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  • Composite Materials  (3)
  • cytokinin  (2)
  • 2020-2021
  • 1995-1999  (5)
  • 1960-1964
  • 1
    Electronic Resource
    Electronic Resource
    Transgenic periwinkle tissues overproducing cytokinins do not accumulate enhanced levels of indole alkaloids (1996)
    Springer
    Plant cell, tissue and organ culture 45 (1996), S. 223-230 
    Details
    ISSN: 1573-5044
    Keywords: Agrobacterium tumefaciens ; Catharanthus roseus ; cytokinin ; isopentenyl-transferase ; stress response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytokinins play a critical role in several aspects of plant growth, metabolism and development. We previously reported that adding cytokinins to the culture medium of a suspension-cultured cell line of periwinkle increased the accumulation of indole alkaloids, and our aim was to compare the effect of exogenously-applied cytokinins with that of elevated levels of endogenous cytokinins on indole alkaloid production. We used an Agrobacterium tumefaciens strain yielding a plasmid with the isopentenyl transferase gene under control of its own promoter. Co-culture of suspension cells with the bacteria caused a severe stress response leading to cell necrosis. Therefore, we failed to transform this material but we succeeded in transforming periwinkle cotyledons. We verified that callus cultures generated from the isopentenyl transferase-transgenic cotyledons accumulated high cytokinin concentrations. Treating normal callus cultures (generated from untransformed cotyledons) with cytokinins enhanced their alkaloid production. By contrast, the enhanced concentration of endogenous cytokinins in transgenic calli did not increase indole alkaloid production, and thus did not mimic the effect of exogenously-applied cytokinins. Hypothesis to explain this discrepancy are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043634
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Molecular characterization of a cytokinin-inducible periwinkle protein showing sequence homology with pathogenesis-related proteins and the Bet v 1 allergen family (1998)
    Springer
    Plant molecular biology 36 (1998), S. 791-798 
    Details
    ISSN: 1573-5028
    Keywords: Catharanthus roseus ; cell biochemical differentiation ; cytokinin ; intracellular pathogenesis-related protein ; pollen allergen ; RT- and RACE-PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytokinin treatment of periwinkle callus cultures increased the accumulation of a protein, designated T1, in two-dimensional separated protein extracts. The first 30 NH2-terminal amino acids were determined by Edman degradation and showed significant sequence homology with intracellular pathogenesis-related (IPR) plant proteins and the Bet v 1 allergen family. The deduced amino acid sequence of cDNAs coding for T1, isolated by RT-PCR and 5′ RACE-PCR, exhibited an average sequence identity of 40% with both IPR and Bet v 1-related allergens. T1 and all related proteins contained a p-loop motif typically found in nucleotide-binding proteins as the most conserved sequence feature. Northern blot analysis showed that cytokinin treatment of periwinkle callus induced T1 transcripts, whereas addition of 2,4-dichlorophenoxyacetic acid inhibited this accumulation. Hybridization of genomic periwinkle DNA with the T1 cDNA suggested that the protein is encoded by a single-copy gene. Immunoblot studies with a panel of Bet v 1-specific antibodies and sera from Bet v 1 allergic individuals identified T1 as a protein that is immunologically distinct from the Bet v 1 allergen family and has no allergenic properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005951208815
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    Paper (German National Licenses)
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  • 3
    facet.materialart.
    Unknown
    Mechanical Behavior of Fabric-Film Laminates (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Inflatable structures are gaining wide support in planetary scientific missions as well as commercial applications. For such applications a new class of materials made of laminating thin homogenous films to lightweight fabrics are being considered us structura1 gas envelops. The emerging composite materials are a result of recent advances in the manufacturing cf 1ightweight, high strength fibers, fabrics and scrims. The lamination of these load-carrying members with the proper gas barrier film results in wide range of materials suitable for various loading and environmental conditions. Polyester - based woven fabrics laminated to thin homogeneus film of polyester (Maylar) is an example of this class. This fabric/ film laminate is being considered for the development a material suitable for building large gas envelopes for use in the NASA Ultra Long Duration Balloon Program (ULDB). Compared to commercial homogeneus films, the material provides relatively high strength to weight ratio as well as better resistance to crack and tear propagation. The purpose of this papers is to introduce the mechanical behavior of this class of multi-layers composite and to highlight some of the concerns observed during the characterization of these laminate composites.
    Keywords: Composite Materials
    Type: ANTEC99; May 02, 1999 - May 06, 1999; New York, NY; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Mechanical and Tear Properties of Fabric/Film Laminates (1998)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Films reinforced with woven fabrics are being considered for the development of a material suitable for long duration scientific balloons under a program managed by the National Aeronautics and Space Administration (NASA). Recently developed woven fabrics provide a relatively high strength to weight ratio compared to standard homogenous films. Woven fabrics also have better crack propagation resistance and rip stop capabilities when compared to homogenous lightweight, high strength polymeric films such as polyester and nylon. If joining is required, such as in the case of scientific balloons, woven fabrics have the advantage over polymeric thin films to utilize traditional textile methods as well as other techniques including hot sealing, adhesion, and ultrasonic means. Woven fabrics, however, lack the barrier properties required for helium filled scientific balloons, therefore lamination with homogenous films is required to provide the gas barrier capabilities required in these applications.
    Keywords: Composite Materials
    Type: Composite Materials; Jul 05, 1998 - Jul 11, 1998; Las Vegas, NV; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Special Considerations in Selection of Fabric Film Laminates for Use in Inflatable Structures (1999)
    In:  Other Sources
    Details
    Publication Date: 2019-07-17
    Description: Inflatable structures are gaining wide support in planetary scientific missions as well as commercial applications. For such applications a new class of fabric/film laminates is being considered for use as a structural gas envelope. The emerging composite materials are a result of recent advances in the manufacturing of lightweight, high strength fibers, fabrics and scrims. The lamination of these load-carrying members with the proper gas barriers results in a wide range of materials suitable for various loading and environmental conditions. Polyester-based woven fabrics laminated to thin homogenous film of polyester are an example of this class. This fabric/film laminate is being considered for the development of a material suitable for building large gas envelopes for use in the NASA ultra long duration balloon program (ULDB). Compared to commercial homogenous films, the material provides relatively high strength to weight ratio as well as better resistance to crack and tear propagation, The mechanical, creep and viscoelastic properties of these fabric film laminates have been studied to form a material model. Preliminary analysis indicates that the material is highly viscoelastic. The mechanical properties of this class of materials will be discussed in some details.
    Keywords: Composite Materials
    Type: Balloon Technology; Jun 29, 1999 - Jul 01, 1999; Norfolk, VA; United States
    Format: text
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    NASA TECHNICAL REPORTS
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