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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 131 (1982), S. 81-86 
    ISSN: 1432-072X
    Keywords: Bacteriocin ; Butyricin 7423 ; Clostridium pasteurianum ; Membrane H+-ATPase ; Adenosine triphosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The bacteriocin butyricin 7423 inhibited the activity of the membrane H+-ATPase (BF0, F1) of vegetative cells of Clostridium pasteurianum but not that of its soluble BF1 component. In vitro studies with the H+-ATPases of mutant strains selected for diminished sensitivity (a) to butyricin 7423 and (b) to dicyclohexylcarbodi-imide, confirmed that butyricin 7423 interacts with the BF0 component of this enzyme complex. Even so, certain other mutant strains displaying decreased sensitivity to butyricin 7423 possessed H+-ATPases which in vitro showed undiminished sensitivity to inhibition by the bacteriocin. Furthermore, from the changes in intracellular ATP concentration and in the rates and net extent of efflux of intracellular 86Rb+ ions that were provoked by exposure of the parent and several of the mutant strains to butyricin 7423, it was concluded that its primary bactericidal action was not attributable to stoichiometric inhibition of the membrane H+-ATPase. High extracellular concentrations of K+ ions enabled Cl. pasteurianum to survive exposure to low concentrations of this membrane-active bacteriocin.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 13 (1983), S. 191-218 
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 34 (1980), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The oxidation of 4-aminobutyric acid (GABA) by nonsynaptosomal mitochondria isolated from rat forebrain and the inhibition of this metabolism by the branched-chain fatty acids 2-methyl-2-ethyl caproate (MEC) and 2, 2-dimethyl valerate (DMV) were studied. The rate of GABA oxidation, as measured by O2 uptake, was determined in medium containing either 5 or 100 mM-[K+]. The apparent Km for GABA was 1.16 ± 0.19 mM and the Vmax in state 3 was 23.8 ± 5.5 ng-atoms O2. min−1. mg protein−1 in 5 mM-[K+]. In a medium with 100 mM-[K+] the apparent Km was 1.11 ± 0.17 mM and Vmax was 47.4 ± 5.7 ng-atoms O2. min−1. mg protein−1. The Km for MEC was determined to be 0.58 ± 0.24 or 0.32 ± 0.08 mM, in 5 or 100 mM-[K+], respectively. For DMV, the Ki was 0.28 ± 0.05 or 0.34 ± 0.06 mM, in 5 or 100 mM-[K+] medium, respectively. The O2 uptake of the mitochondria in the presence of GABA was coupled to the formation of glutamate and aspartate; the ratio of oxygen uptake to the rate of amino acid formation was close to the theoretical value of 3. Neither the [K2] nor any of the above inhibitors had any effect on this ratio. The metabolism of exogenous succinic semialdehyde (SSA) by these same mitochondria was also examined. The Vmax for utilization of oxygen in the presence of SSA was much greater than that found with exogenously added GABA, indicating that the capacity for GABA oxidation by these mitochondria is not limited by SSA dehydrogenase. In addition, the branched-chain fatty acids did not inhibit the metabolism of exogenously added SSA. Thus, the inhibitors examined apparently act by competitively inhibiting the GABA transaminase system of the mitochondria.
    Type of Medium: Electronic Resource
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  • 4
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    Minneapolis : Periodicals Archive Online (PAO)
    Philosophical Studies. 43:3 (1983:May) 349 
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 40 (1984), S. 348-350 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 57 (1983), S. 199-211 
    ISSN: 1435-1463
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kynuramines occur endogenously in brain and peripheral tissues as metabolites of indoleamino acids and indolamines but little is known regarding their possible physiological and/or pharmacological activity. The present study has investigated the effects of kynuramine and 5-hydroxykynuramine on the cardiovascular system of pithed rats and attempted to correlate effects seen on adrenergic and serotonergic receptors with ligand binding experiments donein vitro using rat brain membranes. Kynuramine was found to release cardiac catecholamines and to act as a weak partial agonist on vascular alpha-adrenoceptors. Hydroxylation in the 5-position (5-hydroxykynuramine) did not alter cardiac potency but increased pressor activity 100-fold. Vasopressor responses to 5-hydroxykynuramine were mediated via a dual agonistic action on both postsynapticα 2-adrenoceptors and vascular serotonin2 receptors. These findings were supported by ligand binding studies, in which both kynuramine and 5-hydroxykynuramine showed affinity for cortical [3H]spiroperidol and [3H]clonidine binding sites. Overall, the results show that kynuramines can exert peripheral (and possibly central) actions which may prove to be of physiological and/or pharmacological significance.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Current methods of geothermometry and geobarometry applicable to garnet lherzolite are reviewed with reference to recent experimental studies of the equilibration of natural garnet lherzolite and it is concluded that the Wells and Mori-Green formulations of the two pyroxene solvus provide the most reasonable temperature estimates. Pressures are best estimated by using these temperatures with Wood's formulation of the orthopyroxene-garnet geobarometer without chromium corrections. Pipe 200 garnet lherzolites are considered to have equilibrated at 907°–950° C at 30.0–34.5 kb. It is shown that the transport times of xenoliths from the mantle are sufficiently long (0.5–24 h) to allow thermal equilibration with kimberlite but are too short to allow chemical re-equilibration to occur. Xenolith suites therefore retain information regarding the pressure/temperature history of the upper mantle despite being heated to the temperature of the kimberlite magma during transport. The Pipe 200 xenolith suite indicates that the upper mantle beneath Lesotho has been perturbed to temperatures slightly above those defined by steady state geotherms. The Pipe 200 suite is derived from a narrow depth range (90–110 km) and derivation of chromite and garnet lherzolites from similar depths implies that the mantle is heterogeneous over short vertical distances. No simple stratigraphy, in which chromite lherzolites overlie garnet lherzolites is evident. Comparison with other suites of Lesotho garnet lherzolites shows that it is not possible to construct an upper mantle stratigraphy except in the most general terms because of the prevailing lateral and vertical heterogeneity and apparent limited depth range represented by the xenolith suites.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 83 (1983), S. 117-127 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The late tholeiitic lavas of southwestern Ubekendt Ejland (63-54 Ma) are intruded by lamprophyre dykes (∼33 Ma). The compositional and temporal differences would seem to preclude any genetic relationship between the two igneous episodes. Competing models of renewed partial melting versus extended batch fractionation are considered to explain the origin of the lamprophyres. Mathematically modelled lamprophyres produced by batch fractionation are very close to observed lamprophyre compositions and this, combined with other temporal and spatial evidence, suggests that renewed partial melting of the mantle is not the best way to explain such bimodal suites.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1912
    Keywords: 5-Hydroxytryptamine ; Serotonin receptors ; 5-Hydroxykynuramine ; Alpha1-adrenoceptors ; Perfused rat kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kynuramines are endogenously occurring diamines derived from tryptophan. In the present study, we have compared the pharmacological actions of 5-hydroxykynuramine (5-OH-K) with kynuramine and 5-hydroxytryptamine (5-HT) on vascular resistance changes and responsiveness to adrenergic stimuli in the isolated perfused rat kidney. 5-OH-K was found to mimic the actions of 5-HT in that it produced vasoconstriction, potentiation of alpha1-adrenoceptor-mediated responses to norepinephrine (NE) and periarterial nerve stimulation and displaced specific [3H]spiroperidol binding from rat cortical membranes. With regard to all parameters measured, 5-OH-K was about 15-times less active than 5-HT. Vascular responses to 5-OH-K and 5-HT were inhibited noncompetitively by ketanserin and cyproheptadine. Unlike 5-OH-K, kynuramine, failed to evoke vasoconstriction and Inhibited vascular responses to NE via alpha1-adrenoceptors. Thus, kynuramine lacks serotonin receptor agonist activity but possesses alphaI-adrenoceptor blocking properties. In contrast, 5-OH-K potentiates NE and acts as a serotonin agonist. The present results raise the possibility that kynuramine and 5-OH-K might act as endogenous modulators of serotonergic and adrenergic mechanisms in the renal vascular bed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    World journal of surgery 8 (1984), S. 132-133 
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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