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1978 (2)
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1974 (2)
1Author    Jeffrey Karan, SeymourSteven BrodyRequires cookie*
 Title    Chlorophyll a and Cytochrome c at a Heptane-Water Interface  
 Abstract    The surface pressure was measured as a function of area/molecule for chlorophyll a (Chi) and cytochrome c (Cyt) at a heptane-water interface. At a surface pressure of 6 dyn/cm the area per molecule of C h l(^ 6) = 1 1 3 ±6 Ä 2, for reduced Cyt c (red. Cyt) the A6 = 5000 ± 300 Ä 2 and for oxidized Cyt c (ox. Cyt) /3(6=4100 ± 250 A2. Cyt appears to denature at the interface. Irradiation results in a decrease of the for Chi to ^ 8 = 1 0 0 ± 5 Ä 2. There appears to be interaction between Chi and red. Cyt in a mixed film no interaction is observed between Chi and ox. Cyt. 
  Reference    (Z. Naturforsch. 29c, 506 [1974]; received June 14 1974) 
  Published    1974 
  Keywords    Chlorophyll, Cytochrome, Monolayers, Photosynthesis, Membranes 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0506.pdf 
 Identifier    ZNC-1974-29c-0506 
 Volume    29 
2Author    SeymourSteven BrodyRequires cookie*
 Title    Surface Properties of Monomolecular Films of Reduced Plastocyanin at a Nitrogen-Water Interface  
 Abstract    The area/molecule (A) and surface potential {A V) of reduced plastocyanin (pcyan) was measured as a function of pH. At pH 7.5 a maximum is observed for A while a minimum is ob­ served for A V . At a surface pressure of 5 dyn/cm the maximum ^ 5 = 378 Ä 2 and minimum A V 5 = 335 mV. There is an interaction between pcyan and chlorophyll (Chi) in mixed films. As shown by a decrease of A and V compared to theoretically calculated volues. The largest decrease occurs at a mol ratio of about 2 pcyan: 1 Chi. When mixed films are irradiated in air no changes in surface properties are observed. Irradiation of mixed films of reduced pcyan and Chi in nitrogen results in a decrease in A and an increase of AV. The maximum decrease occurs at a mol ratio of pcyan/Chl between 1.5 and 2.0. The direction of change of A is consistant with a conversion of reduced pcyan to oxidized pcyan. 
  Reference    (Z. Naturforsch. 30c, 318 [1975]; received October 4 1974) 
  Published    1975 
  Keywords    Plastocyanin, Photosynthesis, Monolayers, Model Membranes 
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 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0318.pdf 
 Identifier    ZNC-1975-30c-0318 
 Volume    30 
3Author    Hiroko Ito, K. Aran, RhodaElison Hirsch, SeymourSteven BrodyRequires cookie*
 Title    Stability and Regeneration of Rhodopsin Absorption Spectra at an Air-Water Interface  
 Abstract    Stability and regenerability of the absorption spectrum of CTAB solubilized rhodopsin at an air-water interface is studied. The spectral properties of rhodopsin films in the dark are stable more than 150 minutes. When rhodopsin is bleached (40 — 50%) and maintained in highly com­ pressed films recovery of the spectrum is observed. The recovery is 57% to 100% of the pigment present before irradiation. At low surface pressure or if the films are expanded after irradiation there is no observable recovery. 
  Reference    Z. Naturforsch. 33c, 317 (1978); received March 28 1978 
  Published    1978 
  Keywords    Vision, Rhodopsin, Monolayers, Membranes, Photobiology 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0317.pdf 
 Identifier    ZNC-1978-33c-0317 
 Volume    33 
4Author    N. Yckowski, S. S. BrodyRequires cookie*
 Title    Interactions of Monomolecular Films of Retinal at Alkaline pH  
 Abstract    The surface properties of mixed monomolecular films of retinal and phospholipids were studied at a nitrogen/water interface. The subphase was glycine buffer pH 10.5 with an ionic strength of 0.1. Monomolecular films of retinal in the presence of amino acids were also measured. The area per molecule, at a surface pressure of 10 dyn/cm, A 10, in the dark for 9-cis retinal and 11-ci's retinal are 42 A 2 and 47 A 2, respectively. After irradiation A 10 for 9-cis retinal and 11-cts retinal dcerease to 40 A 2 and 43 A2, respectively. The surface potentials, AV, at a surface pressure of 10 dyn/cm, in the dark for 9-cis retinal and 11-cis retinal are 470 mV and 445 mV, respectively. After irradiation, AV for 9-cis retinal decreases to 435 mV and 11-cis retinal increases to 490 mV. Interaction was observed between retinal and phospholipids and amino acids. The A 10 and AV 10 of mixed films of retinal and phospholipid were measured as a function of the mole fraction of phospholipid. Maximum interaction is observed at mole ratios of; phosphatidylserine/9-ct's = 1; phosphatidylethanolamine/9-m = 2, phosphatidylserine/ll-cis = 3; phosphatidylethanolamine/ H-CJ5 = 3. It is shown that mixing and interaction between phosphatidylethanolamine and retinal is spontaneous. The A 10 and A V 10 of films of retinal were measured as a function of the molar concentration of amino acid in the subphase. The nature of the interaction between retinal and phospholipid and amino acid are discussed. 
  Reference    (Z. Naturforsch. 29c, 327 [1974]; received April 1 1974) 
  Published    1974 
  Keywords    ) Vision, Retinal, Monolayers, Membranes, Model systems 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0327.pdf 
 Identifier    ZNC-1974-29c-0327 
 Volume    29 
5Author    N. Puppala, S. S. BrodyRequires cookie*
 Title    Interactions between Retinal and Phospholipids in Monomolecular Films at Acid pH  
 Abstract    The surface properties of mixed monomolecular films of retinal and phospholipids (p. lipids) are measured as a function of mole fraction at a nitrogen-water interface. An acid pH of 6.0 is maintained in the aqueous phase. Before irradiation the surface potential A V for 9-cis retinal, 11-cis retinal, phosphatidyl serine (PS) and phosphatidyl ethanolamine (PE), at j t = 12 dyn/cm, are 490 mV, 645 mV, 548 mV and 375 mV, respectively. Before irradiation, A 0 for 9-cis and 11-ds are 58 Ä2 and 48 A2, respectively. Experimentally measured isotherms are compared with theo­ retically calculated isotherms. In case of mixed films of retinal and PS the experimental isotherms are greater than theoretical, while mixed films of retinal and PE are smaller than theoretical. A maximum value for the difference between theoretical and experimental areas are obtained at (retinal) / (p. lipid) = 0 .1 . Retinal and p. lipid do not appear to form a Schiff base, charge transfer or any other type of complex at pH 6. A eutectic type mixture between retinal and p. lipid may occur on the surface. A light induced change in A V of —130 mV is observed in the case of 11-cis and PE. The significance of these findings with respect to visual excitation is considered. 
  Reference    (Z. Naturforsch. 30c, 478—483 [1975]; received October 4 1973/October 21 1974) 
  Published    1975 
  Keywords    ) Vision, Retinal, Monolayers, Photobiology, Membranes 
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 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0478.pdf 
 Identifier    ZNC-1975-30c-0478 
 Volume    30 
6Author    S. S. Brody, N. F. OwensRequires cookie*
 Title    Photosynthetic Electron Carriers at a Heptane-Water Interface  
 Abstract    Surface properties of monomolecular films of chlorophyll (Chi), plastocyanin (Pc), cytochrome c (Cyt) and ferridoxin (Fd) were measured at a heptane-water interface. Mixed films of Chi and the other components were examined in darkness and in light. The area/molecule, A, for Fd (from Cl. pasteurianum) is much larger at a heptane-water than Fd (from spinach) at an air-water interface. This difference in A may be the source of the Fd or the extent of denaturation at the different interfaces. There appears to be a photoreaction between Chi and Fd in the presence of ascorbate. The A for Cyt is much larger at a heptane-water than at an air-water interface. In mixed films there is a strong interaction between Chi and reduced Cyt in the dark. No such interaction is ob­ served between Chi and oxidized Cyt. With mixed films of Chi and reduced Pc there is a significant, reversible, light induced change in A V. 
  Reference    (Z. Naturforsch. 31c, 569 [1976]; received May 13 1976) 
  Published    1976 
  Keywords    Monolayers, Artificial Membranes, Photosynthesis, Lipid-Water Interface, Photobiology 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0569.pdf 
 Identifier    ZNC-1976-31c-0569 
 Volume    31 
7Author    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