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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 99 (1977), S. 4111-4118 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 100 (1978), S. 5946-5948 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The absorption, fluorescence, dichroism, and birefringence of stained squid axons were measured during action potentials and voltage clamp steps in an effort to find large optical signals that could be used to monitor membrane potential. Changes in all four optical properties were found that were linearly related to membrane potential and, with several new dyes, the signal-to-noise ratios were larger than any obtained previously. The problem of photodynamic damage was greatly diminished; with a merocyaninerhodanine dye, the photodynamic damage associated with intense light and the presence of oxygen was negligible. The absorption change obtained with this dye was relatively large; it could be measured with a signal-to-noise ratio of 100∶1 during a single action potential.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The mechanism by which the light absorption of cyanine and oxonol dyes changes in response to changes in transmembrane electrical potential has been studied. Trains of membrane potential steps produce changes in the intensity of light passing through glycerylmonooleate (GMO) bilayer lipid membranes (BLM) in the presence of these dyes. The size of the signal-averaged absorbance change for one of the cyanine dyes diS-C2-(5) is ∼10−5. The response time for the absorbance change of all of the dyes was ≦10 μsec. In order for an absorption signal to be observed, the concentration of dye on both sides of the membrane must be different. Since GMO bilayer membranes are permeable to the charged dyes that were studied, the dye concentration asymmetry necessary for the optical signal had to be maintained with a constant dc membrane potential, onto which the trains of potential steps were superimposed. The more hydrophobic dyes were the most permeant. Inclusion of cholesterol in the GMO bilayers decreased the permeance of the positively charged cyanine dyes, but increased the permeance of the negatively charged oxonol dyes. The magnitude and the size of the BLM absorbance change depended on the wavelength of illumination. Comparisons of the wavelength dependence of the BLM spectra with absorption difference spectra obtained with model membrane systems allow us to postulate a mechanism for a BLM absorbance change. For the cyanine and oxonol dyes, the data are consistent with an ON-OFF mechanism where a quantity of dye undergoes a rapid potential-dependent movement between a hydrocarbon-like binding site on the membrane and the aqueous salt solution near the membrane. For some dyes, which readily aggregate on the membrane, part of the absorbance change may possibly be explained by a potential dependent change in the state of aggregation of dye molecules localized on the membrane. Mechanisms involving a potential dependent change in the polarizability of the environment of membrane-localized dye molecules cannot be excluded, but seem unlikely.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 38 (1978), S. 311-331 
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The surface charge density resulting from the adsorption of hydrophobic anions of dipicrylamine onto dioleyl-lecithin bilayer membranes has been measured directly using a high field pulse method. The surface charge density increases linearly with adsorbate concentration in the water until electrostatic repulsion of impinging hydrophobic ions by those already adsorbed becomes appreciable. Then Gouy-Chapman theory predicts that surface charge density will increase sublinearly, with the power [z +/(z ++2)] of the adsorbate concentration, wherez + is the cation valence of the indifferent electrolyte screening the negatively charged membrane surface. The predicted 1/3 and 1/2 power laws for univalent and divalent cations, respectively, have been observed in these experiments using Na+, Mg++, and Ba++ ions. Gouy-Chapman theory predicts further that the change from linear to sublinear dependence takes place at a surface charge density governed by the static dielectric constant of water and the concentration of indifferent electrolyte. Quantitative agreement with experiment is obtained at electrolyte concentrations of 10−4 m and 10−3 m, but can be maintained at higher concentrations only if the aqueous dielectric constant is decreased. A transition field model is proposed in which the Gouy-Chapman theory is modified to take account of dielectric saturation of water in the intense electric fields adjacent to charged membrane surfaces.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 10 (1977), S. 167-182 
    ISSN: 1432-1432
    Keywords: Molecular evolution ; Phylogenetics ; Numerical taxonomy ; Snake venom toxins ; Elapidae ; Hydrophiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phylogenetic trees were constructed for 62 venom toxins of snakes ofProteroglyphae suborder using matrix method. The resulting tree fromMinimum Spanning Tree-Cluster Analysis technique had the lowest “percent deviation” (8.55). The taxonomic relationship of these toxins agrees very well with zoological opinions. However, the appearance of the tree did not directly provide a plausible evolutionary model for the toxins. A model was derived from nodal ancestral sequence calculations, comparisons between intra-and inter-generical rates of amino acid change, and generally held ideas about protein evolution. According to the model, short neurotoxin is the ancient form of snake venom toxins. The courses of evolution leading to the present intraspecific homologous toxins are explained by gene duplication and allelomorphism.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Broccoli was treated at 5°C with 20, 30 and 40% CO2 for 3 and 6 days soon after harvest, and then transferred to storage in air at 5°C. CO2 injury was severe in samples treated with 40% CO2 for 6 days. Offensive odor and flavor also developed by the end of 6 days' treatment with 30% CO2 but dissipated when the broccoli was transferred to air. CO2 delayed yellowing and loss of both chlorophyll and ascorbic acid, and retarded ethylene production. Except at the level that was injurious to the tissue, CO2 retarded mold growth and had no appreciable effect on compactness, turgor, and opening of the florets.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 40 (1975), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food process engineering 1 (1977), S. 0 
    ISSN: 1745-4530
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 101 (1979), S. 260-262 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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