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Retinoschisin
Retinoschisin also known as X-linked juvenile retinoschisis protein is a lectin that in humans is encoded by the ''RS1'' gene. It is a soluble, cell-surface protein that plays an important role in the maintenance of the retina where it is expressed and secreted by retinal bipolar cells and photoreceptors, as well as in the pineal gland. Retinoschisin (RS1) is encoded by the gene ''RS1'' located on the X chromosome at ''p22.1''. Young males who have an ''RS1'' mutation are susceptible to retinoschisis, and X-linked eye disease which causes macular degeneration and can lead to a loss of vision. Function Retinoschisin is an extracellular protein that plays a crucial role in the cellular organization of the retina: it binds the plasma membranes of various retinal cells tightly to maintain the structure of the retina. In addition to enabling cell-to-cell adhesion, it has been shown that retinoschisin interacts with the sodium/potassium-ATPase (Na/K-ATPase) which resides in the pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoidin Domain
Discoidin domain (also known as F5/8 type C domain, or C2-like domain) is major protein domain of many blood coagulation factors. Blood coagulation factors V and VIII contain a C-terminal, twice repeated, domain of about 150 amino acids, which is often called "C2-like domain" (that is unrelated to the C2 domain). In the ''Dictyostelium discoideum'' (Slime mold) cell adhesion protein discoidin, a related domain, named discoidin I-like domain, DLD, or DS, has been found which shares a common C-terminal region of about 110 amino acids with the FA58C domain, but whose N-terminal 40 amino acids are much less conserved. Similar domains have been detected in other extracellular and membrane proteins. In coagulation factors V and VIII the repeated domains compose part of a larger functional domain which promotes binding to anionic phospholipids on the surface of platelets and endothelial cells. The C-terminal domain of the second FA58C repeat (C2) of coagulation factor VIII has been sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lectin
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in recognition at the cellular and molecular level and play numerous roles in biological recognition phenomena involving cells, carbohydrates, and proteins. Lectins also mediate attachment and binding of bacteria, viruses, and fungi to their intended targets. Lectins are ubiquitous in nature and are found in many foods. Some foods, such as beans and grains, need to be cooked, fermented or sprouted to reduce lectin content. Some lectins are beneficial, such as CLEC11A, which promotes bone growth, while others may be powerful toxins such as ricin. Lectins may be disabled by specific mono- and oligosaccharides, which bind to ingested lectins from grains, legumes, nightshade plants, and dairy; binding can prevent their attachment to the carbohy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoreceptor Cell
A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential. There are currently three known types of photoreceptor cells in mammalian eyes: rods, cones, and intrinsically photosensitive retinal ganglion cells. The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form an image of the environment, sight. Rods primarily mediate scotopic vision (dim conditions) whereas cones primarily mediate to photopic vision (bright conditions), but the processes in each that supports phototransduction is similar. A third class of mammalian photoreceptor cell was discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pineal Gland
The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep, sleep patterns in both circadian rhythm, circadian and Season, seasonal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two cerebral hemisphere, hemispheres, tucked in a groove where the two halves of the thalamus join. The pineal gland is one of the neuroendocrinology, neuroendocrine Circumventricular organs, secretory circumventricular organs in which capillaries are mostly Vascular permeability, permeable to solutes in the blood. Nearly all vertebrate species possess a pineal gland. The most important exception is a primitive vertebrate, the hagfish. Even in the hagfish, however, there may be a "pineal equivalent" structure in the dorsal diencephalon. The lanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macular Degeneration
Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, some people experience a gradual worsening of vision that may affect one or both eyes. While it does not result in complete blindness, loss of central vision can make it hard to recognize faces, drive, read, or perform other activities of daily life. Visual hallucinations may also occur. Macular degeneration typically occurs in older people. Genetic factors and smoking also play a role. It is due to damage to the macula of the retina. Diagnosis is by a complete eye exam. The severity is divided into early, intermediate, and late types. The late type is additionally divided into "dry" and "wet" forms with the dry form making up 90% of cases. The difference between the two forms is the change of macula. Those with dry form AMD have drusen, ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoschisis
Retinoschisis is an eye disease characterized by the abnormal splitting of the retina's neurosensory layers, usually in the outer plexiform layer. Retinoschisis can be divided into degenerative forms which are very common and almost exclusively involve the peripheral retina and hereditary forms which are rare and involve the central retina and sometimes the peripheral retina. The degenerative forms are asymptomatic and involve the peripheral retina only and do not affect the visual acuity. Some rarer forms result in a loss of vision in the corresponding visual field.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990. Almost all cases are X-linked recessive and caused by a mutation in the retinoschisin gene (''RS1''). Classification *Hereditary **X linked juvenile retinoschisis **Familial foveal retinoschisis *Tractional *Exudative **Secondary to Optic disc pit *Degenerative **Typical **Reticular Degenerative retin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foveal
The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the macula lutea of the retina. The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving. The fovea is surrounded by the ''parafovea'' belt and the ''perifovea'' outer region. The parafovea is the intermediate belt, where the ganglion cell layer is composed of more than five layers of cells, as well as the highest density of cones; the perifovea is the outermost region where the ganglion cell layer contains two to four layers of cells, and is where visual acuity is below the optimum. The perifovea contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most central fovea. That, in turn, is surrounded by a larger peripheral area, which delivers highly compres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
