Search results for " probes"
showing 10 items of 146 documents
Coumarin-Phosphine-Based Smart Probes for Tracking Biologically Relevant Metal Complexes: From Theoretical to Biological Investigations
2016
International audience; Ten metal-based complexes and associated ligands have been synthesized and characterized. One of the metal ligands is a coumarin-phosphine derivative, which displays tunable fluorescence properties. The fluorescence is quenched in the case of the free ligand and ruthenium and osmium complexes, whereas it is strong for the gold complexes and phosphonium derivatives. These trends were rationalized by theoretical calculations, which revealed non-radiative channels involving a dark state for the free ligands that is lower in energy than the emissive state and is responsible for the quenching of fluorescence. For the Ru-II and Os-II complexes, other non-radiative channels…
A method for taxonomic determination ofCandida albicans with DNA probes
1993
Determination of Candida species represents an important problem derived from the clinical implications of the species belonging to this genus. DNA probes have already been used for the epidemiology of Candida albicans, as well as for taxonomic analysis of Candida and other genera, although these probes are based on non-species-specific DNA sequences. In this work we carried out a 48-h assay, allowing the identification of C. albicans from clinical isolates, using DNA probes based on C. albicans LEU2 and URA3 genes. Another probe related to C. albicans SEC18 gene was shown not to be C. albicans specific.
In situ analysis of the bacterial communities associated to farmed eel by whole-cell hybridization.
1999
Bacterial communities in water samples and eel slime were investigated by fluorescence in situ hybridization of whole bacterial cells in an eel intensive culture system over 1 year. A newly developed probe, matching 27 Vibrio spp., and a specific probe for Vibrio vulnificus were used. Phylogenetic probes complementary to selected regions of the 16S and 23S ribosomal RNA revealed that Proteobacteria of the alpha and beta subclass were predominant in water and eel slime. Members of the gamma subclass (e.g. vibrios and aeromonads) were more abundant in eel slime, although no V. vulnificus was detected.
Photo-DHEA--a functional photoreactive dehydroepiandrosterone (DHEA) analog.
2011
Abstract The steroid hormone dehydroepiandrosterone (DHEA) has beneficial effects on vascular function, survival of neurons, and fatty acid metabolism. However, a specific receptor for DHEA has not been identified to date. Here, we describe the synthesis of a photoreactive DHEA derivative (Photo-DHEA). In Photo-DHEA, typical characteristics of DHEA are conserved: (i) a “planar” tetracyclic ring system with a Δ 5 double bond, (ii) a 3β-hydroxyl group, and (iii) a keto group at C17. In cell-based assays, Photo-DHEA showed the same properties as DHEA. We conclude that Photo-DHEA is suitable for radioiodination to yield a tool for the identification of the elusive DHEA receptor.
Supramolecular Association of Halochromic Switches and Halloysite Nanotubes in Fluorescent Nanoprobes for Tumor Detection
2022
Fluorescence imaging has become an indispensable tool in the biomedical laboratory to elucidate the fundamental dynamic and structural factors regulating cellular processes. The development of fluorescent nanoprobes represents a challenge to detect any cellular process under a microscope. Herein, a fluorescent nanomaterial was synthesized by exploiting the supramolecular interaction between a halochromic switch (1Cl) and halloysite nanotubes (HNTs). The successful synthesis of a HNTs/1Cl nanomaterial was confirmed by thermogravimetric analysis and Fourier transform infrared. The aqueous mobility was investigated by dynamic light scattering and ζ-potential measurements as well. Furthermore, …
Bio-orthogonal Red and Far-Red Fluorogenic Probes for Wash-Free Live-Cell and Super-resolution Microscopy
2021
Small-molecule fluorophores enable the observation of biomolecules in their native context with fluorescence microscopy. Specific labeling via bio-orthogonal tetrazine chemistry combines minimal label size with rapid labeling kinetics. At the same time, fluorogenic tetrazine–dye conjugates exhibit efficient quenching of dyes prior to target binding. However, live-cell compatible long-wavelength fluorophores with strong fluorogenicity have been difficult to realize. Here, we report close proximity tetrazine–dye conjugates with minimal distance between tetrazine and the fluorophore. Two synthetic routes give access to a series of cell-permeable and -impermeable dyes including highly fluorogen…
Using exomarkers to assess mitochondrial reactive species in vivo
2014
Background:\ud The ability to measure the concentrations of small damaging and signalling molecules such as reactive oxygen species (ROS) in vivo is essential to understanding their biological roles. While a range of methods can be applied to in vitro systems, measuring the levels and relative changes in reactive species in vivo is challenging.\ud \ud Scope of review:\ud One approach towards achieving this goal is the use of exomarkers. In this, exogenous probe compounds are administered to the intact organism and are then transformed by the reactive molecules in vivo to produce a diagnostic exomarker. The exomarker and the precursor probe can be analysed ex vivo to infer the identity and a…
Impact of Vanadium Complexes with Tetradentate Schiff Base Ligands on the DPPC and EYL Liposome Membranes: EPR Studies
2023
This paper investigates the effect of three vanadium complexes with Schiff base-type tetradentate ligands of general formula N,N′-1,2-cyclohexylenebis(3,5-dichlorosalicylideneiminate) (V1); LVCl2 (L = N,N′-1,2-cyclohexylenebis(5-chlorosalicylideneiminate) (V2); and N,N′-1,3propylenebis (salicylideneiminate) (V3) on the fluidity of liposome membranes obtained by the sonication of natural lecithin (EYL) and synthetic lecithin (DPPC). The study was carried out with TEMPO and 16DOXYL spin probes using the EPR technique. The results show that the effect of the complexes on the fluidity of liposomes whose membranes are in the liquid crystalline phase is much stronger as compared to the liposome m…
Molecular cloning and characterization of the complementary DNA coding for the B-chain of murine Clq
1989
AbstractcDNA clones coding for the B-chain of murine Clq were isolated from a mouse macrophage library. The characterized clones include the total coding region plus a leader sequence. High homology was found with human Clq B-chain in the coding region (81%). Northern blot analysis of total RNA from different tissues of Balb/c mice showed one band of approximately 1.2 kb. The highest signal was found in RNA preparations of thioglycolate-activated peritoneal macrophages. The probe also hybridized with mRNA from spleen, thymus and heart. Extremely weak signals were found in liver, kidney, lung and intestine tissues.
Distribution of type I and type II collagen gene expression during the development of human long bones
1990
The temporal and spatial gene expression of collagen type I and type II during the development of the human long bones was studied by the technique of in situ hybridization covering the period from the cartilagenous bone anlage to the formation of a regular growth plate in the newborn. Analysis of the early stages around the seventh week of gestation revealed for type II collagen a strong hybridization signal limited to the chondrogenic tissue. The surrounding connective tissue and the perichondrium showed weak type I collagen expression, while the zones of desmal ossification like the clavicle gave a strong signal. Beginning with the eighth week of gestation, type I collagen mRNA was detec…