Search results for "Fluorescence"
showing 10 items of 2463 documents
Dual Labeling of Lipopolysaccharides for SPECT-CT Imaging and Fluorescence Microscopy.
2013
International audience; : Lipopolysaccharides (LPS) or endotoxins are amphipathic, pro-inflammatory components of the outer membrane of Gram-negative bacteria. In the host, LPS can trigger a systemic inflammatory response syndrome. To bring insight into in vivo tissue distribution and cellular uptake of LPS, dual labeling was performed with a bimodal molecular probe designed for fluorescence and nuclear imaging. LPS were labeled with DOTA-Bodipy-NCS, and pro-inflammatory properties were controlled after each labeling step. LPS were then radiolabeled with (111)In and subsequently injected intravenously into wild-type, C57B16 mice, and their in vivo behavior was followed by single photon emis…
Expression and function of the non-neuronal cholinergic system in endothelial cells
2003
Increasing evidence has shown the expression of the non-neuronal cholinergic system in endothelial cells. In the present experiments the expression of choline acetyltransferase (ChAT) was investigated in human endothelial cells by anti-ChAT immunohistochemistry and anti-ChAT immunofluorescence. Positive ChAT immunoreactivity was found in cultures of human umbilical endothelial cells (HUVEC) and a human angiosarcoma cell line (HAEND). In HUVEC and HAEND choline acetyltransferase activity and small amounts of acetylcholine were also detected. Positive ChAT-immunoreactivity was demonstrated in situ in endothelial cells of the human umbilical cord. In addition, in experiments with confocal lase…
Inflamed adult pharynx tissues and swimming larva of Ciona intestinalis share CiTNFalpha-producing cells.
2010
In situ hybridisation and immunohistochemistry analyses have shown that the Ciona intestinalis tumour necrosis factor alpha gene (CiTNFalpha), which has been previously cloned and sequenced, is expressed either during the inflammatory pharynx response to lipopolysaccharide (LPS) or during the swimming larval phase of development. Granulocytes with large granules and compartment/morula cells are CiTNFalpha-producing cells in both inflamed pharynx and larvae. Pharynx vessel endothelium also takes part in the inflammatory response. Haemocyte nodules in the vessel lumen or associated with the endothelium suggest the involvement of CiTNFalpha in recruiting lymphocyte-like cells and promoting the…
Nanoscale distribution of TLR4 on primary human macrophages stimulated with LPS and ATI
2019
Toll-like receptor 4 (TLR4) plays a crucial role in the recognition of invading pathogens. Upon activation by lipopolysaccharides (LPS), TLR4 is recruited into specific membrane domains and dimerizes. In addition to LPS, TLR4 can be stimulated by wheat amylase-trypsin inhibitors (ATI). ATI are proteins associated with gluten containing grains, whose ingestion promotes intestinal and extraintestinal inflammation. However, the effect of ATI vs. LPS on the membrane distribution of TLR4 at the nanoscale has not been analyzed. In this study, we investigated the effect of LPS and ATI stimulation on the membrane distribution of TLR4 in primary human macrophages using single molecule localization m…
Polysialic acid can mediate membrane interactions by interacting with phospholipids
2009
Polysialic acid (polySia) is expressed on the surface of neural cells, neuroinvasive bacterial cells and several tumor cells. PolySia chains attached to NCAM can influence both trans interactions between membranes of two cells and cis interactions. Here, we report on the involvement of phospholipids in regulation of membrane interactions by polySia. The pH at the surface of liposomes, specific molecular area of phosphatidylcholine molecules, phase transition of DPPC bilayers, cyclic voltammograms of BLMs, and electron micrographs of phosphatidylcholine vesicles were studied after addition of polysialic acid free in solution. The results indicate that polySia chains can associate with phosph…
Macromolecules in ordered media VIII. High-performance size-exclusion chromatography as a technique for characterizing the interaction between polyan…
1997
Abstract The association of polyanions with liposomes based on dimyristoyl phosphatidyl choline and stearylamine at a ratio of 50:50 was investigated in terms of the binding model and, to a lesser extent, of the partition model. Aqueous size-exclusion chromatography has been proposed as a major technique for monitoring the interactions between liposomes and polyelectrolytes and the results were compared with those obtained by fluorescence spectroscopy. Quantitatively, the extent of the association follows the order: Sodium poly(styrene sulfonate) ( K A = 10 000 M −1 ), poly (acrylic acid) ( K A = 2000 M −1 ) and poly ( l -glutamic acid) ( K A = 700 M −1 ). Also, the effect of the ionic stre…
Identification of a putative membrane-inserted segment in the alpha-toxin of Staphylococcus aureus.
1994
To gain a fuller understanding of the regions of the Staphylococcus aureus alpha-toxin important in pore formation, we have used Forster dipole-dipole energy transfer to demonstrate that a central glycine-rich region of alpha-toxin (the so-called "hinge" region) inserts deeply into the bilayer on association of toxin with liposomes. Mutant alpha-toxins with unique cysteine (C) residues at positions 69 and 130 [Palmer, M., et al. (1993) J. Biol. Chem. 268, 11959) were reacted with the C-specific fluorophore acrylodan, which acted as an energy donor. The chosen acceptor was N-(7-nitrobenz-2-oxa-13- diazol-4-yl)-1,2-bis(hexadecanoyl)-sn-glycero-3-phosphoethanolamin e (NBD-PE). Measurement of t…
A human renal cancer line as a new antigen source for the detection of antibodies to cytoplasmic and nuclear antigens in sera of patients with Wegene…
1991
Autoantibodies directed against cytoplasmic antigens of neutrophils (ANCA), especially proteinase 3 (C-ANCA), have proved to be a useful clinical tool to support the diagnosis or to monitor disease activity in Wegener's granulomatosis (WG). Till now, human neutrophil granulocytes have represented the major antigen source used to detect antibodies in WG by the immunofluorescence technique (IFT). We have tested serum samples of 164 patients with different connective tissue diseases (50 suffering from clinically active WG) performing IFT on a human renal cancer line (SK-RC11) and have found antibodies against the nuclear and cytoplasmic antigens in 39 patients. C-ANCA+ sera displayed a charact…
Incomplete sequence homogenization in 45S rDNA multigene families: intermixed IGS heterogeneity within the single NOR locus of the polyploid species …
2014
† Background and Aims Ribosomal sequences have become the classical example of the genomic homogenization of nuclear multigene families. Despite theoretical advantages and modelling predictions that support concerted evolution of the 45S rDNA, several reports have found intragenomic polymorphisms. However, the origins and causes of these rDNA polymorphisms are difficult to assess because seed plants show a wide range of 45S rDNA loci number variation, especially in polyploids. Medicago arborea is a tetraploid species that has a single 45S rDNA locus. This feature makes this species a suitable case study to assess the fate of ribosomal IGS homogenization in polyploid species showing nucleolu…
Complement pore genesis observed in erythrocyte membranes by fluorescence microscopic single-channel recording
1991
The formation and opening of single complement pores could be directly observed in erythrocyte ghosts by confocal laser-scanning microscopy employing the recently introduced method of fluorescence microscopic single-channel recording. Resealed sheep erythrocyte ghosts were incubated with human complement. By limiting the concentration of C8, the eighth component of complement, the fraction of cells rendered permeable for the small polar fluorescent probe Lucifer Yellow was varied between 0.50 and 0.90. Under each condition the flux rate, k, of Lucifer Yellow was determined for a substantial number of ghosts. By analysing the sample population distribution of k the flux rate k1 of ghosts wit…