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Scholz M, Konen W, Tombrock S, Fricke B, Adams L, von Düring M, Hentsch A, Heuser L, Harders AG. Development of an Endoscopic Navigation System Based on Digital Image Processing. ACTA ACUST UNITED AC 2010. [DOI: 10.3109/10929089809149841] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Scholz M, Dick S, Fricke B, Schmieder K, Engelhardt M, Tombrock S, Pechlivanis I, Harders A, Konen W. Consideration of ergonomic aspects in the development of a new endoscopic navigation system. Br J Neurosurg 2009; 19:402-8. [PMID: 16455561 DOI: 10.1080/02688690500390037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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: 10/25/2022]
Abstract
During the development of new navigation systems, the ergonomic aspects of the accompanying software are seldom taken into account. The VN system is a navigation system working with real and previously stored neuroendoscopic images. The latter enable the module to execute virtual back movement, e.g. in case of bleeding. Several other modules are offered. The aim of the study was the ergonomic analysis of different modules and their learning curves in cadaveric heads. The endoscope was navigated by the neurosurgeon while another person operated the computer. A total of 128 experiments were performed with two software versions. When the landmark tracking module was used, a real learning curve could be observed. By contrast, testing the measurement module did not produce a learning curve. A significant reduction of the time required by the three modules investigated could be observed with software version 2. The module for virtual back movement works best with a minimum time of 20 s for image storage. During machine-human interactions ergonomic software use is important, especially if operative procedures are performed.
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Affiliation(s)
- M Scholz
- Department of Neurosurgery, Ruhr University Bochum, Germany.
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Yu YJ, Dong CZ, Li JG, Fricke B. The excitation energies, ionization potentials, and oscillator strengths of neutral and ionized species of Uuq (Z=114) and the homolog elements Ge, Sn, and Pb. J Chem Phys 2008; 128:124316. [DOI: 10.1063/1.2838985] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Sateesh A, Vogel J, Dayss E, Fricke B, Dölling K, Rothe U. Surface modification of medical-grade polyurethane by cyanurchloride-activated tetraether lipid (a new approach for bacterial antiadhesion). J Biomed Mater Res A 2008; 84:672-81. [PMID: 17635021 DOI: 10.1002/jbm.a.31345] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [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: 11/11/2022]
Abstract
The surface of high-grade medical polyurethane was chemically modified and coated with tetraether lipid, employing cyanurchloride as coupling agent. The surfaces were initially grafted with hexamethylene diisocyanate and subsequently treated with water or hexamethylene diamine to generate free amino groups on the surface. This provides a convenient way for covalent coupling of tetraether lipids. These lipid-coated surfaces were investigated for bacterial adhesion using Pseudomonas aeruginosa. All lipid-coated surfaces significantly reduced bacterial adhesion. Surface topology and individual modification steps were controlled by contact angle measurements, attenuated total reflectance infrared spectroscopy, X-ray photoelectron spectroscopy, confocal laser scanning microscopy, and environmental scanning electron microscopy. This new surface modification approach may reduce the adhesion of bacteria on biomaterials.
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Affiliation(s)
- Ananthu Sateesh
- Institute of Bioengineering, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
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Pershina V, Anton J, Fricke B. Intermetallic compounds of the heaviest elements and their homologs: The electronic structure and bonding of MM′, where M=Ge, Sn, Pb, and element 114, and M′=Ni, Pd, Pt, Cu, Ag, Au, Sn, Pb, and element 114. J Chem Phys 2007; 127:134310. [DOI: 10.1063/1.2770712] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Sudhaus S, Fricke B, Schneider S, Stachon A, Klein H, von Düring M, Hasenbring M. Die Cortisol-Aufwachreaktion bei Patienten mit akuten und chronischen Rückenschmerzen. Schmerz 2007; 21:202-4, 206-11. [PMID: 17265015 DOI: 10.1007/s00482-006-0521-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [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: 10/23/2022]
Abstract
BACKGROUND Peculiarities of the hypothalamic-pituitary-adrenal axis activity in stress-related pain-disorders and potential relations with psychological risk factors of pain chronicity have been discussed controversially. MATERIAL AND METHODS The cortisol awakening responses of 31 low back pain patients (14 acute, 17 chronic) and 14 healthy controls were compared. In addition the interrelations between awakening response and chronic stress as well as depressive mood and - for the first time - maladaptive painprocessing and -copingstrategies were investigated. RESULTS The groups did not differ in their cortisol awakening responses. Chronic stress, depressive mood and maladaptive cognitive painprocessing did not correlate with the awakening response. There were, however, significant interrelations between awakening responses and the behavioral paincoping-strategies. CONCLUSIONS Behavioral paincoping-strategies should be considered as a potentially important contributing psychological factor in the relation between the activity of the hypothalamic-pituitary-adrenal axis and stress-related pain disorders.
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Affiliation(s)
- S Sudhaus
- Abteilung für Medizinische Psychologie und Medizinische Soziologie, Ruhr-Universität Bochum, Bochum.
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Abstract
Fully relativistic four-component density functional theory with the general gradient approximation calculations have been performed to determine the adsorption energy and position of the superheavy element 112 on a Au surface. Extended cluster as well as embedded cluster calculations were used to simulate the surface which allow for the top, bridge, and hollow adsorption sites without losing the advantage of symmetry considerations. Comparison with analogous calculations of the adsorption of the homologue element Hg allows to predict the adsorption of element 112 at a bridge site with a binding energy of 0.67 eV.
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Fricke B, Bergmann R, Sorger H, Aurich H. Optimierung von Kulturbedingungen für Acinetobacter calcoaceticus beim Wachstum auf n-Alkanen in einem Laborfermentor. J Basic Microbiol 2007. [DOI: 10.1002/jobm.19820220603] [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: 11/07/2022]
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Altenhofer P, Schierhorn A, Fricke B. Agarose isoelectric focusing can improve resolution of membrane proteins in the two-dimensional electrophoresis of bacterial proteins. Electrophoresis 2006; 27:4096-111. [PMID: 16983635 DOI: 10.1002/elps.200600051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [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: 11/07/2022]
Abstract
2-D separation of bacterial membrane proteins is still difficult despite using high-resolution IPG-IEF/SDS-PAGE. We were searching for alternative methods to avoid typical problems such as precipitation, low solubility, and aggregation of membrane proteins in the 1-D separation with IPG-IEF. Blue native electrophoresis (BNE) and agarose IEF (A-IEF) were tested for their separation capacity and their capability of replacing IPG-IEF in the first dimension. SDS-PAGE was chosen for the second dimension on account of its outstanding resolution. We could confirm that only A-IEF was a useful replacement for the IPG-IEF in the first dimension resulting in 2-D protein distributions with additional membrane protein spots not being found after IPG-IEF/SDS-PAGE. A second interesting result was that the agarose IEF mediates the possibility of separation of membrane proteins in a partially native state in the first dimension. This native A-IEF resulted in drastically changed spot patterns with an acidic shift of nearly all spots and divergent distribution of proteins compared to non-native A-IEF and IPG-IEF. We found out that native and non-native A-IEF are powerful tools to supplement IPG-IEF/SDS-PAGE.
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Affiliation(s)
- Pia Altenhofer
- Medical Faculty, Institute of Physiological Chemistry, Martin Luther University, Halle, Saale, Germany.
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Abstract
There is accumulating evidence that transenvelope efflux pumps of the resistance, nodulation, cell division protein family (RND) are excreting toxic substances from the periplasm across the outer membrane directly to the outside. This would mean that resistance of Gram-negative bacteria to organic toxins and heavy metals is in fact a two-step process: one set of resistance factors control the concentration of a toxic substance in the periplasm, another one that in the cytoplasm. Efficient periplasmic detoxification requires periplasmic toxin sensing and transduction of this signal into the cytoplasm to control expression of the periplasmic detoxification system. Such a signal transduction system was analyzed using the Cnr nickel resistance system from Cupriavidus (Wautersia, Ralstonia, Alcaligenes) metallidurans strain CH34. Resistance is based on nickel efflux mediated by the CnrCBA efflux pump encoded by the cnrYHXCBAT metal resistance determinant. The products of the three genes cnrYXH transcriptionally regulate expression of cnr. CnrY and CnrX are membrane-bound proteins probably functioning as anti sigma factors while CnrH is a cnr-specific extracytoplasmic functions (ECF) sigma factors. Experimental data provided here indicate a signal transduction chain leading from nickel in the periplasm to transcription initiation at the cnr promoters cnrYp and cnrCp, which control synthesis of the nickel efflux pump CnrCBA.
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Affiliation(s)
- Gregor Grass
- Institut für Mikrobiologie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099, Halle, Germany, European Community
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Scholz M, Tombrock S, Konen W, Fricke B, Pechlivanis I, Engelhardt M, Schmieder K, Harders A. Application of a Newly Developed Visual Navigation System in Humans. First Results. ACTA ACUST UNITED AC 2005; 48:67-72. [PMID: 15906199 DOI: 10.1055/s-2004-830229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 10/25/2022]
Abstract
A visual navigation system (VN) was developed which uses intraoperatively stored endoscopic images together with their specific 3D-address. A special calibration enables one to recalculate the distortion of the endoscopic images. Several modules (e. g., landmark tracking, virtual back-movement) are offered to the neurosurgeon. The system was tested in 12 human subjects during neuroendoscopic interventions and worked without problems in nearly all cases. The possibilities of digital image navigation can be used especially for control of instrument movement in case of red-out situations or blurred vision. Many further developments of the VN system are possible in order to increase the safety of neuroendoscopic interventions.
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Affiliation(s)
- M Scholz
- Department of Neurosurgery, Ruhr-University Bochum, Bochum, Germany.
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Pershina V, Bastug T, Fricke B. Relativistic effects on the electronic structure and volatility of group-8 tetroxides MO4, where M=Ru, Os, and element 108, Hs. J Chem Phys 2005; 122:124301. [PMID: 15836372 DOI: 10.1063/1.1862241] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of relativistic effects on properties and volatility of the group-8 tetroxides MO4, where M=Ru, Os, and element 108, Hs, was studied on the basis of results of the fully relativistic (four component) and nonrelativistic density functional theory calculations. Relativistic effects were shown to increase bond strengths and decrease bond lengths in these molecules. They are responsible for a decrease in molecular polarizabilities and an increase in ionization potentials. The effects are much stronger in HsO4 than in the lighter congeners. Relativistic effects were also shown to slightly decrease dispersion interaction energies of RuO4, OsO4, and HsO4 with an inert (quartz or silicon nitride) surface, i.e., they increase volatility of these compounds as studied in the "one-atom-at-a-time" gas-phase chromatography experiments. They do, however, not influence the trend in group 8: both relativistically and nonrelativistically, volatility should change as RuO4<OsO4<HsO4. The reason for that is identical trends in the relativistic and nonrelativistic space distributions of the valence d electrons.
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Affiliation(s)
- V Pershina
- Gesellschaft für Schwerionenforschung, D-64291 Darmstadt, Germany
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Grass G, Otto M, Fricke B, Haney CJ, Rensing C, Nies DH, Munkelt D. FieF (YiiP) from Escherichia coli mediates decreased cellular accumulation of iron and relieves iron stress. Arch Microbiol 2004; 183:9-18. [PMID: 15549269 DOI: 10.1007/s00203-004-0739-4] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 09/30/2004] [Accepted: 10/01/2004] [Indexed: 11/28/2022]
Abstract
The Escherichia coli yiiP gene encodes an iron transporter, ferrous iron efflux (FieF), which belongs to the cation diffusion facilitator family (CDF). Transcription of fieF correlated with iron concentration; however, expression appeared to be independent of the ferrous iron uptake regulator Fur. Absence of FieF led to decreased growth of E. coli cells in complex growth medium but only if fur was additionally deleted. The presence of EDTA was partially able to relieve this growth deficiency. Expression of fieF in trans rendered the double deletion strain more tolerant to iron. Furthermore, E. coli cells exhibited reduced accumulation of (55)Fe when FieF was expressed in trans. FieF catalyzed active efflux of Zn(II) in antiport with protons energized by NADH via the transmembrane pH gradient in everted membrane vesicles. Using the iron-sensitive fluorescent indicator PhenGreen-SK encapsulated in proteoliposomes, transmembrane fluxes of iron cations were measured with purified and reconstituted FieF by fluorescence quenching. This suggests that FieF is an iron and zinc efflux system, which would be the first example of iron detoxification by efflux in any organism.
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Affiliation(s)
- Gregor Grass
- Institut für Mikrobiologie, Martin-Luther-Universität Halle, Kurt-Mothes-Str. 3, Halle 06120, Germany.
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Scholz M, Fricke B, Mönnings P, Brendel B, Schmieder K, Siebers S, von Düring M, Ermert H, Harders A. Vibrography: first experimental results in swine brains. ACTA ACUST UNITED AC 2004; 47:79-85. [PMID: 15257479 DOI: 10.1055/s-2004-818450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 10/26/2022]
Abstract
OBJECT The aim of this study was to determine whether vibrography, an ultrasound-based real-time strain imaging method for registering the elastic properties of tissue, is superior to conventional ultrasound imaging techniques for detecting low-contrast space-occupying lesions in brain tissue and for delineating the boundaries between such lesions and the surrounding tissue. METHODS As our experimental model we used swine brains taken from freshly slaughtered pigs. After injecting agarose into these brains at different depths, we compared both the conventional ultrasonographic images and the elastographic images of the region of interest with the corresponding anatomical brain sections. RESULTS In 83.6 % of the experiments, it was possible to detect the polymerized agarose in the brain tissue with vibrographic techniques. In 17 experiments agarose lesions which were not detectable by ultrasound were visualized via vibrography. Furthermore, statistical analysis revealed that elastography is a more precise tool than conventional ultrasound for determining lesion size. CONCLUSION These findings indicate that vibrography is a promising real-time imaging method with numerous potential applications in the field of neurosurgery. Visualization of the elastic properties provides the neurosurgeon with additional data on the lesion and the boundary between the lesion and the surrounding tissue.
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Affiliation(s)
- M Scholz
- Department of Neurosurgery, Ruhr University Bochum, Bochum, Germany.
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Anton J, Ishii T, Fricke B. An ab initio study of the magnetic ground states of organic molecules of di-resp. tetramethyl types as examples with a non-collinear density functional method. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Grass G, Schierhorn A, Sorkau E, Müller H, Rücknagel P, Nies DH, Fricke B. Camelysin is a novel surface metalloproteinase from Bacillus cereus. Infect Immun 2004; 72:219-28. [PMID: 14688099 PMCID: PMC343988 DOI: 10.1128/iai.72.1.219-228.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Revised: 09/02/2003] [Accepted: 10/10/2003] [Indexed: 11/20/2022] Open
Abstract
Bacillus cereus frequently causes food poisoning or nosocomial diseases. Vegetative cells express the novel surface metalloproteinase camelysin (casein-cleaving metalloproteinase) during exponential growth on complex, peptide-rich media. Camelysin is strongly bound to the cell surface and can be solubilized only by detergents or butanol. Camelysin spontaneously migrates from the surface of intact bacterial cells to preformed liposomes. The complete sequence of the camelysin-encoding gene, calY, was determined by reverse PCR on the basis of the N-terminal sequence and some internal tryptic cleavage peptides. The calY gene codes for a polypeptide of 21.569 kDa with a putative signal peptide of 27 amino acids (2.513 kDa) preceding the mature protein (19.056 kDa). Although the predicted amino acid sequence of CalY does not exhibit a typical metalloprotease consensus sequence, high-pressure liquid chromatography-purified camelysin contains one zinc ion per protein molecule. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and tryptic peptide mass fingerprinting confirmed the identity of this zinc-binding protein as CalY. Disruption of the calY gene results in a strong decrease in the cell-bound proteolytic activity on various substrates.
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Affiliation(s)
- Gregor Grass
- Institute for Microbiology, Faculty of Life Sciences, Martin Luther University, D-06097 Halle, Germany
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Argent AC, Chetty MC, Fricke B, Bertrand Y, Philippe N, Khogali S, von Düring M, Delaunay J, Stewart GW. A family showing recessively inherited multisystem pathology with aberrant splicing of the erythrocyte Band 7.2b ('stomatin') gene. J Inherit Metab Dis 2004; 27:29-46. [PMID: 14970744 DOI: 10.1023/b:boli.0000016624.21475.de] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 11/12/2022]
Abstract
The case of a French child, born of consanguineous parents of Tunisian origin, is described. He showed a severe multisystem disease with dyserythropoietic, sideroblastic anaemia, delayed neurological development with hypotonia and convulsions, salt-losing nephropathy, chronic watery diarrhoea, lactic acidosis with mitochondrial dysfunction, brittle hair, hypergammaglobulinaemia, fatty liver with intermittent transaminasaemia, and terminal pulmonary fibrosis. Two siblings, of both sexes, were stillborn; two more lived only a short time. One sister is alive and well. SDS gel analysis of the red cell membranes showed a deficiency within 'Band 7' at 32 kDa. Analysis of the gene encoding 'stomatin', or 'erythrocyte membrane protein 7.2b', the principal protein of 'Band 7', revealed a complex series of aberrant spliceforms centred around exon 3, for which no explanatory genomic lesion could be found. The true underlying molecular cause of this condition remains obscure, but it suggests that the stomatin gene should be studied in other cases.
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Affiliation(s)
- A C Argent
- Department of Medicine, University College London School of Medicine, Rayne Institute, London, UK
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Fricke B, Stewart GW, Treharne K, Mehta A, Knöpfle G, Friedrichs N, Müller KM, Düring MV. Expressionsmuster des integralen Membranproteins Stomatin im bronchopulmonalen System unter normalen und pathologischen Bedingungen. Pneumologie 2003. [DOI: 10.1055/s-2003-815350] [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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Fricke B, Stewart GW, Treharne K, Mehta A, Knöpfle G, Friedrichs N, Müller KM, Düring MV. Expressionsmuster des integralen Membranproteins Stomatin im bronchopulmonalen System unter normalen und pathologischen Bedingungen. Pneumologie 2003. [DOI: 10.1055/s-2003-822455] [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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Anton J, Hirata M, Fricke B, Pershina V. Improved density functional calculations including magnetic effects for RfCl4 and its homologues. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
The human red cell has proved to be an invaluable model cell for the study of many aspects of membrane structure and function. It has a series of transport pathways which mediate the movements of the univalent cations Na and K, which are either identical or similar to systems in other human tissues, including the human kidney. The balance between the energy-consuming NaK pump and a 'passive leak' component maintains a net deficit of cations within the cell, which defends the cell volume against osmotic swelling. There exist a series of dominantly inherited human red cell conditions, gathered under the generic title 'hereditary stomatocytoses', in which the so-called 'passive leak' to Na and K is pathologically increased. In the more severe variants this compromises the integrity of the cell and the patients suffer haemolytic anaemia. Some less severe variants present with pseudohyperkalaemia caused by loss of K from red cells on storage of blood at room temperature. The most severe variants show a deficiency in a widely distributed 'raft' protein known as stomatin. The stomatin protein is homologous to the 'podocin' protein, the gene for which is mutated in a recessively inherited form of nephrotic syndrome. Among other possible functions, both proteins could be involved in the trafficking of membrane proteins to and from the plasma membrane.
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Affiliation(s)
- G W Stewart
- Department of Medicine, University College London, Rayne Institute, London, UK.
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Abstract
First full-relativistic density functional calculations with the extension of the spin-polarization functional for the relativistic density functional theory in their collinear and noncollinear form are presented here for the molecular system Pt2. The agreement with experiment is very good.
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Affiliation(s)
- J Anton
- Universität Kassel, Fachbereich Physik, D-34109 Kassel, Germany
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Pershina V, Bastug T, Jacob T, Fricke B, Varga S. Intermetallic compounds of the heaviest elements: the electronic structure and bonding of dimers of element 112 and its homolog Hg. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)01428-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [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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Pyykko P, Li J, Bastug T, Fricke B, Kolb D. Valence photoelectron spectrum of osmium tetroxide: evidence for 5p semicore effects? Inorg Chem 2002. [DOI: 10.1021/ic00060a034] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pershina V, Fricke B. electronic Structure and Properties of the Group 4, 5, and 6 Highest Chlorides Including Elements 104, 105, and 106. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100077a008] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ionova GV, Pershina V, Johnson E, Fricke B, Schaedel M. Redox reactions for Group 5 elements, including element 105, in aqueous solutions. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100205a086] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pershina V, Fricke B. Group 6 Oxychlorides MOCl4, where M = Mo, W, and element 106 (Sg): Electronic Structure and Thermochemical Stability. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100001a025] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Johnson E, Fricke B, Jacob T, Dong CZ, Fritzsche S, Pershina V. Ionization potentials and radii of neutral and ionized species of elements 107 (bohrium) and 108 (hassium) from extended multiconfiguration Dirac–Fock calculations. J Chem Phys 2002. [DOI: 10.1063/1.1430256] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fricke B, Drössler K, Willhardt I, Schierhorn A, Menge S, Rücknagel P. The cell envelope-bound metalloprotease (camelysin) from Bacillus cereus is a possible pathogenic factor. Biochim Biophys Acta 2001; 1537:132-46. [PMID: 11566257 DOI: 10.1016/s0925-4439(01)00066-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel membrane proteinase of the nosocomial important bacteria species Bacillus cereus (synonyms: camelysin, CCMP) was purified up to homogeneity as was shown by mass spectrometry in its amphiphilic form. Camelysin is a neutral metalloprotease with a molecular mass of 19 kDa. Its unique N-terminus Phe-Phe-Ser-Asp-Lys-Glu-Val-Ser-Asn-Asn-Thr-Phe-Ala-Ala-Gly-Thr-Leu-Asp-Leu-Thr-Leu-Asn-Pro-Lys-Thr-Leu-Val-Asp-(Ile-Lys-Asp)- was not detected in the protein data bases during BLAST searches, but in the partially sequenced genome of Bacillus anthracis, coding for an unknown protein. Cleavage sites of the membrane proteinase for the insulin A- and B-chains were determined by mass spectrometry and N-terminal sequencing. Camelysin prefers cleavage sites in front of aliphatic and hydrophilic amino acid residues (-OH, -SO3H, amido group), avoiding bulky aromatic residues. The internally quenched fluorogenic substrates of the matrix metalloproteases 2 and 7 were cleaved with the highest efficiency at the Leu-decrease-Gly or Leu-decrease-Ala bond with the smaller residue in the P1' position. The protein specificity is broad--all various kinds of casein were cleaved as well as acid-soluble collagen, globin and ovalbumin; intact insulin was destroyed only to a low extent. Actin, collagen type I, fibrinogen, fibrin, alpha2-antiplasmin and alpha1-antitrypsin were cleaved. The protease formed SDS-stable complexes with Glu-plasminogen and antithrombin III, visible after SDS electrophoresis by gold staining and Western blot. The CCMP-plasminogen complex caused a partial activation of plasminogen to plasmin. Camelysin interacts with proteins of the blood coagulation cascade and could facilitate the penetration of fibrin clots and of the extracellular matrix during bacterial invasion.
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Affiliation(s)
- B Fricke
- Institute of Physiological Chemistry, Medical Faculty, Martin Luther University, Halle, Saale, Germany.
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Pershina V, Bastug T, Fricke B, Varga S. The electronic structure and properties of group 8 oxides MO4, where M=Ru, Os, and Element 108, Hs. J Chem Phys 2001. [DOI: 10.1063/1.1379579] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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35
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Fricke B, Andres KH, Von Düring M. Nerve fibers innervating the cranial and spinal meninges: morphology of nerve fiber terminals and their structural integration. Microsc Res Tech 2001; 53:96-105. [PMID: 11301485 DOI: 10.1002/jemt.1074] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [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: 11/11/2022]
Abstract
Pachymeninx and leptomeninx of cranial cavity and spine are considerably different in their collagenous fiber texture, cellular composition, vascularization, and innervation. The majority of meningeal nerve fibers terminate as free nerve endings whereas encapsulated and lamellated nerve terminals additionally occur in higher vertebrates including man. With respect to nerve fiber classification, arborization pattern, topography, and organization of the microenvironment at the termination site afferent and efferent nerve terminals are differentiated. Only the dura mater and the pial subcompartment of the leptomeninx possess the morphological prerequisites for neurogenic inflammation. In the current review, the results of morphological studies regarding the meningeal innervation including the sites of CSF (cerebrospinal fluid) production and absorption are discussed with emphasis on their structure-function relationships.
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Affiliation(s)
- B Fricke
- Department of Neuroanatomy, Institute of Anatomy, Ruhr University, Bochum, Germany.
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36
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Varga S, Fricke B, Nakamatsu H, Mukoyama T, Anton J, Geschke D, Heitmann A, Engel E, Baştuğ T. Response to “Comment on ‘Four-component relativistic density functional calculations of heavy diatomic molecules’ ” [J. Chem. Phys. 113, 2506 (2000)]. J Chem Phys 2000. [DOI: 10.1063/1.482071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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37
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Scholz M, Fricke B, Tombrock S, Hardenack M, Schmieder K, von Düring M, Konen W, Harders A. Virtual image navigation: a new method to control intraoperative bleeding in neuroendoscopic surgery. Technical note. J Neurosurg 2000; 93:342-50. [PMID: 10930024 DOI: 10.3171/jns.2000.93.2.0342] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [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]
Abstract
In this neuroendoscopic study the authors tested the newly developed "red-out module" of their visual navigation system that enables the neurosurgeon to achieve hemostasis if total visualization is lost due to hemorrhage ("red out") within the visual field. An optical position measurement system connected to the endoscope guarantees that digitized endoscopic images are coupled with the accurate endoscopic position. Computerized images are simultaneously stored with their respective position data, and this creates a virtual anatomical landscape. The system was tested in in vivo bleeding conditions in a rat model. Artificial endoscopic cavities were created in the inguinal, pelvic, and jugular regions in rats to imitate the conditions of the human ventricular system. Two experimental settings were tested: Technique I, in which a computer landmark has been previously determined at the point where the vessel will be lesioned; and Technique II, in which a landmark has been previously set in the surrounding area of the vessel. Immediately after hemorrhage obscures the visual field (red out), the computer automatically displays the virtual images on a separate monitor. The previously set landmarks and the graphic overlay of the coagulation fiber enable the surgeon to navigate within the operative field based on the virtual images and to perform coagulation at the site of the lesion. A total of 175 vessels were coagulated: 43 arteries and 132 veins. In using Technique I, 130 (90.9%) of 143 vessels and in using Technique II, 26 (81.2%) of 32 arteries were successfully coagulated. The authors' data revealed that virtual image guidance has the potential to be a helpful tool in neuroendoscopy.
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Affiliation(s)
- M Scholz
- Department of Neurosurgery, Ruhr-University Bochum, and Center of Neuroinformatics, Germany.
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38
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Scholz M, Konen W, Tombrock S, Fricke B, Adams L, von Düring M, Hentsch A, Heuser L, Harders AG. Development of an endoscopic navigation system based on digital image processing. Comput Aided Surg 2000; 3:134-43. [PMID: 9888200 DOI: 10.1002/(sici)1097-0150(1998)3:3<134::aid-igs5>3.0.co;2-t] [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] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We developed a new system to couple the endoscope to an optical position measurement system (OPMS) so that the image frames from the endoscope camera can be labeled with the accurate endoscopic position. This OPMS is part of the EasyGuide Neuro navigation system, which is used for microsurgery and neuroendoscopy. Using standard camera calibration techniques and a newly developed system calibration, any 3-dimensional (3-D) world point can be mapped onto the view from the endoscope. In particular, we can display the coordinates of any anatomical landmark of the patient as it is viewed from the current position of the camera. This and other image-processing techniques are applied to the labeled frame sequence in order to offer the neurosurgeon a variety of control modules that increase the safety and flexibility of neuroendoscopic operations. Several modules, including a new motion alarm system and the "tracking" and "virtual map" modules, were tested in a human cadaveric model using the frontal and occipital approaches. A failure rate of 8.6% was experienced during testing of the first version of the software, but the second version was 100% successful. Thus, an endoscopic navigation system based on digital image processing has been developed that could be a revolutionary advance in image-guided surgery.
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Affiliation(s)
- M Scholz
- Department of Neurosurgery, Ruhr University Bochum, Germany.
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Varga S, Fricke B, Hirata M, Baştuǧ T, Pershina V, Fritzsche S. Total Energy Calculations of RfCl4 and Homologues in the Framework of Relativistic Density Functional Theory. J Phys Chem A 2000. [DOI: 10.1021/jp993980m] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Varga
- Department of Material Sciences, JAERI, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - B. Fricke
- Department of Material Sciences, JAERI, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - M. Hirata
- Department of Material Sciences, JAERI, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - T. Baştuǧ
- Department of Material Sciences, JAERI, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - V. Pershina
- Gesellschaft für Schwerionenforschung (GSI) D-64291 Darmstadt, Germany
| | - S. Fritzsche
- Fachbereich Physik, Universität Kassel, D-34109 Kassel, Germany
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Abstract
Zwitterionic detergents interfere with the salt-induced phase separation for nonionic detergents in a concentration-dependent manner by shifting the normal cloud point of nonionic detergents to a higher ionic strength at room temperature. This phenomenon was used to determine the concentration of the zwitterionic detergents CHAPS, CHAPSO, and sulfobetaine SB-12 in solution by titration with ammonium sulfate in the presence of Triton X-100. Among the ionic detergents tested, the method was only applicable to sodium cholate. The assay can be used to control the removal of zwitterionic detergents during the reconstitution of membrane proteins in liposomes. However, it cannot be used to determine the specific binding of zwitterionic detergents to highly diluted, pure membrane proteins because of the limited sensitivity. Neither proteins nor phospholipids interfered with this method at concentrations up to 20 mg/ml of test solution (human serum albumin) or 10 mg/ml (phospholipids), respectively. Since the assay is based on the competition between salts and nonionic detergents for water molecules, it is important to equalize the ionic strength of samples and calibration standards.
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Affiliation(s)
- B Fricke
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University, Halle, Germany.
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41
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Fricke B, Lints R, Stewart G, Drummond H, Dodt G, Driscoll M, von Düring M. Epithelial Na+ channels and stomatin are expressed in rat trigeminal mechanosensory neurons. Cell Tissue Res 2000; 299:327-34. [PMID: 10772247 DOI: 10.1007/s004419900153] [Citation(s) in RCA: 29] [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] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Caenorhabditis elegans MEC-4 and MEC-10 are subunits of the degenerin/epithelial Na+ channel (DEG/ENaC) ion channel superfamily thought to be associated with MEC-2 (a stomatin-like protein) in a mechanotransducing molecular complex in specialized touch sensory neurons. A key question is whether analogous molecular complexes in higher organisms transduce mechanical signals. To address this question, we selected mechanoreceptors of the rat vibrissal follicle-sinus complex in the mystacial pad and the trigeminal ganglia for an immunocytochemical and molecular biological study. RT-PCR of poly(A+) mRNA of rat trigeminal ganglia indicated that alpha-, beta-, and gamma-ENaC and stomatin mRNA are expressed in rat trigeminal ganglia. Using immunocytochemistry, we found that alpha-, beta-, and gamma-ENaC subunits and stomatin are localized in the perikarya of the trigeminal neurons and in a minor fraction of their termination site in the vibrissal follicle-sinus complex, where longitudinal lanceolate endings are immunopositive. We conclude that alpha-, beta-, and gamma-ENaC subunits as well as the candidate interacting protein stomatin are coexpressed in a mammalian mechanoreceptor, a location consistent with a possible role in mechanotransduction.
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Affiliation(s)
- B Fricke
- Department of Neuroanatomy, Institute of Anatomy MA6/152, Ruhr University, Bochum, Germany.
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42
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Varga S, Fricke B, Nakamatsu H, Mukoyama T, Anton J, Geschke D, Heitmann A, Engel E, Baştuǧ T. Four-component relativistic density functional calculations of heavy diatomic molecules. J Chem Phys 2000. [DOI: 10.1063/1.480934] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Pershina V, Johnson E, Fricke B. Theoretical Estimates of Redox Potentials for Group 6 Elements, Including Element 106, Seaborgium, in Acid Solutions. J Phys Chem A 1999. [DOI: 10.1021/jp990322t] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. Pershina
- Gesellschaft für Schwerionenforschung, Darmstadt, D-64291 Germany
| | - E. Johnson
- Florida Agricultural and Mechanical University, Tallahassee, Florida 32307-6600
| | - B. Fricke
- Theoretical Physics Department, University of Kassel, D-34109 Kassel, Germany
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Affiliation(s)
- E. Johnson
- Environmental Sciences Institute, Florida Agricultural and Mechanical University, Tallahassee, Florida 32307-6600
| | - V. Pershina
- Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt, Germany
| | - B. Fricke
- Fachbereich Physik, Universitaet Kassel, D-34109 Kassel, Germany
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Fricke B, Parchmann O, Kruse K, Rücknagel P, Schierhorn A, Menge S. Characterization and purification of an outer membrane metalloproteinase from Pseudomonas aeruginosa with fibrinogenolytic activity. Biochim Biophys Acta 1999; 1454:236-50. [PMID: 10452958 DOI: 10.1016/s0925-4439(99)00040-x] [Citation(s) in RCA: 28] [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] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A membrane proteinase from Pseudomonas aeruginosa, called insulin-cleaving membrane proteinase (ICMP), was located in the outer membrane leaflet of the cell envelope. The enzyme is expressed early in the logarithmic phase parallel to the bacterial growth during growth on peptide rich media. It is located with its active center facing to the outermost side of the cell, because its whole activity could be measured in intact cells. The very labile membrane proteinase was solubilized by non-ionic detergents (Nonidet P-40, Triton X-100) and purified in its amphiphilic form to apparent homogeneity in SDS-PAGE by copper chelate chromatography and two subsequent chromatographic steps on Red-Sepharose CL-4B (yield 58.3%, purification factor 776.3). It consisted of a single polypeptide chain with a molecular mass of 44.6 kDa, determined by mass spectrometry. ICMP was characterized to be a metalloprotease with pH-optimum in the neutral range. The ICMP readily hydrolyzed Glu(13)-Ala(14) and Tyr(16)-Leu(17) bonds in the insulin B-chain. Phe(25)-Tyr(26) and His(10)-Leu(11) were secondary cleavage sites suggesting a primary specificity of the enzyme for hydrophobic or aromatic residues at P'(1)-position. The ICMP differed from elastase, alkaline protease and LasA in its cleavage specificity, inhibition behavior and was immunologically diverse from elastase. The amino acid sequence of internal peptides showed no homologies with the known proteinases. This outer membrane proteinase was capable of specific cleavage of alpha and beta fibrinogen chains. Among the p-nitroanilide substrates tested, substrates of plasminogen activator, complement convertase and kallikrein with arginine residues in the P(1)-subsite were the substrates best accepted, but they were only cleaved at a very low rate.
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Affiliation(s)
- B Fricke
- Institute of Physiological Chemistry, Medical Faculty, Martin Luther University, 06097, Halle (Saale), Germany.
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46
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47
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Fricke B, Anton J, Schulze K, Sepp WD, Kürpick P. Relativistic and Dynamic Contributions in Ion-Atom and Ion-Solid Collisions. Advances in Quantum Chemistry 1998. [DOI: 10.1016/s0065-3276(08)60511-0] [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: 11/27/2022]
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48
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Leopold I, Fricke B. Inhibition, reactivation, and determination of metal ions in membrane metalloproteases of bacterial origin using high-performance liquid chromatography coupled on-line with inductively coupled plasma mass spectrometry. Anal Biochem 1997; 252:277-85. [PMID: 9344414 DOI: 10.1006/abio.1997.2329] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
High-performance liquid chromatography coupled on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used for the characterization of metal ions in several metalloproteases of bacterial origin. The different components of the bacterial extracts were separated on a size-exclusion column. The eluent of the HPLC system was continuously transported to the ICP-MS system for rapid, reproducible, and sensitive analyses of trace elements in the metalloproteases. Two different membrane proteases from Bacillus cereus and Pseudomonas aeruginosa were characterized to be zinc metalloproteases using enzymological methods and HPLC-ICP-MS. The zinc content was determined to be three molecules of zinc per protein molecule for the B. cereus protease and one molecule of zinc per protein molecule for the P. aeruginosa protease. For another purified protease, a periplasmic alanyl aminopeptidase of P. aeruginosa, the lack of protein-bound metal ions could be clearly determined-a confirmation that this main aminopeptidase of P. aeruginosa belongs to the cysteine protease family. The presence of nonionic detergents can influence the distribution of trace elements during the HPLC separation. Therefore, the use of these substances should be avoided during enzyme purification for metal analyses or they should be exchanged later for zwitterionic and ionic detergents with more strongly dissociating properties.
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Affiliation(s)
- I Leopold
- Department of Stress and Developmental Biology, Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany
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49
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Abstract
Variation on the Y chromosome may permit our understanding the evolution of the human paternal lineage and male gene flow. This study reports upon the distribution and non random association of alleles at four Y-chromosome specific loci in four populations, three Caucasoid (Italian, Greek and Slav) and one Asian. The markers include insertion/deletion (p12f), point mutation (92R7 and pY alpha I), and repeat sequence (p21A1) polymorphisms. Our data confirm that the p12f/TaqI 8 kb allele is a Caucasoid marker and that Asians are monomorphic at three of the loci (p12f, 92R7, and pY alpha I). The alleles at 92R7 and pY alpha I were found to be in complete disequilibrium in Europeans. Y-haplotype diversity was highly significant between Asians and all three European groups (P < 0.001), but the Greeks and Italians were also significantly different with respect to some alleles and haplotypes (P < 0.02). We find strong evidence that the p12f/TaqI 8 kb allele may have arisen only once, as a deletion event, and, additionally, that the present-day frequency distribution of Y chromosomes carrying the p12f/8 kb allele suggests that it may have been spread by colonising sea-faring peoples from the Near East, possibly the Phoenicians, rather than by expansion of Neolithic farmers into continental Europe. The p12f deletion is the key marker of a unique Y chromosome, found only in Caucasians to date, labelled 'Mediterranean' and this further increases the level of Y-chromosome diversity seen among Caucasoids when compared to the other major population groups.
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Affiliation(s)
- R J Mitchell
- School of Genetics and Human Variation, La Trobe University, Melbourne, Victoria, Australia.
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50
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Jensch T, Fricke B. Localization of alanyl aminopeptidase and leucyl aminopeptidase in cells of Pseudomonas aeruginosa by application of different methods for periplasm release. J Basic Microbiol 1997; 37:115-28. [PMID: 9151424 DOI: 10.1002/jobm.3620370206] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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
Various methods for the isolation of periplasm were examined and compared with regard to the complete release of known periplasmic marker enzymes and the contamination of the periplasm by cytosol for Pseudomonas aeruginosa PAO1 as a significant Gram-negative test strain. The aim of the investigations was to clarify the exact localization of alanyl aminopeptidase (AAP) and leucyl aminopeptidase (LAP) of this microorganism and to evaluate these methods. The osmotic shock of NOSSAL and HEPPEL (1996) was the most effective method with the lowest contamination by the cytosolic marker enzyme malic enzyme, but some proteins, which are located near the inner side of the cytoplasmic membrane, can be released additionally into the periplasm. All other procedures like chloroform or polymyxin treatment, the magnesium chloride washing of intact bacteria and spheroblasting by lysozyme in the presence of EDTA or magnesium chloride resulted only in a partial, sometimes only very low release of periplasm. The periplasmic enzymes are bound either more by hydrophobic or more by ionic interactions to the cell envelope and show a different behaviour with the different releasing agents. These methods are useful for a further differentiation between really periplasmic protein, and those proteins, which were false positive found in periplasm as a result of the osmotic shock. Our results show that AAP from Pseudomonas aeruginosa is a periplasmic enzyme with hydrophobic interactions to the cytoplasmic membrane, corresponding to the early results of LAZDUNSKI and MURGIER for Escherichia coli (LAZDUNSKI et al. 1975a and b, MURGIER et al. 1977), and LAP is cytosolic, but located near the cytoplasmic membrane. The AAP is not a real amphipatic membrane protein, as could be demonstrated by phase separation experiments with Triton X-114.
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Affiliation(s)
- T Jensch
- Department of Medicine, Martin Luther University, Halle (Saale), FRG
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