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  • Springer  (167)
  • 1995-1999  (58)
  • 1985-1989  (34)
  • 1980-1984  (52)
  • 1910-1914  (7)
  • 1905-1909  (16)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Semigroup forum 90 (1998), S. 474-477 
    ISSN: 1432-2137
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Fetusca arundinacea Schreber) is rapidly gaining popularity as a turfgrass. Limited information is available on seed yield response of turf-type cultivars to seed production management practices. We tested effects of four management variables on seed yield of Bonanza (late-maturing turf type), Rebel (mid-maturing turf type), Falcon (early-maturing turf type), and Fawn (forage type) tall fescue cultivars. Variables were spring-applied N rates (100, 145, and 190 kg ha-1), N application timing (double-ridge stage, spikelet initiation, and equally split between the two), row spacing (0.3 and 0.6 m), and post-harvest residue managements after removing the straw (flail-chopping or burning the stubble). Seed yields of the second through fifth crops were measured. Nitrogen application timing did not affect seed yield of any cultivar. Effects of the other three variables on seed yield interacted with each other. For both Fawn and Rebel, high seed yields were achieved when 100 kg N ha-1 was applied and residue was burned, irrespective of row spacing. Bonanza produced high seed yields with 145 kg N ha-1 , 0.6-m row spacing, and flail-chopping. In contrast, 0.3-m row spacing and residue burning was required for maximum seed yield in Falcon, whereas N rates did not have an effect. We conclude that seed yield responses of Fawn and rebel to management practices are similar. Results further suggest that, compared with Fawn, the optimum spring N rate was higher for Bonanza seed production, and the optimum row spacing was narrower for Falcon seed production. Also, residue burning was needed for maintaining high seed yield in Fawn, Rebel, and Falcon, whereas, at optimum row spacing and N rate, mechanical removal of post-harvest residue was as effective as burning for Bonanza seed production.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-2137
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Fetusca arundinacea Schreber) cultivars is needed to improve cultural practices for seed production. We tested factorial combinations of two post-harvest residue managements (flail-chopping or burning the stubble), two row spacing (0.3 and 0.6 m), three spring-applied N rates (100, 145, and 190 kg ha-1), and three N application timings (double-ridge, spikelet initiation, and equally split between the two) on seed yield components of turf-type cultivars Falcon, Rebel, and Bonanza, and the forage cultivar Fawn. Seed yields of all cultivars were closely correlated with the number of seeds produced per unit area (m2), but yields were weakly and negatively correlated with weight per seed. Compared with flail-chopping, burning the residue increased the number of fertile tillers, floret sites, and seeds per unit area in all cultivars. The number of seeds per unit area was not affected by row spacing in Fawn and Bonanza, but was increased at 0.3-m row spacing in Falcon when the residue was burned, and was greater at 0.6-m in Rebel when the residue was flail-chopped. Increasing N rate above 100 kg ha-1 decreased floret site utilization and seeds per unit area in Fawn, but did not affect these components in Falcon and Rebel. Seeds per unit area in Bonanza was the greatest at 145 kg N ha-1. For all cultivars, N application timing had little effect on seeds per unit area. We conclude that management practices for the turf-type cultivars should focus on maintaining a high number of fertile tillers throughout the stand life by burning post-harvest residue. Using narrower row spacings for early- and mid-maturing turf-type cultivars also could increase the number of fertile tillers per unit area when the post-harvest residue is burned. The optimum spring-applied N rate for seed production is apparently greater for the late-maturing turf types than for forage cultivars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-1424
    Schlagwort(e): plasma membrane ; lung ; histamine receptors ; 5′ nucleotidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary A simple and rapid method of isolating plasma membranes from human peripheral lung tissue is described. The method involves homogenization of tissue in 0.25m sucrose-buffered medium followed by differential and sucrose density gradient centrifugation. Enzymatic and morphological characterization of the plasma membrane fraction revealed minimal contamination by nonplasma membrane fragments. The isolated plasma membranes showed an 18-fold purification of 5′-nucleotidase activity compared to the original homogenate. Electronmicroscopic studies of the plasma membrane fraction revealed the presence of small membrane vesicles having a trilaminar membrane structure. To further examine the purity of the plasma membrane preparation, the binding of the H1 receptor antagonist,3H pyrilamine, to the plasma membrane-enriched fraction was compared to the binding to crude membrane preparations. Both the plasma membrane-enriched fraction and the crude membrane preparation had similar Kd's for the histamine antagonist, but the plasma membrane-enriched fraction had a threefold greater binding capacity, reflecting the relative enrichment of plasma membranes of the preparation. Thus, a method has been developed for the isolation of plasma membranes from human peripheral lung which should provide material for a variety of biochemical and pharmacological studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1432-2048
    Schlagwort(e): Avena (phytochrome) ; Immunological discrimination ; Monoclonal antibody ; Phytochrome (red-, far-red absorbing forms)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A set of rat monoclonal antibodies (ARC MAC 48 to 52 and 54 to 56), raised to phytochrome from dark-grown seedlings of Avena sativa L. was tested for the ability to discriminate between the red-absorbing (Pr) and far-red-absorbing (Pfr) forms of phytochrome by indirect enzyme-linked immunosorbent assay. MAC 50 bound more strongly to Pfr and MAC 49 and 52 showed preferential binding to Pr from extracts of dark-grown Avena seedlings; MAC 50 also bound more strongly to Pfr from brushite-purified phytochrome. The remainder of the monoclonal antibodies and a rabbit polyclonal antiphytochrome preparation did not discriminate between Pr and Pfr. The results provide evidence for conformational changes in defined regions of the phytochrome apoprotein upon photoconversion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-2048
    Schlagwort(e): Action spectrum ; Light-grown plants ; Photoperiodism ; Phytochrome (type I) ; Triticum (photoperiodism)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fluence-rate response curves for wavelengths from 640 nm to 730 nm were constructed for the day-extension promotion of flowering in green, light-grown, wheat (Triticum aestivum L., cv. Alexandria), a long-day plant. The resultant action spectrum had action maxima at 660 nm and 716 nm and resembles spectra for the high-irradiance reaction (HIR) seen in etiolated plants. Because, the HIR is thought to be controlled by type I pytochrome (that which is most abundant in etiolated tissue) our results indicate the involvement of type I phytochrome in the photomorphogenesis of a light-grown, green plant.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-2048
    Schlagwort(e): Gibberellin and protoplast swelling ; Phytochrome ; Protoplast (swelling) ; Triticum (protoplast swelling)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of light on the size of intact protoplasts isolated from the primary leaves of etiolated Triticum aestivum was studied. A 2-min red-light irradiation in the presence of 1 mM KCl was sufficient to cause a swelling of protoplasts compared with those maintained in darkness. The effect was photoreversible by far-red light over two light cycles, indicating the involvement of phytochrome. At 4°C, escape from reversibility occurred between 2 and 5 min after the exposure to red light. In exposure-response experiments, 20 s red light at 27 μmol m-2s-1 was sufficient to saturate the response. Exogenous gibberellic acid added in darkness in the presence of KCl also induced protoplast swelling. Gibberellins may act as an intermediate in the phytochrome-induced swelling of protoplasts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 49 (1999), S. 23-26 
    ISSN: 1432-1432
    Schlagwort(e): Key words: Genome evolution — Adaptability — Somatic hypermutation — Affinity maturation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. Darwinian theory requires that mutations be produced in a nonanticipatory manner; it is nonetheless consistent to suggest that mutations that have repeatedly led to nonviable phenotypes would be introduced less frequently than others—if under appropriate genetic control. Immunoglobulins produced during infection acquire point mutations that are subsequently selected for improved binding to the eliciting antigen. We and others have speculated that an enhancement of mutability in the complementarity-determining regions (CDR; where mutations have a greater chance of being advantageous) and/or decrement of mutability in the framework regions (FR; where mutations are more likely to be lethal) may be accomplished by differential codon usage in concert with the known sequence specificity of the hypermutation mechanism. We have examined 115 nonproductively rearranged human Ig sequences. The mutation patterns in these unexpressed genes are unselected and therefore directly reflect inherent mutation biases. Using a χ2 test, we have shown that the number of mutations in the CDRs is significantly higher than the number of mutations found in the FRs, providing direct evidence for the hypothesis that mutations are preferentially targeted into the CDRs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Monatshefte für Chemie 126 (1995), S. 839-850 
    ISSN: 1434-4475
    Schlagwort(e): Electrode glasses ; Principal Component Analysis ; Cluster analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Cluster Analysis has been shown to be partially suitable for the classification of glasses. The expansion of the clusters on theSeger's diagram allows an investigation of the influence of the different glass components. Variation of the SiO2 content results in a smaller change of properties than variation of the Na2O/RO relationship. Principal Component Analysis is convenient for showing correlations between the composition of the examined glasses, the glass structure parameters, and the different electrode properties. Properties of electrodes are mostly influenced by the content of Na2O and by the kind of the divalent cations. In contrast thereto structure parameters become basically determined by the content of SiO2 and RO. The field strength of the divalent cations plays the decisive roll again.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 33 (1981), S. 545-548 
    ISSN: 1432-0827
    Schlagwort(e): calmodulin ; calcium ; mineralisation ; tooth germ
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Calmodulin, a calcium binding protein, has been implicated in the regulation of many calcium-dependent biological processes. Since calcium has an important role in hard tissue genesis, both at intra- and extracellular levels, we anticipate that calcium binding proteins may modulate this process. The present study investigated a mineralising tissue, the rat molar tooth germ, to determine the presence of calmodulin-like activity. A heat-treated cell-free extract of tooth germs provided enhancement of Ca2+-dependent Mg2+-ATPase and 3′:5′-nucleotide phosphodiesterase activity. No enhancement occurred in the absence of calcium or in the presence of trifluoperazine. SDS-polyacrylamide gel electrophoresis of this extract revealed a protein band of approximately 18,000 mol. wt. These findings indicate the presence of calmodulin-like activity in rat molar tooth germs and support the proposal that calcium and calcium binding proteins, in particular calmodulin, have a major regulatory role in the biology of mineralising tissues.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Applied microbiology and biotechnology 43 (1995), S. 1050-1055 
    ISSN: 1432-0614
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Two rice α-amylase isozymes, AmylA and Amy3D, were produced by secretion from genetically engineered strains of Saccharomyces cerevisiae. They have distinct differences in enzymatic characteristics that can be related to the physiology of the germinating rice seed. The rice isozymes were purified with immunoaffinity chromatography. The pH optima for amy3D (pH optimum 5.5) and Amy1A (pH optimum 4.2) correlate with the pH of the endosperm tissue at the times in rice seedling development when these isozymes are produced. Amy3D showed 10–14 times higher reactivity to oligosaccharides than Amy1A. Amy1A, on the other hand, showed higher reactivity to soluble starch and starch granules than Amy3D. These results suggest that the isozyme Amy3D, which is expressed at an early stage of germination, produces sugars from soluble starch during the early stage of seed germination and that the isozyme Amy1A works to initiate hydrolysis of the starch granules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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