Structure of Retinal Photoreceptor Membranes

Nature ◽  
1972 ◽  
Vol 236 (5345) ◽  
pp. 313-314 ◽  
Author(s):  
A. E. BLAUROCK ◽  
M. H. F. WILKINS
Keyword(s):  
Retinal Photoreceptor ◽  
Photoreceptor Membranes

Photoreceptor disk membrane substructures by means of the complementary freeze-fracture-replica methods

1978 ◽  
Vol 36 (2) ◽  
pp. 156-157
Author(s):  
A. Tonosaki ◽  
M. Yamasaki ◽  
H. Washioka ◽  
J. Mizoguchi
Keyword(s):  
Cell Membranes ◽  
Freeze Fracture ◽  
Purple Membrane ◽  
Remarkable Case ◽  
Single Face ◽  
Disk Membrane ◽  
Associated Proteins ◽  
Photoreceptor Membranes

A vertebrate disk membrane is composed of 40 % lipids and 60 % proteins. Its fracture faces have been classed into the plasmic (PF) and exoplasmic faces (EF), complementary with each other, like those of most other types of cell membranes. The hypothesis assuming the PF particles as representing membrane-associated proteins has been challenged by serious questions if they in fact emerge from the crystalline formation or decoration effects during freezing and shadowing processes. This problem seems to be yet unanswered, despite the remarkable case of the purple membrane of Halobacterium, partly because most observations have been made on the replicas from a single face of specimen, and partly because, in the case of photoreceptor membranes, the conformation of a rhodopsin and its relatives remains yet uncertain. The former defect seems to be partially fulfilled with complementary replica methods.

Spindle shaped bodies in foveolar cones of the baboon retina

1989 ◽  
Vol 47 ◽  
pp. 960-961
Author(s):  
W. Krebs ◽  
I. Krebs
Keyword(s):  
Cross Sections ◽  
Inclusion Bodies ◽  
Photoreceptor Cells ◽  
Papio Anubis ◽  
Retinal Photoreceptor ◽  
Age Related ◽  
Cone Cells ◽  
Membrane Bound ◽  
Oriented Parallel ◽  
Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

Enzymic and nonenzymic systems protecting photoreceptor membranes against active forms of oxygen and lipid peroxides

1979 ◽  
Vol 88 (2) ◽  
pp. 856-858 ◽  
Author(s):  
V. E. Kagan ◽  
V. Z. Lankin ◽  
A. A. Shvedova ◽  
K. N. Novikov ◽  
S. K. Dobrina ◽  
...  
Keyword(s):  
Lipid Peroxides ◽  
Active Forms Of Oxygen ◽  
Photoreceptor Membranes

scholarly journals UV-light-dependent binding of a visual arrestin 1 isoform to photoreceptor membranes in a neuropteran (Ascalaphus ) compound eye

FEBS Letters ◽  
2001 ◽  
Vol 493 (2-3) ◽  
pp. 112-116 ◽  
Author(s):  
Joachim Bentrop ◽  
Markus Schillo ◽  
Gabriele Gerdon ◽  
Kazimir Draslar ◽  
Reinhard Paulsen
Keyword(s):  
Compound Eye ◽  
Uv Light ◽  
Photoreceptor Membranes

scholarly journals THE ULTRASTRUCTURE OF LIPID-DEPLETED ROD PHOTORECEPTOR MEMBRANES

1974 ◽  
Vol 63 (2) ◽  
pp. 587-598 ◽  
Author(s):  
Izhak Nir ◽  
Michael O. Hall
Keyword(s):  
Lipid Extraction ◽  
Fatty Acid Analysis ◽  
Major Protein ◽  
Rod Photoreceptor ◽  
Thin Sections ◽  
Retinal Rod ◽  
Layer Chromatography ◽  
Chloroform Methanol ◽  
Photoreceptor Membranes

The structure of lipid-depleted retinal rod photoreceptor membranes was studied by means of electron microscopy. Aldehyde-fixed retinas were exhaustively extracted with acetone, chloroform-methanol, and acidified chloroform-methanol. The effect of prefixation on the extractability of lipids was evaluated by means of thin-layer chromatography and fatty acid analysis. Prefixation with glutaraldehyde rendered 38% of the phospholipids unextractable, while only 7% were unextractable after formaldehyde fixation. Embedding the retina in a lipid-retaining, polymerizable glutaraldehyde-urea mixture allows a comparison of the interaction of OsO4 with lipid-depleted membranes and rod disk membranes which contain all their lipids. A decrease in electron density and a deterioration of membrane fine structure in lipid-depleted tissue are correlated with the extent of lipid extraction. These observations are indicative of the role of the lipid bilayer in the ultrastructural visualization of membrane structure with OsO4. Negatively stained thin sections of extracted tissue reveal substructures in the lipid-depleted rod membranes. These substructures are probably the opsin molecules which are the major protein component of retinal rod photoreceptor membranes.

“Tho' she kneel'd in that place where they grew…” The uses and origins of primate colour vision

1989 ◽  
Vol 146 (1) ◽  
pp. 21-38 ◽  
Author(s):  
J. D. Mollon
Keyword(s):  
X Chromosome ◽  
Colour Vision ◽  
Visual Pathway ◽  
New World Monkeys ◽  
Old World Monkeys ◽  
Old World ◽  
Early Stages ◽  
Local Sign ◽  
Retinal Photoreceptor ◽  
Recent Duplication

The disabilities experienced by colour-blind people show us the biological advantages of colour vision in detecting targets, in segregating the visual field and in identifying particular objects or states. Human dichromats have especial difficulty in detecting coloured fruit against dappled foliage that varies randomly in luminosity; it is suggested that yellow and orange tropical fruits have co-evolved with the trichromatic colour vision of Old World monkeys. It is argued that the colour vision of man and of the Old World monkeys depends on two subsystems that remain parallel and independent at early stages of the visual pathway. The primordial subsystem, which is shared with most mammals, depends on a comparison of the rates of quantum catch in the short- and middle-wave cones; this system exists almost exclusively for colour vision, although the chromatic signals carry with them a local sign that allows them to sustain several of the functions of spatiochromatic vision. The second subsystem arose from the phylogenetically recent duplication of a gene on the X-chromosome, and depends on a comparison of the rates of quantum catch in the long- and middle-wave receptors. At the early stages of the visual pathway, this chromatic information is carried by a channel that is also sensitive to spatial contrast. The New World monkeys have taken a different route to trichromacy: in species that are basically dichromatic, heterozygous females gain trichromacy as a result of X-chromosome inactivation, which ensures that different photopigments are expressed in two subsets of retinal photoreceptor.

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