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  • 1990-1994  (13)
  • 1960-1964
  • 1920-1924
  • 1991  (8)
  • 1990  (5)
  • Alkaloids
  • Fibers
  • 1
    Electronic Resource
    Electronic Resource
    Venom alkaloids in Monomorium “rothsteini” Forel repel other ants: is this the secret to success by Monomorium in Australian ant communities? (1991)
    Springer
    Oecologia 88 (1991), S. 157-160 
    Details
    ISSN: 1432-1939
    Keywords: Alkaloids ; Ant communities ; Interference competition ; Monomorium ; Venom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Species of the cosmopolitan ant genus Monomorium are small, slow-moving and non-aggressive ants that are extremely successful members of diverse Australian ant communities. Unlike other abundant taxa, they have no obvious specializations enabling them to co-exist with the highly aggressive species of Iridomyrmex that dominate these communities. Here we report results which suggest that Monomorium species owe their success to the topical application of venom alkaloids which repel other ants. The venom alkaloids (trans-2-ethyl-5-undecylpyrrolidine and trans-2-ethyl-5-tridecylpyrrolidine) of Monomorium “rothsteini” were identified and synthesized, and the repellency to other ants of the synthetic alkaloids were tested using bioassays involving the attraction to honey baits of three native species of Iridomyrmex, three tropical “tramp” species, and M. “rothsteini” itself. Repellency to all other ant species was total or nearly so, but only partial to M. “rothsteini”. Defensive alkaloids produced from a variety of glands are found in other ant genera, and may be a potent yet poorly appreciated force in interference competition between ant species and thereby the structure of ant communities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320805
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  • 2
    Electronic Resource
    Electronic Resource
    Inactivation modifiers of Na+ currents and the gating of rat brain Na+ channels in planar lipid membranes (1991)
    Springer
    Pflügers Archiv 419 (1991), S. 514-521 
    Details
    ISSN: 1432-2013
    Keywords: Na+ channels ; Inactivation ; Membrane currents ; Gating trypsin ; Chloramine-T ; Alkaloids ; Membrane conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rat brain Na+ channels whose inactivation process had been removed either by batrachotoxin (BTX) or veratridine (VT) were reconstituted into planar lipid membranes. The voltage dependence of the open probability (P o) of the channel, of the opening and closing rate constants, and the conductance and relative permeability for Na+ and K+ were studied in voltage-clamp conditions in the presence of agents known to modify the inactivation of Na+ currents. In relation to alkaloids (BTX, VT, and aconitine), it was found that once a Na+ channel was modified by BTX or VT, the addition of another alkaloid did not change further the gating and permeation properties of the channel over a period of about 1 h. Once the inactivation process of the channels is removed by BTX, the addition of a proteolytic enzyme (trypsin) or an halogenated compound (chloramine-T, CT) induced profound and specific modifications on the opening and closing events of Na+ channels: (1) the voltage dependence of the channel P o shifted to more hyperpolarized potentials; (2) this voltage shift can be explained by equal hyperpolarizing voltage shifts of the opening and closing rate constants of the channel; (3) although the gating properties of the channel were modified by these compounds, the permeation properties of the channel, as evaluated by the conductance and the selectivity to Na+ and K+ ions, were unaltered; (4) trypsin and CT were active only in the intracellular side of the channel and were irreversible within the time course of the experiments, suggesting covalent modifications of the channel. Inactivation modifiers also affected the gating of toxin-activated single Na+ channels. This alteration is compatible with a simple increase in the intracellular potential as seen by the voltage sensor of the channel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00370798
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  • 3
    Electronic Resource
    Electronic Resource
    Inheritance of morphological and chemical characters in interspecific hybrids between Papaver bracteatum and Papaver pseudo-orientale (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 537-540 
    Details
    ISSN: 1432-2242
    Keywords: Papaver bracteatum ; P. pseudo-orientale ; Interspecific hybrids ; Alkaloids ; Thebaine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The alkaloid profiles and morphological traits of the capsules of Papaver bracteatum, P. pseudo-orientale, and their hybrids were studied. Dominance of the hexaploid parent P. pseudo-orientale was observed for various characters. A genetic model assuming allelic additive effects and polysomic inheritance was elaborated for the control of isothebaine content in the capsules. The distribution of thebaine content in the segregating generations, F2 and BCF1 was evidence of the transfer of genes from the diploid parent P. bracteatum in the gametes of the interspecific hybrid and their expression in its progenies. These findings indicate the potential use of inter-specific hybrids between the Oxytona species in the breeding of cultivars for industrial or ornamental purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219446
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  • 4
    Electronic Resource
    Electronic Resource
    Design of high-capacity, reversible polymeric adsorbents for acidic gases (1991)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 2 (1991), S. 87-91 
    Details
    ISSN: 1042-7147
    Keywords: Adsorption of CO2 and SOx ; Polyamines ; High Capacity ; Reversible ; Fibers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Polyethyleneimine (PEIM) samples crosslinked by a commercial epoxy resin (Epon 828) were prepared, and their adsorption capacity for acidic gases was studied. The swelling and deswelling characteristics of the crosslinked samples were also examined as part of this program. Reactivation of these adsorbents could be carried out by heat, or by a combination of heat and treatment in dilute alkalies.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1991.220020206
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  • 5
    Electronic Resource
    Electronic Resource
    Acetogenic isoquinoline alkaloids, XXI. An atropisomer-differentiating reaction for the chemical analysis of axial chirality and its computational investigation: Proof of the stereostructure of dioncophylline ADedicated to Professor Dr. Dr. h. c. mult. Siegfried Hünig on the occasion of his 70th birthday. (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 803-809 
    Details
    ISSN: 0170-2041
    Keywords: Alkaloids ; Axial chirality, determination of ; Calculations, AM1, MM2, MMX ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A chemical method for the unambiguous elucidation of axial chirality in naphthylisoquinoline alkaloids such as dioncophylline A (1a) is described. It involves synthetic connection of the stereogenic axis to be investigated with the stereocenters present in the same molecule. The resulting macrocyclic ansa compound 7c is formed in high yield, yet exclusively for only one of the two atropodiastereomers (4c), the other isomer (4b) does not cyclize at all. This cyclization behavior fully confirms the stereostructure 1a of dioncophylline A, as postulated by us earlier. For an interpretation of the striking atropisomer specificity of this ring closure reaction, computer-assisted theoretical investigations on the molecular geometries and thus thermodynamical properties of both of the imaginable cyclization products 7b/c have been performed by using force-field (MM2, MMX) and semiempirical methods (AM1). The optimized structures show the obtained macrocycle 7c to be a nonstrained, stable compound, whereas the other possible product 7b (which definitely is not formed) should be severely distorted.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1991199101137
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese von 6-Methoxy-2,5-dimethyl-2H-isoindol-4,7-dion, einem Alkaloid aus Reniera-Arten (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 973-973 
    Details
    ISSN: 0170-2041
    Keywords: Alkaloids ; Isoindole derivative ; 1,3-Dipolar cycloaddition ; Reniera species ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 6-Methoxy-2,5-dimethyl-2H-isoindole-4,7-dione, an Alkaloid from Reniera Species6-Methoxy-2,5-dimethyl-2H-isoindole-4,7-dione (4) can easily be obtained in high yields in a one-pot synthesis by heating sarcosine (2) and paraformaldehyde in the presence of 3-methoxy-2-methyl-1,4-benzoquinone (1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1991199101168
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  • 7
    Electronic Resource
    Electronic Resource
    Application of two-dimensional shift correlated NMR techniques to the structure determination of an unusual marine alkaloid, isosaraine-2 (1991)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 29 (1991), S. 327-332 
    Details
    ISSN: 0749-1581
    Keywords: Saraines ; 2D COSY NMR ; 2D 1H-13C COSY NMR ; Alkaloids ; Sponge ; Reniera sarai ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An extensive application of two-dimensional proton-proton and proton-carbon shift correlated spectroscopy allowed the structural elucidation of isosaraine-2, a minor component of an unique family of alkaloids from the sponge Reniera sarai.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260290408
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  • 8
    Electronic Resource
    Electronic Resource
    Synthetic and stereochemical studies on phthalideisoquinoline hemiacetals (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 287-289 
    Details
    ISSN: 0170-2041
    Keywords: Isoquinoline alkaloids ; Egenine ; Corytensine ; Alkaloids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The two new phthalideisoquinoline hemiacetals rac-egenine (3) and rac-corytensine (4) are prepared by stereoselective DIBAL reduction of rac-bicuculline (1) and rac-adlumidine (2), respectively. The identity of egenine (3) with decumbensine as well as of corytensine (4) with epi-α-decumbensine and humosine A is postulated. The configuration around the anomeric center in natural (+)-egenine (3), (+)-corytensine (4) and (-)-narcotine hemiacetal (7) is deduced as (7′S), (7′R) and (7′R), respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199119910148
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  • 9
    Electronic Resource
    Electronic Resource
    Microbial degradation of the morphine alkaloids: identification of morphinone as an intermediate in the metabolism of morphine by Pseudomonas putida M10 (1990)
    Springer
    Archives of microbiology 154 (1990), S. 465-470 
    Details
    ISSN: 1432-072X
    Keywords: Pseudomnas putida ; Morphine ; Codeine ; Codeinone ; Morphinone ; Alkaloids ; Morphine dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A strain of Pseudomonas putida was isolated by selective enrichment with morphine that was capable of utilising morphine as a primary source of carbon and energy for growth. Experiments with whole cells showed that both morphine and codeine, but not thebaine, could be utilised. A novel NADP-dependent dehydrogenase, morphine dehydrogenase, was purified from crude cell extracts and was shown to be capable of oxidising morphine and codeine to morphinone and codeinone, respectively. This NADP-dependent morphine dehydrogenase was not observed in any other species of pseudomonads examined and was quite distinct from the β-hydroxysteroid dehydrogenase found in Pseudomonas testosteroni, which had previously been shown to have activity against morphine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00245229
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  • 10
    Electronic Resource
    Electronic Resource
    Occurrence of bombesin-like immunoreactivity in the brain of the cartilaginous fish,Scyliorhinus canicula (1990)
    Springer
    Cell & tissue research 259 (1990), S. 177-181 
    Details
    ISSN: 1432-0878
    Keywords: Bombesin-like peptide ; Immunocytochemistry ; Hypothalamus ; Neurosecretory ; Fibers ; Scyliorhinus canicula (Elasmobranchii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence and distribution of bombesin-like material were investigated in the brain of the cartilaginous fishScyliorhinus canicula using conventional immunocytochemical techniques. Perikarya containing bombesin-like immunoreactivity were identified in the hypothalamus, within the magnocellular component of the preoptic nucleus. Some immunopositive elements appeared to be of cerebrospinal fluid-contacting type. Beaded immunoreactive fibers were seen crossing the ventral telencephalon and the whole hypothalamus. An important tract of fibers was found in the infundibular floor and in the median eminence, in close contact with the vascular system of the pituitary portal plexus. A moderate number of positive fibers innervated the habenular complex and the dorsal wall of the posterior tuberculum. These findings indicate that a neuropeptide strictly related to amphibian bombesin is located in specific hypothalamic neurons ofS. canicula. The distribution of the immunoreactive fibers and terminals suggests that, in fish, this peptide, may be involved in neuroendocrine and neuromodulator functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571441
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  • 11
    Electronic Resource
    Electronic Resource
    SAXS experiments on gel-spun polyethylene fibers (1990)
    Springer
    Colloid & polymer science 268 (1990), S. 245-255 
    Details
    ISSN: 1435-1536
    Keywords: Fibers ; polyethylene ; gel-spinning ; smallanglex-rayscattering ; spinningconditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The properties of gel-spun polyethylene fibers hot-drawn to the maximum draw ratio depend on the spinning conditions. Different spinning conditions result in two types of structure in the paraffin oil containing fibers: an isotropic lamellar structure or a shish-kebab structure. Meridional SAXS experiments can identify the structure present. After extraction, these structures are still present but can be detected only in a more indirect way by SAXS experiments because of an excessive contribution of void scattering. During hot-drawing both structures are transformed into a more fibrillar structure. The shish-kebab structures can be drawn only to relatively low hot-draw ratios with an incomplete transformation of the lamellar overgrowth into the fibrils, as demonstrated by the presence of a meridional SAXS maximum/shoulder. This leads to relatively weak fibers. Lamellar structures can be drawn to high draw ratios by chain unfolding. A nearly complete transformation of the lamellae into fibrils is obtained and the fibers have excellent properties. The information about the morphology obtained by SAXS, DSC, WAXS, and SEM can be used to establish a relation between morphology and properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01490249
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  • 12
    Electronic Resource
    Electronic Resource
    Fate of plant-derived secondary metabolites in three moth species (Syntomis mogadorensis, Syntomeida epilais, andCreatonotos transiens) (1990)
    Springer
    Journal of comparative physiology 160 (1990), S. 389-400 
    Details
    ISSN: 1432-136X
    Keywords: Lepidoptera ; Herbivores ; Resorption ; Cardenolides ; Alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Larvae of three moth species were compared with respect to strategies used to cope with secondary metabolites (allelochemicals) present in their diet.Syntomeida epilais is monophagous and accepted only oleander (which contains cardenolides, CG). CG were detected as stored products in the larvae and also in the faeces and exuviae. Pure CG (digoxin and gitoxin) which do not occur in oleander fed on oleander leaves were sequestered as the oleander CG.Syntomis mogadorensis is polyphagous: given a choice larvae avoided plants with a high load of allelochemicals. Upon shortage of preferred plants they ate a wide variety of plants which contain alkaloids, terpenes, or phenolics. Of these allelochemicals, alkaloids and CG were mainly recovered in the faeces and only minute fractions in the larvae.Creatonotos transiens larvae behaved similarly toSyntomis in terms of polyphagy and non-resorption. However, the larvae took up and stored pyrrolizidine alkaloids (PA) such as heliotrine selectively.Creatonotos is thus polyphagous (a generalist) but also a PA-specialist which exploits PA as defensive agents, as a morphogen for the male pheromone gland, and as a precursor for the male pheromone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01075670
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  • 13
    Electronic Resource
    Electronic Resource
    Natural product chemistry, 140. Synthesis of some new acridones (1990)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 1047-1049 
    Details
    ISSN: 0170-2041
    Keywords: Acridones ; Alkaloids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl 6-amino-2,3-dimethoxybenzoate (6) which was obtained from 6-formyl-2,3-dimethoxybenzoic acid (1), was treated with phloroglucinol to give two new acridone alkaloids, 1,3,8-trihydroxy-7-methoxy-9-acridone (7) and 1,3-dihydroxy-7,8-dimethoxy-9-acridone (8). Methylation of 7 and 8 gave another four new acridone alkaloids, 1,8-dihydroxy-3,7-dimethoxy-9-acridone (9), 1,8-dihydroxy-3,7-dimethoxy-10-methyl-9-acridone (10), 1-hydroxy-3,7,8-trimethoxy-10-methyl-9-acridone (11) and 1,3,7,8-tetramethoxy-10-methyl-9-acridone (12).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1990199001189
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