Search results for "Biophysic"
showing 10 items of 3565 documents
Fishing for G-quadruplexes in solution with a perylene diimide derivative labeled with biotins
2018
A new fluorescent, non‐cytotoxic perylene diimide derivative with two biotins at the peri position, PDI2B, has been synthesized. This molecule is able to interact selectively with G‐quadruplexes with scarce or no affinity towards single‐ or double‐stranded DNA. These features have made it possible to design a simple, effective, safe, cheap, and selective method for fishing G‐quadruplex structures in solution by use of PDI2B and streptavidin coated magnetic beads. The new cyclic method reported leads to the recovery of more than 80 % of G‐quadruplex structures from solution, even in the presence of an excess of single‐stranded or duplex DNA as competitors. Moreover, PDI2B is a G4 ligand that…
Comparison Study of Two Differently Clicked 18F-Folates—Lipophilicity Plays a Key Role
2018
Within the last decade, several folate-based radiopharmaceuticals for Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) have been evaluated; however, there is still a lack of suitable 18F-folates for clinical PET imaging. Herein, we report the synthesis and evaluation of two novel 18F-folates employing strain-promoted and copper-catalyzed click chemistry. Furthermore, the influence of both click-methods on lipophilicity and pharmacokinetics of the 18F-folates was investigated. 18F-Ala-folate and 18F-DBCO-folate were both stable in human serum albumin. In vitro studies proved their high affinity to the folate receptor (FR). The lipophilic character of …
Biochemical characterization and antioxidant activity of grape ( Vitis vinifera L.) seed oils from nine Tunisian varieties
2018
IF 1.552; International audience
Antiinflammatory and antioxidant activities of a polyphenol‐rich extract from Zizyphus lotus L fruit pulp play a protective role against obesity
2018
Zizyphus lotus (Zl) is used widely as a source of food and for the treatment of various ailments. Therefore, we investigated the biological activities of Zl against obesity and related disorders. Hence, male Wistar rats received either control diet, high fat diet (HFAD), or HFAD supplemented with the Zl pulp (HFADP) for 14 weeks. RAW 264.7 cells were used for the determination of antiinflammatory activities in vitro. It was observed that HFDP resulted in significantly reduced weight, blood sugar, and oxidative stress than HFAD. In addition, Zl extract co‐treatment with LPS reduced the mRNA expression of MCP‐1, pro‐inflammatory cytokines (IL‐6, TNF‐α), and increased the level of IL‐10, an an…
Physical mechanisms of micro- and nanodomain formation in multicomponent lipid membranes.
2016
This article summarizes a variety of physical mechanisms proposed in the literature, which can generate micro- and nanodomains in multicomponent lipid bilayers and biomembranes. It mainly focusses on lipid-driven mechanisms that do not involve direct protein-protein interactions. Specifically, it considers (i) equilibrium mechanisms based on lipid-lipid phase separation such as critical cluster formation close to critical points, and multiple domain formation in curved geometries, (ii) equilibrium mechanisms that stabilize two-dimensional microemulsions, such as the effect of linactants and the effect of curvature-composition coupling in bilayers and monolayers, and (iii) non-equilibrium me…
Intramolecular structural parameters are key modulators of the gel-liquid transition in coarse grained simulations of DPPC and DOPC lipid bilayers
2018
The capability of coarse-grained models based on the MARTINI mapping to reproduce the gel-liquid phase transition in saturated and unsaturated model lipids was investigated. We found that the model is able to reproduce a lower critical temperature for 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with respect to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Nonetheless, the appearance of a gel phase for DOPC is strictly dependent on the intramolecular parameters chosen to model its molecular structure. In particular, we show that the bending angle at the coarse-grained bead corresponding to the unsaturated carbon-carbon bond acts as an order parameter determining the temperature of …
Femtosecond Structural Dynamics of Proteins
2016
Proteins are the workhorses of living cells, providing essential functions such as structural support, signal transduction, enzymatic catalysis, transport and storage of small ligands. Atomic-resolution structures obtained with conventional X-ray crystallography show proteins essentially as static. In reality, however, proteins move and their motion is crucial for functioning. Although the structure and dynamics of proteins are intimately related, they are not equally well understood. A very large number of protein structures have been determined, but only a few studies have been able to monitor experimentally the dynamics of proteins in real time. In the last two decades, the availability …
Bioelectrical coupling in multicellular domains regulated by gap junctions: A conceptual approach.
2018
We review the basic concepts involved in bioelectrically-coupled multicellular domains, focusing on the role of membrane potentials (Vmem). In the first model, single-cell Vmem is modulated by two generic polarizing and depolarizing ion channels, while intercellular coupling is implemented via voltage-gated gap junctions. Biochemical and bioelectrical signals are integrated via a feedback loop between Vmem and the transcription and translation of a protein forming an ion channel. The effective rate constants depend on the single-cell Vmem because these potentials modulate the local concentrations of signaling molecules and ions. This electrochemically-based idealization of the complex bioph…
Intercellular Connectivity and Multicellular Bioelectric Oscillations in Nonexcitable Cells: A Biophysical Model
2018
Bioelectricity is emerging as a crucial mechanism for signal transmission and processing from the single-cell level to multicellular domains. We explore theoretically the oscillatory dynamics that result from the coupling between the genetic and bioelectric descriptions of nonexcitable cells in multicellular ensembles, connecting the genetic prepatterns defined over the ensemble with the resulting spatio-temporal map of cell potentials. These prepatterns assume the existence of a small patch in the ensemble with locally low values of the genetic rate constants that produce a specific ion channel protein whose conductance promotes the cell-polarized state (inward-rectifying channel). In this…
MicroRNA Intercellular Transfer and Bioelectrical Regulation of Model Multicellular Ensembles by the Gap Junction Connectivity.
2017
We have studied theoretically the microRNA (miRNA) intercellular transfer through voltage-gated gap junctions in terms of a biophysically grounded system of coupled differential equations. Instead of modeling a specific system, we use a general approach describing the interplay between the genetic mechanisms and the single-cell electric potentials. The dynamics of the multicellular ensemble are simulated under different conditions including spatially inhomogeneous transcription rates and local intercellular transfer of miRNAs. These processes result in spatiotemporal changes of miRNA, mRNA, and ion channel protein concentrations that eventually modify the bioelectrical states of small multi…