Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ultrastructural aspects of the interaction of Mycoplasma gallisepticum with specific rabbit antibody have been studied. In particular, fixation conditions which allow the simultaneous preservation of cellular fine structure and membrane antigenicity have been established and applied in a procedure of indirect immunological labelling of the antibody-coated organisms with ferritin conjugated sheep anti-rabbit IgG. The advantages of working with agar embedded organisms in a multistep labelling procedure are discussed. In membrane fractions of M. gallisepticum, prepared by osmolysis and freeze-thawing, only sealed membranes retained their antibody-binding capacity. Electron microscopical examination of "break-through" colonies from immune growth inhibition zones revealed that the majority of cells in these colonies were destroyed, sometimes limited only by a single-layered membrane and without extracellular antibody coat. An exception from this was the presumedly young cells in the periphery of colonies and in microcolonies which appeared to be intact and had a heavy antibody layer surrounding the cells. Based on these characteristics, a possible sequence of events is suggested eventually leading to destruction of mycoplasma organisms in immune growth inhibition zones.
 ...
PMID:Electron microscopical study of antibody binding to Mycoplasma gallisepticum: indirect immunoferritin labelling. 43 99

Respiratory infection with Mycoplasma pneumoniae evokes immunoglobulin M autoantibody which agglutinates human erythrocytes at 4 degrees C (cold agglutinin) and is specific for I antigen. Cross-reactions between surface antigens of M. pneumoniae and human erythrocytes, previously examined by serological analysis, were examined by transmission and scanning electron microscopy. Ferritin-labeled human antimycoplasmal and rabbit antisera to erythrocyte membrane components reacted with antigens on the surface of both M. pneumoniae and erythrocytes. Adsorption of human erythrocytes to M. pneumoniae was blocked by the same antisera without ferritin label. It is proposed that the cross-reactive specificity lies in peripheral areas of the mycoplasmal cell, probably in a surface carbohydrate which has antigenic identity with erythrocyte glycoprotein.
 ...
PMID:Immune electron microscopy of cross-reactions between Mycoplasma pneumoniae and human erythrocytes. 45 71

Anionic sites on mycoplasma membranes were visualized in the electron microscope by a polycationized ferritin derivative. The technique of thin sectioning was used. Staining prior to fixation led to clustering of ferritin granules on the mycoplasma cell surface. On glutaraldehyde-fixed Mycoplasma mycoides subsp. capri, M. gallisepticum, M. pneumoniae, and Acholeplasma laidlawii, the anionic sites were uniformly distributed over the entire membrane surface. M. hominis did not bind the polycationic ferritin label. Chemical and enzymatic treatments of the mycoplasmas indicated that the anionic sites may be lipid phosphate groups. Isolated M. mycoides subsp. capri membranes were labeled exclusively on only one membrane surface, presumably the outer one. Liposomes prepared from diphosphatidylglycerol and phosphatidylcholine were also labeled by the polycationic ferritin.
 ...
PMID:Ultrastructural visualization of anionic sites on mycoplasma membranes by polycationic ferritin. 77 36

Cell surface hydrophobicity of Mycoplasma hyopneumoniae was evaluated by phase partitioning in a hydrocarbon-aqueous mixture, by hydrophobic interaction chromatography, and by salting out with ammonium sulfate. Results obtained by use of these techniques gave evidence that the cell surface of M hyopneumoniae is weakly hydrophobic, compared with strongly hydrophobic Staphylococcus aureus Cowan I and hydrophilic Klebsiella pneumoniae. After treatment of the organisms with trypsin, M hyopneumoniae became less hydrophobic as measured by hydrophobic interaction chromatography. Significant changes in hydrophobicity were not seen after periodate treatment. Electron microscopy of M hyopneumoniae treated with polycationic ferritin revealed an intermediate, compact, unlabeled layer between the cytoplasmic membrane and an external, heavily labeled layer. Electron microscopy of ferritin-labeled M hyopneumoniae after treatment with trypsin or periodate revealed the intermediate layer to be composed of a trypsin-sensitive protein(s). The outer layer was made of periodate-sensitive carbohydrate(s). Therefore, it appears that proteins in the intermediate layer confer at least part of the total hydrophobicity of the mycoplasmal cell and may contribute to adherence of M hyopneumoniae to target respiratory cells by hydrophobic interactions.
 ...
PMID:Morphologic features and hydrophobicity of the cell surface of Mycoplasma hyopneumoniae. 132 25

Electron microscopy has been used to show that Mycoplasma dispar produces an external capsulelike material in vivo that has an affinity for both ruthenium red and polycationic ferritin. This extracellular material is lost upon passage in culture medium but can be regained with a single passage on bovine lung fibroblast (BLF) cells. To confirm that the extracellular material associated with cell-grown mycoplasmas was the same as that observed in infected calves, rabbit antibodies were produced to purified capsulelike material isolated by protease digestion of cell-grown organisms. These antibodies bound to capsulelike material on the surface of M. dispar cells colonizing the bronchial epithelium of infected calves and to capsulelike material from cell-grown mycoplasmas. Calves infected with M. dispar produced antibodies in lung secretions that were capable of binding to the purified capsulelike material. The Fab fragments of rabbit antibodies to in vitro-produced capsulelike material could block this binding, indicating that the capsulelike material was similar in both in vivo-grown and cell-grown organisms. The carbohydrate nature of the capsular material suggested by the ruthenium red and polycationic staining characteristics was confirmed by its binding to Ricinus communis agglutinin, a galactose-specific lectin. These studies confirm that capsule material produced during infections with M. dispar share antigenic determinants with the material produced under in vitro conditions and that association with mammalian cells induces production of this material.
 ...
PMID:Capsulelike surface material of Mycoplasma dispar induced by in vitro growth in culture with bovine cells is antigenically related to similar structures expressed in vivo. 171 19

Pleuropneumonia is an important disease of swine caused by Actinobacillus pleuropneumoniae. Putative virulence determinants include capsule, lipopolysaccharide, and cytotoxin. We studied the virulence and virulence determinants of 2 strains: CM5 and CM5A of serotype 1. Strain CM5 was isolated from a pig with pleuropneumonia and passaged once in vitro; strain CM5A was a substrain of CM5 passaged 70 times in vitro. Pigs challenge exposed to an aerosol of 1.3 x 10(7) colony-forming units of CM5/ml died within 30 hours; pigs challenge exposed to an aerosol of 1.6 x 10(8) colony-forming units of CM5A/ml survived. The average thickness of the capsular layer was 137 nm in strain CM5 and 53 nm in strain CM5A in bacteria treated with homologous antibody and examined by transmission electron microscopy. Similarly, capsular material binding polycationic ferritin was found in colonies of strain CM5, but not in strain CM5A. The ratio of hexosamine to protein in extracted capsule of CM5 was more than twice that of CM5A. The polyacrylamide gel electrophoretic profile of the lipopolysaccharide, outer membrane proteins, and whole cell proteins did not differ between the 2 strains. Also, the amount of cytotoxin or endotoxin produced by the 2 strains during the logarithmic growth phase was not different. The electrophoretic profile of restriction endonuclease digested DNA was similar, with the exception of bands in the 750- and 620-basepair regions. It was concluded that attenuation of strain CM5A during in vitro passage was a result of reduced capsule production and that encapsulation is an important virulence determinant of A pleuropneumoniae, serotype 1.
 ...
PMID:Characterization of an attenuated strain of Actinobacillus pleuropneumoniae, serotype 1. 233 67

A method is described for the detection of cholesterol in membranes from erythrocytes, mycoplasmas, and bacterial cells by a ferritin-labeling technique. Membranes treated with cereolysin, a bacterial hemolysin which specifically binds to cholesterol, and then treated with ferritin-antitetanolysin, were specifically ferritin-labeled for cholesterol. A similar antigen-antibody system, streptolysin O-ferritin-antistreptolysin, was also used successfully with erythrocyte membranes. There was an uneven distribution of ferritin in erythrocyte membranes suggesting that the distribution of cholesterol may not be entirely random. Mycoplasma gallisepticum was intensely labeled, but Acholeplasma laidlawii with or without cholesterol in the membranes was not labeled, suggesting an unusual location for cholesterol in A. laidlawii membranes. As controls, two of three species of bacterial membranes lacking cholesterol were not ferritin-labeled.
 ...
PMID:Detection of cholesterol in cell membranes by use of bacterial toxins. 462 12

Mycoplasma pneumoniae initiates infection in the human host by attachment to respiratory epithelium. The organism attaches by a specialized terminal structure. Monoclonal antibodies to an organism surface protein (P1) inhibited attachment to respiratory epithelium and were localized to the tip structure by a ferritin antibody label. The P1 protein was degraded by trypsin treatment to smaller polypeptides that possessed the same antigenic determinants as the larger P1 protein when reacted with the specific monoclonal antibody, and evidence has been provided for the existence of multiple antigenic determinants on the attachment protein.
 ...
PMID:Location of attachment moiety on Mycoplasma pneumoniae. 620 59

The application of a protamine-ferritin conjugate for labelling of isolated protoplast membranes of Bacillus subtilis S 13/1 is described. Contrary to Mycoplasma membranes which could only be labelled on the outer side of the membrane, ferritin was deposited on both membrane sides as a single layer without cluster formation.
 ...
PMID:Electron microscopic demonstration of negative surface charges on cytoplasmic membranes of Bacillus subtilis with protamine-ferritin. 680 50

Among the wall-less mycoplasmas only a few species have been identified with a capsule at their cell surface. Mycoplasma penetrans is a recently identified mycoplasma with unique morphology, isolated from HIV-infected patients. Using transmission electron microscopy, it was found that M. penetrans is surrounded by capsular material 11 nm (strain GTU-54-6A1) to 30 nm (strain HF-2) thick, which can be stained with ruthenium red and labelled with cationized ferritin. The polysaccharide composition of this capsule was indicated by its staining with periodic acid-thiocarbohydrazide silver proteinate and the abolition of ruthenium red staining of the cell surface by neuraminidase treatment. In addition, proteinase K treatment of the M. penetrans cells resulted in removal of the capsule, suggesting that polypeptides may contribute in anchoring it to the membrane or in its stability. Two different types of glycosylated material were detected in mycoplasma extracts by SDS-PAGE and periodic acid-Schiff staining. The first component was a high-molecular-mass material, which was heat- and proteinase-K-labile and which probably constitutes the capsular polymer. The other component was a low-molecular-mass glycolipid fraction, which was proteinase-K-, heat- and EDTA-resistant. The identification of a capsule at the M. penetrans cell surface is of particular interest for a mycoplasma which has been shown to adhere to various host cells and to penetrate into their intracellular compartments. The capsule may have significance in the pathogenesis of disease associated with infection by this organism.
 ...
PMID:Identification of two glycosylated components of Mycoplasma penetrans: a surface-exposed capsular polysaccharide and a glycolipid fraction. 961 99


1 2 Next >>