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  • 1
    ISSN: 1420-9071
    Keywords: Bradyrhizobium ; communication ; competitiveness ; Rhizobium ; vesicular-arbuscular (VA) mycorrhiza fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract After a short summary on the ecology and rhizosphere biology of symbiotic bacteria and vesicular-arbuscular (VA) mycorrhiza fungi and their application as microbial inocula, results on competitiveness and communication are summarized. Stress factors such as high temperature, low soil pH, aluminium concentrations and phytoalexins produced by the host plants were studied withRhizobium leguminosarum bv.phaseoli andRhizobium tropici onPhaseolus beans. Quantitative data for competitiveness were obtained by usinggus + (glucoronidase) labelled strains, which produce blue-coloured nodules. ForPhaseolus-nodulating rhizobia, a group specific DNA probe was also developed, which did not hybridize with more than 20 other common soil and rhizosphere bacteria. Results from several laboratories contributing to knowledge of signal exchange and communication in theRhizobium/Bradyrhizobium legume system are summarized in a new scheme, including also defense reactions at the early stages of legume nodule initiation. Stimulating effects of flavonoids on germination and growth of VA mycorrhiza fungi were also found. A constitutive antifungal compound in pea roots, β-isoxazolinonyl-alanine, was characterized.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Human placenta ; Smooth muscle-like cells ; Perivascular contractile sheath ; Nitric oxide synthase type I ; Dipeptidyl peptidase IV
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the human placenta, besides the fetal blood vessel system a second extravascular contractile system exists. It is localized in the chorionic plate and runs in a longitudinal direction and adjacent to fetal blood vessels into the stem villi, where it forms perivascular contractile sheaths. Characteristically, cells of the extravascular contractile system are extremely long and spindle-shaped and give rise to fine cell processes, by which they obviously contact each other or insert into the basement membrane of the trophoblast. They show immunoreactivity with desmin, vimentin, α-actin, myosin, nitric oxide synthase type I (brain form) and dipeptidyl peptidase IV. The ultrastructure suggests that cells of the extravascular contractile system are related to smooth muscle cells, including subpopulations with myofibroblastic features. In stem villi a few cells are nitric oxide synthase type I immunoreactive. These cells are thought to be specialized smooth-muscle-like cells of the extravascular contractile system or cells of the extravascular contractile system related to paraneurons that generate nitric oxide, which, in turn, may modulate the tone of perivascular contractile sheaths. The high dipeptidyl peptidase IV activity suggests that modulation of the extravascular contractile system may also occur by substance P.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 48 (1999), S. 178-186 
    ISSN: 1432-1432
    Keywords: Key words:l-Amino acid oxidase —Archaeoglobus fulgidus—Arthrobacter globiformis—Arthrobacter nicotinovorans—Aspergillus niger—Methanococcus jannaschii— Monoamine oxidase — Nicotine degradation, bacterial — Putrescine oxidase —Salmo gairdneri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The D- and L-specific nicotine oxidases are flavoproteins involved in the oxidative degradation of nicotine by the Gram-positive soil bacterium Arthrobacter nicotinovorans. Their structural genes are located on a 160-kbp plasmid together with those of other nicotine-degrading enzymes. They are structurally unrelated at the DNA as well as at the protein level. Each of these oxidases possesses a high degree of substrate specificity; their catalytic stereoselectivity is absolute, although they are able to bind both enantiomeric substrates with a similar affinity. It appears that the existence of these enzymes is the result of convergent evolution. The amino acid sequence of 6-hydroxy-l-nicotine oxidase (EC 1.5.3.6) as derived from the respective structural gene shows considerable structural similarity with eukaryotic monoamine oxidases (EC 1.4.3.4) but not with monoamine oxidases from prokaryotic bacteria including those of the genus Arthrobacter. These similarities are not confined to the nucleotide-binding sites. A 100-amino acid stretch at the N-terminal regions of 6-hydroxy-l-nicotine oxidase and human monoamine oxidases A possess a 35% homology. Overall, 27.0, 26.9, and 25.8% of the amino acid positions of the monoamine oxidases of Aspergillus niger (N), humans (A), and rainbow trout (Salmo gairdneri) are identical to those of 6-hydroxy-l-nicotine oxidase (Smith–Waterman algorithm). In addition, the G+C content of the latter enzyme is in the range of that of eukaryotic monoamine oxidases and definitely lower than that of the A. nicotinovorans DNA and even that of the pAO1 DNA. The primary structure of 6-hydroxy-d-nicotine oxidase (EC 1.5.3.5) does not reveal its evolutionary history as easily. Significant similarities are found with a mitomycin radical oxidase from Streptomyces lavendulae (23.3%) and a ``hypothetical protein'' from Mycobacterium tuberculosis (26.0%). It is proposed that the plasmid-encoded gene of 6-hydroxy-l-nicotine oxidase evolved after horizontal transfer from an eukaryotic source.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0789
    Keywords: Antifungal activity ; Saccharomyces cerevisiae ; Phytopathogenic fungi ; Heterocyclic non-protein amino acid ; Pisum sativum ; Constitutive plant defence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary β-(Isoxazolin-5-on-2-yl)-alanine (βIA), a heterocyclic non-protein amino acid from root extracts and root exudates of pea seedlings, acts as a potent growth inhibitor of several eukaryotic organisms, including yeasts, phytopathogenic fungi, unicellular green algae, and higher plants. The antibiotic effect on baker's yeast was reversed by l-methionine, l-cysteine, and l-homocysteine. Phytopathogenic fungi such as Botrytis cinerea, Pythium ultimum, and Rhizoctonia solani grown on agar containing βIA were inhibited in the growth of mycelia or in the production of sclerotia. In contrast, no significant inhibition of either Gram-positive or Gram-negative bacteria was observed. Rhizobium leguminosarum, the compatible microsymbiont of Pisum spp., and Rhizobium meliloti were able to tolerate up to 2.9 mM βIA (500 ppm) without any effect on the growth rate. Bradyrhizobium japonicum even gave a positive chemotactic response to βIA. The ecological significance of βIA as a preformed plant protectant during the seedling stage of Pisum spp. and other βIA-containing legumes is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Pharmacology, Biochemistry and Behavior 45 (1993), S. 729-732 
    ISSN: 0091-3057
    Keywords: Amphetamine ; Dopamine ; Methylphenidate ; Motor activity ; Sensitization ; Tolerance
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Pharmacology, Biochemistry and Behavior 48 (1994), S. 473-478 
    ISSN: 0091-3057
    Keywords: Cocaine ; Drug discrimination ; Locomotor activity ; Ritanserin ; Self-administration
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Pharmacology, Biochemistry and Behavior 47 (1994), S. 203-205 
    ISSN: 0091-3057
    Keywords: Amphetamine ; Cocaine ; Self-administration ; Sensitization
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Pharmacology, Biochemistry and Behavior 48 (1994), S. 217-221 
    ISSN: 0091-3057
    Keywords: Caffeine ; Cocaine ; Extinction ; Reinstatement ; Reinstatement of cocaine-taking behavior ; Self-administration
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background and Objective The mechanisms operative in specific immunotherapy (SIT) of Type I allergy are not completely understood. In the present study we evaluated immunological changes during SIT in pollinosis.Method Eight patients suffering from pollinosis (monosensitized to grass pollen) were treated with conventional SIT. All subjects had IgE specific for Phi p 1. a major allergen of timothy grass. In vitro changes in the immunological reactivity to grass pollen extract and to recombinant Phi p 1 were evaluated. Subjects were examined at three occasions: before, after 3 months and after I year of SIT.Results Serological analysis revealed a marked increase of grass pollen- and Phi p 1-specific IgG, titres of specific IgE did not change significantly. Lymphoproliferative responses to grass pollen extract and rPhl p 1 were reduced already after 3 months of treatment. Accordingly, the cloning efficiency for Ph1 p 1-specific T-cell clones (TCC) dropped markedly in all patients. The majority of allergen-specific TCC raised before SIT revealed a TH2-like pattern of cytokine production. TCC established after SIT revealed TH1 characteristics. This shift was due to a decrease in IL-4 rather than an increase in IFN-production by T cells. Investigations of the epitopes recognized by T cells before and after SIT did not reveal the outgrowth of new (ldquo;protecting”) specificities. We could not observe induction of allergen-speeific CD8+ lymphocytes (supressor cells).Conclusion Our data indicate that — on the level of TH lymphocytes — SIT induces tolerance to the allergen and a modulation of the cytokine pattern produced in response to allergen stimulation.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 133 (1995), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Tenascin, a large glycoprotein of the extracellular matrix, shows a site-restricted distribution during embryogenesis. and can be found in adults in a variety of pathological conditions. In normal skin, tenascin is expressed at low levels, but it is upregulated in skin tumours, in a number of skin diseases with epidermal hyperproliferatkm and during wound healing. Several tenascin variants have been described, and these arise by alternative splicing. Using a monoclonal antibody recognizing all tenascin variants, and polyclonal antibodies specific for the large tenascin variants, we have investigated tenascin expression in bullous diseases such as epidermolysis bullosa, pemphigus, bullous pemphigoid and pemphigoid gestationis. By immunohistochemistry, we have found increased tenascin staining in ail patient skin samples, with a more pronounced tenascin expression in samples of autoimmune bullous diseases. The large tenascin variants seem to be major forms of tenascin occurring in healthy skin. In patients with blistering diseases, however, these large variants appear to represent a subpopulation of the induced tenascin accumulation. These findings suggest different functions for the tenascin variants in normal and diseased skin.
    Type of Medium: Electronic Resource
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