Synonyms for pigment_rhodopsin or Related words with pigment_rhodopsin
Examples of "pigment_rhodopsin"
As a postdoctoral researcher, Wald discovered that vitamin A was a component of the retina. His further experiments showed that when the
was exposed to light, it yielded the protein opsin and a compound containing vitamin A. This suggested that vitamin A was essential in retinal function.
Haloarchaea can grow aerobically or anaerobically. Parts of the membranes of haloarchaea are purplish in color, and large blooms of haloarchaea appear reddish, from the pigment bacteriorhodopsin, related to the retinal
which it uses to transform light energy into chemical energy by a process unrelated to chlorophyll-based photosynthesis.
Rods cannot distinguish colours, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a
(visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina.
Following isomerization and release from the opsin protein, all-trans retinal is reduced to all-trans retinol and travels back to the retinal pigment epithelium to be "recharged". It is first esterified by lecithin retinol acyltransferase (LRAT) and then converted to 11-cis retinol by the isomerohydrolase RPE65. The isomerase activity of RPE65 has been shown; it is still uncertain whether it also acts as hydrolase. Finally, it is oxidized to 11-cis retinal before traveling back to the rod outer segment where it is again conjugated to an opsin to form new, functional visual
Matthews was born in Cambridge, England while her father, biochemist David E. Green, was on sabbatical there. Matthews earned her B.A. in biology "summa cum laude" from Radcliffe College in 1960. As an undergraduate, and for three years thereafter, she worked with George Wald studying a new intermediate in the bleaching of the visual
that temporally coincided with initiation of visual excitation. She then went to graduate school in biophysics at the University of Michigan, where she did her dissertation research in the laboratory of Vincent Massey. She received her Ph.D. in 1969.
The most sensitive
, has a peak response at 500 nm. Small changes to the genes coding for this protein can tweak the peak response by a few nm; pigments in the lens can also filter incoming light, changing the peak response. Many organisms are unable to discriminate between colours, seeing instead in shades of grey; colour vision necessitates a range of pigment cells which are primarily sensitive to smaller ranges of the spectrum. In primates, geckos, and other organisms, these take the form of cone cells, from which the more sensitive rod cells evolved. Even if organisms are physically capable of discriminating different colours, this does not necessarily mean that they can perceive the different colours; only with behavioural tests can this be deduced.
PDE6 is a highly concentrated protein in retinal photoreceptors. With the presence of the GAF domain, PDE6 can actively bind to the cGMP. The inactive PDE6 in the dark allows cGMP to bind to cGMP gated ion channels. The channel remains open as long as cGMP is binding to it, which allows constant electron flow in to the photoreceptor cell through the plasma membrane. Light causes the visual
, to activate. This process leads to the release of subunit PDE6γ from PDE6αβ, activating PDE6 which leads to the hydrolysis of cGMP. Without the cGMP binding, the ion channel closes, leading to the hyperpolarization. After hyperpolarization the presnaptic transimitter is reduced. Next, the enzyme guanylate cyclase restores cGMP, which reopens the membrane channels. This process is called light adaptation.
There are two sorts of light receptors in a bird’s eye, rods and cones. Rods, which contain the visual
are better for night vision because they are sensitive to small quantities of light. Cones detect specific colours (or wavelengths) of light, so they are more important to colour-orientated animals such as birds. Most birds are tetrachromatic, possessing four types of cone cells each with a distinctive maximal absorption peak. In some birds, the maximal absorption peak of the cone cell responsible for the shortest wavelength extends to the ultraviolet (UV) range, making them UV-sensitive. In addition to that, the cones at bird's retina are arranged in a characteristic form of spatial distribution, known as hyperuniform distribution, which maximizes its light and color absorption. This form of spatial distributions are only observed as a result of some optimization process, which in this case can be described in terms of bird's evolutionary history.
The Bonin petrel and the closely related mottled petrel are the only "Pterodroma" petrels with a fish dominated diet. Principal prey items are fish from the family Myctophidae (lantern fish) and Sternoptychidae (hatchetfish). Squid from the family Ommastrephidae are also consumed. All of these prey are midwater residents that use photophores and migrate to the surface during the night to feed; thus it is assumed that Bonin petrels are nocturnal feeders that seize prey at the surface while resting on the sea or in flight. Bonin petrel eyes contain high levels of the
which aids nocturnal vision. The Bonin petrel is usually solitary at sea, but is occasionally seen in large multi-species flocks. Like all procellariids the Bonin petrel has a modified area of the gut known as a proventriculus which partly digests prey to create stomach oil, an energy rich oil which is lighter to carry than prey.
Hubbard made many important contributions to the visual sciences but her single most important was the fact that visual excitation is initiated by a chemical rearrangement of the visual
) which is called a cis-trans isomerization. She showed that this is the only direct action of light on the visual system. She also identified the specific intermediate in the visual cycle (called metarhodopsin2) that leads to downstream effects, that culminate in a light-activated neural signaling to the brain Hubbard also described the bleaching and resynthesis of the rhodopsin molecule each time a photon is absorbed. She also discovered retinene isomerase (now called RPE65) that converts all-trans retinal (the post-illumination form) back into 11-cis retinal. She also studied the visual pigments in several new species. Her early work focused on the basic properties of rhodopsin, which is a combination of the chromophore (retinal) and a protein called opsin, which is reutilized in the resynthesis of rhodopsin. Hubbard published at least 31 scientific papers devoted to vision. Like her husband, she remained scientifically active until about 1975, and she made an excellent scientific presentation of her husband's work at a symposium in his honor. George Wald was 18 years older than Hubbard and he died in 1996.
USML-2 Experiments included: the Surface Tension Driven Convection Experiment (STDCE), the Drop Physics Module, the Drop Dynamics Experiment; the Science and Technology of Surface-Controlled Phenomena experiment; the Geophysical Fluid Flow Cell Experiment; the Crystal Growth Furnace, the Orbital Processing of High Quality Cadmium Zinc Telluride Compound Semiconductors experiment; the Study of Dopant Segregation Behavior During the Crystal Growth of Gallium Arsenide (GaAs) in Microgravity experiment; the Crystal Growth of Selected II-VI Semiconducting Alloys by Directional Solidification experiment; the Vapor Transport Crystal Growth of Mercury Cadmium Tellurida in Microgravity experiment; the Zeolite Crystal Growth Furnace (ZCG), the Interface Configuration Experiment (ICE), the Oscillatory Thermocapillary Flow Experiment; the Fiber Supported Droplet Combustion Experiment; the Particle Dispersion Experiment; the Single-Locker Protein Crystal Growth experiment; (including the Protein Crystallization Apparatus for Microgravity (PCAM) and the Diffusion-controlled Crystallization Apparatus for Microgravity (DCAM)); the Crystal Growth by Liquid-Liquid Diffusion, the Commercial Protein Crystal Growth experiment; the Advanced Protein Crystallization Facility, Crystallization of Apocrystacyanin C experiment; Crystal Structure Analysis of the Bacteriophage Lambda Lysozyme, Crystallization of RNA Molecules Under Microgravity Conditions experiment; Crystallization of the Protein Grb2 and Triclinic Lysozyme experiment; Microgravity Crystallization of Thermophilic Aspartyl-tRNA Synthetase and Thaumatin experiment; Crystallization in a Microgravity Environment of CcdB experiment; A Multivariate Analysis of X-ray Diffraction Data Obtained from Glutathione S Transferase experiment; Protein Crystal Growth: Light-driven Charge Translocation Through Bacteriorhodopsin experiment; Crystallization of Ribosome experiment; Crystallization of Sulfolobus Solfataricus Alcohol Dehydrogenase experiment; Crystallization of Turnip Yellow Mosaic Virus, Tomato Aspermy Virus, Satellite Panicum Mosaic Virus, Canavalin, Beef Liver Catalase, Concanavalin B experiment; Crystallization of the Epidermal Growth Factor (EGF); Structure of the Membrane-Embedded Protein Complex Photosystem I; Crystallization of Visual
; Commercial Generic Bioprocessing Apparatus; Astroculture Facility and Experiment. Spacelab Glovebox Facility experiments included the Zeolite Crystal Growth Glovebox, Protein Crystal Growth Glovebox and the Colloidal Disorder-Order Transitions,
The genus "Halobacterium" ("salt" or "ocean bacterium") consists of several species of the Archaea with an aerobic metabolism which requires an environment with a high concentration of salt; many of their proteins will not function in low-salt environments. They grow on amino acids in their aerobic conditions. Their cell walls are also quite different from those of bacteria, as ordinary lipoprotein membranes fail in high salt concentrations. In shape, they may be either rods or cocci, and in color, either red or purple. They reproduce using binary fission (by constriction), and are motile. "Halobacterium" grows best in a 42°C environment. The genome of an unspecified "Halobacterium" species, sequenced by Shiladitya DasSarma, comprises 2,571,010 bp (base pairs) of DNA compiled into three circular strands: one large chromosome with 2,014,239 bp, and two smaller ones with 191,346 and 365,425 bp. This species, called "Halobacterium" sp. NRC-1, has been extensively used for postgenomic analysis. "Halobacterium" species can be found in the Great Salt Lake, the Dead Sea, Lake Magadi, and any other waters with high salt concentration. Purple "Halobacterium" species owe their color to bacteriorhodopsin, a light-sensitive protein which provides chemical energy for the cell by using sunlight to pump protons out of the cell. The resulting proton gradient across the cell membrane is used to drive the synthesis of the energy carrier ATP. Thus, when these protons flow back in, they are used in the synthesis of ATP (this proton flow can be emulated with a decrease in pH outside the cell, causing a flow of H ions). The bacteriorhodopsin protein is chemically very similar to the light-detecting
, found in the vertebrate retina.
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