Search results for "Rabbits"
showing 10 items of 501 documents
Inhibition of ubiquitin-dependent proteolysis by a synthetic glycine-alanine repeat peptide that mimics an inhibitory viral sequence.
2002
AbstractThe glycine–alanine repeat (GAr) of the Epstein–Barr virus nuclear antigen-1 is a cis-acting transferable element that inhibits ubiquitin/proteasome-dependent proteolysis in vitro and in vivo. We have here examined the effect of a synthetic 20-mer GAr oligopeptide on the degradation of iodinated or biotin labeled lysozyme in a rabbit reticulocyte lysates in vitro assay. Micromolar concentrations of the GA-20 peptide inhibited the hydrolysis of lysozyme without significant effect on ubiquitination. Addition of the peptide did not inhibit the hydrolysis of fluorogenic substrate by purified proteasomes and did not affect the ubiquitination of lysozyme. An excess of the peptide failed t…
Bioactive and biodegradable silica biomaterial for bone regeneration.
2014
Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads (microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented with silica or silicatein, into the biodegradable copolymer poly(d,l-lactide-co-glycolide) [PLGA]. Under the conditions used, ≈5% β-TCP, ≈9% silica, and 0.32μg/mg of silicatein were entrapped into the PLGA microspheres (diameter≈800μm). Determination of …
Isoproterenol inhibits fluid-phase endocytosis from early to late endosomes
1999
We have shown recently that isoproterenol affects both the cellular location and the morphology of late endosomes in a pH-dependent manner [Marjomäki et al., Eur. J. Cell Biol. 65, 1-13 (1994)]. In this study, using fluorescence and quantitative electron microscopy, we wanted to examine further what is the fate of internalized markers during their translocation from early to late endosomes under isoproterenol treatment. Fluorescein dextran internalized for 30 min (10-min pulse followed by a 20-min chase) showed accumulation in the cellular periphery during isoproterenol treatment in contrast to the control cells, which accumulated dextran in the perinuclear region. Quantitative electron mic…
Analyzing the electrophysiological effects of local epicardial temperature in experimental studies with isolated hearts
2008
As a result of their modulating effects upon myocardial electrophysiology, both hypo- and hyperthermia can be used to study the mechanisms that generate or sustain cardiac arrhythmias. The present study describes an original electrode developed with thick-film technology and capable of controlling regional temperature variations in the epicardium while simultaneously registering its electrical activity. In this way, it is possible to measure electrophysiological parameters of the heart at different temperatures. The results obtained with this device in a study with isolated and perfused rabbit hearts are reported. An exploration has been made of the effects of local temperature changes upon…
Forchlorfenuron-mimicking haptens: From immunogen design to antibody characterization by hierarchical clustering analysis
2011
To obtain highly-specific and selective forchlorfenuron binders, a collection of functionalized derivatives with different spacer arm locations and lengths was prepared. By immunization with target-mimicking haptens, a large battery of monoclonal and polyclonal antibodies against this synthetic cell regulator was produced and exhaustively characterized in two immunoassay formats using homologous and heterologous conjugates. Antibodies with IC50 values lower than 0.3 nM were successfully raised from the prepared immunogens, thus evidencing the efficacy of the explored strategies. In order to identify significant epitopes in the antibody-antigen interaction, a series of new chemical forchlorf…
Production of specific antibodies and development of a non-isotopic immunoassay for carbamazepine by the carbonyl metallo-immunoassay (CMIA) method.
1995
Abstract As part of our ongoing work to extend the range of applications of the non-isotopic carbonyl metalloimmunoassay (CMIA), previously developed in our laboratory, we describe here the first CMIA study of carbamazepine. The CMIA method uses a metal carbonyl complex as a non-isotopic tracer, and in this case we chose to employ the dicobalt hexacarbonyl moiety (Co2(CO)6) attached to an alkyne. Two organometallic tracers, 3 and 7 , were synthesized, differentiated by the nature and length of the spacer arm of the Co2(CO)6 moiety. Two different coupling methods were subsequently used to synthesize the immunogens 1 and 2, the first one used a carbodiimide, while the second, employed dimethy…
Evidence for the presence of collagenous domains in Candida albicans cell surface proteins
1995
Rabbit polyclonal antibodies (PAbs) directed towards the amino-terminal cysteine-rich 7S domain (PAb anti-7S), the major internal collagenous domain (PAb anti-type IV), and the C-terminal noncollagenous region (PAb anti-NC1) of the type IV collagen molecule were probed by indirect immunofluorescence against Candida albicans blastoconidia and germinated blastoconidia. Most nongerminating cells and mother blastoconidia from which germ tubes originated showed strong fluorescence when PAb anti-7S was used, whereas with PAb anti-type IV, fluorescence was found almost exclusively on the surface of filamentous forms. A patched fluorescent pattern rather than a homogenous confluent fluorescence was…
Identification of a 58-kilodalton cell surface fibrinogen-binding mannoprotein from Candida albicans.
1992
Treatment of both yeast (blastoconidia) and hyphal (blastoconidia with germ tubes) cells of Candida albicans with beta-mercaptoethanol (beta ME) releases a complex array of cell wall-bound proteins and glycoproteins. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting with fibrinogen-anti-fibrinogen antibody allowed the identification of a 58-kDa mannoprotein (mp58) in both extracts which specifically interacts with human fibrinogen. Treatment of intact cells with low concentrations of beta-glucanase (Zymolyase 20T) for short periods or with beta ME abolished or significantly reduced binding of fibrinogen. A rabbit polyclonal antiserum was raised…
Myxoma virus Leukemia-associated protein is responsible for major histocompatibility complex class I and Fas-CD95 down-regulation and defines scrapin…
2002
ABSTRACTDown-modulation of major histocompatibility class I (MHC-I) molecules is a viral strategy for survival in the host.Myxoma virus, a member of thePoxviridaefamily responsible for rabbit myxomatosis, can down-modulate the expression of MHC-I molecules, but the viral factor(s) has not been described. We cloned and characterized a gene coding for an endoplasmic reticulum (ER)-resident protein containing an atypical zinc finger and two transmembrane domains, which we called myxoma virus leukemia-associated protein (MV-LAP). MV-LAP down-regulated surface MHC-I and Fas-CD95 molecules upon transfection; the mechanism probably involves an exacerbation of endocytosis and was lost when the ER r…
Histidine residues near the N terminus of staphylococcal alpha-toxin as reporters of regions that are critical for oligomerization and pore formation.
1994
Chemical modification of histidine residues in staphylococcal alpha-toxin leads to loss of functional activity. Site-directed mutants of the toxin in which each of the four histidine residues was replaced by several amino acids were therefore produced. The mutant proteins were purified and characterized. Exchange of H-259 or H-144 was sometimes tolerated without reduction in hemolytic activity. These histidine residues are thus not essential for toxin function. Exchange of H-35 and H-48, however, had marked effects. H-35 mutant toxins bound with high affinity to rabbit erythrocytes but displayed faulty oligomerization and were unable to form pores. H-48 mutant toxins also had severely impai…