, where more than 60 lipid species are represented, asymmetrically distributed between leaflets. The simulations detail how each protein modulates its local lipid environment through local lipid composition, thickness, curvature and lipid dynamics. Our results provide a molecular glimpse of the complexity of lipid-protein interactions, with potentially far reaching implications for the overall organization of the cell membrane.

scholarly journals Phenobarbital selectively modulates the glucagon-stimulated activity of adenylate cyclase by depressing the lipid phase separation occurring in the outer half of the bilayer of liver plasma membranes

1981 ◽  
Vol 197 (3) ◽  
pp. 675-681 ◽  
Author(s):  
M D Houslay ◽  
I Dipple ◽  
L M Gordon
Keyword(s):  
Adenylate Cyclase ◽  
Spin Probe ◽  
Plasma Membranes ◽  
Chemical Constituents ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Arrhenius Plots ◽  
Lipid Environment ◽  
Lipid Phase Separation ◽  
Outer Half

The glucagon-stimulated (coupled) activity of rat liver plasma-membrane adenylate cyclase could be selectively modulated by the anionic drug phenobarbital, whereas the fluoride-stimulated (uncoupled) activity remained unaffected. It is suggested that the cationic drug phenobarbital preferentially interacts with the external half of the bilayer, as the negatively charged phospholipids are found at the cytosol-facing side. This results in a selective fluidization of the external half of the bilayer, leading to a depression in the high-temperature onset of the lipid phase transition (from 28 degree to 16 degree C) occurring there. This was detected both by e.s.r. analysis, using a fatty acid spin probe, and also by Arrhenius plots of glucagon-stimulated activity, where the enzyme forms a transmembrane complex with the receptor and is sensitive to the lipid environment of both halves of the bilayer. However, in the absence of hormone, adenylate cyclase only senses the lipid environment of the inner (cytosol) half of the bilayer. Thus its fluoride stimulated activity and Arrhenius plots of this activity remained unaffected by the presence of phenobarbital (less than 12 mM) in the assay. These results support the view that independent modulation of the fluidity or chemical constituents of each half of the bilayer can selectively affect the receptor-coupled and uncoupled activities of adenylate cyclase.

INTERACTIVE REGISTRATION OF INTRACELLULAR VOLUMES WITH RADIAL BASIS FUNCTIONS

2010 ◽  
Vol 09 (03) ◽  
pp. 207-224 ◽  
Author(s):  
SHIN YOSHIZAWA ◽  
SATOKO TAKEMOTO ◽  
MIWA TAKAHASHI ◽  
MAKOTO MUROI ◽  
SAYAKA KAZAMI ◽  
...  
Keyword(s):  
Image Registration ◽  
Radial Basis Functions ◽  
Plasma Membranes ◽  
Mapping Function ◽  
Basis Functions ◽  
Cell Geometry ◽  
Registration System ◽  
Barycentric Interpolation ◽  
Novel Approach ◽  
Radial Basis

We propose a novel approach to 3D image registration of intracellular volumes. The approach extends a standard image registration framework to the curved cell geometry. An intracellular volume is mapped onto another intracellular domain by using two pairs of point set surfaces approximating their nuclear and plasma membranes. The mapping function consists of the affine transformation, tetrahedral barycentric interpolation, and least-squares formulation of radial basis functions for extracted cell geometry features. An interactive volume registration system is also developed based on our approach. We demonstrate that our approach is capable of creating cell models containing multiple organelles from observed data of living cells.

Fabrication and physical properties of self-assembled ultralong polymer/small molecule hybrid microstructures

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25550-25554 ◽  
Author(s):  
Jing Zhang ◽  
Chengyuan Wang ◽  
Wangqiao Chen ◽  
Jiansheng Wu ◽  
Qichun Zhang
Keyword(s):  
Physical Properties ◽  
Small Molecule ◽  
Novel Approach ◽  
Self Assembled

The present work showed a novel approach to fabricate polymer/small molecule hybrid microstructures, and the transport characteristics and morphologies of the as-fabricated wires with different ratios of the two different components.

scholarly journals Relationship between lipoproteins, thrombosis, and atrial fibrillation

2021 ◽  
Author(s):  
Wern Yew Ding ◽  
Majd B Protty ◽  
Ian G Davies ◽  
Gregory Y H Lip
Keyword(s):  
Atrial Fibrillation ◽  
Low Density Lipoprotein ◽  
Blood Stasis ◽  
Density Lipoprotein ◽  
Potential Contribution ◽  
Low Density ◽  
Traditional Role ◽  
Lipid Species ◽  
Structural Abnormalities ◽  
Myocardial Membranes

Abstract The prothrombotic state in atrial fibrillation (AF) occurs as a result of multifaceted interactions, known as Virchow’s triad of hypercoagulability, structural abnormalities, and blood stasis. More recently, there is emerging evidence that lipoproteins are implicated in this process, beyond their traditional role in atherosclerosis. In this review, we provide an overview of the various lipoproteins and explore the association between lipoproteins and AF, the effects of lipoproteins on haemostasis, and the potential contribution of lipoproteins to thrombogenesis in AF. There are several types of lipoproteins based on size, lipid composition, and apolipoprotein category, namely: chylomicrons, very low-density lipoprotein, low-density lipoprotein (LDL), intermediate-density lipoprotein, and high-density lipoprotein. Each of these lipoproteins may contain numerous lipid species and proteins with a variety of different functions. Furthermore, the lipoprotein particles may be oxidized causing an alteration in their structure and content. Of note, there is a paradoxical inverse relationship between total cholesterol and LDL cholesterol (LDL-C) levels, and incident AF. The mechanism by which this occurs may be related to the stabilizing effect of cholesterol on myocardial membranes, along with its role in inflammation. Overall, specific lipoproteins may interact with haemostatic pathways to promote excess platelet activation and thrombin generation, as well as inhibiting fibrinolysis. In this regard, LDL-C has been shown to be an independent risk factor for thromboembolic events in AF. The complex relationship between lipoproteins, thrombosis and AF warrants further research with an aim to improve our knowledge base and contribute to our overall understanding of lipoprotein-mediated thrombosis.

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