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Jäger R, Schmidt F, Schilling B, Brickmann J. Localization and quantification of hydrophobicity: the molecular free energy density (MolFESD) concept and its application to sweetness recognition. J Comput Aided Mol Des 2000; 14:631-46. [PMID: 11008885 DOI: 10.1023/a:1008181611372] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A method for the localization, the quantification, and the analysis of hydrophobicity of a molecule or a molecular fragment is presented. It is shown that the free energy of solvation for a molecule or the transfer free energy from one solvent to another can be represented by a surface integral of a scalar quantity, the molecular free energy surface density (MolFESD), over the solvent accessible surface of that molecule. This MolFESD concept is based on a model approach where the solvent molecules are considered to be small in comparison to the solute molecule, and the solvent can be represented by a continuous medium with a given dielectric constant. The transfer energy surface density for a 1-octanol/water system is empirically determined employing a set of atomic increment contributions and distance dependent membership functions measuring the contribution of the increments to the surface value of the MolFESD. The MolFESD concept can be well used for the quantification of the purely hydrophobic contribution to the binding constants of molecule-receptor complexes. This is demonstrated with the sweeteners sucrose and sucralose and various halogen derivatives. Therein the relative sweetness, which is assumed to be proportional to the binding constant, nicely correlates to the surface integral over the positive, hydrophobic part of the MolFESD, indicating that the sweetness receptor can be characterized by a highly flexible hydrophobic pocket instead of a localized binding site.
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Benzing T, Yaffe MB, Arnould T, Sellin L, Schermer B, Schilling B, Schreiber R, Kunzelmann K, Leparc GG, Kim E, Walz G. 14-3-3 interacts with regulator of G protein signaling proteins and modulates their activity. J Biol Chem 2000; 275:28167-72. [PMID: 10862767 DOI: 10.1074/jbc.m002905200] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling (RGS) proteins function as GTPase-activating proteins (GAPs) that stimulate the inactivation of heterotrimeric G proteins. We have recently shown that RGS proteins may be regulated on a post-translational level (Benzing, T., Brandes, R., Sellin, L., Schermer, B., Lecker, S., Walz, G., and Kim, E. (1999) Nat. Med. 5, 913-918). However, mechanisms controlling the GAP activity of RGS proteins are poorly understood. Here we show that 14-3-3 proteins associate with RGS7 and RGS3. Binding of 14-3-3 is mediated by a conserved phosphoserine located in the Galpha-interacting portion of the RGS domain; interaction with 14-3-3 inhibits the GAP activity of RGS7, depends upon phosphorylation of a conserved residue within the RGS domain, and results in inhibition of GAP function. Collectively, these data indicate that phosphorylation-dependent binding of 14-3-3 may act as molecular switch that controls the GAP activity keeping a substantial fraction of RGS proteins in a dormant state.
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Schilling B, Yeh J. Transforming growth factor-beta(1), -beta(2), -beta(3) and their type I and II receptors in human term placenta. Gynecol Obstet Invest 2000; 50:19-23. [PMID: 10895022 DOI: 10.1159/000010272] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of transforming growth factor (TGF)-beta(3) as well as cellular localization of TGF-beta receptors has not been demonstrated in placenta. TGF-beta receptor type I (RI) and type II (RII) are required to transmit TGF-beta signals, therefore the determination of cells expressing both receptors in concert is necessary to identify target cells for TGF-beta. We investigated presence and localization of TGF-betas and their receptors (RI, RII) in human term placenta using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. RT-PCR showed that messenger RNA for TGF-beta(1), -beta(2), -beta(3), and RI and RII is present in human term placenta. We found intense staining for all TGF-beta isoform and receptor proteins in the syncytiotrophoblastic layer, chorionic plate, and in cells of the extravillous trophoblasts using immunohistochemistry. The simultaneous expression of ligands and their receptors support the hypothesis that TGF-beta may play an important role in regulating growth, differentiation, and function of the human placenta.
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Schilling B, Heller D, Graulich Y, Göttlich E. [Determining the emission of microorganisms from biofilters and emission concentrations at the site of composting areas]. SCHRIFTENREIHE DES VEREINS FUR WASSER-, BODEN- UND LUFTHYGIENE 2000; 104:685-701. [PMID: 10803244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
In order to assess source emissions and dispersal of airborne culturable microorganisms from composting plants, measurements at three composting plants have been carried out. The downwind concentrations of dispersed microorganisms differed greatly, depending on the type of plant design. At 200 metres downwind from the totally enclosed composting plant, levels of spore concentrations of thermotolerant fungi and Aspergillus fumigatus, which may be regarded as characteristic for composting operations, were not above the magnitude of background concentrations. In contrast, spore concentrations in excess of the background level occurred within 500 metres of the partly open plant. Moreover, the ranges of airborne concentrations at similar distances from the enclosed plant were much smaller relative to the partly open plant. Measurement of source emissions from biofilters showed concentrations in the raw and purified gases in the range of up to three orders of magnitude. The operational characteristics of the plants generally contributing to bioaerosol emissions on-site were found to have an influence on the concentration levels in the raw gas. A decrease in the microbiological parameters which may be regarded as specific for composting operations, was attributed to a reduced rate of passage through the biofilters. The magnitude of reduction as well as the concentrations varied greatly.
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Kummer V, Benning C, Fischer K, Hake J, Hofmann R, Hoppenheidt K, Jager E, Kühner M, Philipp W, Schilling B, Schnorr KE. ['Microbial air pollutants'. Emission sources and preventive measures]. SCHRIFTENREIHE DES VEREINS FUR WASSER-, BODEN- UND LUFTHYGIENE 2000; 104:483-500. [PMID: 10803230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Already in the planning or monitoring phase, measures have to be realized for the reduction in emissions of bio-aerosols in biological waste treatment plants. For this purpose, operation-related measures (in open and partially closed plants) and technology-related measures (in closed plants with automatic ventilation) can be taken. A survey on the currently feasible measures for reduction is submitted. The realization has to be adapted to the individual site and type of plant. An enormous demand for examinations is envisaged in order to enable a qualified assessment of the emission behaviour of diverse waste air systems or process steps.
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Hofmann R, Beck EM, Böhm R, Danneberg G, Gerbl-Rieger S, Göttlich E, Koch A, Kühner M, Kummer V, Liebl K, Martens W, Missel T, Neef A, Palmgren U, Rabe R, Schilling B, Schneider F, Tilkes F, Wieser P. [Detection of airborne cultivatable microorganisms from compost sites--emissions and imissions]. SCHRIFTENREIHE DES VEREINS FUR WASSER-, BODEN- UND LUFTHYGIENE 2000; 104:245-320. [PMID: 10803227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The statement presented here gives an overview and assessment of the procedures and concepts currently used for the collection and determination of airborne, culturable microorganisms at sources of emission within composting plants and in their near vicinity. The paper focuses on "classical" methods, which involve cultivation as an intermediate step for the determination of viable, airborne microorganisms. The theoretical and practical requirements on such methods are discussed. Results and experiences from recent investigations are described.
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Filiatrault MJ, Gibson BW, Schilling B, Sun S, Munson RS, Campagnari AA. Construction and characterization of Haemophilus ducreyi lipooligosaccharide (LOS) mutants defective in expression of heptosyltransferase III and beta1,4-glucosyltransferase: identification of LOS glycoforms containing lactosamine repeats. Infect Immun 2000; 68:3352-61. [PMID: 10816485 PMCID: PMC97600 DOI: 10.1128/iai.68.6.3352-3361.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
To begin to understand the role of the lipooligosaccharide (LOS) molecule in chancroid infections, we constructed mutants defective in expression of glycosyltransferase genes. Pyocin lysis and immunoscreening was used to identify a LOS mutant of Haemophilus ducreyi 35000. This mutant, HD35000R, produced a LOS molecule that lacked the monoclonal antibody 3F11 epitope and migrated with an increased mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Structural studies indicated that the principal LOS glycoform contains lipid A, Kdo, and two of the three core heptose residues. HD35000R was transformed with a plasmid library of H. ducreyi 35000 DNA, and a clone producing the wild-type LOS was identified. Sequence analysis of the plasmid insert revealed one open reading frame (ORF) that encodes a protein with homology to the WaaQ (heptosyltransferase III) of Escherichia coli. A second ORF had homology to the LgtF (glucosyltransferase) of Neisseria meningitidis. Individual isogenic mutants lacking expression of the putative H. ducreyi heptosyltransferase III, the putative glucosyltransferase, and both glycosyltransferases were constructed and characterized. Each mutant was complemented with the representative wild-type genes in trans to restore expression of parental LOS and confirm the function of each enzyme. Matrix-assisted laser desorption ionization mass spectrometry and SDS-PAGE analysis identified several unique LOS glycoforms containing di-, tri-, and poly-N-acetyllactosamine repeats added to the terminal region of the main LOS branch synthesized by the heptosyltransferase III mutant. These novel H. ducreyi mutants provide important tools for studying the regulation of LOS assembly and biosynthesis.
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Sun S, Schilling B, Tarantino L, Tullius MV, Gibson BW, Munson RS. Cloning and characterization of the lipooligosaccharide galactosyltransferase II gene of Haemophilus ducreyi. J Bacteriol 2000; 182:2292-8. [PMID: 10735874 PMCID: PMC111280 DOI: 10.1128/jb.182.8.2292-2298.2000] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Haemophilus ducreyi is the etiologic agent of chancroid, a genital ulcer disease. The lipooligosaccharide (LOS) is considered to be a major virulence determinant and has been implicated in the adherence of H. ducreyi to keratinocytes. Strain A77, an isolate from the Paris collection, is serum sensitive, poorly adherent to fibroblasts, and deficient in microcolony formation. Structural analysis indicates that the LOS of strain A77 lacks the galactose residue found in the N-acetyllactosamine portion of the strain 35000HP LOS as well as the sialic acid substitution. From an H. ducreyi 35000HP genomic DNA library, a clone complementing the defect in A77 was identified by immunologic screening with monoclonal antibody (MAb) 3F11, a MAb which recognizes the N-acetyllactosamine portion of strain 35000HP LOS. The clone contained a 4-kb insert that was sequenced. One open reading frame which encodes a protein with a molecular weight of 33,400 was identified. This protein has homology to glycosyltransferases of Haemophilus influenzae, Haemophilus somnus, Neisseria species, and Pasteurella haemolytica. The putative H. ducreyi glycosyltransferase gene was insertionally inactivated, and an isogenic mutant of strain 35000HP was constructed. The most complex LOS glycoform produced by the mutant has a mobility on sodium dodecyl sulfate-polyacrylamide gel identical to that of the LOS of strain A77 and lacks the 3F11-binding epitope. Structural studies confirm that the most complex glycoform of the LOS isolated from the mutant lacks the galactose residue found in the N-acetyllactosamine portion of the strain 35000HP LOS. Although previously published data suggested that the serum-sensitive phenotype of A77 was due to the LOS mutation, we observed that the complemented A77 strain retained its serum-sensitive phenotype and that the galactosyltransferase mutant retained its serum-resistant phenotype. Thus, the serum sensitivity of strain A77 cannot be attributed to the galactosyltransferase mutation in strain A77.
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Schilling B, Yeh J. Expression of transforming growth factor (TGF)-beta1, TGF-beta2, and TGF-beta3 and of type I and II TGF-beta receptors during the development of the human fetal ovary. Fertil Steril 1999; 72:147-53. [PMID: 10428164 DOI: 10.1016/s0015-0282(99)00182-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To investigate the role of transforming growth factor-beta (TGF-beta) in the regulation of human fetal ovarian development. DESIGN Reverse transcription-polymerase chain reaction and comparative immunohistochemical analysis of the localization and staining intensity of TGF-beta1, TGF-beta2, and TGF-beta3, and of their receptors. SETTING Academic research environment. PATIENT(S) Human fetal ovaries were obtained from terminated normal intact pregnancies at 11-24 weeks' gestation. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Messenger RNA analysis and protein expression of TGF-beta isoforms and their receptors in human fetal ovaries at 11-24 weeks of gestational age. RESULT(S) Messenger RNAs for the three TGF-beta isoforms and the two TGF-beta receptors were demonstrated in all the developmental ages studied: 11, 14, 18, 20, and 22 weeks of gestation. During the first trimester, immunohistochemical analysis for TGF-beta1, TGF-beta2, and TGF-beta receptor type I revealed homogeneous light staining of the ovary. Staining for TGF-beta3 and TGF-beta receptor type II was predominantly in the oocytes. During the second trimester, staining for all three TGF-beta isoforms and both receptors was predominantly in the oocytes. In addition, for receptor types I and II, staining was observed in the pregranulosa cells. CONCLUSION(S) Our findings support the hypothesis that expression of the TGF-beta system changes from the first to the second trimester of fetal development and may have an autocrine and/or paracrine regulatory role during ovarian development.
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Hogen E, Rananto C, Person K, Mercer J, Johnson R, Schilling B, Wojeck J, Smith L. PRO- AND ANTI-INFLAMMATORY CYTOKINES AFTER ECCENTRICALLY INDUCED MUSCLE DAMAGE. Med Sci Sports Exerc 1999. [DOI: 10.1097/00005768-199905001-00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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61
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Schilling B, Wang W, McMurray JS, Medzihradszky KF. Fragmentation and sequencing of cyclic peptides by matrix-assisted laser desorption/ionization post-source decay mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 1999; 13:2174-2179. [PMID: 10523777 DOI: 10.1002/(sici)1097-0231(19991115)13:21<2174::aid-rcm771>3.0.co;2-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A series of synthetic cyclic decapeptides and other smaller cyclic peptides were analyzed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The investigated compounds were cyclized in a head-to-tail manner and contained non-proteinaceous amino acids, such as D-phenylalanine, D,L-4-carboxyphenylalanine, epsilon-aminocaproic acid, and gamma-aminobutyric acid, and were synthesized in a program to develop inhibitors of pp60(c-src) (Src), a tyrosine kinase that is involved in signal transduction and growth regulation. Post-source decay (PSD) spectra of the cyclic peptides featured abundant sequence ions. Two preferential ring opening reactions were detected resulting in linear fragment ions with an N-terminus of proline and a C-terminus of glutamic acid, respectively. MALDI-PSD spectra even permitted de novo sequencing of some cyclic peptides. Systematic studies on cyclic peptides using this method of fragmentation have not been reported to date. This work presents an easy mass spectrometric method, MALDI-PSD, for the characterization and identification of cyclic peptides.
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Schilling B, De-Medina T, Syken J, Vidal M, Münger K. A novel human DnaJ protein, hTid-1, a homolog of the Drosophila tumor suppressor protein Tid56, can interact with the human papillomavirus type 16 E7 oncoprotein. Virology 1998; 247:74-85. [PMID: 9683573 DOI: 10.1006/viro.1998.9220] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have cloned hTid-1, a human homolog of the Drosophila tumor suppressor protein Tid56, by virtue of its ability to form complexes with the human papillomavirus E7 oncoprotein. The carboxyl terminal cysteine-rich metal binding domain of E7 is the major determinant for interaction with hTid-1. The carboxyl terminus of E7 is essential for the functional and structural integrity of E7 and has previously been shown to function as a multimerization domain. The hTid-1 protein is a member of the DnaJ-family of chaperones. Its mRNA is widely expressed in human tissues, including the HPV-18-positive cervical carcinoma cell line HeLa and human genital keratinocytes, the normal host cells of the HPVs. The hTid-1 gene has been mapped to the short arm of chromosome 16. The large tumor antigens of polyomaviruses encode functional J-domains that are important for viral replication as well as cellular transformation. The ability of HPV E7 to interact with a cellular DnaJ protein suggests that these two viral oncoproteins may target common regulatory pathways through J-domains.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Cell Line
- Chromosome Mapping
- Chromosomes, Human, Pair 16/genetics
- Cloning, Molecular
- Drosophila/genetics
- Drosophila Proteins
- Female
- Gene Expression
- Genes, Tumor Suppressor
- HSP40 Heat-Shock Proteins
- Heat-Shock Proteins/genetics
- Heat-Shock Proteins/metabolism
- Humans
- Insect Proteins/genetics
- Insect Proteins/metabolism
- Male
- Mitochondrial Proteins
- Molecular Sequence Data
- Oncogene Proteins, Viral/chemistry
- Oncogene Proteins, Viral/genetics
- Oncogene Proteins, Viral/metabolism
- Papillomavirus E7 Proteins
- Pregnancy
- Protein Binding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Homology, Amino Acid
- Tissue Distribution
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Schilling B, Kaufmann DE, Kaiser V. Crystal structure of 2,2'-bis(trimethylgermyl)-1,1'-binaphthyl, (C10H6Ge(CH3)3)2. Z KRIST-NEW CRYST ST 1997. [DOI: 10.1524/ncrs.1997.212.1.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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64
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Lewerenz M, Schilling B, Toennies JP. Response to “Comment on: ‘Successive capture and coagulation of atoms and molecules to small clusters in large liquid helium clusters’ ’’ [J. Chem. Phys. 106, 5785 (1997)]. J Chem Phys 1997. [DOI: 10.1063/1.473998] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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65
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Sorbara LR, Maldarelli F, Chamoun G, Schilling B, Chokekijcahi S, Staudt L, Mitsuya H, Simpson IA, Zeichner SL. Human immunodeficiency virus type 1 infection of H9 cells induces increased glucose transporter expression. J Virol 1996; 70:7275-9. [PMID: 8794382 PMCID: PMC190788 DOI: 10.1128/jvi.70.10.7275-7279.1996] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A clone obtained from a differential display screen for cellular genes with altered expression during human immunodeficiency virus (HIV) infection matched the sequence for the human GLUT3 facilitative glucose transporter, a high-velocity-high-affinity facilitative transporter commonly expressed in neurons of the central nervous system. Northern (RNA) analysis showed that GLUT3 expression increased during infection. Flow cytometry showed that GLUT3 protein expression increased specifically in the HIV-infected cells; this increase correlated with increased 2-deoxyglucose transport in the HIV-infected culture. HIV infection therefore leads to increased expression of a glucose transporter normally expressed at high levels in other cell types and a corresponding increase in glucose transport activity. If HIV infection places increased metabolic demands on the host cell, changes in the expression of a cellular gene that plays an important role in cellular metabolism might provide a more favorable environment for viral replication.
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Krylov AI, Gerber RB, Gaveau MA, Mestdagh JM, Schilling B, Visticot JP. Spectroscopy, polarization and nonadiabatic dynamics of electronically excited Ba(Ar)n clusters: Theory and experiment. J Chem Phys 1996. [DOI: 10.1063/1.471021] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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67
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Gaveau M, Schilling B, Gée C, Sublemontier O, Visticot JP, Mestdagh J, Berlande J. Chemiluminescent Ba + N2O reaction in molecular clusters of CH4 and mixed ArCH4 clusters. Chem Phys Lett 1995. [DOI: 10.1016/0009-2614(95)01105-i] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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68
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Lewerenz M, Schilling B, Toennies JP. Successive capture and coagulation of atoms and molecules to small clusters in large liquid helium clusters. J Chem Phys 1995. [DOI: 10.1063/1.469231] [Citation(s) in RCA: 323] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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69
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Schilling B, Lerch K. Cloning, sequencing and heterologous expression of the monoamine oxidase gene from Aspergillus niger. MOLECULAR & GENERAL GENETICS : MGG 1995; 247:430-8. [PMID: 7770050 DOI: 10.1007/bf00293144] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The gene encoding the flavin-containing monoamine oxidase (MAO-N) of the filamentous fungus Aspergillus niger was cloned. MAO-N is the first nonvertebrate monoamine oxidase described to date. Three partial cDNA clones, isolated from an expression library, were used to identify and clone the structural gene (maoN) from an A. niger genomic DNA library. The maoN gene was sequenced, and analysis revealed an open reading frame that codes for a protein of 495 amino acids with a calculated molecular mass of 55.6 kDa. Sequencing of an internal proteolytic fragment of the purified enzyme confirmed the derived amino acid sequence. Analysis of the deduced amino acid sequence indicates that MAO-N is structurally related to the human monoamine oxidases MAO-A and MAO-B. In particular, the regions known to be involved in the binding of the FAD cofactor show a high degree of homology; however, the conserved cysteine residue to which the flavin cofactor is covalently bound in the mammalian forms is absent in the fungal enzyme. MAO-N has the C-terminal tripeptide Ala-Arg-Leu, which corresponds to the consensus targeting sequence found in many peroxisomal enzymes. The full-length cDNA for MAO-N was expressed in Escherichia coli from the T7 promoter of the expression vector pET3a, yielding a soluble and fully active enzyme form.
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Schilling B, Lerch K. Amine oxidases from Aspergillus niger: identification of a novel flavin-dependent enzyme. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1243:529-37. [PMID: 7727530 DOI: 10.1016/0304-4165(94)00183-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Upon induction with various amine sources, two different amine oxidases are expressed in the filamentous fungus Aspergillus niger. The enzymes which can be separated by anion exchange chromatography exhibit a similar substrate specificity pattern. From cofactor and inhibitor analysis it was found that one amine oxidase is identical to the earlier reported copper-containing amine oxidase (Yamada, H., Adachi, O. and Ogata, K. (1965) Agric. Biol. Chem. 29, 912-917) with 6-hydroxydopa (TOPA) quinone as the active site cofactor. The second form is a hitherto unknown flavoprotein of 55 kDa, which shows many of the characteristic properties of the mammalian monoamine oxidases (MAO). From substrate specificity and inhibitor susceptibility, it is suggested that the monoamine oxidase from A. niger (MAO-N) is a prototype of the two mammalian enzymes, MAO-A and MAO-B. A partial cDNA clone which encodes an amino-terminal peptide of 53 amino acid residues was identified by lambda gt11 immunoscreening. The consensus sequence of the putative flavin adenine dinucleotide (FAD) binding site is found within this sequence.
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Schilling B, Gaveau MA, Sublemontier O, Mestdagh JM, Visticot J, Biquard X, Berlande J. Photodesorption dynamics of Ba atoms from large Ar clusters. J Chem Phys 1994. [DOI: 10.1063/1.467361] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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72
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Lewerenz M, Schilling B, Toennies J. A new scattering deflection method for determining and selecting the sizes of large liquid clusters of 4He. Chem Phys Lett 1993. [DOI: 10.1016/0009-2614(93)85569-a] [Citation(s) in RCA: 242] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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73
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Schilling B, Linden RM, Kupper U, Lerch K. Expression of Neurospora crassa laccase under the control of the copper-inducible metallothionein-promoter. Curr Genet 1992; 22:197-203. [PMID: 1388108 DOI: 10.1007/bf00351726] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Laccase from the ascomycete Neurospora crassa is an inducible secretory enzyme. In vegetatively growing cultures its biosynthesis is repressed but can be induced by different protein synthesis inhibitors. Transformation of the N. crassa wild-type strain Singapore with a fusion gene consisting of the N. crassa copper-metallothionein promoter and the laccase gene are described in this report. Correct integration of the 3.6 kilobase (kb) promoter-fragment fused with the laccase gene containing a 5' consensus region leads to copper-dependent expression of the enzyme during the vegetative growth phase. The enzyme is glycosylated and secreted, and high amounts of extracellular activity can be detected. The regulation of laccase biosynthesis of one examined transformant, followed at both the transcriptional and the translational level, indicates co-induction of both copper-metallothionein and laccase. The data presented show that expression of the recombinant laccase gene is exclusively regulated by the transformed N. crassa metallothionein-promoter.
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Michaelis HC, Kietzmann D, Neurath H, Jongepier U, Schilling B. Sensitive determination of piritramide in human plasma by gas chromatography. JOURNAL OF CHROMATOGRAPHY 1991; 571:257-62. [PMID: 1810954 DOI: 10.1016/0378-4347(91)80453-j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A selective and sensitive method for the determination of piritramide in human plasma is described. A 1-ml aliquot of plasma was extracted with 10 ml of hexane-isoamyl alcohol (99.5:0.5, v/v) (extraction efficiency 86%) after addition of 50 microliters of 2 M ammonia and 20 microliters of aqueous strychnine solution (100 ng per 10 microliters) as internal standard. Gas chromatography was performed with J&W DB-1, 30 m x 0.53 mm I.D. separation column, film thickness 1.5 microns, using an nitrogen-phosphorus-sensitive detector. The assay was linear in the concentration range 3.75-2250 ng/ml (r = 0.999), with a lower limit of detection of 1-2 ng/ml. The precision was determined using spiked plasma samples (10 and 50 ng/ml), with coefficients of variation of 3.5 and 3.1% (intra-day; n = 5) and 4.6 and 4.1% (inter-day; n = 4). In the range 3.75-150 ng/ml, the accuracy of the assay was 3.36%. The method was used for the determination of piritramide plasma concentrations in patients receiving intra- or post-operative analgesia.
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Abstract
Uncoated but deactivated pre-columns have become a widely used tool in capillary gas chromatography (GC), serving strongly differing purposes. Pre-columns are often used as guard columns, reducing the effects of involatile sample by-products on chromatographic performance and rendering exchange of contaminated column inlets simple. Wide-bore pre-columns facilitate introduction of the syringe needle and open the way for a relatively robust on-column autosampler. Other pre-columns are used for re-concentrating solute bands that are broadened due to the flow of sample liquid in the column inlet (retention gap). Long pre-columns allow on-column injection of large sample volumes (e.g., 50-80 microliter when a 15 m X 0.32 mm I.D. pre-column is used). The background of the various uses of pre-columns is discussed, concluding with an evaluation of different deactivation methods for the internal wall of the pre-columns. Critical parameters are inertness, wettability and retention power. Press-fit connections are recommended for coupling pre-columns to the coated columns.
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