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  • deterrent activity  (3)
  • plant resistance  (2)
  • Chemical Engineering  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 26 (2000), S. 429-441 
    ISSN: 1573-1561
    Schlagwort(e): Lupinus luteus ; Halotydeus destructor ; plant resistance ; deterrent activity ; quinolizidine alkaloids ; ammodendrine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Eleven varieties of Lupinus luteus were tested in choice and no-choice experiments for their resistance to feeding by the red-legged earth mite (Halotydeus destructor). Three were found to show resistance, and the alkaloid fraction from these varieties strongly deterred mites from feeding. The alkaloid components of the extracts, lupinine, a number of acyl derivatives of lupinine, and sparteine were tested for deterrent activity. Sparteine was the most potent, with significant activity at 0.001% concentration. Quantitation of the levels of nonpolar alkaloids in the cotyledons and leaves of the 11 varieties was by gas chromatography–mass spectrometry. An inverse correlation was found between the concentrations of these alkaloids and the damage caused by the mites; varieties with levels 〈100 μg/g (fresh wt) showed a high damage index. The involvement of sparteine and the bipiperidine alkaloid ammodendrine in the deterrence to mite feeding is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 24 (1998), S. 2089-2100 
    ISSN: 1573-1561
    Schlagwort(e): Trifolium subterraneum ; trifoliates ; Halotydeus destructor ; free isoflavones ; bound isoflavones ; resistance ; deterrent activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Mature leaves of variety SE014 of Trifolium subterraneum are resistant to the redlegged earth mite (Halotydeus destructor). Compounds with feeding deterrent activity present in the leaves were isolated and identified by using a membrane bioassay technique. The free isoflavones, formononetin, genistein, and biochanin A, their corresponding 7-O-glucosides, and biochanin A 7-O-glucoside-6″-O-malonate and genistein 7-O-glucoside-6″-O-malonate, were active. In addition, the biosynthetic precursors of formononetin and genistein, 2,5,7-trihydroxy-4′-methoxyisoflavanol and 2,5,7,4′-tetrahydroxyisoflavanol, also were deterrent to the redlegged mites. The relative activity of these compounds was determined and some structure-activity correlations are noted. The constitutive defense mechanism that contributes to the resistance of subclover trifoliates to the mite contrasts with the induced chemical mechanism previously found for subterranean clover cotyledons.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-1561
    Schlagwort(e): Trifolium subterraneum ; trifoliate leaves ; Halotydeus destructor ; free isoflavones ; bound isoflavones ; plant resistance ; deterrent activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The extracts, obtained with methanol from crushed trifoliates and from the surface layer of the trifoliates, contained isoflavones in both the free and bound forms as the major components, compounds known to exhibit feeding deterrence towards the redlegged earth mite. The levels of these compounds were quantified and showed considerable variation in extracts of one susceptible variety and four varieties with differing levels of resistance. The relative resistance of the five varieties established from field observations was compared with the amounts of isoflavone derivatives obtained in the two extracts. A better ranking of resistance was found with levels of isoflavones on the leaf surface than with the total amount of isoflavones in the trifoliates. These results suggest a simple method for determining the relative resistance of subterranean clover to the mite.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 1273-1278 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The effects of physical aging on dynamic mechanical and transient stress-relaxation properties of a high performance thermoplastic, polyetheretherketone (PEEK), are reported in this study. The aging effects are shown to be physical effects (and not chemical degradation) by establishing thermoreversibility of the aging process. The unique aspect of the present study is the simultaneous investigation of both dynamic and transient properties in the same mode of loading, namely, in shear. The influence of continuous dynamic deformation on the aging process is also reported. The results for the aging rate, obtained from dynamic and transient testing under shear load, agree with one another and verify the equivalence of dynamic and transient viscoelastic properties. However, these results differ significantly from the aging rate results reported in an earlier study for tensile loading. A possible explanation for the difference has been proposed in terms of the volume change that accompanies tensile creep deformation.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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