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Dunkel M, Schmidtke G. Trinkwasserhygiene bei Neubauten und Altbausanierung/Inbetriebnahmen. Gesundheitswesen 2014. [DOI: 10.1055/s-0034-1371677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Schmidtke G, Dunkel M. Trinkwasserhygiene: Neue Wege in der Dokumentation „Das Raumbuch“. Gesundheitswesen 2013. [DOI: 10.1055/s-0033-1337588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Dunkel M, Schmidtke G. Der Trinkwasserhygieneplan für einen bestimmungsgemäßen Betrieb. Gesundheitswesen 2013. [DOI: 10.1055/s-0033-1337587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Groettrup M, van den Broek M, Schwarz K, Macagno A, Khan S, de Giuli R, Schmidtke G. Structural plasticity of the proteasome and its function in antigen processing. Crit Rev Immunol 2002; 21:339-58. [PMID: 11922078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The proteasome is the main provider of peptide ligands for major histocompatibility complex class I molecules. During an immune response to pathogens, the proinflammatory cytokine interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha are released, which induce the proteasome subunits LMP2, LMP7, and MECL-1. These replace the constitutively expressed active site subunits of the proteasome (delta, MB1, and Z) leading to a marked change in the cleavage preference of the proteasome and the production of T-cell epitopes. Proteasome activity is further changed by the IFN-gamma-mediated induction of the proteasome regulator PA28alpha/beta and the downregulation of PA28gamma. Why such an extensive exchange of proteasome active site subunits and regulators occurs is still poorly understood. In this article we discuss recent insights in the structural consequences of proteasome reorganization and their effects on epitope generation and shaping of the cytotoxic immune response. Moreover, we review the latest data on how the ubiquitin pathway targets protein antigens for peptide processing and discuss the potential of proteasome inhibitors for the modulation of antigen presentation.
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Affiliation(s)
- M Groettrup
- Research Department, Cantonal Hospital St. Gallen, Switzerland.
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Khan S, de Giuli R, Schmidtke G, Bruns M, Buchmeier M, van den Broek M, Groettrup M. Cutting edge: neosynthesis is required for the presentation of a T cell epitope from a long-lived viral protein. J Immunol 2001; 167:4801-4. [PMID: 11673482 DOI: 10.4049/jimmunol.167.9.4801] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CTLs recognize peptide epitopes which are proteolytically generated by the proteasome and presented on MHC class I molecules. According to the defective ribosomal product (DRiP) hypothesis, epitopes originate from newly synthesized polypeptides which are degraded shortly after their translation. The DRiP hypothesis would explain how epitopes can be generated from long-lived proteins. We examined whether neosynthesis is required for presentation of the immunodominant epitope NP118 of the lymphocytic choriomeningitis virus nucleoprotein, which has a half-life of >3 days. Two days after nucleoprotein biosynthesis was terminated in a tetracycline-regulated transfectant, the presentation of the NP118 epitope ceased. This indicates that NP118 epitopes are generated from newly synthesized nucleoproteins rather than from the long-lived pool of nucleoproteins in the cell. Therefore, the lymphocytic choriomeningitis virus nucleoprotein is the first substrate for which a major prediction of the DRiP hypothesis, namely the requirement for neosynthesis, is shown to hold true.
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Affiliation(s)
- S Khan
- Research Department, Cantonal Hospital, St. Gallen, Switzerland
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Abstract
FAT10 is a ubiquitin-like protein that is encoded in the major histocompatibility complex class I locus and is synergistically inducible with interferon-gamma and tumor necrosis factor alpha. The molecule consists of two ubiquitin-like domains in tandem arrangement and bears a conserved diglycine motif at its carboxyl terminus commonly used in ubiquitin-like proteins for isopeptide linkage to conjugated proteins. We investigated the function of FAT10 by expressing murine FAT10 in a hemagglutinin-tagged wild type form as well as a diglycine-deficient mutant form in mouse fibroblasts in a tetracycline-repressible manner. FAT10 expression did not affect major histocompatibility complex class I cell surface expression or antigen presentation. However, we found that wild type but not mutant FAT10 caused apoptosis within 24 h of induction in a caspase-dependent manner as indicated by annexin V cell surface staining and DNA fragmentation. Wild type FAT10, but not its diglycine mutant, was covalently conjugated to thus far unidentified proteins, indicating that specific FAT10 activating and conjugating enzymes must be operative in unstimulated fibroblasts. Because FAT10 expression causes apoptosis and is inducible with tumor necrosis factor alpha, it may be functionally involved in the programmed cell death mediated by this cytokine.
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Affiliation(s)
- S Raasi
- Research Department, Cantonal Hospital St. Gallen, CH-9007 St. Gallen, Switzerland
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Moradpour D, Grabscheid B, Kammer AR, Schmidtke G, Groettrup M, Blum HE, Cerny A. Expression of hepatitis C virus proteins does not interfere with major histocompatibility complex class I processing and presentation in vitro. Hepatology 2001; 33:1282-7. [PMID: 11343257 DOI: 10.1053/jhep.2001.23793] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Hepatitis C virus (HCV) infection takes a chronic course in the majority of patients. The mechanisms underlying the evasion of the host immune response and viral persistence are poorly understood. In this context, we investigated interactions of HCV proteins with major histocompatibility complex (MHC) class I processing and presentation pathways using cell lines that allow the tetracycline-regulated expression of viral structural and nonstructural proteins. These well-characterized inducible cell lines were found to efficiently process and present endogenously synthesized HCV proteins via MHC class I. Functional MHC class I cell-surface expression and intracellular proteasome activity were not affected by the expression of HCV proteins. These results suggest that viral evasion of the host immune response does not involve interactions of HCV with MHC class I processing and presentation. Other mechanisms, such as interference with the interferon system, may be operative in HCV infection, leading to viral persistence.
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Affiliation(s)
- D Moradpour
- Department of Medicine II, University of Freiburg, Germany
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Abstract
When cells are stimulated with the cytokines IFN-gamma or TNF-alpha, the synthesis of three proteasome subunits LMP2 (beta1i), LMP7 (beta5i), and MECL-1 (beta2i) is induced. These subunits replace the three subunits delta (beta1), MB1 (beta5), and Z (beta2), which bear the catalytically active sites of the proteasome, during proteasome neosynthesis. The cytokine-induced exchanges of three active site subunits of a complex protease is unprecedented in biology and one may expect a strong functional driving force for this system to evolve. These cytokine-induced replacements of proteasome subunits are believed to favour the production of peptide ligands of major histocompatibility complex (MHC) class I molecules for the stimulation of cytotoxic T cells. Although the peptide production by constitutive proteasomes is able to maintain peptide-dependent MHC class I cell surface expression in the absence of LMP2 and LMP7, these subunits were recently shown to be pivotal for the generation or destruction of several unique epitopes. In this review we discuss the recent data on LMP2/LMP7/MECL-1-dependent epitope generation and the functions of each of these subunit exchanges. We propose that these subunit exchanges have evolved not only to optimize class I peptide loading but also to generate LMP2/LMP7/MECL-1-dependent epitopes in inflammatory sites which are not proteolytically generated in uninflamed tissues. This difference in epitope generation may serve to better stimulate T cells in the sites of an ongoing immune response and to avoid autoimmunity in uninflamed tissues.
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Affiliation(s)
- M Groettrup
- Research Department, Cantonal Hospital St. Gall, 9007, St. Gallen, Switzerland.
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Schmidtke G, Emch S, Groettrup M, Holzhutter HG. Evidence for the existence of a non-catalytic modifier site of peptide hydrolysis by the 20 S proteasome. J Biol Chem 2000; 275:22056-63. [PMID: 10806206 DOI: 10.1074/jbc.m002513200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 20 S proteasome is an endoprotease complex that preferentially cleaves peptides C-terminal of hydrophobic, basic, and acidic residues. Recently, we showed that these specific activities, classified as chymotrypsin-like, trypsin-like, and peptidylglutamyl peptide-hydrolyzing (PGPH) activity, are differently affected by Ritonavir, an inhibitor of human immunodeficiency virus-1 protease. Ritonavir competitively inhibited the chymotrypsin-like activity, whereas the trypsin-like activity was enhanced. Here we demonstrate that the Ritonavir-mediated up-regulation of the trypsin-like activity is not affected by specific active site inhibitors of the chymo-trypsin-like and PGPH activity. Moreover, we show that the mutual regulation of chymotrypsin-like and PGPH activities by their substrates as described previously by a "cyclical bite-chew" model is not affected by selective inhibitors of the respective active sites. These data challenge the bite-chew model and suggest that effectors of proteasome activity can act by binding to non-catalytic sites. Accordingly, we propose a kinetic "two-site modifier" model that assumes that the substrate (or effector) may bind to an active site as well as to a second non-catalytic modifier site. This model appears to be valid as it describes the complex kinetic effects of Ritonavir very well. Since Ritonavir partially inhibits major histocompatibility complex class I restricted antigen presentation, the postulated modifier site may be required to coordinate the active centers of the proteasome for the production of class I peptide ligands.
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Affiliation(s)
- G Schmidtke
- Research Department, Cantonal Hospital St. Gall, CH-9007 St. Gallen, Switzerland
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Schwarz K, van Den Broek M, Kostka S, Kraft R, Soza A, Schmidtke G, Kloetzel PM, Groettrup M. Overexpression of the proteasome subunits LMP2, LMP7, and MECL-1, but not PA28 alpha/beta, enhances the presentation of an immunodominant lymphocytic choriomeningitis virus T cell epitope. J Immunol 2000; 165:768-78. [PMID: 10878350 DOI: 10.4049/jimmunol.165.2.768] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The proteasome is a large protease complex that generates most of the peptide ligands of MHC class I molecules either in their final form or in the form of N-terminally extended precursors. Upon the stimulation of cells with IFN-gamma, three constitutively expressed subunits of the 20S proteasome are replaced by the inducible subunits LMP2 (low-molecular mass polypeptide 2), LMP7, and MECL-1 (multicatalytic endopeptidase complex-like-1) to form so-called immunoproteasomes. We show in this study that overexpression of these three subunits in triple transfectants led to a marked enhancement in the H-2Ld-restricted presentation of the immunodominant nonameric epitope NP118, which is derived from the nucleoprotein (NP) of lymphocytic choriomeningitis virus. Overexpression of the alpha and beta subunits of the IFN-gamma-inducible proteasome regulator PA28, in contrast, did not have a comparable effect. In vitro, immunoproteasomes as compared with constitutive proteasomes generated higher amounts of 11- and 12-mer fragments containing the NP118 epitope. These are likely to be cytosolic precursors of NP118, as a proline anchor residue in the second position of NP118 may interfere with TAP-mediated transport of the nonameric epitope itself. In conclusion, we provide evidence that up-regulation of the three inducible subunits, LMP2, LMP7, and MECL-1, can result in a marked improvement of Ag presentation and that, depending on the epitope, PA28 and immunoproteasomes may differentially affect Ag processing.
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Affiliation(s)
- K Schwarz
- Research Department, Cantonal Hospital St. Gall, St. Gallen, Switzerland
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Schmidtke G, Holzhütter HG, Bogyo M, Kairies N, Groll M, de Giuli R, Emch S, Groettrup M. How an inhibitor of the HIV-I protease modulates proteasome activity. J Biol Chem 1999; 274:35734-40. [PMID: 10585454 DOI: 10.1074/jbc.274.50.35734] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human immunodeficiency virus, type I protease inhibitor Ritonavir has been used successfully in AIDS therapy for 4 years. Clinical observations suggested that Ritonavir may exert a direct effect on the immune system unrelated to inhibition of the human immunodeficiency virus, type I protease. In fact, Ritonavir inhibited the major histocompatibility complex class I restricted presentation of several viral antigens at therapeutically relevant concentrations (5 microM). In search of a molecular target we found that Ritonavir inhibited the chymotrypsin-like activity of the proteasome whereas the tryptic activity was enhanced. In this study we kinetically analyzed how Ritonavir modulates proteasome activity and what consequences this has on cellular functions of the proteasome. Ritonavir is a reversible effector of proteasome activity that protected the subunits MB-1 (X) and/or LMP7 from covalent active site modification with the vinyl sulfone inhibitor(125)I-NLVS, suggesting that they are the prime targets for competitive inhibition by Ritonavir. At low concentrations of Ritonavir (5 microM) cells were more sensitive to canavanine but proliferated normally whereas at higher concentrations (50 microM) protein degradation was affected, and the cell cycle was arrested in the G(1)/S phase. Ritonavir thus modulates antigen processing at concentrations at which vital cellular functions of the proteasome are not yet severely impeded. Proteasome modulators may hence qualify as therapeutics for the control of the cytotoxic immune response.
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Affiliation(s)
- G Schmidtke
- Research Department, Cantonal Hospital St. Gall, CH-9007 St. Gallen, Switzerland
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Abstract
A means of regulating the fate of intracellular proteins is their covalent conjugation to ubiquitin-like proteins. A recently discovered ubiquitin-like protein is called "diubiquitin" because it consists of two ubiquitin-like domains in head-to-tail arrangement. Human diubiquitin is encoded at the telomeric end of the MHC class I locus and was previously found to be expressed in dendritic cells and mature B cells. We have extended the expression analysis of diubiquitin by reverse transcriptase-PCR and Northern blotting in primary endothelial cells and human cancer cell lines derived from nine different tissues. Diubiquitin expression was found to be generally and synergistically inducible with the cytokines IFN-gamma and TNF-alpha but not with IFN-alpha. Diubiquitin mRNA expression was induced within 2 h after cytokine stimulation and was independent of protein neosynthesis but dependent on proteasome activity. The mouse homologue of diubiquitin which is also encoded in the MHC class I locus was likewise induced with IFN-gamma and TNF-alpha. A general and synergistic induction with IFN-gamma and TNF-alpha suggests that diubiquitin may exert its functions in antigen presentation or other cellular processes controlled by these two cytokines.
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Affiliation(s)
- S Raasi
- Research Department, Cantonal Hospital St. Gall, St. Gallen, Switzerland
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Groettrup M, Schmidtke G. [Intracellular processing of viral and tumor antigens by proteasomes]. Schweiz Med Wochenschr 1999; 129:1660-5. [PMID: 10588025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Cytotoxic T cells are able to recognise whether a cell of our body is infected by a virus or whether it has acquired mutations leading to tumour formation. The cells show on their surface what kind of proteins are synthesised intracellularly and whether non-self proteins encoded by a virus or tumour antigens are among them. The proteins are presented not as functionally intact proteins but as peptide fragments which originate from their regular intracellular degradation. This fragmentation is accomplished by the proteasome, a large proteinase complex in the cytoplasm and nucleus of all cells. Upon stimulation with the antiviral cytokine interferon-gamma, subunits of the proteasome are exchanged, thus leading to optimised production of peptide antigens. In this review we introduce the system of antigen processing by the proteasome and sum up our latest results on the question how the interferon-gamma-mediated reorganisation of the proteasome occurs and what consequences and benefits this has for the cytotoxic immune response against viruses and tumours.
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Affiliation(s)
- M Groettrup
- Laborforschungsabteilung, Kantonsspital, St. Gallen.
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Küttner G, Kramer A, Schmidtke G, Giessmann E, Dong L, Roggenbuck D, Scholz C, Seifert M, Stigler RD, Schneider-Mergener J, Porstmann T, Höhne W. Characterization of neutralizing anti-pre-S1 and anti-pre-S2 (HBV) monoclonal antibodies and their fragments. Mol Immunol 1999; 36:669-83. [PMID: 10509818 DOI: 10.1016/s0161-5890(99)00074-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Single-chain Fv fragments (scFv) were generated from two murine monoclonal antibodies directed to the neutralizing epitopes of the pre-S1 and pre-S2 region of hepatitis B virus, respectively, using different assembly cloning strategies. The scFv fragments were solubly expressed in E. coli. Dissociation constants were in the nanomolar range for all forms (whole IgG antibodies, Fab fragment and scFv fragments). The epitopes of both antibodies were mapped using solid phase peptide synthesis on continuous cellulose membranes and turned out to be linear determinants. The minimal epitope for the anti-pre-S2 antibody 1F6 was identified to be DPRVRGLYF (amino acid 133-141 of the pre-S region). For the anti-pre-S1 antibody MA 18/7 the minimal epitope proved to be the hexamer LDPAFR (amino acid 30-35 of the pre-S region). Complete substitutional analyses as well as truncation experiments revealed key residues for these antibody-antigen interactions. On the basis of those results we used computer-assisted modeling techniques to suggest models for both antibody-peptide interactions providing insight into the structural basis of these molecular recognitions.
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Affiliation(s)
- G Küttner
- Institut für Biochemie, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany.
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Schmidtke G, Schmucker U, Brittinger G, Höffkes HG. Comparative flow cytometric study of clonal excess in leukaemic peripheral blood from patients suffering from chronic lymphocytic leukaemia (B-CLL) by different antibodies, staining techniques and the effects of blood storage. Clin Lab Haematol 1999; 21:103-12. [PMID: 10342069 DOI: 10.1046/j.1365-2257.1999.00203.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This investigation studied the effects of cell preparation methods, different antibody panels and blood storage on antigen expression of abnormal B lymphocytes from patients with B-CLL. Blood specimens collected in Heparin de novo were processed by using conventional Hypaque-Ficoll density gradient centrifugation and whole blood lysis. These were stored for 3 days at 4 degrees C, 24 degrees C and 30 degrees C. Although clonal excess was detected by all antibody panels, significant differences could be observed in terms of molecules of equivalent fluorochromes (MEF/MESF units). Evaluation of 'weak and strong' staining is dependent on the antibody panel used. Immunofluorescent values for CD19 and CD45 were unchanged at 4 degrees C and 24 degrees C but immunoglobulin staining showed best results when blood was stored at 4 degrees C. Storage at 30 degrees C produced unreliable results. Abnormal B lymphocytes should be analysed immediately after the specimen is obtained. If shipment is necessary they should be kept at 4 degrees C. Surface immunoglobulins are the 'antigens' most sensitive to storage alterations. Sample alterations alone are sufficient to the correct classification of NHL, especially in the case of low-grade NHL.
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Affiliation(s)
- G Schmidtke
- Department of Internal Medicine, Otto-von-Guericke-University of Magdeburg, Germany
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Schmidtke G, Eggers M, Ruppert T, Groettrup M, Koszinowski UH, Kloetzel PM. Inactivation of a defined active site in the mouse 20S proteasome complex enhances major histocompatibility complex class I antigen presentation of a murine cytomegalovirus protein. J Exp Med 1998; 187:1641-6. [PMID: 9584142 PMCID: PMC2212286 DOI: 10.1084/jem.187.10.1641] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Proteasomes generate peptides bound by major histocompatibility complex (MHC) class I molecules. Avoiding proteasome inhibitors, which in most cases do not distinguish between individual active sites within the cell, we used a molecular genetic approach that allowed for the first time the in vivo analysis of defined proteasomal active sites with regard to their significance for antigen processing. Functional elimination of the delta/low molecular weight protein (LMP) 2 sites by substitution with a mutated inactive LMP2 T1A subunit results in reduced cell surface expression of the MHC class I H-2Ld and H-2Dd molecules. Surface levels of H-2Ld and H-2Dd molecules were restored by external loading with peptides. However, as a result of the active site mutation, MHC class I presentation of a 9-mer peptide derived from a protein of murine cytomegalovirus was enhanced about three- to fivefold. Our experiments provide evidence that the delta/LMP2 active site elimination limits the processing and presentation of several peptides, but may be, nonetheless, beneficial for the generation and presentation of others.
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Affiliation(s)
- G Schmidtke
- Zentrum für Experimentelle Medizin (ZEM), Institut für Biochemie, Charité, Humboldt Universität zu Berlin, 10117 Berlin, Germany
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Schmidtke G, Schmidt M, Kloetzel PM. Maturation of mammalian 20 S proteasome: purification and characterization of 13 S and 16 S proteasome precursor complexes. J Mol Biol 1997; 268:95-106. [PMID: 9149144 DOI: 10.1006/jmbi.1997.0947] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The maturation of the eukaryotic 20 S proteasome complex occurs via 13 S and 16 S precursor complexes in a multistep assembly pathway. These precursor complexes contain alpha-subunits as well as unprocessed beta-subunit proproteins. We have purified and characterized the different proteasome assembly intermediates and analysed their ability to support beta-subunit proprotein processing in vitro. Our data show that 13 S and 16 S proteasome precursor complexes differ not only in size but also in their protein content and behaviour during hydrophobic chromatography. By establishing conditions which allowed us to analyse beta-prosubunit maturation in vitro we demonstrate that the processing of the homologous proproteins of the beta-subunits LMP2 and delta essentially takes place in 16 S precursor complexes. No proprotein processing activity was observed in 13 S precursor complexes. Furthermore, proprotein processing in vitro can be inhibited with a proteasome specific inhibitor, but with different efficiency for LMP2 and delta. A peptide, which represents the sequence of the proprotein processing site HGTT, exhibited no inhibitory effect on the processing of either subunit. These data provide further evidence that proprotein processing occurs via an autocatalytic mechanism. Our experiments also demonstrate that the chaperone protein hsc73 is associated with 16 S but not with 13 S precursor complexes. In support of the specificity of this interaction incubation with ATP leads to the dissociation of hsc73 from 16 S complexes and to the formation of high molecular weight aggregates. Prosubunit processing in isolated 16 S complexes does not, however, result in the formation of proteolytically active 20 S proteasomes which may be due to the fact that not all beta-subunits can be efficiently processed in vitro. In contrast to previous assumptions subunit processing and formation of proteolytic activity do not coincide and final 20 S complex assembly seems to represent in part a separate event which requires additional factors or proteins which are not present or active in the purified 16 S precursor complexes.
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Affiliation(s)
- G Schmidtke
- Zentrum für Experimentelle Medizin (ZEM), Institut für Biochemie, Charité, Humboldt Universität zu Berlin, Germany
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Abstract
Eukaryotic 20S proteasomes are complex oligomeric proteins. The maturation process of the 14 different alpha- and beta-subunits has to occur in a highly coordinate manner. In addition beta-subunits are synthesized as proproteins and correct processing has to be guaranteed during complex maturation. The structure formation can be subdivided in different phases. The knowledge of the individual phases is summarized in this publication. As a first step the newly synthesized monomers have to adopt the correct tertiary structure, a process that might be supported in the case of the beta-subunits by the intramolecular chaperone activity postulated for the prosequences. Subsequently the alpha-subunits form ring-like structures thereby providing docking sites for the different beta-subunits. The result most likely is a double ring structure (13S precursor) representing half-proteasomes, which contain immature proproteins. Two 13S precursors associate to form the proteolytically inactive 16S assembly intermediate which still contains unprocessed beta-monomers. In addition the chaperone Hsc73 is present within these particles suggesting an essential role during the structure formation process. The processing of monomers with an N-terminal threonine occurs within the 16S particles and is achieved autocatalytically by two subsequent processing events finally leading to the mature, active 20S proteasome.
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Affiliation(s)
- M Schmidt
- Zentrum für experimentelle Medizin, Institut für Biochemie, Medizinische Fakultät der Humboldt Universität zu Berlin (Charité), Germany
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20
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Schmidtke G, Kraft R, Kostka S, Henklein P, Frömmel C, Löwe J, Huber R, Kloetzel PM, Schmidt M. Analysis of mammalian 20S proteasome biogenesis: the maturation of beta-subunits is an ordered two-step mechanism involving autocatalysis. EMBO J 1996. [DOI: 10.1002/j.1460-2075.1996.tb01081.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Schmidtke G, Kraft R, Kostka S, Henklein P, Frömmel C, Löwe J, Huber R, Kloetzel PM, Schmidt M. Analysis of mammalian 20S proteasome biogenesis: the maturation of beta-subunits is an ordered two-step mechanism involving autocatalysis. EMBO J 1996; 15:6887-98. [PMID: 9003765 PMCID: PMC452515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Maturation of eukaryotic 20S proteasomes involves the processing of beta-subunits by limited proteolysis. To study the processing mechanism we analysed different point mutations of the beta-subunit LMP2 in transfected human T2 cells. Here we show that the presence of the intact Gly-1Thr1 consensus motif and Lys33 are essential for correct processing. Mutation of Thr1, the active site residue in mature subunits, or of Lys33, results in complete inhibition of processing at the consensus site. In addition, proprotein processing in vitro of wild-type LMP2, incorporated in immature 16S precursor complexes, can be blocked by a proteasome-specific inhibitor. While the processing of inhibitor-treated wild-type proprotein was completely prevented, the site-directed mutagenesis of LMP2 results in processing intermediates carrying an extension of 8-10 residues preceding Thr1, suggesting an additional cleavage event within the prosequence. Furthermore, exchange of mammalian prosequences interferes with processing efficiency and suggests subunit specificity. Based on our data we propose a model for self-activation of proteasomal beta-subunits in which residue Thr1 serves as nucleophile and Lys33 as proton donor/acceptor. We provide evidence that subunit processing of mammalian beta-subunits proceeds via a novel ordered two-step mechanism involving autocatalysis.
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Affiliation(s)
- G Schmidtke
- Institut für Biochemie, Charité, Humboldt Universität zu Berlin, Germany
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Feist E, Dörner T, Kuckelkorn U, Schmidtke G, Micheel B, Hiepe F, Burmester GR, Kloetzel PM. Proteasome alpha-type subunit C9 is a primary target of autoantibodies in sera of patients with myositis and systemic lupus erythematosus. J Exp Med 1996; 184:1313-8. [PMID: 8879203 PMCID: PMC2192827 DOI: 10.1084/jem.184.4.1313] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Autoantibodies occur in low frequencies among patients with myositis characterizing only distinct subsets of this disease. Most of these known antibodies are directed to enzymatically active complexes. The 20S proteasome represents an essential cytoplasmatic protein complex for intracellular nonlysosomal protein degradation, and is involved in major histocompatibility complex class I restricted antigen processing. In this study we investigated whether the 20S proteasome complex is an antibody target in myositis and in other autoimmune diseases. 34 sera of poly/dermatomyositis patients were assayed for antiproteasomal antibodies using enzyme-linked immunosorbent assay, immunoblot, and two-dimensional non-equilibrium pH gradient electrophoresis (NEPHGE). Sera was from patients with systemic lupus erythematosus (SLE), mixed connective tissue disease, and rheumatoid arthritis; healthy volunteers served as controls. In 62% (21/34) of the cases sera from patients with myositis and in 58% (30/52) of the cases sera from patients with SLE reacted with the 20S proteasome. These frequencies exceeded those of sera from patients with mixed connective tissue disease, rheumatoid arthritis, and healthy controls. The alpha-type subunit C9 of the 20S proteasome was determined to be the predominant target of the autoimmune sera in myositis and SLE. Lacking other frequent autoantibodies in myositis, the antiproteasome antibodies are the most common humoral immune response so far detected in this disease entity.
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Affiliation(s)
- E Feist
- Department of Medicine III, Charité University Hospital, Humboldt University of Berlin, Germany
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Höffkes HG, Schmidtke G. [Quality control of flow cytometry by means of fluorescent particles ("beads")]. Infusionsther Transfusionsmed 1996; 23:115-6. [PMID: 8777361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H G Höffkes
- Klinik für Hämatologie/Onkologie, Otto-von-Guericke-Universität Magdeburg, Deutschland
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Höffkes HG, Schmidtke G, Schmucker U, Brittinger G. Lymphocyte gating of peripheral blood in patients with leukemic low-grade non-Hodgkin's lymphoma by multiparametric flow cytometry. Eur J Med Res 1996; 1:215-22. [PMID: 9445762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The standardized fluorescence intensity as expressed in molecules of equivalent soluble fluorescence (MESF) of lymphocytes from normal individuals and patients suffering from low-grade non-Hodgkin's-lymphomas was obtained comparing different staining patterns of CD45(FITC) and CD20(PerCP). After standardization of the flow cytometer using standardized fluorescent particles ('beads') significant differences could be obtained for hairy cell leukemia, chronic lymphocytic leukemia and immunocytomas in the peripheral blood. In contrast, centroblastic-centrocytic as well as centrocytic lymphomas showed no significant variations as compared to normal peripheral blood lymphocytes. According to these results, a new lymphocyte gating procedure was established by adding CD14(PE) and three-color measurement by CD45/CD14/CD20 staining of peripheral blood using erythrocyte lysis. The established gating procedure leads to a crucial discrimination and quantification of abnormal and normal lymphocytes per one measurement, whereas the 'leucogate' as defined by CD45/CD14 staining alone was insufficient for correct lymphocyte gate setting. In conclusion, the different staining of CD45 and CD20 in leukemic peripheral blood should be considered when fluorescence intensity or atypical peaks occurred in flow cytometric histograms suggesting for abnormal cell populations. In addition, it is possible to use this information to classify low-grade lymphomas.
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Affiliation(s)
- H G Höffkes
- Division of Hematology, Department of Medicine, University of Essen, Germany
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Höfftesa HG, Schmidtke G. Qualitätskontrolle durchflußzytometrischer Meßverfahren mittels fluoreszenter Partikel («beads»). Transfus Med Hemother 1996. [DOI: 10.1159/000223274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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26
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Höffkes HG, Schmidtke G, Uppenkamp M, Schmücker U. Multiparametric immunophenotyping of B cells in peripheral blood of healthy adults by flow cytometry. Clin Diagn Lab Immunol 1996; 3:30-6. [PMID: 8770500 PMCID: PMC170243 DOI: 10.1128/cdli.3.1.30-36.1996] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The investigation of patients suffering from malignant lymphomas of the B-cell type requires flow cytometric immunophenotyping. Several reports described the expression of almost all B lineage antigens on normal and abnormal B lymphocytes. Thus, immunophenotyping of lymphomas must be interpreted in the context of the reference values obtained for healthy control individuals. For this purpose multiparametric flow cytometric analysis offers the unique feature for lymphocyte subset analysis. In the present study B lymphocytes in the peripheral blood of healthy adults were investigated by multiparametric flow cytometric immunophenotyping for the detection of the frequency (in percent) of antigens provided by the revised European-American classification of lymphoid neoplasms (REAL) classification. Thus, 84 healthy adults were investigated and grouped by age (average ages were as follows: group 1, 25.38 years; group 2, 33.86 years; group 3, 44.17 years; group 4, 55.67 years; group 5, 66.67 years). Analysis was done for surface immunoglobulins (kappa and lambda chains of immunoglobulin M [IgM] and IgD) as well as CD10, CD11c, CD23, CD38, CD103, FMC-7, and B-B4. Three-color immunophenotyping was performed for kappa/CD19/CD5, lambda/CD19/CD5, surface IgM/surface IgD/CD19, FMC-7/CD19/CD5, CD103/CD11c/CD19, CD10/CD23/CD19, and CD38/B-B4/CD19 by live gating of CD19+ events (n = 2,000). Although some numerical differences could be obtained for the different groups, statistical differences (P < 0.005) could only be obtained for the CD19+/CD5+ B-cell subset, which was decreased in the elderly patients (group 5). The established two-color and three-color stainings will serve as a basis for future multiparametric immunophenotyping of abnormal lymphocytes (e.g., for patients suffering from non-Hodgkin's lymphoma of the B-cell type).
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Affiliation(s)
- H G Höffkes
- Department of Medicine, University of Essen, Germany
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27
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Höffkes H, Schmidtke G, Schmücker U, Uppenkamp M, Brittinger G. Immunophenotyping of B lymphocytes by multiparametric flow cytometry in bone marrow aspirates and peripheral blood of healthy adults. Eur J Med Res 1995; 1:2-8. [PMID: 9392686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Establishing reference ranges by multiparametric immunophenotyping of mature B cells in bone marrow and peripheral blood of healthy adults is of interest because the detection of bone marrow infiltration, persistance of light chain restriction as well as discrimination between reactice and malignant lymphocytes are important applications of B-cell immunophenotyping. To determine the pattern of antigens as expressed by malignant mature B lymphocytes, bone marrow aspirates and peripheral blood of healthy adults in the present study were investigated for the presence and percentage frequency of those antigens as defined for immunophenotyping of B-cells by the REAL-Classification. For this purpose analysis of CD19 positive B lymphocytes by Live Gate analysis was performed. The established two-color as well as three-color stainings will serve as a basis for future investigations designed to test multiparametric analysis of B lymphocytes in bone marrow aspirates and peripheral blood. In conclusion, all investigated antibodies stained in varying percentage frequency on B-cell subtypes and statistical significant differences could be considered only for the CD19/CD10 staining in bone marrow aspirates. On the basis of this analysis, all the reported lineage antigen combinations are present both in malignant B lymphocytes as well as normal B cells in considerable percentage frequency. These findings are of important interest for follow-up investigations of patients with non-Hodgkin s lymphomas by multiparametric immunophenotyping.
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Affiliation(s)
- H Höffkes
- University of Essen, Division of Hematology, Department of Medicine, Essen, Germany
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Höffkes HG, Schmidtke G, Schmücker U, Uppenkamp M, Brittinger G. Immunophenotyping of B lymphocytes by multiparametric flow cytometry in bone marrow aspirates of healthy adults. Ann Hematol 1995; 71:123-8. [PMID: 7548330 DOI: 10.1007/bf01702647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Establishing reference ranges by multiparametric immunophenotyping of mature B cells in bone marrow of healthy adults is of interest because the detection of bone marrow infiltration and persistence of light chain restriction, as well as discrimination between reactive and malignant lymphocytes are important applications of B-cell immunophenotyping. To determine the pattern of antigens as expressed by malignant mature B lymphocytes in the present study, bone marrow aspirates of healthy adults were investigated for the presence and percentage frequency of those antigens as defined for immunophenotyping of B cells by the REAL Classification. For this purpose, analysis of CD19-positive B lymphocytes by 'live gate' analysis was performed. The established two-color as well as three-color stainings will serve as a basis for future investigations designed to test multiparametric analysis of B lymphocytes in bone marrow aspirates. All investigated antibodies stained with varying percentage frequency on B-cell subtypes, and no statistical significant difference was found between bone marrow aspirates of women and those of men. On the basis of this analysis, all the reported lineage antigen combinations are present both in malignant B lymphocytes and in normal B cells in considerable percentage frequency. These findings are of importance for follow-up investigations of patients with non-Hodgkin's lymphomas by multiparametric immunophenotyping.
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Affiliation(s)
- H G Höffkes
- University of Essen, Department of Medicine, Germany
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Schmidtke G, Kohn W, Klocke U, Knothe M, Riedel WJ, Wolf H. Diode laser spectrometer for monitoring up to five atmospheric trace gases in unattended operation. Appl Opt 1989; 28:3665-3670. [PMID: 20555754 DOI: 10.1364/ao.28.003665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
An automated diode laser spectrometer for recording concentrations of trace gases is described. It has been tested for unattended operation in the laboratory and at an atmospheric surveillance station for several months. The sensitivities reached are, e.g., 50 ppt for NO(2) and 300 ppt for NO. In an optical path length of 100 m the lowest extinction measured in unattended operation is ~1.5 x 10(-5) for a measuring time of ~60 s. Recordings of trace gases are shown for urban and rural atmospheric conditions.
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Schmidtke G, Seidl P, Wita C. Airglow-solar spectrometer instrument (20-700 nm) aboard the San Marco D/L satellite. Appl Opt 1985; 24:3206. [PMID: 18224029 DOI: 10.1364/ao.24.003206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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31
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Schmidtke G, Henneberg P, Hager KH, Busch F, Reinhardt D. Parabolic telescope and spectrometer combination. Appl Opt 1980; 19:1822-1832. [PMID: 20221130 DOI: 10.1364/ao.19.001822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The properties of a nonfocusing collimating parabolic telescope are studied in detail by a ray-tracing method. The best optical quality with respect to coma and astigmatism is calculated for rays close to the optical axis of the telescope. For rectangular fields of view the borders are not sharp because of the aberration. A combination of a parabolic telescope and an echelle-type spectrometer gives very high spectral resolution. Wadsworth, Ebert-Fastie, and other types of spectrometers are equally well suited to be combined with this telescope. For some cases spot diagrams demonstrate the optical performance. In addition, diffraction by the aperture and its implications are discussed.
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Crifo JF, Seidl P, Delaboudinière JP, Schmidtke G. Compact resonance absorption spectrometer to monitor the profile of the solar He 58.4 nanometer line. Rev Sci Instrum 1980; 51:321. [PMID: 18647059 DOI: 10.1063/1.1136210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A miniature resonance absorption spectrometer is able to perform a routine monitoring in space of the line profile and intensity of the He i resonance line from the solar disk with a time resolution of about 1 min and a spectral resolution of 10(5). It consists of a predispersive spectrometer incorporating a helium gas absorption cell. The instrument has been designed to meet a small size and weight. It was tested on a rocket flight in June 1976. The construction, principles of operation, and laboratory calibration of the instrument are presented. Its capability to resolve details of the order of 0.3 pm FWHM and its sensitivity to the intensity of line wings three order of magnitudes fainter than the peak of the line have been established by laboratory investigation.
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Affiliation(s)
- J F Crifo
- Laboratoire de Physique Stellaire et Planetaire, B.P. N degrees 10, 91370 Verrieres le Buisson, France
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Hsieh KC, Keppler E, Schmidtke G. Forward photoemission from thin carbon foils. Appl Opt 1979; 18:3732-3733. [PMID: 20216685 DOI: 10.1364/ao.18.003732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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34
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Seidl P, Schmidtke G, Acton LW. Diffraction properties of hydrogen-phthalate-crystals in the 0.1-2-nm region. Appl Opt 1977; 16:578-581. [PMID: 20168545 DOI: 10.1364/ao.16.000578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
By means of single- and double-crystal spectrometers, the integrated and the percent reflectivities and the halfwidth of the KAP, NaAP, RbAP, and NH(4)AP crystals have been measured in several orders within the (0.147-1.76-nm) spectral range. The reflection plane for all crystals is the 001 plane, which is also the cleavage plane. Among the selected crystals RbAP shows the highest reflectivity. Comparison with the theory leads in a first approximation to the conclusion that all these crystals are of nearly perfect and not of a mosaiclike structure.
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35
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Schmidtke G. Infrared-XUV telescope for multipurpose applications. Appl Opt 1977; 16:244-247. [PMID: 20168460 DOI: 10.1364/ao.16.000244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A nonfocusing, collimating telescope is described to be used for spectral regions from x-rays to the ir. In combination with optical components such as spectrometers, there is a wide range of applications in space research, earth sciences, and related fields.
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Abstract
During the mission of AEROS-A satellite the recorded calibration data exhibited a strong variation of the magnetic electron multiplier efficiency. Drastic changes do correlate with temperature; however, a clear separation of the temperature effect cannot be derived from the measurements. In space they have been impeded, e.g., by long-term efficiency changes, while in the laboratory ion feedback and other effects interfered with the measurements. The results affect the design of future space experiments especially for solar XUV measurements.
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Abstract
The transmission of diffraction filters depends mainly on the geometrical parameters, the slit width 2d, the distance x(n,n-1) of the slits from each other, and the number n of the slits. Therefore the filter curve may be "shifted" continuously throughout the XUV spectral region simply by changing the corresponding parameters. This is discussed in detail. Diffraction filters can be utilized in a wide range of experiments in solar, stellar, and laboratory spectroscopy. As is shown for three well known optical arrangements, diffraction filters improve the signal-to-noise ratio considerably, to some extent simplifying the experiment at the same time. Consequently this new technique is an efficient optical tool.
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