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  • 1
    Electronic Resource
    Electronic Resource
    Sequestration ofVeratrum alkaloids by specialistRhadinoceraea nodicornis konow (Hymenoptera, Tenthredinidae) and its ecoethological implications (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 3233-3250 
    Details
    ISSN: 1573-1561
    Keywords: Veratrum album ; ceveratrum alkaloids ; plant-insect interactions ; sequestration ; hemolymph ; feeding deterrence ; Rhadinoceraea nodicornis ; Aglaostigma sp. ; Hymenoptera ; Tenthredinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The larvae of the specialist sawflyRhadinoceraea nodicornis Konow (Hymenoptera, Tenthredinidae) store in their hemolymph ceveratrum alkaloids originating from the host plantVeratrum album L. (Liliales, Melanthiaceae). The major alkaloid found in the hemolymph is 3-acetyl-zygadenine. Qualitative and quantitative data showed that the plant alkaloid 3-angeloylzygadenine is most probably metabolized in the larval gut to zygadenine and then acetylated. A still unidentified alkaloid with a molecular weight of 591 Da was detected in plant leaves as well as in the gut, hemolymph, and excrement of larvae. Protoveratrine A and B, on the other hand, seem to be degraded by the larvae. These findings indicate that the pathway of ceveratrum alkaloids inR. nodicornis larvae is fourfold: direct sequestration, metabolism followed by sequestration, excretion of intact alkaloids, and degradation. In contrast, no ceveratrum alkaloids were detected in the hemolymph and excrement of larvae of the generalist sawflyAglaostigma sp. fed withV. album leaves. Bioassays with the antMyrmica rubra L. proved that the hemolymph ofR. nodicornis larvae is highly deterrent and toxic. In bioassays evaluating defensive efficiency against predators (ants, spiders, and bushcrickets), no larvae were eaten. Ceveratrum alkaloids were also detected in the hibernating prepupae ofR. nodicornis. In feeding bioassays, the shrewCrocidura russula Hermann rarely fed upon prepupae, suggesting that this stage is also protected from predation to some degree. In field surveys, the only parasitoids recorded were two ichneumonid species that are believed to be specialized onR. nodicornis. Bioassays and field observations enable us to suppose thatR. nodicornis and its enemies produce a food web of ion connectance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033723
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  • 2
    Electronic Resource
    Electronic Resource
    Negative-ion mass spectrometry of substituted adenine bases and adenosine nucleosides (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 249-254 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The negative-ion chemical ionization (ammonia, 5 Pa source pressure) mass spectra of a series of substituted adenine bases, adenosine nucleosides, and the trimethylsilyl derivatives of the nucleosides are described. Selected ions from these spectra were subject to collisionally activated dissociation with mass-analysed ion kinetic energy (CAD/MIKE) analysis of the products and the spectra assessed for information content. In addition to observing strong peaks due to quasimolecular ions and heterocyclic-base ions, it proved possible to differentiate between 2′-, 3′- and 5′-deoxy and between 2′- and 3′-O-methyl isomers. The negative-ion chemical ionization spectra of four methyladenines are essentially identical, but could be clearly distinguished from each other by CAD/MIKE analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030802
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  • 3
    Electronic Resource
    Electronic Resource
    Negative ion mass spectrometry of silylated cytokinins (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 36-38 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The negative ion mass spectra or trimethylsilylzeatin riboside and t-butyldimethylsilylzeatin, generated using either ammonia or 10% CO2/Ar as reagent gas, are described. Optimal yields of [M-H]- ions were obtained with a source pressure of 5 Pa in the electron ionization source of a ZAB-2F mass spectrometer, compared with 15 Pa to generate [M+H]+ in the chemical ionization mode. At 15 Pa no negative ions could be observed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030208
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  • 4
    Electronic Resource
    Electronic Resource
    Vinceten, ein Benzopyrroloisochinolin-Alkaloid, aus Cynanchum vincetoxicum (L.) Pers. (Asclepiadaceae) (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1212-1231 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vincetene, a Benzopyrroloisoquinoline Alkaloid, from Cynanchum Vincetoxicum (L.) Pers. (Asclepiadaceae)Cynanchum vincetoxicum contains traces of an alkaloid C22H27NO3, whose structure has been shown to be 6-(3-hydroxy-cis-1-butenyl)-2,3-dimethoxy-7,9,10,11,11a,12-hexahydrobenzo[f]-pyrrolo[1,2-6]isoquinoline (2) and has been confirmed by synthesis of the rac-dihydrodesoxy-derivative 18.
    Notes: Cynanchum vincetoxicum (L.) Pers. enthält Spuren eines Alkaloids C22H27NO3, dessen Struktur als 6-(3-Hydroxy-cis-1-butenyl)-2,3-dimethoxy-7,9,10,11,11a, 12-hexahydrobenzo[f]pyrrolo[1,2-b]-isochinolin (2) geklärt und durch Synthese des rac-Dihydrodesoxy-Derivates 18 gesichert wurde.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790815
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  • 5
    Electronic Resource
    Electronic Resource
    Peptide sequencing by metastable mapping (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1983), S. 612-616 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The amino acid sequence of three simple peptides has been determined by the technique of metastable mapping. The products of decompositions in the first field free region of a forward geometry double focussing mass spectrometer are studied by decreasing the electric sector field between scans of the magnetic field.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210181222
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of the chemical defence system in an insect larva by tandem mass spectrometry (1995)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 30 (1995), S. 1291-1295 
    Details
    ISSN: 1076-5174
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Larvae of the sawfly Rhadinoceraea nodicornis Konow (Hymenoptera, Tenthredinidae) living on the plant Veratrum album L. (Liliales, Melanthiaceae) are efficiently protected against ants and spiders. Moreover, when their haemolymph was offered in a sugar solution, ants were still deterred. The chemical defence system of these larvae was investigated and the structures of the biologically active compounds determined by tandem mass spectrometry. Plant-derived alkaloids both in original and metabolized form were found in the larval haemolymph.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jms.1190300913
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