Search results for "Cell aggregation"
showing 10 items of 42 documents
Identification and isolation of the primary aggregation factor from the cell membrane of the sponge Geodia cydonium
1985
The primary aggregation factor (pAF) of sponge cells is a glycoprotein that is firmly associated with the cell membrane. Polyspecific antibodies (anti-GM) prepared from sera raised against membranes of cells from the siliceous sponge Geodia cydonium were found to inhibit initial aggregation of homologous cells. The inhibition of aggregation, caused by anti-GM was neutralized by pAF. The pAF had been successfully solubilized and enriched by affinity chromatography, gel filtration and density gradient centrifugation, if checked by polyacrylamide gel electrophoresis in the presence of urea. The Mr of the native pAF was approximately 40 000 as estimated by gel filtration; under denaturing condi…
Sponge aggregation factor and sponge hemagglutinin: possible relationships between two different molecules.
1979
Abstract A lectin from the marine sponge GEODIA CYDONIUM was isolated and characterized. GEODIA lectin (GL) agglutinates human red blood cells irrespective of the ABO blood group and precipitates with a variety of D -galactose containing glycosubstances, i.e. certain snail galactans, bovine erythrocyte glycoprotein and PNEUMOCOCCUS type XIV polysaccharide. The only simple sugars inhibiting the GL-mediated hemagglutination were lactose and n -acetyl- D -galactosamine. GL was purified by affinity chromatography on Sepharose 4B almost to homogeneity as tested by polyacrylamide disc gel electrophoresis. Positive staining of the lectin band with Coomassie brilliant blue and PAS suggest that GL i…
Leukocyte–platelet aggregates—a phenotypic characterization of different stages of peripheral arterial disease
2016
The formation of monocyte-platelet aggregates and neutrophil-platelet aggregates (MPA and NPA, respectively) is influenced by inflammation, but also might contribute to an exacerbation of inflammatory responses in atherosclerotic plaque. The purpose of this study was to analyze MPA and NPA proportions in regard to different stages of peripheral arterial disease (PAD). Forty-five patients with intermittent claudication (IC) (3 groups: Rutherford (R)-1, R-2, and R-3; each n = 15), 20 patients with critical limb ischemia (CLI) (Rutherford 5 (40%) and 6 (60%)), and 20 healthy controls were studied. Analyses of monocyte (Mon) subpopulations (CD14++CD16- (classical) Mon1, CD14++CD16+ (intermediat…
Antagonistic effects of fluconazole and 5-fluorocytosine on candidacidal action of amphotericin B in human serum
1994
This study addressed the effects of fluconazole and 5-fluorocytosine on the candidacidal activity of amphotericin B in the presence of human serum. A Candida albicans isolate that was susceptible to all three agents according to standard testing procedures was employed. Fungicidal activity was estimated by using a flow cytometric procedure that exploited the fact that yeast cells killed by amphotericin B diminish in size and take up propidium iodide. The following findings were made. (i) Fluconazole and 5-fluorocytosine each failed to inhibit pseudohyphal formation and cell aggregation even when applied at 10 and 50 micrograms/ml, respectively, for up to 10 h. Hence, these agents were not f…
Effect of PCL/PEG-Based Membranes on Actinorhodin Production in Streptomyces coelicolor Cultivations
2015
The actinomycetes, Gram-positive filamentous bacteria, are the most prolific source of natural occurring antibiotics. At an industrial level, antibiotics from actinomycete strains are produced by means of submerged fermentations, where one of the major factors negatively affecting bioproductivity is the pellet-shaped biomass growth. The immobilization of microorganisms on properly chosen supports prevents cell-cell aggregation resulting in improving the biosynthetic capability. Thus, novel porous biopolymer-based devices are developed by combining melt mixing and particulate leaching. In particular, polycaprolactone (PCL), polyethylene glycol (PEG), and sodium chloride (NaCl) with different…
Cloning and expression of the putative aggregation factor from the marine sponge Geodia cydonium.
2001
Sponges (phylum Porifera) have extensively been used as a model system to study cell-cell interaction on molecular level. Recently, we identified and cloned the putative aggregation receptor (AR) of the sponge Geodia cydonium, which interacts in a heterophilic way with the aggregation factor (AF) complex. In the present study, antibodies against this complex have been raised that abolish the adhesion function of the enriched sponge AF, the AF-Fraction 6B. Using this antibody as a tool, a complete 1.7 kb long cDNA, GEOCYAF, could be isolated from a cDNA library that encodes the putative AF. Its deduced aa sequence in the N-terminal section comprises high similarity to amphiphysin/BIN1 sequen…
Differentiation capacity of epithelial cells in the sponge Suberites domuncula.
2004
Sponges (phylum Porifera) represent the oldest metazoans. Their characteristic metazoan adhesion molecules and transcription factors enable them to establish a complex "Bauplan" ; three major differentiated cell types (epithelial cells, skeletal cells/sclerocytes, and contractile cells) can be distinguished. Since no molecular markers are as yet available to distinguish these somatic cells or the corresponding embryonic cells from which they originate, we have selected the following three genes for their characterization: noggin (a signaling molecule in development), a caspase that encodes an apoptotic molecule, and silicatein. Silicatein is an enzyme that is involved in the synthesis of si…
Community effects allow bioelectrical reprogramming of cell membrane potentials in multicellular aggregates: Model simulations.
2020
Bioelectrical patterns are established by spatiotemporal correlations of cell membrane potentials at the multicellular level, being crucial to development, regeneration, and tumorigenesis. We have conducted multicellular simulations on bioelectrical community effects and intercellular coupling in multicellular aggregates. The simulations aim at establishing under which conditions a local heterogeneity consisting of a small patch of cells can be stabilized against a large aggregate of surrounding identical cells which are in a different bioelectrical state. In this way, instructive bioelectrical information can be persistently encoded in spatiotemporal patterns of separated domains with diff…
Focal lymphocytic aggregates in chronic hepatitis C: occurrence, immunohistochemical characterization, and relation to markers of autoimmunity.
1995
Intrahepatic lymphocytic aggregates are observed in chronic hepatitis C as well as in autoimmune chronic hepatitis. Autoantibodies and autoimmune manifestations may occur in hepatitis C. It has been suggested that the lymphocytic aggregates play a role in the liver injury of chronic hepatitis C by an immune-mediated mechanism. We studied the occurrence of intrahepatic lymphocytic aggregates and of autoantibodies in a consecutive series of 128 patients with chronic hepatitis C. For the phenotypic characterization of the lymphocytic aggregates cryostat sections and microwaved paraffin embedded sections were immunostained with monoclonal antibodies directed against T cell subsets, B cells, kil…
Matrix-mediated canal formation in primmorphs from the sponge Suberites domuncula involves the expression of a CD36 receptor-ligand system.
2004
Sponges (Porifera), represent the phylogenetically oldest metazoan phylum still extant today. Recently, molecular biological studies provided compelling evidence that these animals share basic receptor/ligand systems, especially those involved in bodyplan formation and in immune recognition, with the higher metazoan phyla. An in vitro cell/organ-like culture system, the primmorphs, has been established that consists of proliferating and differentiating cells, but no canals of the aquiferous system. We show that after the transfer of primmorphs from the demosponge Suberites domuncula to a homologous matrix (galectin), canal-like structures are formed in these 3D-cell aggregates. In parallel …