Search results for "Microscopy"
showing 10 items of 3390 documents
Isoindolo[2,1-a]quinoxaline derivatives, novel potent antitumor agents with dual inhibition of tubulin polymerization and topoisomerase I.
2008
Isoindoloquinoxalines 4 and 5 were obtained by refluxing 2-(2'-aminoaryl)-1-cyanoisoindoles 3a- e in acetic or formic acid. All derivatives were screened by the National Cancer Institute (Bethesda, MD) for the in vitro one dose primary anticancer assay against a 3-cell line panel. Compounds 4a- e, screened against a panel of about 60 human tumor cell lines, showed remarkable antineoplastic activity; they had GI 50 values in the low micromolar or submicromolar range and reached, in the case of 4c, nanomolar concentrations on 88% of the 59 tested cell lines. Flow cytometric analysis of cell cycle after treatment with 4c demonstrated an arrest of the cell cycle in G2/M phase. This effect was a…
Revisiting Plant Plasma Membrane Lipids in Tobacco: A Focus on Sphingolipids
2016
International audience; The lipid composition of plasma membrane (PM) and the corresponding detergent-insoluble membrane (DIM) fraction were analyzed with a specific focus on highly polar sphingolipids, so-called glycosyl inositol phosphorylceramides (GIPCs). Using tobacco (Nicotiana tabacum) 'Bright Yellow 2' cell suspension and leaves, evidence is provided that GIPCs represent up to 40 mol % of the PM lipids. Comparative analysis of DIMs with the PM showed an enrichment of 2-hydroxylated very-long-chain fatty acid-containing GIPCs and polyglycosylated GIPCs in the DIMs. Purified antibodies raised against these GIPCs were further used for immunogold-electron microscopy strategy, revealing …
A novel rat CVB1-VP1 monoclonal antibody 3A6 detects a broad range of enteroviruses
2018
AbstractEnteroviruses (EVs) are common RNA viruses that cause diseases ranging from rash to paralytic poliomyelitis. For example, EV-A and EV-C viruses cause hand-foot and mouth disease and EV-B viruses cause encephalitis and myocarditis, which can result in severe morbidity and mortality. While new vaccines and treatments for EVs are under development, methods for studying and diagnosing EV infections are still limited and therefore new diagnostic tools are required. Our aim was to produce and characterize new antibodies that work in multiple applications and detect EVs in tissues and in vitro. Rats were immunized with Coxsackievirus B1 capsid protein VP1 and hybridomas were produced. Hybr…
Molecular architecture and activation of the insecticidal protein Vip3Aa from Bacillus thuringiensis
2020
9 p.-5 fig.
Effect of cholesterol on the physical properties of pulmonary surfactant films: Atomic force measurements study
2006
International audience; Atomic force measurements were performed on supported pulmonary surfactant (PS) films to address the effect of cholesterol on the physical properties of lung surfactant films. We recently found that cholesterol in excess of a physiological proportion abolishes surfactant function, and is the reason that surfactant fails to lower the surface tension upon compression. In this study, we investigated how the loss of mechanical stability observed earlier is related to the local mechanical properties of the film by local force measurements. The presence of 20% of cholesterol in bovine lipid extract surfactant (BLES) resulted in a decrease of the observed adhesive interacti…
The route to protein aggregate superstructures: Particulates and amyloid-like spherulites.
2015
AbstractDepending on external conditions, native proteins may change their structure and undergo different association routes leading to a large scale polymorphism of the aggregates. This feature has been widely observed but is not fully understood yet. This review focuses on morphologies, physico-chemical properties and mechanisms of formation of amyloid structures and protein superstructures. In particular, the main focus will be on protein particulates and amyloid-like spherulites, briefly summarizing possible experimental methods of analysis. Moreover, we will highlight the role of protein conformational changes and dominant forces in driving association together with their connection w…
Fractal-related assembly of the axial filament in the demosponge Suberites domuncula: relevance to biomineralization and the formation of biogenic si…
2007
Abstract The siliceous spicules of sponges (Porifera) show great variations of sizes, shapes and forms; they constitute the chief supporting framework of these animals; these skeletal elements are synthesized enzymatically by silicatein. Each sponge species synthesizes at least two silicateins, which are termed − α and − β . In the present study, using the demosponge Suberites domuncula , we studied if the silicateins of the axial filament contribute to the shape formation of the spicules. For these experiments native silicateins have been isolated by a new Tris/glycerol extraction procedure. Silicateins isolated by this procedure are monomeric (24 kDa), but readily form dimers through non-…
Design and construction of highly stable, protease-resistant chimeric avidins.
2005
The chicken avidin gene family consists of avidin and seven separate avidin-related genes (AVRs) 1-7. Avidin protein is a widely used biochemical tool, whereas the other family members have only recently been produced as recombinant proteins and characterized. In our previous study, AVR4 was found to be the most stable biotin binding protein thus far characterized (T(m) = 106.4 degrees C). In this study, we studied further the biotin-binding properties of AVR4. A decrease in the energy barrier between the biotin-bound and unbound state of AVR4 was observed when compared with that of avidin. The high resolution structure of AVR4 facilitated comparison of the structural details of avidin and …
Morphology of hybrid polystyrene-block-poly(ethylene oxide) micelles: Analytical ultracentrifugation and SANS studies
2006
Abstract Morphology and structure of aqueous block copolymer solutions based on polystyrene- block -poly(ethylene oxide) (PS- b -PEO) of two different compositions, a cationic surfactant, cetyl pyridinium chloride (CPC), and either platinic acid (H 2 PtCl 6 ⋅6H 2 O) or Pt nanoparticles were studied using a combination of analytical ultracentrifugation (AUC), transmission electron microscopy (TEM), and small angle neutron scattering (SANS). These studies combining methods contributing supplemental and analogous structural information allowed us to comprehensively characterize the complex hybrid systems and to discover an isotope effect when H 2 O was replaced with D 2 O. In particular, TEM s…
Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes
2015
Contains fulltext : 153827.pdf (Publisher’s version ) (Open Access) Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based s…