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'Phase Transitions' in keywords Facet   section ZfN Section C  [X]
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1Author    G. W. PohlRequires cookie*
 Title    Spectral Properties of Fluorescent Dyes in Lecithin Vesicles Probes for the Structure of Lipid Bilayer Membranes and for Membrane Potentials  
 Abstract    Three fluorescent dyes (a merocyanin, a cyanin and a modified umbelliferon) have been in­ corporated into vesicles from three different lecithins. Their absorption spectrum, emission spectrum and fluorescence polarization in the lipid vesicles has been studied and compared with the spectral properties in homogeneous organic solutions. The reactivity of lipid bound dyes with reagents in the aqueous phase was investigated. The location use as indicators of phase transitions or membrane 
  Reference    (Z. Naturforsch. 31c, 575 [1976]; received May 10 1976) 
  Published    1976 
  Keywords    Lecithin Vesicles, Fluorescent Probes, Phase Transitions, Membrane Potentials 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0575.pdf 
 Identifier    ZNC-1976-31c-0575 
 Volume    31 
2Author    H. Heithier, H.-J Galla, H. MöhwaldRequires cookie*
 Title    Fluorescence Spectroscopic and Thermodynamic Studies of Chlorophyll Containing Monolayers and Vesicles. Part I: Mixed Monolayers of Pheophytin A and Lecithin  
 Abstract    Mixed monolayers of pheophytin a and a-L-dimyristoyl lecithin (DML) are investigated on the water surface. The studies gain their special value from the simultaneous measurement of surface pressure and fluorescence intensity as a function of the covered area per molecule. A phase separation in the liquid state of the monolayer is established. Phase 1 exists almost exclusively of pheophytin molecules. Phase 2 exists essentially of D M L domains solubilizing pheo­ phytin in a concentration of 15 mol%. During the D M L main transition the pheophytin solubility decreases to about 2 mol%, the excess pheophytin being precipitated within the surface layer. During the pheophytin main transition an ordered structure below the surface layer is formed. A stabilizing interaction between the pheophytin domains and their environment is observed and discussed. A sharp fluorescence change at a pressure below 0.5 dyn/cm indicates another phase transition. It very probably involves an unwrapping of pheophytin from water molecules. 
  Reference    Z. Naturforsch. 33c, 382 (1978); received March 15/April 3 1978 
  Published    1978 
  Keywords    Monolayers, Chlorophyll, Energy Transfer, Fluorescence Spectroscopy, Phase Transitions 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0382.pdf 
 Identifier    ZNC-1978-33c-0382 
 Volume    33 
3Author    Srabani Banerjee, S. N. ChatterjeeRequires cookie*
 Title    Effect of Sodium Cholate on the Phase Transition Temperature of Dipalmitoyl Phosphatidylcholine  
 Abstract    On treatm ent with sodium cholate, the phase transition tem perature (Tc) of m ultilam ellar liposomes derived from dipalm itoyl phosphatidylcholine (DPPC) progressively decreased with increasing cholate: lipid-P m olar ratio. A molar ratio of 4.5 caused a one degree depression in Tc. The unilamellar cholate vesicles o f DPPC exhibited the same Tc as that o f the m ultilam ellar ones. The formation of unilam ellar vesicles from the m ultilam ellar ones by cholate treatm ent was in­ vestigated by electron microscopy. 
  Reference    Z. Naturforsch. 38c, 302—306 (1983); received Septem ber 20/N ovem ber 15 1982 
  Published    1983 
  Keywords    Liposomes, DPPC, Sodium Cholate, Phase Transition, Electron Microscopy 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0302.pdf 
 Identifier    ZNC-1983-38c-0302 
 Volume    38 
4Author    S. Mazzuca, L. SportelliRequires cookie*
 Title    Thermal Behaviour of Lymphocyte Membrane: ESR Investigation  
 Abstract    The order parameter, S, of the plasma membrane of in toto human peripheral blood lym­ phocytes was obtained by electron spin resonance spectroscopy in the temperature range 25-41 C. This membrane is completely in the liquid crystalline state above 31 C. In presence of the antigen ETB from Staphylococcus aureus at the concentration of 4 (ig/3 * 107 cells an overall decrease of the order parameter for this membrane is observed. The decrease of 5 is followed by an upwards shift at about 35 C of the temperature of the liquid crystalline state. 
  Reference    Z. Naturforsch. 45c, 1060—1062 (1990); received April 6 1990 
  Published    1990 
  Keywords    Plasma Membrane, Lymphocyte, Phase Transition, Staphylococcal Enterotoxin B, Spin Labeling 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-1060.pdf 
 Identifier    ZNC-1990-45c-1060 
 Volume    45 
5Author    U. Kreibig, C. W. EtterRequires cookie*
 Title    Light Diffraction of in vitro Crystals of Six Tobacco Mosaic Viruses  
 Abstract    Iridescent gels o f the common, tomato mosaic, para-tobacco mosaic, ribgrass mosaic, sunnhemp mosaic, and cucumber 4 tobacco mosaic virus strains were prepared using the purification method of Boedtker and Simmons (J. Amer. Chem. Soc. 1958). Macrocrystals which were stable for many months could be grown from iridescent gels of all viruses when stored at 0 -1 0 °C. The gels exhibited various structural phases (nematic and smectic) differing in density. The structure of the microcrystalline gels and of macrocrystals was investigated by means of optical diffraction. Distinct Bragg reflections were observed from which a mean periodicity of 340 nm was derived for all virus strains. The results indicate a crystalline multilayer structure as first proposed by Oster (J. Gen. Physiol. 33, 445, [1950]). The angular positions and widths of the Bragg reflections depended on the concentration of virus and the ionic strength. The periodicity decreased from 365 nm at 30 mg/ml virus to about 315 nm at 109 mg/ml virus, i.e. the periodicity approached the 300 nm length o f the virion. Model calculations taking into account Debye-Hückel repulsive and van der Waals attractive forces gave a qualitative explanation for the crystalline structure and its observed concentration dependence. The in vitro crystals resemble immature crystal forms observed in the living cell. 
  Reference    Z. Naturforsch. 35c, 750—762 (1980); received March 7 1980 
  Published    1980 
  Keywords    Tobacco Mosaic Viruses, Crystallization, Phase Transitions, Light Diffraction, Crystal Structure, Model Calculations 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0750.pdf 
 Identifier    ZNC-1980-35c-0750 
 Volume    35