Search results for "Fluorescence microscope"
showing 10 items of 117 documents
Two simple criteria to estimate an objective's performance when imaging in non design tissue clearing solutions
2019
Tissue clearing techniques are undergoing a renaissance motivated by the need to image fluorescent neurons, and other cells, deep in the sample without physical sectioning. Optical transparency is achieved by equilibrating tissues with high refractive index (RI) solutions. When the microscope objective is not perfectly matched to the RI of the cleared sample, aberrations are introduced. We present two simple-to-calculate numerical criteria predicting: (i) the degradation in image quality (brightness and resolution) from optimal conditions of any clearing solution/objective combination; (ii) which objective, among several available, achieves the highest resolution in a given medium. We deriv…
Microtubule disruption changes endothelial cell mechanics and adhesion
2019
AbstractThe interest in studying the mechanical and adhesive properties of cells has increased in recent years. The cytoskeleton is known to play a key role in cell mechanics. However, the role of the microtubules in shaping cell mechanics is not yet well understood. We have employed Atomic Force Microscopy (AFM) together with confocal fluorescence microscopy to determine the role of microtubules in cytomechanics of Human Umbilical Vein Endothelial Cells (HUVECs). Additionally, the time variation of the adhesion between tip and cell surface was studied. The disruption of microtubules by exposing the cells to two colchicine concentrations was monitored as a function of time. Already, after 3…
Resveratrol-Induced Temporal Variation in the Mechanical Properties of MCF-7 Breast Cancer Cells Investigated by Atomic Force Microscopy
2019
Atomic force microscopy (AFM) combined with fluorescence microscopy has been used to quantify cytomechanical modifications induced by resveratrol (at a fixed concentration of 50 µ
Study of interaction of antimutagenic 1,4-dihydropyridine AV-153-Na with DNA-damaging molecules and its impact on DNA repair activity
2018
Background1,4-dihydropyridines (1,4-DHP) possesses important biochemical and pharmacological properties, including antioxidant and antimutagenic activities. It was shown that the antimutagenic 1,4-dihydropyridine AV-153-Na interacts with DNA. The aim of the current study was to test the capability of the compound to scavenge peroxynitrite and hydroxyl radical, to test intracellular distribution of the compound, and to assess the ability of the compound to modify the activity of DNA repair enzymes and to protect the DNA in living cells against peroxynitrite-induced damage.MethodsPeroxynitrite decomposition was assayed by UV spectroscopy, hydroxyl radical scavenging—by EPR spectroscopy. DNA b…
Visualizing the spatiotemporal map of Rac activation in bovine aortic endothelial cells under laminar and disturbed flows.
2017
Disturbed flow can eliminate the alignment of endothelial cells in the direction of laminar flow, and significantly impacts on atherosclerosis in collateral arteries near the bifurcation and high curvature regions. While shear stress induced Rac polarity has been shown to play crucial roles in cell polarity and migration, little is known about the spatiotemporal map of Rac under disturbed flow, and the mechanism of flow-induced cell polarity still needs to be elucidated. In this paper, disturbed flow or laminar flow with 15 dyn/cm2 of average shear stress was applied on bovine aortic endothelial cells (BAECs) for 30 minutes. A genetically-encoded PAK-PBD-GFP reporter was transfected into BA…
Direct observation of alpha-lactalbumin, adsorption and incorporation into lipid membrane and formation of lipid/protein hybrid structures
2019
The interaction between proteins and membranes is of great interest in biomedical and biotechnological research for its implication in many functional and dysfunctional processes. We present an experimental study on the interaction between model membranes and alpha-lactalbumin (alpha-La). alpha-La is widely studied for both its biological function and its anti-tumoral properties. We use advanced fluorescence microscopy and spectroscopy techniques to characterize alpha-La-membrane mechanisms of interaction and alpha-La-induced modifications of membranes when insertion of partially disordered regions of protein chains in the lipid bilayer is favored. Moreover, using fluorescence lifetime imag…
2019
Purpose: Clear resection margins are paramount for good outcome in children undergoing solid tumor resections. Multiphoton microscopy (MPM) can provide high-resolution, real-time, intraoperative microscopic images of tumor tissue. Objective: This prospective international multicenter study evaluates the diagnostic accuracy, feasibility, and interobserver congruence of MPM in diagnosing solid pediatric tissue and tumors for the first time. Material and methods: Representative fresh sections from six different neonatal solid tissues (liver, lung, kidney, adrenal gland, heart muscle, testicle) and two types of typical pediatric solid tumors (neuroblastoma, rhabdomyosarcoma) with adjacent nonne…
Flexible multi-beam light-sheet fluorescence microscope for live imaging without striping artifacts
2018
The development of light-sheet fluorescence microscopy (LSFM) has greatly expanded the experimental capabilities in many biological and biomedical research fields, enabling for example live studies of murine and zebrafish neural activity or of cell growth and division. The key feature of the method is the selective illumination of a sample single plane, providing an intrinsic optical sectioning and allowing direct 2D image recording. On the other hand, this excitation scheme is more affected by absorption or scattering artifacts in comparison to point scanning methods, leading to un-even illumination. We present here an easily implementable method, based on acousto-optical deflectors (AOD),…
Comparative morphological characteristics of three Brettanomyces bruxellensis wine strains in the presence/absence of sulfur dioxide
2016
International audience; The red wine spoilage yeast Brettanomyces bruxellensis has been the subject of numerous investigations. Some of these studies focused on spoilage mechanisms, sulfur dioxide tolerance and nutrient requirements. Pseudomycelium formation, although a striking feature of this species, has however been poorly investigated. Furthermore, literature regarding the induction mechanism of pseudomycelium formation in this yeast is limited and lacks clarity, as results published are contradictory. This study elucidates this phenomenon among strains from geographically different areas. Potential environmental cues were investigated, to attain a better understanding of this mechanis…
Flow Cytometric Analysis of the Expression Pattern of Peroxisomal Proteins, Abcd1, Abcd2, and Abcd3 in BV-2 Murine Microglial Cells
2017
Microglial cells play important roles in neurodegenerative diseases including peroxisomal leukodystrophies. The BV-2 murine immortalized cells are widely used in the context of neurodegenerative researches. It is therefore important to establish the expression pattern of peroxisomal proteins by flow cytometry in these cells. So, the expression pattern of various peroxisomal transporters (Abcd1, Abcd2, Abcd3) contributing to peroxisomal β-oxidation was evaluated on BV-2 cells by flow cytometry and complementary methods (fluorescence microscopy, and RT-qPCR). By flow cytometry a strong expression of peroxisomal proteins (Abcd1, Abcd2, Abcd3) was observed. These data were in agreement with tho…