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  • Analytical Chemistry and Spectroscopy  (12)
  • Homoptera  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 16 (1990), S. 1899-1909 
    ISSN: 1573-1561
    Schlagwort(e): Castanospermum australe ; Moreton Bay chestnut ; Senecio vulgaris ; groundsel ; Pseudococcus longispinus ; mealybug ; aphid ; Schizaphis graminum ; greenbug ; Myzus persicae ; green peach aphid ; Aphis nerii ; oleander aphid ; Homoptera ; Aphididae ; Coccidae ; phloem transport ; honeydew ; indolizidine ; pyrrolizidine alkaloid ; gramine ; DIMBOA ; cardenolide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Analysis of honeydew excreted by various sap-sucking insects indicated the presence of certain plant secondary constituents in the phloem of their host plants. Honeydew excreted by mealybugs (Pseudococcus longispinus), living onCastanospermum australe, contained the indolizidine alkaloid castanospermine, a potent β-glucosidase inhibitor. Similarly, honeydew from green peach aphids (Myzus persicae), feeding onSenecio vulgaris flower buds, contained the pyrrolizidine alkaloid senecionine, itsN-oxide, and hydrolytic products including retronecine. Cardenolides were detected in the honeydew of oleander aphids (Aphis nerii) feeding on oleander (Nerium oleander), indicating that these compounds are translocated in the phloem. On the other hand, honeydew from greenbugs (Schizaphis graminum), feeding on barley, lacked gramine or related indole metabolites. Similarly MBOA, the breakdown product of DIMBOA, was not detected in the honeydew of greenbugs living on DIMBOA-containing wheat.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-1561
    Schlagwort(e): Feeding deterrents ; Acyrthosiphon pisum ; Homoptera ; Aphi-didae ; host-plant resistance ; pyrrolizidine ; indolizidine ; quinolizidine ; alkaloids ; locoweed ; honeydew ; Astragalus lentiginosus ; phloem transport
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The feeding deterrency of a series of pyrrolizidine, indolizidine, and quinolizidine alkaloids and selected derivatives was measured against the pea aphid (Acyrthosiphon pisum Harris). The indolizidine alkaloid, castanospermine, was intensely active (ED50, 20 ppm) as were the quinolizidine alkaloids, but only modest feeding deterrency was observed with most of the pyrrolizidine alkaloids tested. The insect survival rate of aphids on a castanospermine-supplemented diet over 24 hr was also very low relative to the controls. Castanospermine does not inhibit aphid trehalase. The indolizidine alkaloid swainsonine occurred in the honeydew of pea aphid feeding on the locoweed,Astragalus lentiginosus. Since the pea aphid is a phloem feeder, swainsonine must be transported in the phloem.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 13 (1987), S. 1759-1770 
    ISSN: 1573-1561
    Schlagwort(e): Castanospermine ; 6-epicastanospermine ; deoxynojirimycin ; cellobiase ; lactase ; maltase ; sucrase ; trehalase ; endosymbiote ; insect-plant interactions ; allelochemicals ; Homoptera ; Coleoptera ; Lepidoptera ; Diptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The indolizidine alkaloid, castanospermine (1,6,7,8-tetrahydroxy-octahydroindolizidine—a stereochemical mimic of glucose found in the Australian legumeCastanospermum australe), differentially inhibited cellobiose, lactose, maltose, sucrose, and trehalose hydrolyzing enzymes from a broad taxonomic spectrum of insects (19 species from 12 different families). It was a potent inhibitor of cellobiase activity of all insects tested (50% inhibition at 〈3.2 × 10−5 M castanospermine). With one exception, it also inhibited lactase activity of all insects examined. Only in the sap-feeding Homoptera did castanospermine inhibit all disaccharidase activities assayed. Trehalase activity of the Lepidoptera and Diptera was generally inhibited by castanospermine, whereas inhibition of trehalase activity of the Coleoptera by castanospermine was exiguous or not detectable. Castanospermine was a significant feeding deterrent towards pea aphids,Acyrthosiphon pisum, with an ED50 of 1 × 10−4 M in artificial diets. Two compounds stereochemically related to castanospermine, deoxynojirimycin and 6-epicastanospermine, were each slightly active at deterring the feeding of green peach aphids,Myzus persicae, (ED50=2.5 × 10−3 M) and greenbugs,Schizaphis graminum (ED50=5 × 10−3 M), respectively. Among the insects studied there was no distinct relationship between enzyme inhibition and adaptation to host plants containing castanospermine or other toxic alkaloids.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 623-625 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The collisional activation mass spectra of the [M - H]- ions of dipeptides containing Met or Cys show the usual backbone fragmentation allowing the sequence of the peptide to be determined. A methionine residue may be identified by the presence of a pronounced peak resulting from loss of MeSH, while a cysteine residue may be identified by the presence of a peak corresponding to loss of either H2S or (H2S + CO2).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 5
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Phenylthiohydantoin (PTH) amino acid derivatives are formed during sequential Edman degradation of peptides and proteins. Isomeric Leu and Ile (which differ only in respectively having iso-butyl and sec-butyl chains, and are often difficult to distinguish by conventional mass spectrometric techniques) may be readily identified by the characteristic decompositions of the [M — H]- ions of their PTH derivatives. The Leu spectrum shows major loss of propane, while that of the Ile derivative shows elimination of both methane and ethane. This method may be used routinely with 10 μg quantities of peptide material.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 169-173 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The structures of underivatized di- and tripeptides may be determined from a consideration of the collision-induced dissociations of their [M - H]- ions. There are three types of fragmentation, viz. (i) the backbone cleavage which provides sequencing information, (ii) α side-chain cleavage irrespective of the position of the amino acid residue, and (iii) cleavages which are characteristic of amino acid residues in specific positions, in particular the N- or C-terminal positions.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 677-685 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The [M — H]- ions derived from tetrapeptides generally show two different collision-induced backbone cleavages which allow the determination of the amino acid sequence of the peptide. The first of these involves the formation of the carboxylate anions of either constituent amino acids or fragment peptides. In the second, amino acids or fragment peptides are eliminated as neutrals. There are a number of residues which undergo characteristic sidechain fragmentations irrespective of their position in the tetrapeptide, e.g. Ser, Thr, Cys, Met, Phe and Tyr. However, there are also some residues which, when situated at the C-terminal end of the peptide, promote pronounced fragmentation at the C-terminal position which occurs to the exclusion of the normal backbone cleavages. We conclude that the data obtained from these negative-ion cleavages are analytically useful, and complement those provided by the cognate positive-ion technique.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 151-152 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Ab initio calculations indicate that the ion [ONCO]- is linear, whereas [HNNCO]- is effectively coplanar. The ions may be formed by collisional activation of deprotonated hydroxy and aminocarbamates. The characteristic fragmentations of [ONCO]- and [HNNOO]- are losses of O and NH respectively.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 338-339 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The ion MeOCO2- fragments upon collisional activation by competitive losses of Me, CH2 and CO2. The loss of formaldehyde involves hydride-ion transfer to form HCO2-. MeOCO2- reacts as a methoxyl-ion donor in a characteristic reaction with sulphur dioxide, i.e. MeOCO2- + SO2→ MeOSO2-+ CO2.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 4 (1972), S. 433-439 
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The PMR spectra of 1,4-dioxin and 1,4-dithiin have been studied in nematic phase liquid crystalline solvents. The ratio of the interproton distances r12 and r13 and the CCH angles have been determined.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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