Search results for "Rhodamines"
showing 10 items of 36 documents
Spontaneous domain formation of phospholipase A2 at interfaces: fluorescence microscopy of the interaction of phospholipase A2 with mixed monolayers …
1992
Abstract Fluorescence microscopy has recently been proven to be an ideal tool to investigated the specific interaction of phospholipase A 2 with oriented substrate monolayers. Using a dual labeling technique, it could be shown that phospholipase A 2 can specifically attack and hydrolyze solid analogous l -α-DPPC domains. After a critical extent of monolayer hydrolysis the enzyme itself starts to aggregate forming regular shaped protein domains (Grainger et al. (1990) Biochim. Biophys. Acta 1023. 365–379). In order to confirm that the existence of hydrolysis products in the mononlayer is necessary for the observed aggregation of phospholipase A 2 , mixed monolayers of d - and l -α-DPPC, l -α…
Nanoprobing the acidification process during intracellular uptake and trafficking
2015
Abstract Many nanoparticular drug delivery approaches rely on a detailed knowledge of the acidification process during intracellular trafficking of endocytosed nanoparticles (NPs). Therefore we produced a nanoparticular pH sensor composed of the fluorescent pH-sensitive dual wavelength dye carboxy seminaphthorhodafluor-1 (carboxy SNARF-1) coupled to the surface of amino-functionalized polystyrene NPs (SNARF-1-NP). By applying a calibration fit function to confocal laser scanning microscopy (CLSM) images, local pH values were determined. The acidification and ripening process of endo/lysosomal compartments containing nanoparticles was followed over time and was found to progress up to 6h to …
Retrograde transport of sodium selenite and intracellular injection of micro-ruby: a combined method to describe the morphology of zinc-rich neurones.
2003
Abstract Zinc is found in synaptic vesicles in a large number of glutamatergic systems. Its involvement in neurotransmission and neurological disorders has been suggested. There are methods for tracing these circuits, but they do not fill the dendritic tree. In this study, extracellular selenite injections in vivo were combined with intracellular injection of fluorochromes in fixed tissue to reveal the morphology of these zinc-rich neurones. Intraperitoneal and intracerebral injections of sodium selenite alone or intracerebral injections of selenite combined with bisbenzimide were made in the visual cortex of the rat in order to locate the somata of zinc-rich neurones. After 24 h of retrogr…
Isoprenylhydroquinone glucoside: a new non-antioxidant inhibitor of peroxynitrite-mediated tyrosine nitration
2004
Abstract Three hydroquinone glucosides and four caffeoylquinic esters were examined for their effect on tyrosine nitration, as well as on the oxidation of dihydrorhodamine (DHR) 123 and cytochrome c 2+ induced by peroxynitrite. All these phenolics, which had previously been characterized as the active principles of the plant Phagnalon rupestre , were fairly active in preventing the oxidation of DHR 123, though inefficient in the cytochrome c test. While their antioxidant potency is associated with the presence of a caffeoyl moiety, not so an obvious chemical character was correlated to a greater activity against nitration of tyrosine. Here, the highest potency corresponded to 2-isoprenylhyd…
Selective, Sensitive, and Rapid Analysis with Lateral-Flow Assays Based on Antibody-Gated Dye-Delivery Systems: The Example of Triacetone Triperoxide
2013
[EN] Antibodygated MSNs that are loaded with a rhodamine dye and that can be used for the determination of the presence of peroxide-based explosive TATP with a lateral-flow fluorescence reader have been designed and prepared, thereby allowing for detection limits in the lower ppb range. The mechanism of the detection relies on a displacement of the antibody from the surface of the hybrid material because of highly affine antibody-TATP interactions, which release a much larger number of entrapped dye molecules from the pores than antibodies are displaced. The high selectivity of the antibody is retained in the gated material, thus allowing for a remarkable discrimination against H2O2. System…
Filling the “green gap” of the major light-harvesting chlorophyll a/b complex by covalent attachment of Rhodamine Red
2009
AbstractThe major light-harvesting chlorophyll a/b complex (LHCII) greatly enhances the efficiency of photosynthesis in green plants. Recombinant LHCII can be assembled in vitro from its denatured, bacterially expressed apoprotein and plant pigments. This makes it an interesting candidate for biomimetic light-harvesting in photovoltaic applications. Due to its almost 20 pigments bound per apoprotein, LHCII absorbs efficiently in the blue and red spectral domains of visible light but less efficiently in the green domain, the so-called “green gap” in its absorption spectrum. Here we present a hybrid complex of recombinant LHCII with organic dyes that add to LHCII absorption in the green spect…
Amphiphilic poly(hydroxyethylaspartamide) derivative-based micelles as drug delivery systems for ferulic acid
2008
Self-assembling micelles, potentially useful as drug delivery systems for ferulic acid (FA), were obtained in aqueous media from amphiphilic alpha,beta-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) copolymers bearing at the polyamino acidic backbone both poly(ethyleneglycol) (2000 or 5000 Da) and hexadecylamine (C(16)) moieties, at a concentration of 7 x 10(- 3) and 4 x 10(- 3) g/l, respectively, with nanometre size and negative zeta potential. These micelles were able to entrap FA and to release it in a prolonged way in phosphate buffer solution at pH 7.4 and human plasma. These systems were also stable in storage conditions and have no cytotoxic effects on Caco-2, 16 HBE, HuDe and K562 cel…
TWJ-Screen: an isothermal screening assay to assess ligand/DNA junction interactions in vitro
2017
International audience; The quest for chemicals able to operate at selected genomic loci in a spatiotemporally controlled manner is desirable to create manageable DNA damages. Mounting evidence now shows that alternative DNA structures, including G-quadruplexes and branched DNA (or DNA junctions), might hamper proper progression of replication fork, thus triggering DNA damages and genomic instability. Therefore, small molecules that stabilize these DNA structures are currently scrutinized as a promising way to create genomic defects that cannot be dealt with properly by cancer cells. While much emphasis has been recently given to G-quadruplexes and related ligands, we report herein on three…
Oligonucleotide-capped mesoporous silica nanoparticles as DNA-responsive dye delivery systems for genomic DNA detection
2015
[EN] New hybrid oligonucleotide-capped mesoporous silica nanoparticles able to detect genomic DNA were designed.
Flotillin-involved uptake of silica nanoparticles and responses of an alveolar-capillary barrier in vitro
2013
AbstractDrug and gene delivery via nanoparticles across biological barriers such as the alveolar-capillary barrier of the lung constitutes an interesting and increasingly relevant field in nanomedicine. Nevertheless, potential hazardous effects of nanoparticles (NPs) as well as their cellular and systemic fate should be thoroughly examined. Hence, this study was designed to evaluate the effects of amorphous silica NPs (Sicastar) and (poly)organosiloxane NPs (AmOrSil) on the viability and the inflammatory response as well as on the cellular uptake mechanisms and fate in cells of the alveolar barrier. For this purpose, the alveolar epithelial cell line (NCI H441) and microvascular endothelial…