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1Author    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 
2Author    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 
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    David Dvorak, Allan SnyderRequires cookie*
 Title    The Relationship between Visual Acuity and Illumination in the Fly, Lucilia sericata  
 Abstract    The variation in visual acuity with illumination has been studied by monitoring the extracellular response of direction sensitive motion detecting neurons to a drifting sine wave grating displayed upon an oscilloscope spreen. Acuity reaches a maximum value of 0.46 cycles/degree at luminances above 1.0 cd/m2 and decreases gradually over a 3.8 log unit attenuation in intensity to a minimum value of 0.05 cycles/degree. The results have been compared with theoretical acuity curves for the coupound eye with various dark adaptation mechanisms. The analysis indicates that a major strategy of dark adaptation in the fly is a process involving intensity-dependent neural summation of signals from photoreceptors having different visual axes. 
  Reference    Z. Naturforsch. 33c, 139 (1978); received November 9 1977 
  Published    1978 
  Keywords    Diptera, Insect, Vision, Visual Acuity, Electrophysiology 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0139.pdf 
 Identifier    ZNC-1978-33c-0139 
 Volume    33 
5Author    Hermann Wagner, Harald LukschRequires cookie*
 Title    Effect of Ecological Pressures on Brains: Examples from Avian Neuroethology and General Meanings  
 Abstract    Comparative neuroethological research emphasizes that brains of animals have been shaped by the specific demands and constraints imposed by the ecological niche that a species occupies. Since avian species have developed very diverse life styles and occupy extreme ecological niches, bird brains should show many specializations, which may be revealed in species that have survived under high ecological pressures. In this paper, we will give several examples of adaptations, in which we are able to correlate structural and physiological spe­ cializations to the specific ecological demands: adaptations found to nocturnal hunting in barn owls, the characteristics of bird song and its underlying neurobiological correlates, reti-nopetal projections and their relation to peripheral attentional switching, looming detection, and adaptations related to memory capacities of food-storing birds. We stress especially that the analysis of the anim al's ecological situation is important in understanding the factors that shaped both behavior and the neuronal substrate. 
  Reference    Z. Naturforsch. 53c, 560 (1998); received April 2 1998 
  Published    1998 
  Keywords    Neural Computation, Vision, Audition, Comparative, Sensory 
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 TEI-XML for    default:Reihe_C/53/ZNC-1998-53c-0560.pdf 
 Identifier    ZNC-1998-53c-0560 
 Volume    53 
6Author    Martin Egelhaaf, Roland Kern, Anne-Kathrin WarzechaRequires cookie*
 Title    Sensory Ecology and Neural Coding in Arthropods  
 Abstract    Arthropods live in almost any conceivable habitat. Accordingly, structural and functional specialisations have been described in many species which allow them to behave in an adap­ tive way with the limited computational resources of their small brains. These adaptations range from the special design of the eyes, the spectral sensitivities of their photoreceptors to the specific properties of neural circuits. 
  Reference    Z. Naturforsch. 53c, 582 (1998); received April 9 1998 
  Published    1998 
  Keywords    Sensory Ecology, Behaviour, Neural Coding, Vision, Arthropods 
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 TEI-XML for    default:Reihe_C/53/ZNC-1998-53c-0582.pdf 
 Identifier    ZNC-1998-53c-0582 
 Volume    53 
7Author    H. Endrick, E. A. Eckert, K. Urt, H. Am DorfRequires cookie*
 Title    Action Potentials in "Non-Spiking" Visual Interneurones  
 Abstract    The response o f the homolateral "horizontal cells" (H-cells) o f the third visual neuropile o f the blowfly, Phoenicia sericata, has been investigated by intracellular recordings coupled with dye injections (Procion Yellow, cobaltous chloride). Responses were obtained from their terminal axon endings in the central protocerebrum. Under natural conditions, the horizontal cells respond not with graded potentials as reported previously, but with action potentials upon stimulation by regressive pattern motion within the contralateral receptive field. The stimulus-induced responses change from action potentials to graded signals within a few minutes after opening the head capsule. The possible causes o f this change, namely hypoxic conditions and a consequent depletion of the ATP-supply, are consistent with the experimental data: a change in the resting potential as well a reduction o f the spike amplitude. Furthermore, the possibility of two functionally different output regions o f the H-cells is discussed, namely, (1) the terminal axon endings appear to conduct action potentials induced by the contralateral input (to the H-cells). Thus, these endings provide a solely contralateral, i.e. "monocular output". Whereas (2) the axonal arborisation appears to conduct graded signals elicited by the ipsilateral input onto which the contralateral input is superimposed, thus providing a "binocular output". 
  Reference    Z. Naturforsch. 36c, 470—4 (1981); received August 7 1980/January 21 1981 
  Published    1981 
  Keywords    Vision, Diptera, Central Nervous System, Identified Neurones, Graded Signal Transmission 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0470.pdf 
 Identifier    ZNC-1981-36c-0470 
 Volume    36