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  • Analytical Chemistry and Spectroscopy  (9)
  • Germination (seed)  (3)
  • brine shrimp  (3)
  • rat  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Antinociceptive effects of the stereoisomers of nicotine given intrathecally in spinal rats (1990)
    Springer
    Journal of neural transmission 80 (1990), S. 189-194 
    Details
    ISSN: 1435-1463
    Keywords: Nicotine enantiomers ; pain ; spinal analgesia ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spinalized rats received an intrathecal injection of either (−)-nicotine or (+)-nicotine in order to study the stereoselectivity of antinociception. Pain threshold was measured using the tail-flick test. Both stereoisomers had antinociceptive effects, but (−)-nicotine was up to 970 times more potent, depending on test conditions. The antinociceptive action of (−)-nicotine was antagonized by mecamylamine and yohimbine but not by naloxone and atropine. The findings show that spinal mechanisms are highly stereoselective toward nicotine, and suggest that primarily nicotinergic andalpha-adrenergic receptors are involved in its central antinociceptive effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245120
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of tranylcypromine enantiomers on monoamine uptake and release and imipramine binding (1986)
    Springer
    Journal of neural transmission 65 (1986), S. 135-145 
    Details
    ISSN: 1435-1463
    Keywords: Tranylcypromine enantiomers ; monoamine uptake ; monoamine release ; dopamine ; noradrenaline ; serotonin ; synaptosome ; imipramine binding ; blood platelet ; stereoselectivity ; rat ; rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Studies were carried outin vitro to determine effects of tranylcypromine enantiomers ([+]- and [−]-TCP) on uptake and release of 5-HT, DA and NA in rat synaptosomes and on imipramine binding to rabbit platelets. (+)-TCP was more potent than (−)-TCP as inhibitor of 5-HT uptake and imipramine binding, whereas (−)-TCP was more potent than (+)-TCP as inhibitor of DA and NA uptake. The enantiomers differed only slightly in their effects on monoamine release. The findings agree with previous reports on the stereoselectivity of monoaminergic mechanisms toward TCP enantiomers, and support the notion that the 5-HT uptake site may be associated with the imipramine binding site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01256489
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  • 3
    Electronic Resource
    Electronic Resource
    Sylvaticin: A new cytotoxic and insecticidal acetogenin fromRollinia sylvatica (Annonaceae) (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 324-327 
    Details
    ISSN: 1420-9071
    Keywords: Sylvaticin ; acetogenin ; Rollinia sylvatica ; Annonaceae ; brine shrimp ; cytotoxicity ; insecticidal ; striped cucumber beetle ; European corn borer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sylvaticin (I), a new tetrahydroxy annonaceous acetogenin with nonadjacent tetrahydrofuran rings, has been isolated from the dried fruits ofRollinia sylvatica St. Hil. (Annonaceae). This compound is extremely cytotoxic to human tumor cells and shows promising insect control properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951779
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  • 4
    Electronic Resource
    Electronic Resource
    Goniothalamicin and annonacin: Bioactive acetogenins fromGoniothalamus giganteus (Annonaceae) (1988)
    Springer
    Cellular and molecular life sciences 44 (1988), S. 83-85 
    Details
    ISSN: 1420-9071
    Keywords: Goniothalamicin ; annonacin ; acetogenins ; Goniothalamus giganteus ; Annonaceae ; brine shrimp ; insecticidal ; cytotoxic ; antileukemic activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using brine shrimp lethality for activity-directed fractionation, goniothalamicin (I), a new tetrahydroxy-mono-tetrahydrofuran fatty acid γ-lactone (acetogenin), has been isolated from ethanolic extracts of the stem bark ofGoniothalamus giganteus Hook. f., Thomas (Annonaceae). This novel compound was found to be cytotoxic and insecticidal and inhibited the formation of crown gall tumors on potato discs. Annonacin (II), the only other reported mono-tetrahydrofuran acetogenin, was also isolated; the previously reported 9ASK (astrocytoma reversal) activity ofII was confirmed, andII is now also found to be weakly active against 3PS murine leukemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01960258
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  • 5
    Electronic Resource
    Electronic Resource
    Gigantecin: A novel antimitotic and cytotoxic acetogenin, with nonadjacent tetrahydrofuran rings, fromGoniothalamus giganteus (Annonaceae) (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 539-541 
    Details
    ISSN: 1420-9071
    Keywords: Gigantecin ; acetogenins ; Goniothalamus giganteus ; Annonaceae ; brine shrimp ; antimitotic ; cytotoxic ; crown gall tumors ; potato disc assay ; 9 ASK
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gigantecin (I), a novel tetrahydroxy-di-tetrahydrofuran fatty acid γ-lactone (acetogenin), was isolated from an ethanolic extract of the stem bark ofGoniothalamus giganteus Hook. f., Thomas (Annonaceae), by means of activity-directed fractionation (brine shrimp lethality test). This new compound is extremely cytotoxic to human tumor cells, inhibits crown gall tumors on potato discs, and is active in an assay designed to detect antimitotic agents (9 ASK).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01954260
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  • 6
    Electronic Resource
    Electronic Resource
    Characteristics of the protein carrier of the peptide-transport system in the scutellum of germinating barley embryos (1984)
    Springer
    Planta 162 (1984), S. 166-173 
    Details
    ISSN: 1432-2048
    Keywords: N-Ethylmalemide ; Germination (seed) ; Hordeum (embryo, peptide) ; Peptide transport ; Thiol group ; Transport carrier protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Through the use of the protein reagents N-ethylmaleimide, p-chloromercuribenzenesulphonic acid and phenylarsine oxide, it is shown that in the scutellum of the germinating barley embryo, the transport of peptides, but not the transport of amino acids or glucose is specifically thiol-dependent. Furthermore, these essential thiol groups are shown to exist as redox-sensitive, vicinal-dithiols that lie at the substrate-binding sites of the peptide-transport proteins. The binding of N-ethylmaleimide to these dithiols is shown to be very fast, matching the kinetics of inhibition of peptide transport by this reagent. A technique for the specific labelling of the dithiols with N-ethyl[2,3-14C]maleimide is described, which allows the carrier proteins to be visualized at the scutellar epithelium using radioautography and permits calculation of the approximate amount of peptide-transport protein present per scutellum. In related studies, the importance of arginyl and histidyl residues to both amino-acid and peptide transport is shown, although other residues, e.g. carboxyl ligands do not seem to be critically involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410214
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  • 7
    Electronic Resource
    Electronic Resource
    Characteristics of the active transport of peptides and amino acids by germinating barley embryos (1984)
    Springer
    Planta 162 (1984), S. 159-165 
    Details
    ISSN: 1432-2048
    Keywords: Amino acid transport ; Germination (seed) ; Hordeum (peptide) ; Peptide transport ; Scutellum ; Storage protein mobilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Use of two different assays involving either radioactively labelled substrates or a fluorescent-labelling procedure, gave good agreement for the rates of transport of peptides and amino acids into the scutellum of germinating grains of barley (Hordeum vulgare cv. Maris Otter, Winter). However, evidence was obtained for the enzymic decarboxylation of transpored substrate, which can cause underestimates of transport rates when using radioactively labelled substrates. The peptide Gly-Phe, was shown to be rapidly hydrolysed after uptake, and autoradiography of transported Gly-[U-14C]Phe indicated a rapid distribution of tracer, i.e. [U-14C] phenylalanine into the epithelium and sub-epithelial layers of the scutellum. The developmental patterns of transport activity indicate that peptide transport is more important nutritionally during the early stages of germination (1–3 d) whereas amino acids become relatively more important later (4–6 d). A range of amino acids is shown to be actively transported and several compete for uptake. At physiological concentrations, e.g. 2mM, transport of peptides and amino acids is inhibited about 80% by protonophore uncouplers, but at higher concentrations (10–100 mM) passive uptake predominates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410213
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis of the peptide-transport carrier of barley scutellum during the early stages of germination (1985)
    Springer
    Planta 164 (1985), S. 550-556 
    Details
    ISSN: 1432-2048
    Keywords: Germination (seed) ; Hordeum (peptide transport) ; Peptide transport ; Protein synthesis ; Scutellum ; Seed germination ; Thiol group
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Development of peptide-transport activity in the scutella of isolated barley (Hordeum vulgare l. cv. Maris Otter, Winter) embryos is shown to increase rapidly after about 15 h of imbibition, with the bulk of the transport activity being expressed by 24 h. This development is prevented by treatment of 15 h embryos with cycloheximide. Protein synthesis is found to increase in a closely related manner and also to be abolished by cycloheximide. Measurement of the incorporation of bound [35S]methionine by 15 to 21-h embryos indicates that de-novo protein synthesis during this period is greater in the scutellum than in the embryonic axis. Previous studies have shown that the peptide-transport system possesses essential dithiol groups, probably located at the substrate-binding site (Walker-Smith and Payne 1983 b, 1984b). Treatment of 15-h embryos with the non-penetrant thiol reagent p-chloromercuribenzene sulphonic acid did not affect development of peptide-transport activity during the following 6 h, whereas with 3-d embryos identical treatment inhibited uptake almost completely during a subsequent 6-h period. Radioautography revealed that amongst the proteins synthesised during this early phase of germination and labelled in vitro with [35S]methionine some are found within the epithelial plasmalemmae of the scutellum, which is the location of the peptide-transport carrier identified previously by externally labelling with a radioactive thiol reagent. The results provide evidence that protein(s) of the peptide-transport system are synthesised and inserted into the scutellum during early germination, allowing the system to play a major role in the nitrogen nutrition of the embryo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395974
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of 3,N,N′-trimethyl-2-phenyl-1,4-piperazine diastereomers on monoamine uptake and monoamine oxidase in rat brain (1992)
    Springer
    Journal of neural transmission 88 (1992), S. 177-185 
    Details
    ISSN: 1435-1463
    Keywords: Phenylpiperazine ; monoamine uptake ; NA ; DA ; 5-HT ; MAO ; phenylethylamine ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The diastereomers of 3,N,N′-trimethyl-2-phenyl-1,4-piperazine dihydrochloride (TPP) were tested for their effects on NA, DA and 5-HT uptake in synaptosomes prepared from hypothalamus, corpus striatum, and frontal cortex, respectively. The diastereomers differed with respect to their inhibitory properties. (2R, 3R)-TPP was more potent than the other diastereomers on NA and DA uptake, whereas (2S, 3S)-TPP was least potent. In contrast, the (2S, 3S)- and (2 S, 3R)-diastereomers of TPP were more potent than (2R, 3R)- and (2R, 3S)-TPP as inhibitors of 5-HT uptake. None of the diastereomers affected monoamine oxidase activity. The findings show that the diastereomers of TPP interact stereoselectively with neuronal mechanisms for monoamine uptake, and that the (S)-configuration at the 2 carbon is important for inhibitory actions of TPP on 5-HT uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244731
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  • 10
    Electronic Resource
    Electronic Resource
    Kβ/Kα intensity ratios for elements of atomic number 20 to 30 (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 3 (1974), S. 149-150 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Twenty-five new measurements of Kβ/Kα X-ray intensity ratios for elements in the atomic number range 20 to 30 confirm other recent evidence that the variation with atomic number in this region is much less than previously thought, but there is still some disagreement for atomic numbers above 27. A table of recommended values is given.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300030405
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