scholarly journals Structural features underlying recognition and translocation of extracellular polysaccharides

2019 ◽  
Vol 9 (2) ◽  
pp. 20180060 ◽  
Author(s):  
Jochen Zimmer
Keyword(s):  
Energy Source ◽  
Chemical Composition ◽  
Cell Surface ◽  
Cell Attachment ◽  
Structural Features ◽  
Living Systems ◽  
Extracellular Polysaccharides ◽  
Transport Mechanisms ◽  
Complex Carbohydrates ◽  
Insoluble Polymers

Essentially all living systems produce complex carbohydrates as an energy source, structural component, protective coat or adhesive for cell attachment. Many polysaccharides are displayed on the cell surface or are threaded through proteinaceous tunnels for degradation. Dictated by their chemical composition and mode of polymerization, the physical properties of complex carbohydrates differ substantially, from amphipathic water-insoluble polymers to highly hydrated hydrogel-forming macromolecules. Accordingly, diverse recognition and translocation mechanisms evolved to transport polysaccharides to their final destinations. This review will summarize and compare diverse polysaccharide transport mechanisms implicated in the biosynthesis and degradation of cell surface polymers in pro- and eukaryotes.

Structural features and strength behavior of TRIP/TWIP steels

2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Thermomechanical Processing ◽  
Maximum Load ◽  
Structural Features ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Structural And Functional Properties ◽  
Twip Steels ◽  
The Creation

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.

scholarly journals Identification of a novel cell attachment domain in the HIV-1 Tat protein and its 90-kDa cell surface binding protein.

1993 ◽  
Vol 268 (7) ◽  
pp. 5279-5284
Author(s):  
B.S. Weeks ◽  
K. Desai ◽  
P.M. Loewenstein ◽  
M.E. Klotman ◽  
P.E. Klotman ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Attachment ◽  
Binding Protein ◽  
Tat Protein ◽  
Surface Binding ◽  
Cell Surface Binding ◽  
Hiv 1

scholarly journals The VP5 Domain of VP4 Can Mediate Attachment of Rotaviruses to Cells

2000 ◽  
Vol 74 (2) ◽  
pp. 593-599 ◽  
Author(s):  
Selene Zárate ◽  
Rafaela Espinosa ◽  
Pedro Romero ◽  
Ernesto Méndez ◽  
Carlos F. Arias ◽  
...  
Keyword(s):  
Cell Surface ◽  
Binding Assay ◽  
Cell Attachment ◽  
Wild Type ◽  
Binding Assays ◽  
Virus Binding ◽  
Binding Characteristics ◽  
Surface Receptors ◽  
Infectivity Assay ◽  
Fusion Products

ABSTRACT Some animal rotaviruses require the presence of sialic acid (SA) on the cell surface to infect the cell. We have isolated variants of rhesus rotavirus (RRV) whose infectivity no longer depends on SA. Both the SA-dependent and -independent interactions of these viruses with the cell are mediated by the virus spike protein VP4, which is cleaved by trypsin into two domains, VP5 and VP8. In this work we have compared the binding characteristics of wild-type RRV and its variant nar3 to MA104 cells. In a direct nonradioactive binding assay, both viruses bound to the cells in a saturable and specific manner. When neutralizing monoclonal antibodies directed to both the VP8 and VP5 domains of VP4 were used to block virus binding, antibodies to VP8 blocked the cell attachment of wild-type RRV but not that of the variant nar3. Conversely, an antibody to VP5 inhibited the binding of nar3 but not that of RRV. These results suggest that while RRV binds to the cell through VP8, the variant does so through the VP5 domain of VP4. This observation was further sustained by the fact that recombinant VP8 and VP5 proteins, produced in bacteria as fusion products with glutathione S-transferase, were found to bind to MA104 cells in a specific and saturable manner and, when preincubated with the cell, were capable of inhibiting the binding of wild-type and variant viruses, respectively. In addition, the VP5 and VP8 recombinant proteins inhibited the infectivity of nar3 and RRV, respectively, confirming the results obtained in the binding assays. Interestingly, when the infectivity assay was performed on neuraminidase-treated cells, the VP5 fusion protein was also found to inhibit the infectivity of RRV, suggesting that RRV could bind to the cell through two sequential steps mediated by the interaction of VP8 and VP5 with SA-containing and SA-independent cell surface receptors, respectively.

scholarly journals Preparation of Sticky Escherichia coli through Surface Display of an Adhesive Catecholamine Moiety

2013 ◽  
Vol 80 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Joseph P. Park ◽  
Min-Jung Choi ◽  
Se Hun Kim ◽  
Seung Hwan Lee ◽  
Haeshin Lee
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Communication Systems ◽  
Cell Attachment ◽  
Surface Display ◽  
Content Type ◽  
E Coli ◽  
Material Surfaces ◽  
Mussel Adhesive ◽  
Adhesive Proteins

ABSTRACTMussels attach to virtually all types of inorganic and organic surfaces in aqueous environments, and catecholamines composed of 3,4-dihydroxy-l-phenylalanine (DOPA), lysine, and histidine in mussel adhesive proteins play a key role in the robust adhesion. DOPA is an unusual catecholic amino acid, and its side chain is called catechol. In this study, we displayed the adhesive moiety of DOPA-histidine onEscherichia colisurfaces using outer membrane protein W as an anchoring motif for the first time. Localization of catecholamines on the cell surface was confirmed by Western blot and immunofluorescence microscopy. Furthermore, cell-to-cell cohesion (i.e., cellular aggregation) induced by the displayed catecholamine and synthesis of gold nanoparticles on the cell surface support functional display of adhesive catecholamines. The engineeredE. coliexhibited significant adhesion onto various material surfaces, including silica and glass microparticles, gold, titanium, silicon, poly(ethylene terephthalate), poly(urethane), and poly(dimethylsiloxane). The uniqueness of this approach utilizing the engineered stickyE. coliis that no chemistry for cell attachment are necessary, and the ability of spontaneousE. coliattachment allows one to immobilize the cells on challenging material surfaces such as synthetic polymers. Therefore, we envision that mussel-inspired catecholamine yielded stickyE. colithat can be used as a new type of engineered microbe for various emerging fields, such as whole living cell attachment on versatile material surfaces, cell-to-cell communication systems, and many others.

scholarly journals Optimization of Magnetic Properties of Magnetic Microwires by Post-Processing

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1006
Author(s):  
Valentina Zhukova ◽  
Paula Corte-Leon ◽  
Lorena González-Legarreta ◽  
Ahmed Talaat ◽  
Juan Maria Blanco ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Chemical Composition ◽  
Hysteresis Loops ◽  
Structural Features ◽  
Post Processing ◽  
Soft Magnetic ◽  
Magnetic Microwires ◽  
Prepared State ◽  
Induced Magnetic Anisotropy ◽  
Selection Of

The influence of post-processing conditions on the magnetic properties of amorphous and nanocrystalline microwires has been thoroughly analyzed, paying attention to the influence of magnetoelastic, induced and magnetocrystalline anisotropies on the hysteresis loops of Fe-, Ni-, and Co-rich microwires. We showed that magnetic properties of glass-coated microwires can be tuned by the selection of appropriate chemical composition and geometry in as-prepared state or further considerably modified by appropriate post-processing, which consists of either annealing or glass-coated removal. Furthermore, stress-annealing or Joule heating can further effectively modify the magnetic properties of amorphous magnetic microwires owing to induced magnetic anisotropy. Devitrification of microwires can be useful for either magnetic softening or magnetic hardening of the microwires. Depending on the chemical composition of the metallic nucleus and on structural features (grain size, precipitating phases), nanocrystalline microwires can exhibit either soft magnetic properties or semi-hard magnetic properties. We demonstrated that the microwires with coercivities from 1 A/m to 40 kA/m can be prepared.

scholarly journals Variations in MHC class I antigen presentation and immunopeptidome selection pathways

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1177
Author(s):  
Anita J. Zaitouna ◽  
Amanpreet Kaur ◽  
Malini Raghavan
Keyword(s):  
Cell Surface ◽  
Antigen Presentation ◽  
Surface Expression ◽  
Structural Features ◽  
Class I ◽  
Cell Surface Expression ◽  
Immune Recognition ◽  
Antigen Receptors ◽  
Class I Mhc ◽  
Mhc I

Major histocompatibility class I (MHC-I) proteins mediate immunosurveillance against pathogens and cancers by presenting antigenic or mutated peptides to antigen receptors of CD8+ T cells and by engaging receptors of natural killer (NK) cells. In humans, MHC-I molecules are highly polymorphic. MHC-I variations permit the display of thousands of distinct peptides at the cell surface. Recent mass spectrometric studies have revealed unique and shared characteristics of the peptidomes of individual MHC-I variants. The cell surface expression of MHC-I–peptide complexes requires the functions of many intracellular assembly factors, including the transporter associated with antigen presentation (TAP), tapasin, calreticulin, ERp57, TAP-binding protein related (TAPBPR), endoplasmic reticulum aminopeptidases (ERAPs), and the proteasomes. Recent studies provide important insights into the structural features of these factors that govern MHC-I assembly as well as the mechanisms underlying peptide exchange. Conformational sensing of MHC-I molecules mediates the quality control of intracellular MHC-I assembly and contributes to immune recognition by CD8 at the cell surface. Recent studies also show that several MHC-I variants can follow unconventional assembly routes to the cell surface, conferring selective immune advantages that can be exploited for immunotherapy.

scholarly journals Structural Features of Ingots Made of Al-Cu-Li System Alloys Depending on its Chemical Composition

2016 ◽  
Author(s):  
Н.И. Колобнев ◽  
◽  
Е.Н. Рябова ◽  
Л.Б. Хохлатова ◽  
М.С. Оглодков ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Structural Features

scholarly journals Shared paramyxoviral glycoprotein architecture is adapted for diverse attachment strategies

2010 ◽  
Vol 38 (5) ◽  
pp. 1349-1355 ◽  
Author(s):  
Thomas A. Bowden ◽  
Max Crispin ◽  
E. Yvonne Jones ◽  
David I. Stuart
Keyword(s):  
Cell Surface ◽  
Viral Entry ◽  
Cell Attachment ◽  
Structural Information ◽  
Cell Receptor ◽  
Specific Protein ◽  
Cell Surface Receptors ◽  
Surface Receptors ◽  
Entry Inhibitors ◽  
Animal Pathogens

Members within the paramyxovirus subfamily Paramyxovirinae constitute a large number of highly virulent human and animal pathogens. The glycoproteins present on these viruses are responsible for mediating host cell attachment and fusion and are key targets for the design of antiviral entry inhibitors. In the present review, we discuss recent structural studies which have led to a better understanding of the various mechanisms by which different paramyxoviruses use their attachment glycoproteins to hijack specific protein and glycan cell-surface receptors to facilitate viral entry. It is observed that the paramyxovirus attachment glycoprotein consists of a conserved overall structure which includes an N-terminal six-bladed β-propeller domain which is responsible for cell receptor binding. Crystal structures of this domain from different biomedically important paramyxoviruses, including measles, Nipah, Hendra, Newcastle disease and parainfluenza viruses, alone and in complex with their functional cell-surface receptors, demonstrate three contrasting mechanisms of receptor engagement that paramyxoviruses have evolved to confer discreet protein- and glycan-receptor specificity. This structural information highlights the adaptability of the paramyxovirus attachment glycoprotein surface and the potential for the emergence of new and potentially harmful viruses in human hosts.

Fate and Transport of PPCPs in the Environment: A Review on Occurrences, Sources, and Cases

2019 ◽  
Vol 967 ◽  
pp. 179-188
Author(s):  
Mohamad Padri ◽  
Mohamed Sahrul Tamzil
Keyword(s):  
Chemical Composition ◽  
Human Health ◽  
Personal Care Products ◽  
Fate And Transport ◽  
General Information ◽  
Transport Mechanisms ◽  
Personal Care ◽  
Low Concentration ◽  
Broad Understanding

Pharmaceuticals and personal care products (PPCPs) in the environment have been intensively studied recently. These compounds can cause serious problem in environment. Intake of these compounds in low concentration can threat human health due to its reactivity and chemical composition. Occurrences of PPCPs in environments are important to recognize in order to draw broad understanding on which mitigation of PPCPs can be deliberated. This review provides general information about occurrence of PPCPs. Moreover, sources of PPCPs in the environment are comprehensively explained. The fate and transport mechanisms of PPCPs are summarized based on important studies of selected groups of PPCPs which conducted through years based on several previous study cases are mentioned and elaborated to pinpoint the existence of these pollutants. In the end, identification of the current research limitation and further recommendations are proposed for improving mitigation process and addressing further research.

scholarly journals Embryonic neural retinal cell response to extracellular matrix proteins: developmental changes and effects of the cell substratum attachment antibody (CSAT).

1987 ◽  
Vol 104 (3) ◽  
pp. 623-634 ◽  
Author(s):  
D E Hall ◽  
K M Neugebauer ◽  
L F Reichardt
Keyword(s):  
Extracellular Matrix ◽  
Cell Surface ◽  
Neurite Outgrowth ◽  
Cellular Response ◽  
Cell Attachment ◽  
Collagen Iv ◽  
Substrate Preference ◽  
Retinal Cell ◽  
Retinal Cells ◽  
Cell Surface Glycoprotein

Cell attachment and neurite outgrowth by embryonic neural retinal cells were measured in separate quantitative assays to define differences in substrate preference and to demonstrate developmentally regulated changes in cellular response to different extracellular matrix glycoproteins. Cells attached to laminin, fibronectin, and collagen IV in a concentration-dependent fashion, though fibronectin was less effective for attachment than the other two substrates. Neurite outgrowth was much more extensive on laminin than on fibronectin or collagen IV. These results suggest that different substrates have distinct effects on neuronal differentiation. Neural retinal cell attachment and neurite outgrowth were inhibited on all three substrates by two antibodies, cell substratum attachment antibody (CSAT) and JG22, which recognize a cell surface glycoprotein complex required for cell interactions with several extracellular matrix constituents. In addition, retinal cells grew neurites on substrates coated with the CSAT antibodies. These results suggest that cell surface molecules recognized by this antibody are directly involved in cell attachment and neurite extension. Neural retinal cells from embryos of different ages varied in their capacity to interact with extracellular matrix substrates. Cells of all ages, embryonic day 6 (E6) to E12, attached to collagen IV and CSAT antibody substrates. In contrast, cell attachment to laminin and fibronectin diminished with increasing embryonic age. Age-dependent differences were found in the profile of proteins precipitated by the CSAT antibody, raising the possibility that modifications of these proteins are responsible for the dramatic changes in substrate preference of retinal cells between E6 and E12.

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