Lateral diffusion in synthetic membranes: models and experiments on protein influence

1991 ◽  
Vol 87 (13) ◽  
pp. 2039 ◽  
Author(s):  
Francis Baros ◽  
Abderrahim Naoumi ◽  
Marie-Laure Viriot ◽  
Jean-Claude Andre
Keyword(s):  
Lateral Diffusion ◽  
Synthetic Membranes

scholarly journals Mapping bilayer thickness in the ER membrane

2020 ◽  
Vol 6 (46) ◽  
pp. eaba5130 ◽  
Author(s):  
Rupali Prasad ◽  
Andrzej Sliwa-Gonzalez ◽  
Yves Barral
Keyword(s):  
Cleavage Plane ◽  
Lateral Diffusion ◽  
Physical Nature ◽  
Diffusion Barriers ◽  
Bilayer Thickness ◽  
Synthetic Membranes ◽  
Fluorescent Reporters ◽  
Discrete Domains ◽  
Lateral Organization ◽  
Er Membrane

In the plasma membrane and in synthetic membranes, resident lipids may laterally unmix to form domains of distinct biophysical properties. Whether lipids also drive the lateral organization of intracellular membranes is largely unknown. Here, we describe genetically encoded fluorescent reporters visualizing local variations in bilayer thickness. Using them, we demonstrate that long-chained ceramides promote the formation of discrete domains of increased bilayer thickness in the yeast ER, particularly in the future plane of cleavage and at ER–trans-Golgi contact sites. Thickening of the ER membrane in the cleavage plane contributed to the formation of lateral diffusion barriers, which restricted the passage of short, but not long, protein transmembrane domains between the mother and bud ER compartments. Together, our data establish that the ER membrane is laterally organized and that ceramides drive this process, and provide insights into the physical nature and biophysical mechanisms of the lateral diffusion barriers that compartmentalize the ER.

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

scholarly journals A Comprehensive Review of Polymeric Wastewater Purification Membranes

2021 ◽  
Vol 5 (6) ◽  
pp. 162
Author(s):  
Rasmeet Singh ◽  
Mandeep Singh ◽  
Nisha Kumari ◽  
Janak ◽  
Sthitapragyan Maharana ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pore Formation ◽  
Inorganic Materials ◽  
Special Focus ◽  
Nanocomposite Membranes ◽  
Wastewater Purification ◽  
Comprehensive Review ◽  
Synthetic Membranes ◽  
Purification Membranes ◽  
Thermal And Chemical Stability

Synthetic membranes are currently employed for multiple separation applications in various industries. They may have been prepared from organic or inorganic materials. Present research majorly focuses on polymeric (i.e., organic) membranes because they show better flexibility, pore formation mechanism, and thermal and chemical stability, and demand less area for installation. Dendritic, carbon nanotube, graphene and graphene oxide, metal and metal oxide, zwitter-ionic, and zeolite-based membranes are among the most promised water treatment membranes. This paper critically reviews the ongoing developments to utilize nanocomposite membranes to purify water. Various membranes have been reported to study their resistance and fouling properties. A special focus is given towards multiple ways in which these nanocomposite membranes can be employed. Therefore, this review provides a platform to develop the awareness of current research and motivate its readers to make further progress for utilizing nanocomposite membranes in water purification.

scholarly journals Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 194
Author(s):  
Maxime Bouschet ◽  
Ulises Zavala-Moran ◽  
Vignesh Arounassalame ◽  
Rodolphe Alchaar ◽  
Clara Bataillon ◽  
...  
Keyword(s):  
Dark Current ◽  
Infrared Imaging ◽  
Diffusion Length ◽  
Lateral Diffusion ◽  
Pixel Detector ◽  
Dark Current Density ◽  
Etching Depth ◽  
Photo Response ◽  
Wet Chemical ◽  
Absorbing Layer

In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

Lateral Mobility of Integrin αIIbβ3 (Glycoprotein IIb/IIIa) in the Plasma Membrane of a Human Megakaryocyte

1997 ◽  
Vol 77 (01) ◽  
pp. 143-149 ◽  
Author(s):  
Annelies Schootemeijer ◽  
Gijsbert van Willigen ◽  
Hans van der Vuurst ◽  
Leon G J Tertoolen ◽  
Siegfried W De Laat ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fluorescence Recovery After Photobleaching ◽  
Cell Activation ◽  
Lateral Diffusion ◽  
Cytochalasin D ◽  
Lag Phase ◽  
Integrin Αiibβ3 ◽  
Cell Matrix ◽  
Cytoplasmic Actin ◽  
Mobile Fraction

SummaryThe migration of integrins to sites of cell-cell and cell-matrix contact is thought to be important for adhesion strengthening. We studied the lateral diffusion of integrin αIIbβ3 (glycoprotein Ilb/IIIa) in the plasma membrane of a cultured human megakaryocyte by fluorescence recovery after photobleaching of FITC-labelled monovalent Fab fragments directed against the P3 subunit. The diffusion of P3 on the unstimulated megakaryocyte showed a lateral diffusion coefficient (D) of 0.37 X10'9 cm2/s and a mobile fraction of about 50%. Stimulation with ADP (20 μM) or α-thrombin (10 U/ml) at 22° C induced transient decreases in both parameters reducing D to 0.21 X 10‘9 cm2/s and the mobile fraction to about 25%. The fall in D was observed within 1 min after stimulation but the fall in mobile fraction showed a lag phase of 5 min. The lag phase was absent in the presence of Calpain I inhibitor, whereas cytochalasin D completely abolished the decrease in mobile fraction. The data are compatible with the concept that cell activation induces anchorage of 50% of the mobile αIIbβ3 (25% of the whole population of receptor) to the cytoplasmic actin filaments, although, as discussed, other rationals are not ruled out.

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.

Clinical manifestations of VX poisoning following percutaneous exposure in the domestic white pig

2003 ◽  
Vol 22 (5) ◽  
pp. 255-261 ◽  
Author(s):  
R P Chilcott ◽  
C H Dalton ◽  
I Hill ◽  
C M Davidson ◽  
K L Blohm ◽  
...  
Keyword(s):  
Glucose Utilization ◽  
Clinical Manifestations ◽  
Lateral Diffusion ◽  
Nerve Agents ◽  
Application Site ◽  
Rodent Models ◽  
Skin Model ◽  
Exposed Skin ◽  
Percutaneous Exposure ◽  
Qualitative Relationship

Nerve agents are a class of organophosphorus chemicals that inhibit certain cholinesterase enzymes (ChE). If untreated, percutaneous exposure to nerve agents, such as VX (O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate) can cause paralysis, apnoea and death. Much of the information concerning the percutaneous absorption and subsequent toxicity of nerve agents has been obtained using various rodent models. However, the most relevant ‘skin model’ is arguably the pig. Therefore, the purpose of this study was to examine the clinical manifestations of VX intoxication in the domestic white pig following a 2 LD50 (120 mg/kg) percutaneous challenge. There was a consistent onset of signs (where present) in each animal: mastication was followed by miosis, salivation, fasciculations and apnoea. Whilst ChE activity did not correlate with the onset of signs, there was a qualitative relationship in that mastication preceded substantial ChE inhibition, miosis lagged behind the linear decrease in acetylcholinesterase (AChE) activity and fasciculations and apnoea occurred after maximum ChE inhibition had been attained (5 / 10% of normal). These observations may be of use for the triage of patients exposed to VX. In comparison with similar studies with GD, VX did not affect glucose utilization. However, VX was similar to GD in that it caused a mild hyperkalaemia and hyperphosphataemia, although the significance of this observation was not clear. There was substantial lateral diffusion of the initial droplet of VX over the application site, indicating that, when decontaminating exposed skin, attention should also be directed to areas peripheral to the original site of exposure.

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