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  • 1980-1984  (9)
  • Torpedo marmorata  (4)
  • Hymenoptera  (2)
  • compartmental analysis  (2)
  • Salt tolerance
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 27 (1984), S. 207-211 
    ISSN: 1432-0428
    Keywords: Insulin binding ; insulin metabolism ; receptor ; compartmental analysis ; degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A simple model of the distribution and metabolism of insulin in vivo has been evaluated using data from insulin infusion into a group of normal subjects. The major rate-limiting step for access to degradation pathways is assumed to consist of binding of the ligand to a single population of insulin receptor sites, except that provision is made for the possibility of linear non-receptor-mediated degradation and for the phenomenon of negative cooperativity. The model has been shown to accommodate the non-linearity of insulin metabo lism, allows evaluation of receptor association and dissociation constants and provides for the first time an estimate of total accessible receptor number in the intact organism. For normal fasting man the model predicts 1.00±0.05 nmol accessible binding sites/kg (mean±SD).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Planta 157 (1983), S. 344-349 
    ISSN: 1432-2048
    Keywords: Glycinebetaine ; Ion, inorganic (distribution) ; Salt tolerance ; Shoot (solutes) ; Solute distribution ; Suaeda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution of sodium, potassium and glycinebetaine in shoot tissues of salt-treated Suaeda maritima was examined by semi-micro techniques after extraction into toluene-water. Much higher K/Na ratios were observed in the apical regions and in axillary buds than in more mature, fully vacuolated tissues. The younger tissues also contained very high levels of glycinebetaine. Electron-probe X-ray microanalysis of bulkfrozen and fractured preparations showed higher K/Na ratios and higher levels of sulphur and phosphorus in the cytoplasm of leaf primordial cells than in vacuoles of either young or old leaves, although the total counts were higher in the vacuolar samples. The results are discussed in relation to current models of subcellular solute compartmentation and salt tolerance in the Chenopodiaceae.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 633-648 
    ISSN: 1573-8744
    Keywords: compartmental analysis ; dynamic response ; identification ; linear systems ; modeling ; parameter estimation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Single input, single output experiments can result in nonunique solutions for the rate constants of a linear compartmental model used to describe the pharmacokinetics. Where a finite number of solutions exists, a priori knowledge has to be used to distinguish between the solutions. Where there is an infinite number of solutions, assumptions have to be made about the values of some rate constants in order to obtain a unique solution for the others. This paper considers such experiments and determines whether either the addition of an extra input (simultaneously with the first input) or the taking of an extra measurement would result in a unique solution. It is found that perturbing a second input can be useful, but only if the perturbation is of different shape from the first input. Measurements of drug in urine and metabolite in plasma are generally not helpful in resolving identifiability of the drug dynamic model. If a radioactive tracer is used, though, the second measurement (for example, by externally scanning the radioactivity of the liver) can prove useful, but only if the gain of the measuring device is known.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 95-114 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Tenthredinidae ; Pikonema alaskensis ; hydrocarbons ; dienes ; synergists ; experimental design ; ozonolysis ; mass spectra ; methoxymercuration ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-6830
    Keywords: Torpedo marmorata ; rat ; ox ; frog ; synaptic vesicles ; antiserum ; retina ; cholinergic nerve terminals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. An antiserum to cholinergic synaptic vesicles fromTorpedo marmorata which recognizes the heparan-like glycosaminoglycan present in these vesicles and reacts specifically with peripheral and presumed central cholinergic nerve terminals in mammalian species has been tested with retinas from a variety of species. 2. The antiserum recognizes specific sites in the inner and outer plexiform layers of retinas of rat, ox and frog. 3. The distribution is similar to that reported forα-bungarotoxin, a reagent specific for acetylcholine receptors. 4. Immunoreactive material was absent from retinal cell bodies. 5. Its appearance in development in the two layers coincided with the appearance of synapses in these layers. 6. We conclude that the antigenic sites responding to the anti-vesicle anti-serum are associated with the cholinergic endings in the retina.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 10 (1984), S. 291-300 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Hymenoptera ; Ichneumonidae ; Syndipnus rubiginosus ; ethyl (Z)-9-hexadecenoate ; parasitoid ; Pikonema alaskensis ; mass spectra ; ozonolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A female-produced sex pheromone ofSyndipnus rubiginosus Walley (Hymenoptera: Ichneumonidae), a parasitoid of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was isolated and identified from hexane extracts of 250 virgin females. Column chromatography (Florisil), gas chromatography, mass spectrometry, high performance liquid chromatography, and ozonolysis indicated the structure was ethyl (Z)-9-hexadecenoate. The optimum male response is at 300–1000 ng (3–10FE). No cross-attraction betweenS. rubiginosus and the sympatric sawfly parasitoidS. gaspesianus (Provancher) could be demonstrated.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 218 (1981), S. 355-373 
    ISSN: 1432-0878
    Keywords: Cholinergic nerve terminals ; Presynaptic plasma membrane ; Indirect immunofluorescence histochemistry ; Torpedo marmorata ; Mammals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Most of the published light-microscopic methods for the localization of cholinergic nerve pathways present various difficulties of interpretation. The production and characterization of an antiserum that binds specifically to cholinergic terminals is described. The antiserum was raised to small synaptosomes prepared from the purely cholinergic electric organ of Torpedo marmorata. It was shown to lyse cholinergic synaptosomes in a mixed population derived from guinea-pig cortex. After partial purification by adsorption onto nonspecific antigens, it was used to label nerve endings in several tissues of Torpedo, rats and guinea pigs using indirect immunofluorescence histochemistry. The antiserum appears to provide a highly specific means of localizing cholinergic nerve endings in these tissues.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Vesicle recycling ; Immunohistochemistry ; Glycosaminoglycan ; Electrical stimulation ; Torpedo marmorata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Semiquantitative immunohistochemical methods were used to demonstrate that at least some of the glycosaminoglycan contained within cholinergic synaptic vesicles is recycled during successive electrical stimulations of the electric organ of Torpedo marmorata.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: Cholinergic vesicle antigen ; Axonal transport ; Exo/endocytosis ; Indirect immunofluorescence histochemistry ; Torpedo marmorata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum against a specific component (a glycosamino glycan) of the cholinergic synaptic-vesicle of Torpedo marmorata has been used to investigate the localization of the component in the cell body, its movement within the electromotor axon and its fate within the nerve terminal upon electrical stimulation. After immunofluorescent staining, spots are observed throughout the cytoplasm of the lobe perikarya, although they are concentrated in the region of the axon hillock. Ligation of the electromotor nerves leading from the lobe to electric organ produces a proximal build-up of material which stains readily with the antivesicle antiserum, indicating that the vesicle antigen is transported from the cell body to the nerve terminal. A marked increase in indirect immunofluorescent staining of the electric organ is observed in the nerve ending upon electrical stimulation. We interpret this result as fusion of the vesicles with the presynaptic plasma membrane and exteriorization of the vesicle antigen to the extracellular space, thereby facilitating its staining. After recovery of the system the fluorescence declines, a result that is consistent with the reinternalization of the vesicle antigen into the core of reformed vesicles. The results support a mechanism whereby vesicles recycle within the nerve terminal and transmitter is released by exocytosis.
    Type of Medium: Electronic Resource
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