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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rat liver after extrahepatic biliary obstruction was studied by SEM and TEM in correlation with basic histochemical techniques. Cholestasis was verified by serological methods. The biochemical data (increase in serum bilirubin values, a gradual lowering of the albumin fraction), in agreement with the ultrastructural results of a sparse RER, suggested a gradual decrease of the protein synthetic activity of the hepatocyte. SEM and TEM revealed numerous fat-storing cells, closely associated with patches of connective fibrils in the subendothelial spaces. Further ultrastructural observations demonstrated: a) a proliferation of the intrahepatic biliary tree (ductular proliferation, including newly formed ducts with sacculation and diverticuli); b) an increased number of canaliculo-ductular junctions and, c) an increase in the length of the bile canalicular network due to its tortuous course, pocketing and side branching. The occurrence of an intact cytoplasmic barrier separating the bile canalicular lumen from the Disse's space together with the results obtained by retrograde infusion of ferritin into the biliary tree suggested that the regurgitation pathway by ductular reabsorption and by transhepatocytic transport is the best documented and most acceptable, at least in the rat.
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PMID:A scanning and transmission electron microscopic study of experimental extrahepatic cholestasis in the rat. 733 53

In situ functional assay of each ferritin molecule in single-layer 2D arrays for horse spleen apoferritin and recombinant horse L- and human H-apoferritins was conducted by observing the iron-cores formed in the arrays by TEM. The study of the time-course, pH-dependence, and temperature-dependence of the function confirmed the iron-core formation to be due to the native function of apoferritins in array. Dark-field TEM imaging revealed that there was crystallinity in the cores in the array of recombinant human H-apoferritin. This iron-core formation was perfectly preserved in the array even after 3 months of storage at room temperature and low humidity. Moreover, about 50% of the function was found to remain in the array after it was exposed to 150 degrees C in vacuum for 1 hr.
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PMID:Single molecular functional assay of ferritin arrays. 920 35

Recently, Quintana and others published the results of TEM investigations of ferritin cores extracted from the brain tissue of patients suffering from progressive supranuclear palsy (PSP) and Alzheimer's disease (AD). These ferrihydrite (fFe2O3.9H2O) cores from the iron storage protein ferritin were found to contain a ferrous (Fe2+) iron-bearing biomineral with cubic structure similar to the magnetite standards which were measured. This is a highly important result as magnetic and electron microscopy analysis has demonstrated the presence of magnetite (Fe3O4) and maghemite (gammaFe2O3) in human brain tissue.
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PMID:On the structural form of iron in ferritin cores associated with progressive supranuclear palsy and Alzheimer's disease. 1087 42

A large number of different proteins or protein domains have been investigated as possible scaffolds to engineer antibody-like molecules. We have previously shown that the TEM-1 beta-lactamase can accommodate insertions of random sequences in two loops surrounding its active site without compromising its activity. From the libraries that were generated, active enzymes binding with high affinities to monoclonal antibodies raised against prostate-specific antigen, a protein unrelated to beta-lactamase, could be isolated. Antibody binding was shown to affect markedly the enzyme activity. As a consequence, these enzymes have the potential to be used as signaling molecules in direct or competitive homogeneous immunoassay. Preliminary results showed that beta-lactamase clones binding to streptavidin could also be isolated, indicating that some enzymes in the libraries have the ability to recognize proteins other than antibodies. In this paper, we show that, in addition to beta-lactamases binding to streptavidin, beta-lactamase clones binding to horse spleen ferritin and beta-galactosidase could be isolated. Affinity maturation of a clone binding to ferritin allowed obtaining beta-lactamases with affinities comprised between 10 and 20 nM (Kd) for the protein. Contrary to what was observed for beta-lactamases issued from selections on antibodies, enzyme complexation induced only a modest effect on enzyme activity, in the three cases studied. This kind of enzyme could prove useful in replacement of enzyme-conjugated antibodies in enzyme-linked immunosorbant assays (ELISA) or in other applications that use antibodies conjugated to an enzyme.
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PMID:TEM-1 beta-lactamase as a scaffold for protein recognition and assay. 1202 49

The dissociation of apoferritin into subunits at pH 2 followed by its re-formation at pH 8.5 in the presence of hexacyanoferrate(III) gave rise to a solution containing hexacyanoferrate(III) trapped within the apoferritin and hexacyanoferrate(III) outside it. The addition of Fe(II) to the dialyzed solution resulted in the appearance of the characteristic Prussian blue color. The UV-vis spectrum of this solution showed a broad band centered at 710 nm, and the IR spectrum contained a broad-medium band at 2083 cm(-1). Both features are consistent with the charge-transfer band and the C[bond]N stretching mode in the Fe(II)[bond]CN[bond]Fe(III) fragment of PB. TEM images of the obtained Prussian blue solution showed discrete spherical electron dense iron particles with an average size of about 5 nm. This represents a new route for preparing metallic nanoparticles that offers control over the size and protection against aggregation. Moreover, the fact that the particles are obtained by reaction of hexacyanoferrate(III) and iron(II) building blocks opens up the possibility of obtaining not only homo- but also heterobimetallic nanoparticles.
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PMID:Nanoparticles of Prussian blue ferritin: a new route for obtaining nanomaterials. 1457 62

This paper reports novel findings of an investigation of the formation of water-soluble iron oxide nanoparticles from iron-storage protein ferritin. The strategy couples thermal removal of the protein shell on a planar substrate and subsequent sonication in aqueous solution under controlled temperature. Advantages of using ferritin as a precursor include well-defined core size, core composition, water-solubility and processibility. The formation of the nanoparticles was characterized using TEM, UV-Vis and FTIR techniques. Iron oxide nanoparticles in the size range of 5-20 nm diameters were produced. In addition to thermal treatment conditions, the sonication temperature of the nanoparticles in water was found to play an important role in determining the resulting particle size. This simple and effective route has important implications to the design of composite nanoparticles for potential magnetic, catalytic, biomedical sensing and other nanotechnological applications.
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PMID:Formation of water-soluble iron oxide nanoparticles derived from iron storage protein. 1557 Sep 48

Nanoparticles of iron phosphate, iron arsenate, iron molybdate, and iron vanadate were synthesized within the 8 nm interior of ferritin. The synthesis involved reacting Fe(II) with ferritin in a buffered solution at pH 7.4 in the presence of phosphate, arsenate, vanadate, or molybdate. O2 was used as the oxidant to deposit the Fe(III) mineral inside ferritin. The rate of iron incorporation into ferritin was stimulated when oxo-anions were present. The simultaneous deposition of both iron and the oxo-anion was confirmed by elemental analysis and energy-dispersive X-ray analysis. The ferritin samples containing iron and one of the oxo-anions possessed different UV/vis spectra depending on the anion used during mineral formation. TEM analysis showed mineral cores with approximately 8 nm mineral particles consistent with the formation of mineral phases inside ferritin.
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PMID:Nanophase iron phosphate, iron arsenate, iron vanadate, and iron molybdate minerals synthesized within the protein cage of ferritin. 1584 28

In an attempt to design a targeted drug delivery system to tumors' over-expressing H-ferritin specifically recognized by a monoclonal antibody, AMB8LK, a cationic emulsion - AMB8LK conjugate was prepared. A novel cross-linker molecule bearing maleimide group was synthesized and added to cationic emulsion formulation for AMB8LK Fab' fragment covalent coupling. NMR spectroscopy confirmed the cross-linker synthesis and the preservation of the active maleimide function. SDS gel-electrophoresis results corroborated the formation of the Fab' fragment. Different densities of Fab' fragments (10-200 Fab'/oil droplet) were conjugated to emulsion droplet interface and no changes in the physico-chemical properties were observed ( approximately 120 nm size and zeta potential of approximately +30 mV). The coupling efficiency ranged from 55% to 70% and was visualized by TEM showing gold particles attached to the droplet interface. Cell culture studies demonstrated specific binding to cells as confirmed by the occurrence of the marked reduction in binding when free AMB8LK Mab was incubated before adding the AMB8LK-emulsion conjugate to the cells. The coupling of AMB8LK Fab' fragment to the cationic emulsion increased the cells uptake by 50% as compared to non-conjugated respective cationic emulsion. Appropriate conditions were, thus, identified for coupling AMB8LK Fab' fragment to cationic emulsion without altering the specificity and affinity of the Mab fragment to the tumor antigen.
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PMID:The design and evaluation of a novel targeted drug delivery system using cationic emulsion-antibody conjugates. 1622 21

Ferritin, the iron storage protein, was recently suggested to be a candidate reporter for the detection of gene expression by magnetic resonance imaging (MRI). Here we report the generation of TET:EGFP-HAferritin (tet-hfer) transgenic mice, in which tissue-specific inducible transcriptional regulation of expression of the heavy chain of ferritin could be detected in vivo by MRI. We show organ specificity by mating the tet-hfer mice with transgenic mice expressing tetracycline transactivator (tTA) in liver hepatocytes and in vascular endothelial cells. Tetracycline-regulated overexpression of ferritin resulted in specific alterations of the transverse relaxation rate (R(2)) of water. Transgene-dependent changes in R(2) were detectable by MRI in adult mice, and we also found fetal developmental induction of transgene expression in utero. Thus, the tet-hfer MRI reporter mice provide a new transgenic mouse platform for in vivo molecular imaging of reporter gene expression by MRI during both embryonic and adult life.
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PMID:MRI detection of transcriptional regulation of gene expression in transgenic mice. 1735 27

Solid nanotubes comprising alpha-Fe2O3 nanoparticles were prepared from iron-storage protein ferritin. Their structure, magnetic properties, and photocatalytic activities were characterized. The initial ferritin nanotube precursors were fabricated using alternating layer-by-layer depositions of poly-L-arginine (PLA) and ferritin into a track-etched polycarbonate membrane (pore diameter, 400 nm) with subsequent dissolution of the template. The obtained uniform cylinders of (PLA/ferritin)3 (outer diameter, 410 +/- 14 nm) were calcinated at 500 degrees C under air, yielding reddish-brown iron oxide nanotubes. The one-dimensional hollow structure remained perfect, but its diameter, wall thickness, and maximum length were markedly diminished. Disappearance of the protein shell and the PLA layers were confirmed using IR and EDX spectroscopy. Subsequent SEM, TEM, and XPS measurements showed that the tubular walls comprise fine alpha-Fe2O3 nanoparticles with a 5 nm diameter. These alpha-Fe2O3 nanotubes demonstrated superparamagnetic properties with a blocking temperature of 37 K and efficient photocatalytic activity for degradation of 4-chlorophenol.
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PMID:Solid nanotubes comprising alpha-Fe2O3 nanoparticles prepared from ferritin protein. 2016


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