| | 1 | Author
| Hiroko Ito, K. Aran, RhodaElison Hirsch, SeymourSteven Brody | Requires 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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| default:Reihe_C/33/ZNC-1978-33c-0317.pdf | | | | Identifier
| ZNC-1978-33c-0317 | | | | Volume
| 33 | |
| 2 | Author
| N. Puppala, S. S. Brody | Requires 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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| default:Reihe_C/30/ZNC-1975-30c-0478.pdf | | | | Identifier
| ZNC-1975-30c-0478 | | | | Volume
| 30 | |
| 3 | Author
| S. S. Brody, N. F. Owens | Requires 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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| default:Reihe_C/31/ZNC-1976-31c-0569.pdf | | | | Identifier
| ZNC-1976-31c-0569 | | | | Volume
| 31 | |
| 4 | Author
| H. W. Eißhaar, P. Böger | Requires cookie* | | | Title
| Sulfide Stimulation of Light-Induced Hydrogen Evolution by the Cyanobacterium Nostoc muscorum | | | | Abstract
| Light-induced hydrogen evolution by the blue-green alga N ostoc muscorum is stim ulated by sulfide with a rate of about 20 (imol H 2 per mg chlorophyll and h our stable for about one day at low light intensities (7 W /m 2). Oxygen evolution does not im pair sulfide-stim ulated hydrogen formation. Increased hydrogen evolution is catalyzed by nitrogenase, its activity is not influenced by sulfide. Apparently, sulfide inhibits the hydrogen-uptake pathw ay(s), thereby increasing net hydrogen evolution. — Furtherm ore, photosynthetic electron flow is inhibited by sulfide, essen tially at the oxidizing side o f photosystem II, as was dem onstrated by fluorescence-signal changes. This leads to decreased electron supply o f nitrogenase. Hydrogen production apparently is at optim um when both the effect o f sulfide on photo synthesis is moderate and when uptake-hydrogenase activity is abolished. | | | |
Reference
| Z. Naturforsch. 38c, 237 (1983); received D ecem ber 8 1982 | | | |
Published
| 1983 | | | |
Keywords
| Hydrogen Production, Photobiology, Sulfide, Blue-Greens | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0237.pdf | | | | Identifier
| ZNC-1983-38c-0237 | | | | Volume
| 38 | |
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