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  • 2002  (15)
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  • 2002  (15)
  • 1
    In: EMBO Journal, 15 July 2002, Vol.21(14), pp.3794-3803
    Description: Lariat formation has been studied intensively only with a few self‐splicing group II introns, and little is known about how the numerous diverse introns in plant organelles are excised. Several of these introns have branch‐points that are not a single bulge but are adjoined by A:A, A:C, A:G and G:G pairs. Using a highly sensitive approach, we demonstrate that all but one of the barley chloroplast introns splice via the common pathway that produces a branched product. RNA editing does not improve domain 5 and 6 structures of these introns. The conserved branch‐point in tobacco is chosen even if an adjacent unpaired adenosine is available, suggesting that spatial arrangements in domain 6 determine correct branch‐point selection. Lariats were not detected for the chloroplast intron, which lacks an unpaired adenosine in domain 6. Instead, this intron is released as linear molecules that undergo further polyadenylation. , which is conserved throughout plant evolution, constitutes the first example of naturally occurring hydrolytic group II intron splicing .
    Keywords: Branch‐Point ; Intron Circle ; Reverse Transcription ; Rna Editing ; ‐Splicing
    ISSN: 0261-4189
    E-ISSN: 1460-2075
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  • 2
    Language: English
    In: Information and Computation, 15 March 2002, Vol.173(2), pp.123-131
    Description: Consider the problem of computing a function given only an oracle for its graph. For this problem, we present optimal trade-offs between serial and parallel queries. In particular, we give a function for which parallel access to its own graph is exponentially more expensive than sequential access.
    Keywords: Computational Complexity Theory ; Polynomial-Time Reductions ; Series-Parallel Trade-Offs ; Graphs of Functions
    ISSN: 0890-5401
    E-ISSN: 10902651
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  • 3
    Language: English
    In: Journal of Biological Chemistry, 08/09/2002, Vol.277(32), pp.29078-29085
    Description: ElaC is a widespread gene found in eubacteria, archaebacteria, and mammals with a highly conserved sequence. Two human ElaC variants were recently associated with cancer (Tavtigian, S. V., Simard, J., Teng, D. H., Abtin, V., Baumgard, M., Beck, A., Camp, N. J., Carillo, A. R., Chen, Y., Dayananth, P., Desrochers, M., Dumont, M., Farnham, J. M., Frank, D., Frye, C., Ghaffari, S., Gupte, J. S., Hu, R., Iliev, D., Janecki, T., Kort, E. N., Laity, K. E., Leavitt, A., Leblanc, G., McArthur-Morrison, J., Pederson, A., Penn, B., Peterson, K. T., Reid, J. E., Richards, S., Schroeder, M., Smith, R., Snyder, S. C., Swedlund, B., Swensen, J., Thomas, A., Tranchant, M., Woodland, A. M., Labrie, F., Skolnick, M. H., Neuhausen, S., Rommens, J., and Cannon-Albright, L. A. (2001) Nat. Genet. 27, 172-180; Yanaihara, N., Kohno, T., Takakura, S., Takei, K., Otsuka, A., Sunaga, N., Takahashi, M., Yamazaki, M., Tashiro, H., Fukuzumi, Y., Fujimori, Y., Hagiwara, K., Tanaka, T., and Yokota, J. (2001) Genomics 72, 169-179). Analysis of the primary sequence indicates homology to an arylsulfatase and predicts a metallo-beta-lactamase fold. At present, no ElaC gene product has been investigated. We cloned the Escherichia coli ElaC gene and purified the recombinant gene product. An enzymatic analysis showed that ElaC does not encode an arylsulfatase but rather encodes a phosphodiesterase that hydrolyzes bis(p-nitrophenyl)phosphate with a k(cat) of 59 s(-1) and K' of 4 mm. Kinetic analysis of the dimeric enzyme revealed positive cooperativity for the substrate bis(p-nitrophenyl)phosphate with a Hill coefficient of 1.6, whereas hydrolysis of the substrate thymidine-5'-p-nitrophenyl phosphate followed Michaelis-Menten kinetics. Furthermore, the enzyme is capable of binding two zinc or two iron ions. However, it displays phosphodiesterase activity only in the zinc form. The metal environment characterized by zinc K-edge x-ray absorption spectroscopy was modeled with two histidine residues, one carboxylate group, and 1.5 oxygen atoms. This corresponds to the coordination found in other metallo-beta-lactamase domain proteins. Phosphodiesterase activity is strongly dependent on the presence of zinc. These results identify the currently unassigned gene product ElaC to be a novel binuclear zinc phosphodiesterase.
    Keywords: Chemistry ; Anatomy & Physiology;
    ISSN: 0021-9258
    E-ISSN: 1083-351X
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  • 4
    Language: English
    In: Sensors and Actuators B: Chemical, 03/2002, Vol.83(1-3), pp.285-289
    ISSN: 09254005
    Source: Elsevier (via CrossRef)
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  • 5
    Language: English
    In: The Journal of Allergy and Clinical Immunology, November 2002, Vol.110(5), pp.797-804
    Description: Background: Anaphylactic reactions to soy products have been attributed to stable class 1 food allergens. Objective: IgE- mediated reactions to a soy- containing dietary food product in patients allergic to birch pollen were investigated. Methods: Detailed case histories were taken from 20 patients. Their sera were analyzed for IgE (UniCAP) specific for birch, grass, mugwort, the recombinant birch allergens rBet v 1 and rBet v2, and soy protein. Extracts from birch pollen, soy isolate, rBet v 1, and the recombinant PR-10 soy protein rSAM22 were coupled to paper disks or nitrocellulose for IgE measurements (enzyme allergosorbent test) or Western blot analysis. Enzyme allergosorbent testing, Western blot inhibition, and histamine release studies were performed with the same allergens. Results: Most patients (17/20) experienced facial, oropharyngeal, and/or systemic allergic symptoms within 20 minutes after ingesting the soy product for the first time. Birch pollen allergy (16/20) was common, along with oral allergy syndrome to apple (12/20) or hazelnut (11/20). IgE levels to birch and Bet v 1 but not to other inhalants were high in 18 of 20 patients. Significant IgE binding to rSAM22 occurred in 17 of 20 patients. Blot experiments with the soy isolate revealed IgE- binding bands at 17 kd (15/20), 22 kd (1/20), and 35 to 38 kd (2/20); the former was inhibited by preincubation of the sera with rBet v 1 or rSAM22. Birch extract and soy isolate, rBet v 1, and rSAM22 induced dose-dependent histamine release in the nanomolar range. Conclusion: Immediate-type allergic symptoms in patients with birch pollen allergy after ingestion of soy protein–containing food items can result from cross- reactivity of Bet v 1 – specific IgE to homologous pathogenesis-related proteins, particularly the PR-10 protein SAM22. (J Allergy Clin Immunol 2002;110:797-804.)
    Keywords: Food Allergy ; Soy Protein ; Sam22 ; Pathogenesis-Related Protein ; Birch Pollen Allergy ; Bet V 1 ; Ige ; Dbpcfc ; East ; OAS
    ISSN: 0091-6749
    E-ISSN: 10976825
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  • 6
    In: Sensors & Actuators: B. Chemical, 15 March 2002, Vol.83(1-3), pp.285-289
    Description: The Technical University Hamburg-Harburg and ABB Corporate Research are currently exploring the potential to apply silicon–glass microsystems as technology platform for creating a miniaturized flame ionization detector (FID). This device can be used for the detection of hydrocarbons in gas chromatography. Design and first characterizations of such micro-FIDs have been published elsewhere in Ref. [1] [Sens. Actuators 63B (3) (2000)]. For a deeper understanding of the performance and further optimization potential, the detectors have now been investigated more detailed. The results of those tests show a detection limit of 104 ppb pentane and 441 ppb methane.
    Keywords: Gas Chromatography ; Flame Ionization Detector ; Hydrocarbon Detection
    ISSN: 0925-4005
    Source: ScienceDirect (Elsevier B.V.)
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  • 7
    Language: English
    In: Molecular Immunology, 2002, Vol.39(5), pp.357-365
    Description: Cobra venom factor (CVF), the anticomplementary protein in cobra venom, activates the alternative complement pathway, eventually leading to complement consumption. Here, we describe the development of a transgenic mouse model for CVF. We generated a DNA construct containing the full-length cDNA for single-chain pre-pro-CVF. Expression of CVF was controlled by the α 1 -antitrypsin promoter to achieve liver-specific expression. Linearized DNA was microinjected into murine ovary cells (strain CD 2 F 1 (BALB/c×DBA/2J)) and the newborn mice were analyzed for stable integration of CVF DNA. After establishing the transgene, mice were propagated in a BALB/c background. The CVF mRNA was detected in the liver and, in some animals, in the kidney. CVF protein was detected in small amounts in the serum. Serum complement hemolytic activity in CVF-transgenic mice was virtually absent. The concentration of plasma C3 was significantly reduced. The CVF-transgenic animals show no unusual phenotype. They provide an animal model to study the effect of long-term complement depletion by continued activation, as well as the role of complement in host immune response and pathogenesis of disease.
    Keywords: Cvf, Cobra Venom Factor ; Complement ; Cobra Venom Factor ; Complement Inhibition ; C3 Depletion
    ISSN: 0161-5890
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  • 8
    Language: English
    In: Arzneimittelforschung, 5/2002, Vol.52(05), pp.393-399
    ISSN: 0004-4172
    E-ISSN: 1616-7066
    Source: Thieme Publishing Group (via CrossRef)
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  • 9
    Language: English
    In: Experimental Hematology, 2002, Vol.30(6), pp.537-545
    Description: Objectives Monoclonal antibody (mAb) 9C4 detects a surface antigen expressed on immature erythroid progenitor cells and epithelial tumor cell lines. The aim of this study was to identify the recognized surface antigen and to analyze a potential role of this molecule in early steps of erythropoiesis. Materials and Methods. A pituitary-derived retroviral cDNA library was used to generate viruses and infect NIH-3T3 fibroblasts. The transfected cells were stained with mAb 9C4; positive cells were sorted by FACS; and a clonal cell line binding mAb 9C4 was established. cDNA encoding the 9C4-binding protein was amplified by polymerase chain reaction and cloned. Reactivity of mAb 9C4 with human bone marrow (BM) cells was analyzed by flow cytometry. Results. Sequence analysis of the isolated cDNA uncovered a 100% identity with the epithelial cellular adhesion molecule (Ep-CAM). Two-color flow cytometric analysis revealed that almost 100% of Ep-CAM + BM cells coexpressed CD105, E-cadherin, and high levels of CD71. Fractions of Ep-CAM + BM cells also were CD34 + but lacked glycophorin A expression, suggesting that Ep-CAM + cells represent immature erythroid cells. Reverse transcriptase polymerase chain reaction analysis of BM mononuclear cells revealed that the 9C4 + erythroblast population but not the 9C4 − fraction expressed Ep-CAM mRNA. Peripheral blood CD34 + cells induced in vitro to differentiate into the erythroid lineage showed strong Ep-CAM expression on days 3 to 7 of culture. The addition of Ep-CAM–specific mAbs 9C4 or KS1/4 to the culture resulted in two- to three-fold up-regulation of Ep-CAM protein expression. Conclusion. mAb 9C4 recognizes Ep-CAM, a molecule expressed in the early steps of erythropoiesis.
    Keywords: 3t3 Cells–Analysis ; Animals–Genetics ; Antibodies, Monoclonal–Analysis ; Antibody Specificity–Analysis ; Antigens, Neoplasm–Immunology ; Antigens, Surface–Analysis ; Biomarkers, Tumor–Genetics ; Bone Marrow Cells–Physiology ; Cell Adhesion Molecules–Analysis ; DNA Primers–Analysis ; Epithelial Cell Adhesion Molecule–Analysis ; Erythropoiesis–Analysis ; Flow Cytometry–Analysis ; Gene Library–Analysis ; Humans–Analysis ; Mice–Analysis ; Recombinant Proteins–Analysis ; Reverse Transcriptase Polymerase Chain Reaction–Analysis ; Transfection–Analysis ; Antibodies, Monoclonal ; Antigens, Neoplasm ; Antigens, Surface ; Biomarkers, Tumor ; Cell Adhesion Molecules ; DNA Primers ; Epithelial Cell Adhesion Molecule ; Recombinant Proteins;
    ISSN: 0301-472X
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  • 10
    In: Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association, 2002, Vol.22(6), pp.914-920
    Description: Inflammatory response and chemotaxis of vascular wall cells play an important pathogenic role in the development of atherosclerosis. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for monocytes. Besides the induction of monocyte recruitment, it has been suggested that MCP-1 may directly activate smooth muscle cells. We investigated whether MCP-1 affects the proliferation and cytokine production of human vascular smooth muscle cells (VSMCs) and determined the underlying signal transduction pathways. Stimulation of VSMCs with MCP-1 induced proliferation and resulted in a concentration- and time-dependent release of the proinflammatory cytokine interleukin-6 (IL-6). Pretreatment with pertussis toxin, GF109203X, and pyrrolidine dithiocarbamate inhibited MCP-1–dependent IL-6 release, suggesting the involvement of Gi proteins, protein kinase C, and nuclear factor-κB (NF-κB). MCP-1 also induced extracellular signal–regulated kinase, which, along with IL-6 release, was inhibited by pertussis toxin. PD98059 prevented MCP-1–induced extracellular signal–regulated kinase activation and cell proliferation. MCP-1 stimulated the binding activity of NF-κB and of activator protein-1 (AP-1). As demonstrated by cis element double-stranded (decoy) oligodeoxynucleotides, NF-κB was involved in IL-6 release by MCP-1, whereas proliferation was dependent on AP-1. The results clearly demonstrate that MCP-1 induces differential activation of NF-κB and AP-1 in VSMCs. Thus, our data propose a new mechanism for the proatherogenic effect of MCP-1.
    Keywords: Medicine;
    ISSN: 1079-5642
    E-ISSN: 15244636
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