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  • Analytical Chemistry and Spectroscopy  (5)
  • Noctuidae  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Effect of ergot alkaloids from fungal endophyte-infected grasses on fall armyworm (Spodoptera frugiperda) (1989)
    Springer
    Journal of chemical ecology 15 (1989), S. 169-182 
    Details
    ISSN: 1573-1561
    Keywords: Balansiae ; Clavicipitaceae ; ergot alkaloids ; fall armyworm ; feeding deterrents ; acquired chemical defense ; fungal endophytes ; grasses ; Lepidoptera ; Noctuidae ; Spodoptera frugiperda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ergot alkaloids produced by endophytic fungi in the tribe Balansiae (Clavicipitaceae, Ascomycetes), which infect grasses, may provide plant defense against herbivores. This study examined the effects of six ergot alkaloids on survivorship, feeding, and growth of larvae of the fall armyworm (Spodoptera frugiperda, Lepidoptera: Noctuidae), a generalist herbivore of grasses. Corn leaf disks were soaked in solutions of individual ergot alkaloids at different concentrations and presented to neonate larvae. At the highest concentrations (77–100 mg/liter) of ergonovine, ergotamine, ergocryptine, agroclavine, and elymoclavine, larval weights and/or leaf area consumed after eight days were reduced relative to controls. Lysergol had no effect on larval weights and leaf consumption at any concentration. Although active concentrations were higher than those reported from two host grasses, in vivo levels of ergot alkaloids have not been quantified for most endophyte-infected grasses. The detrimental effects on fall armyworm observed in this study suggest that ergot alkaloids could be responsible, at least in part, for the greater insect resistance of endophyte-infected grasses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02027781
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  • 2
    Electronic Resource
    Electronic Resource
    The exchange of [18O]-H2O with the aromatic oxygen atoms of catecholamine metabolites (1980)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 345-348 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Catechol oxygen atoms can be exchanged with oxygen-18 atoms in [18O]-H2O under acidic conditions. The catechol oxygen atoms in L-3, 4-dihydroxyphenylalanine both underwent significant exchange with water when heated in 3 N HC1 at 150 °C for 20 days. Under the same conditions of heat and strong acid, vanillylmandelic acid was degarded to homovanillic and dihydroxyphenylacetic acid in two hours. Exchange of the catechol oxygen with the solvent occurred simultaneously with degradation. This degradation of vanillylmandelic acid formally involves reductive cleavage of the aliphatic hydroxyl in a reaction which is probably general for compounds of similar structure. An analogous, although slower, degradation of dihydroxyphenyllactic acid to dihydroxyphenylpropionic acid accompanied by catechol oxygen atom exchange was observed. Direct exchange of catechol oxygen atoms and degradation of appropriate precursor molecules are two facile methods for the preparation of oxygen-18 labelled compounds containing the catechol moiety.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200070806
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of oxygen-18-labeled lipoxygenase metabolites of arachidonic acid (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1985), S. 714-718 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma pseudocholinesterase and porcine liver esterase were used to catalyse the incorporation of the stable isotope oxygen-18 into the carboxyl moiety of lipoxygenase metabolites of arachidonic acid. This simple method produces eicosanoid products containing two oxygen-18 atoms; but the enzymes studied were found to display large substrate specificity in the efficiencies at which oxygen-18 could be incorporated into the lipoxygenase metabolites. Furthermore, [18O2]LTB4 was found not to back exchange during in vitro incubation with human neutrophils. The methods involved for stable isotope incorporation are simple, efficient and produce highly enriched species in a short time. By varying the type of esterase, the amount of esterase or the length of incubation highly enriched species of all eicosanoids tested could be prepared.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200121208
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and back exchange of 18O labeled amino acids for use as internal standards with mass spectrometry (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 309-314 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acids with two oxygen-18 atoms in the carboxyl moiety can be synthesized easily from the amino acids and H218O through exchange. The exchange conditions are simply solution of the amino acid (1-4 mg) in acidic H218O (0.1-0.2 ml) followed by heating at 60-70°C for several days. Eighteen oxygen-18 amino acids with incorporations typically greater than 90 atom% 18O2 have been achieved and characterized by mass spectrometry. The exchange conditions do not lead to racemization. Loss of the oxygen-18 atoms through back exchange was found to be pH and temperature dependent, but yet slow enough to allow these isotopimers to be used in most studies as internal standards for quantitative mass spectrometry. The 18O carboxylic atoms were not exchanged upon incubation in plasma for three days at 37°C,pH 7.4. The exchange reaction is general enough to allow the simultaneous synthesis of several [18O]amino-acids.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200060709
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative analysis of platelet activating factor (AGEPC) by fast atom bombardment mass spectrometry (1984)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 47-49 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Platelet activating factor has recently been structurally described as the phospholipid 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine. It has been reported to be a putative chemical mediator of immunological reactions as well as an antihypertensive agent. A method to quantitate 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine using deuterium labeled 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine as an internal standard is described. When 60 ng of the2H3 labeled compound is employed, quantities as low as 10 ng can be measured. The standard curve for this quantitative analysis typically had a correlation coefficient of 0.999 even when the signal saturation effect of FAB was apparent. Thus quantitative analysis using the FAB ionization technique is feasible when one employs the stable isotope internal standard method.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200110109
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  • 6
    Electronic Resource
    Electronic Resource
    Interlaboratory reproducibility of relative abundances of ion currents in fast atom bombardment mass spectral data (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 489-494 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reproducibility of ion abundances in the fast atom bombardment experiment was evaluated by comparing mass spectral data obtained with the same sample analysed by eight different laboratories. Instrumentation included magnetic sector and quadrupole analysers and several different types of atom guns for the primary particle beam. A special fast atom bombardment gun was constructed which, by design, did not include ions or electrons in the particle beam. In addition this atom gun had a 0.1 eV beam energy spread and could be focused. The molecules in the study included dihexadecanoyl phosphatidyl choline, bradykinin, oxidized glutathione, sulfotaurolithocholic acid, ATP, NAD+ and stachyose. Major differences in the FAB data between laboratories were in the absolute signal-to-noise and abundance of glycerol-cluster ions. The relative abundances for analyte-related ions were very reproducible in spite of major instrumental differences. The coefficients of variation for analyte-ions included in the study typically ranged from 20-80% which was similar to those found for the electron impact mass spectrum of methyl stearate obtained by these laboratories. These data suggest that the relative intensities of analyte-related ions obtained fast atom bombardment mass spectrometry are as reproducible as electron impact mass spectrometry.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200100902
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