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  • Articles: DFG German National Licenses  (14)
  • 1990-1994
  • 1985-1989  (14)
  • 1988  (6)
  • 1985  (8)
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  • Articles: DFG German National Licenses  (14)
Material
Years
  • 1990-1994
  • 1985-1989  (14)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Oxford journal of archaeology 4 (1985), S. 0 
    ISSN: 1468-0092
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Archaeology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 11 (1988), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. The formation of nitrogen-fixing nodules on leguminous plants is the culmination of an integrated development involving many plant and bacterial genes. This review focuses on the structure, function and regulation of the bacterial genes involved in the nodulation process. We attempt to interpret recent observations on these genes in the context of signal exchanges which occur between the macro-and micro-symbionts.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 8 (1985), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Photosynthesis by aquatic plants based on the supply of CO2 from air-equilibrated solutions may be limited by the low diffusion coefficient of CO2 in water. For plants in which the transport of CO2 from the bulk medium is by diffusion, and the initial carboxylation uses RUBISCO, CO2 supply can be increased by growth in habitats with fast water flow over the surface (reducing unstirred layer thickness), or with heterotrophically-augmented CO2 levels, including the direct use of sediment CO2. Many aquatic plants using RUBISCO as their initial carboxylase counter the limitations on CO2 supply via the operation of biophysical CO2 concentrating mechanisms which are based on active transport of HCO−3, CO2 or H+ at the plasmalemma, and use bulk-phase HCO−3 or CO2 as the C source. A final group of aquatic plants use biochemical CO2 concentrating mechanisms based on auxiliary carboxylation by PEPc: C4-like and Crassulacean Acid Metabolism–like processes are involved. These various mechanisms for increasing CO2 supply to RUBISCO also help to offset the low specific reaction rate of aquatic plant RUBISCOs at low [CO2] and low [CO2]: [CO2]. In addition to overcoming restrictions on CO2 supply, the various methods of increasing inorganic C availability may also be important in alleviating shortages of nitrogen or photons.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The Rhizobium leguminosarum biovar phaseoli symbiotic plasmid pRP2JI carries a gene, melA, specifying the enzyme tyrosinase, which is responsible for the production of the pigment melanin in these bacteria. Transcription of melA is activated by the nifA gene of Rhizobium and, when the cloned melA gene is transferred to Escherichia coli, melA is expressed if the recipients contain nifA gene of Klebsiella pneumoniae. This nifA-dependent activation was temperature sensitive and required the ntrA gene. The cloned nifA gene of K. pneumoniae, when transferred to a nifA mutant of Rhizobium phaseoli biovar phaseoli, corrected the Mer− but not the Fix− phenotype. nifA of R. leguminosarum biovar phaseoli activated melA at higher levels in cells grown in low concentrations of oxygen. Also, nifA of fl. leguminosarum biovar phaseoli activated nifH of K. pneumoniae in Escherichia coli cells grown In low-oxygen concentrations.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 2 (1988), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The chemotactic behaviour of a strain of Rhizobium leguminosarum biovar viciae was investigated. The flavanoids apigenin and naringenin, inducers of transcription of the nodulation (nod) genes, were both potent attractants but hesperitin, another flavone nod gene inducer, was not. The response of strains containing the Sym plasmid pRL1JI to apigenin and naringenin was significantly greater than the response of a strain cured of the plasmid, although both strains gave a positive response. Addition of the flavanol kaempferol, an antagonist of nod gene induction, had no detectable effect on the chemotactic response to naringenin or aplgenin, but was itself found to be an attractant. The attractant response to a variety of amino acids and sugars was not affected by the presence of the Sym plasmid. Homoserine, the most abundant nitrogenous compound in legume exudates, was also found to be an attractant. However, although the Sym plasmid is required for the biovar to metabolize homoserine as a carbon source, it was not required for the chemotactic response. A group of membrane proteins showed increased methylation in response to stimulation with serine. There was no measurable change in methylation after stimulation with apigenin.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 98 (1988), S. 352-362 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Experiments designed to simulate the interaction of juxtaposed rhyolitic and basic magmas were conducted at 10 kbar with H2O, using reaction-couples consisting of Westerly granite (WG) against basalt (DW-1) and WG against a synthetic mafic glass (SMG, enriched in MgO and Na2O relative to DW-1). Each couple was run with ∼5 and ∼10 wt% H2O corresponding respectively to H2O-undersaturated and H2O-oversaturated conditions. Experiments were run for 42–44 h at 920° C, above the liquidus of WG and within the melting intervals of DW-1 and SMG. WG was run above the basic material in all but one experiment. The composition of the granitic melt was altered only through material exchange with the adjacent basic melts, whereas that of the basic melts also changed (relative to the bulk basic composition) due to partial crystallization. Some crystallization also occurred within the zone of interaction. For control, the basic compositions were also run alone under the same conditions as the reaction-couple experiments. The crystalline phase assemblages in the basic ends of the coupled experiments differed from those produced from the basic materials alone, demonstrating interaction with the granite melt. Moreover, compositional gradients within the basic ends of coupled experiments are indicated by changes in phase assemblage and compositions with distance from the interface with WG. Microprobe analyses of glass collected along the length of the capsules confirm published observations that alkali diffusion is very fast: K2O and Na2O homogenized throughout the capsules in less than the two-day run times. This, coupled with the fact that introduction of K2O into SMG stabilized biotite, produced the result that after interaction the bulk basic material (melt+crystals) contained more K2O than the coexisting felsic melt. Only very gentle gradients for CaO, FeO, and MgO are preserved in our experiments, in contrast with published anhydrous results, suggesting that the difference in activity coefficients for these components between basic and felsic melts is reduced by the introduction of H2O. Gradients for SiO2 and Al2O3 are of comparable length to those of the divalent cations, confirming earlier results that the diffusivities of the network-formers limit the rate of diffusion of Ca, Fe, and Mg.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 100 (1988), S. 35-46 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract We report the T-X(H2O) phase relations for the trondhjemitic Nûk gneiss which comprises the principal component of the second phase of Archean (3.0–2.8 by) igneous activity in the Godthåb region of southwestern Greenland. A pressure of 15 kbar was chosen to place constraints on possible protoliths for trondhjemitic melts at lower crustal depths. Under H2O-saturated conditions, a melting interval of ∼135° C separates the solidus at ∼610° C from the liquidus at 745° C. H2O-saturation at 15 kbar occurs at approximately 15.5 wt % H2O. The H2O-undersaturated liquidus extends along a curved path from ∼745° C at 15.5 wt % H2O to ∼1100° C at 2% H2O. Lower H2O contents were not investigated. At low H2O contents (〈6%) sodic plagioclase (Pl, An32) is the liquidus phase followed at lower but still near-liquidus temperatures by quartz (Qz) and then garnet (Ga). At 6% H2O, Ga replaces Pl on the liquidus and is joined at slightly lower temperatures by Pl and hornblende (Hb). The field for liquidus Ga extends to only ∼7.5% H2O where it is replaced by Hb which is the liquidus phase up to 13% H2O. At all higher H2O contents, epidote (Ep) is the first phase to crystallize, followed by biotite (Bi) at slightly lower temperatures. Following the standard inverse approach, the near-liquidus phase assemblages are interpreted as potential residues from which trondhjemitic melts could be extracted. At high melt H2O contents (〉7%), mafic residues consisting of some combination of Hb, Ga, Ep, and Bi are possible and could correspond to amphibolitic source rocks. At lower melt H2O contents (〈 5%), possible residues consist of Na-Pl+Qz±Ga and could correspond to an earlier generation of tonalitic-trondhjemitic rocks. However, such residues would not impart the highly fractionated REE patterns characteristic of Archean trondhjemites. If a first generation of tonalitic-trondhjemitic melts was generated by higher pressure partial fusion of eclogite and emplaced at 55 km depth, it would crystallize to an assemblage consisting almost entirely of Na-Pl+Qz with highly fractionated REE patterns. These rocks in turn could be partially melted to yield a second generation of trondhjemites which would inherit the highly fractionated REE patterns because neigher Pl nor Qz is capable of significantly fractionating HREE from LREE.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 29 (1985), S. 177-179 
    ISSN: 1432-1041
    Keywords: theophylline clearance ; age ; adult age range ; normal subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty volunteers aged between 20 and 57 years were given 197 mg of theophylline (as lysine theophylline) by iv infusion over 5 minutes to test the hypothesis that within the adult age range theophylline clearance declines with age. Samples were assayed for theophylline using the EMIT assay and clearance was determined by standard methods. Clearance values were 0.73 ml/min/kg below age 38 years and 0.75 ml/min/kg at and above age 38 years. Multiple regression analysis using age as a continuous variable showed no relationship between age and clearance.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 28 (1985), S. 253-255 
    ISSN: 1432-1041
    Keywords: disopyramide ; flecainide ; myocardial infarction ; drug plasma binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In the serum basic drugs are principally bound to alpha1-acid glycoprotein (AAG). Following acute myocardial infarction it has been shown that the levels of AAG rise. The serum levels of total protein, albumin, AAG and the protein binding of 2 antiarrhythmic drugs which are bases, disopyramide and flecainide, was measured in vitro with blood samples from eleven patients taken over the first 5 days following myocardial infarction. Mean AAG levels significantly increased from 1.04 g/l on Day 1 to 1.80 g/l on Day 5. The binding of disopyramide, which is highly bound, rose from 80% to 87%, representing a 35% decrease in free drug concentration. In contrast the binding of flecainide fell from 61% to 53%, a 20% increase in free drug concentration. These data suggest that although the binding of strongly bound drugs responds appropriately to increases in binding protein after acute myocardial infarction, poorly bound drugs are displaced from binding sites possibly by endogenous substances. Since the pharmacological effects of a drug are related to its free (unbound) concentration, the changes in the proportions of free to bound drug after myocardial infarction may have important clinical implications.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A strain of R. phaseoli cured of its symbiotic plasmid, pRP2JI, retained the ability to make exopolysaccharide (EPS). However, a region of pRP2JI, when cloned at an increased copy number in wide host-range vectors and transferred to this and other strains of Rhizobium, inhibited EPS synthesis. The gene responsible was termed psi (polysaccharide inhibition) and was located in a region of the symbiotic plasmid close to nodulation and nitrogen fixation genes. psi is important in the symbiosis since a wild-type strain containing psi cloned on a multicopy plasmid failed to form Phaseolus nodules, and mutant strains containing psi::Tn5 mutations failed to fix nitrogen in Phaseolus nodules. It is proposed that the function of psi may be to repress in the bacteriod the expression of genes such as those for EPS synthesis which are normally expressed in free-living culture.
    Type of Medium: Electronic Resource
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