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

Major surface antigens of Bactmbrane complex by gentle methods, purified, and characterized immunochemically. A lipopolysaccharide (LPS) was found to be chemically distinct from the LPS of facultative gram-negative bacteria in that it lacked two core sugars, 2-keto-3-deoxyoctonate and heptose, as well as beta-hydroxymyristic acid, the predominant fatty acid in the lipid A moiety. The LPS was further atypical in that it had a very low level of biologic activity. A capsular polysaccharide was demonstrated morphologically by electron microscopy with ruthenium red staining and a ferritin-labeled antibody technique. This antigen was shown to be subspecies-specific by indirect immunofluorescence. Antibody to the capsular polysaccharide was measured by an enzyme-linked immunospecific assay. The presence of a relatively impotent LPS and a surface capsular antigen may partly explain the rarity of bacteremia and septic shock due to B. melaninogenicus subspecies asaccharolyticus and the common association of this organism with abscess formation.
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PMID:Immunochemical characterization of surface antigens of Bacteroides melaninogenicus. 4 22

When cells of a wild-type Eschericia coli O8 strain bearing a complete lipopolysaccharide were incubated for alkaline phosphatase reaction product and examined by electron microscopy, the depostion of lead salts was to be observed primarily within the periplasmic space. A similar treatment of cells derived from this strain, which bears a highly abbreviated lipopolysaccharide, showed a mixed cell surface and periplasmic localization of reaction product, suggesting a surface association of a portion of the enzyme. To further explore this possibility, ferritin-antibody conjugates against the active enzyme and its irreversibly dissociated subunits were prepared and allowed to react with cells of both strains. The results obtained from these experiments revealed the presence of both the active enzyme and inactive subunits of the enzyme at the cell surface of the mutant strain. The evidence obtained offers further proof of the validity of the reaction product deposition technique and indicates that alkaline phosphatase may be associated with some component of the outer membrane in this organism. The observation of enzyme subunits at the cell surface further suggests that an association of these subunits with structural components of the cell envelope may provide a locus at which they may dimerize to form active enzyme.
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PMID:Cell surface-localized alkaline phosphatase of Escherichia coli as visualized by reaction product deposition and ferritin-labeled antibodies. 32 32

Chinese hamster ovary (CHO . K1 . PRO) cell growth was inhibited by addition of a gram-negative bacterial lipopolysaccharide (LPS) to the cell culture medium. Growth inhibition began after three or four days of incubation, was dose-dependent up to a maximum at an LPS concentration of 500 microgram/ml and was accompanied by cell shape changes and enhanced cytoplasmic vacuolization. Formation of bizarre CHO . K1 . PRO cell shapes and vacuole formation were most pronounced after seven days of incubation with LPS and could be observed by light and electron microscopy. An LPS-resistant cell population was obtained by intermittent in vitro exposure to high levels of LPS; these variant cells or clones derived from them failed to display growth inhibition in the presence of LPS. A clone from the LPS-resistant variant population showed altered cell properties compared to the parental cell line which included changes in cell morphology, adhesion, and endocytosis. Parental cells was markedly density-inhibited, whereas the cariant clone exhibited considerable growth after confluency. The LPS-resistant variant cells showed a more elongated morphology than the parental line. No significant differences were observed between rates of detachment of parental and variant cells when sparse cultures of either line were removed from tissue culture dishes by ethylenediaminetetracetate (EDTA). However, at confluency approximately 100% of the variant cells versus 35% of the parental cells were removed by EDTA in one hour. Measurements of 125I-ferritin uptake by parental and variant cells showed approximately twenty-fold and twofold increases, respectively, in uptake induced by LPS when compared to untreated control cultures.
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PMID:Lipopolysaccharide effects on sensitive and resistant variant Chinese hamster ovary cell lines. 74 76

Labelling of cell walls or outer membranes from Salmonella typhimurium with ferritin-conjugated antibodies directed against the polysaccharide moiety of the lipopolysaccharide gave the following results: 1. Cell walls or outer membranes from which the mucopeptide had been removed by lysozyme digestion at 0 degrees C carried the label on the outer face of the membrane. 2. When the murein layer was removed by either lysozyme or trypsin at physiological temperature (25-37 degrees C) subsequent labelling showed the lipopolysaccharide to be present on both membrane faces. 3. This reorientation could be achieved by a 1-min treatment of the membranes at 37 degrees C. 4. Glutaraldehyde fixation of the outer membranes did not entirely prevent but somewhat inhibited the temperature-induced reorientation process. 5. The same reorientation phenomenon was observed in lysozyme spheroplasts, which were prepared at 37 degrees C and were subsequently lysed in hypotonic medium at 0 degrees C. These observations are discussed as evidence for a transmembrane movement of lipopolysaccharide, which only takes place in areas where the mucopeptide layer is defective, and only when the temperature is sufficiently high to allow such movement.
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PMID:Asymmetrical distribution and artifactual reorientation of lipopolysaccharide in the outer membrane bilayer of Salmonella typhimurium. 80 74

We used lipopolysaccharide (LPS) to provoke immune responses and observed the changes in the localization of iron and iron-related proteins, such as transferrin receptor, ferritin and hemosiderin in the rat spleen. After intravenous injection of 250 micrograms LPS (salmonella minnesota R595), spleen weight and serum IgM levels increased, cells incorporating 5-bromo-2'-deoxyuridine (BrdU), and transferrin receptor positive cells increased in the peripheral portion of the periarterial lymphoid sheath (PALS), the marginal zone (MZ) and the follicles. Ferritin positive cells increased markedly in the white pulp and stainable iron increased in the marginal metallophils (MM) and in the macrophages in the MZ and the outer PALS. Even in iron deficient rats, a similar change was observed for the localization of iron and iron-related proteins after injection of LPS. After injection of 0.4 mg keyhole limpet hemocyanin (KLH), changes similar to but less pronounced than that in the LPS injected rats were observed for serum IgM levels and for the localization of iron and iron-related proteins. These results showed that the iron in the MM and the macrophages in the white pulp have a dynamic response to immunological challenges and suggested that they play some role in immune responses.
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PMID:Mobilization of iron and iron-related proteins in rat spleen after intravenous injection of lipopolysaccharides (LPS). 144 84

The passage of different-sized marker molecules over the lower respiratory tract into the blood circulation during pulmonary inflammation induced by dextran, endotoxin [i.e., lipopolysaccharide from Escherichia coli (LPS)], or ferritin was assessed in the rat. Bovine immunoglobulin G (BIgG, mol wt = 150,000 Da), bovine serum albumin (BSA, mol wt = 67,000 Da), and the nonapeptide 1-deaminocysteine-8-D-arginine vasopressin (dDAVP, mol wt = 1,067 Da) were used as permeability markers after intratracheal instillation. The pathophysiological indexes of a proceeding lung inflammation were increased total cell number, changed leukocyte proportions and increased total protein content obtained in bronchoalveolar lavage, and lung edema formation shown as an increased lung wet-dry weight difference. Intratracheal instillation of dextran induced a moderate neutrophil invasion into the lungs but had no effect on the passage of the different markers over the lungs (BIgG 1.8 +/- 0.6%, BSA 3.5 +/- 1.2%, dDAVP 26.1 +/- 20.7%) compared with control rats instilled with the markers alone (1.8 +/- 0.4%, 4.1 +/- 1.3%, 20.0 +/- 3.8%, respectively). Endotoxin administration resulted in markedly higher lavage cell counts and lung edema concomitantly with an increased lung passage of the markers (3.2 +/- 0.9%, 22.0 +/- 6.1%, 33.3 +/- 12.0%, respectively; P less than 0.01-P less than 0.001). The highest marker passage was obtained when the inflammation was most severe, i.e., after ferritin administration (17.6 +/- 2.3%, 60.0 +/- 6.7%, 41.6 +/- 6.9%, respectively; P less than 0.001), which resulted in markedly elevated lavage cell numbers and protein content as well as edema formation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lung to blood passage of different-sized molecules during lung inflammation in the rat. 172 3

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.
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PMID:Characterization of an attenuated strain of Actinobacillus pleuropneumoniae, serotype 1. 233 67

The terminal step in the maturation of mononuclear cells from circulating monocytes to resident macrophages is accompanied by dramatic changes in cell morphology and physiology. Applying a cultivation system which allows peripheral monocytes to undergo terminal maturation in vitro under absolutely endotoxin-free conditions, we have determined the pattern of expression of a set of eight genes by mRNA phenotyping. The results can be summarized as follows: the two protease inhibitors alpha 1-antitrypsin and alpha 2-macroglobulin show a inverse pattern of expression. alpha 1-Antitrypsin mRNA is repressed, alpha 2-macroglobulin mRNA is strongly induced during maturation to macrophages. Therefore, these two genes are excellent markers of the terminal maturation. In addition, ferritin-light-chain mRNA progressively increases during the course of differentiation, providing a further marker for maturation. Gene expression as a function of activation was studied in mononuclear cells stimulated with bacterial endotoxin (lipopolysaccharide). In monocytes, complement-factor-B, interleukin-1 and interleukin-6 mRNAs are drastically induced upon lipopolysaccharide activation whereas lysozyme RNA is strongly repressed. However, the ability of all four genes to respond to endotoxin was markedly diminished or abolished in mature macrophages, indicating that susceptibility to a certain type of activation may be restricted to a specific stage of maturation. Our data show that mRNA phenotyping is excellently suited for the characterization of the differentiation and activation state of mononuclear phagocytes.
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PMID:Characterization of mononuclear-phagocyte terminal maturation by mRNA phenotyping using a set of cloned cDNA probes. 258 84

Expression of alpha 1 proteinase inhibitor (alpha 1-PI) in human mononuclear phagocytes may provide a local mechanism for inactivation of serine proteases at sites of tissue injury, thereby preventing incidental damage to surrounding tissue and allowing for orderly initiation of repair. We have previously shown that serine (neutrophilic or pancreatic) elastase and lipopolysaccharide (LPS) each mediate an increase in the expression of alpha 1-PI in human peripheral blood monocytes and bronchoalveolar macrophages. In this study we demonstrate that elastase and LPS have an additive positive regulatory effect on alpha 1-PI expression. Distinct pretranslational and translational mechanisms of action for elastase and LPS, respectively, account for the additive effect. The possibility that translational regulation of alpha 1-PI by LPS involves a mechanism analogous to that of the yeast gene GCN4 during amino acid starvation and that of the human ferritin gene in response to iron is discussed.
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PMID:Distinct and additive effects of elastase and endotoxin on expression of alpha 1 proteinase inhibitor in mononuclear phagocytes. 326 70

Evidence is presented that the ferritin-inhibitable, Ia+ monocyte progenitor in murine marrow requires two signals for stimulation of clonal proliferation. Escherichia coli K235 lipopolysaccharide (LPS) at 0.1 ng/ml enhanced macrophage colony formation by 25 to 70% in murine marrow cultures stimulated with colony-stimulating factor (CSF-1). The progenitors which responded to LPS and CSF-1 represented a distinct subpopulation. Pretreatment of marrow cells with complement plus anti-Ia, anti-H2, anti-asialo GM1, and anti-Mac-1 antibodies specifically depleted the two-signal-requiring progenitors. In addition, the same progenitors were depleted by preincubation with hydroxyurea, indicating that these cells were in cell cycle when removed from the marrow. When compared with the quiescent progenitors, the Ia+, cycling cells were more sensitive to the antiproliferative effects of interferon alpha/beta but were more resistant to inhibition by E prostaglandins. Pretreatment with T cell-specific antibodies and complement specifically enhanced cloning of quiescent progenitors without affecting cloning of the Ia+, cycling subpopulation. Moreover, rat liver ferritin at 10(-8) to 10(-10) M specifically inhibited clonal proliferation of the Ia+ progenitors. Finally, the requirement for LPS as the additional stimulant could be replaced by the addition of haplotype-specific anti-Ia antibody to CSF-stimulated cultures. In contrast to LPS, anti-IA was competitive with inhibitory ferritin in clonal proliferation of the Ia+ progenitors. The significance of these observations in regulation of monocytopoiesis is discussed.
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PMID:Characterization of a two-signal-dependent, Ia+ mononuclear phagocyte progenitor subpopulation that is sensitive to inhibition by ferritin. 345 88


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