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Aquaporin
Aquaporins, also called water channels, are channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells. The cell membranes of a variety of different bacteria, fungi, animal and plant cells contain aquaporins through which water can flow more rapidly into and out of the cell than by diffusing through the phospholipid bilayer. Aquaporins have six membrane-spanning alpha helical domains with both carboxylic and amino terminals on the cytoplasmic side. Two hydrophobic loops contain conserved asparagine– proline– alanine ("NPA motif") which form a barrel surrounding a central pore-like region that contains additional protein density. Because aquaporins are usually always open and are prevalent in just about every cell type, this leads to a misconception that water readily passes through the cell membrane down its concentration gradient. Water can pass through th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major Intrinsic Proteins
Major intrinsic proteins comprise a large superfamily of transmembrane protein channels that are grouped together on the basis of homology. The MIP superfamily includes three subfamilies: aquaporins, aquaglyceroporins and S-aquaporins. # The aquaporins (AQPs) are water selective. # The aquaglyceroporins are permeable to water, but also to other small uncharged molecules such as glycerol. # The third subfamily, with little conserved amino acid sequences around the NPA boxes, include 'superaquaporins' (S-aquaporins). The phylogeny of insect MIP family channels has been published. Families There are two families that belong to thMIP Superfamily 1.A.8- The Major Intrinsic Protein (MIP) Family 1.A.16- Formate-nitrite transporter, The Formate-Nitrite Transporter (FNT) Family The Major Intrinsic Protein Family (TC# 1.A.8) The MIP family is large and diverse, possessing thousands of members that form transmembrane channels. These channel proteins function in transporting water, smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuromyelitis Optica
Neuromyelitis optica spectrum disorders (NMOSD) are a spectrum of autoimmune diseases characterized by acute inflammation of the optic nerve (optic neuritis, ON) and the spinal cord ( myelitis).Banerjee S, Butcher R. Rituximab for the Treatment of Neuromyelitis Optica Spectrum Disorder nternet Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2021 Feb. Available from: https://www.ncbi.nlm.nih.gov/books/NBK571350/ Episodes of ON and myelitis can be simultaneous or successive. A relapsing disease course is common, especially in untreated patients. * Neuromyelitis optica (NMO) is a particular disease within the NMOSD spectrum. It is characterised by optic neuritis and longitudinally extensive myelitis. In more than 80% of NMO cases, the cause is immunoglobulin G autoantibodies to aquaporin 4 ( anti-AQP4), the most abundant water channel protein in the central nervous system. * Less common diseases with other manifestations are also part of the NMOSD spectrum. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaporin 1
Aquaporin 1 (AQP-1) is a protein that in humans is encoded by the ''AQP1'' gene. AQP-1 is a widely expressed water channel, whose physiological function has been most thoroughly characterized in the kidney. It is found in the basolateral and apical plasma membranes of the proximal tubules, the descending limb of the loop of Henle, and in the descending portion of the vasa recta. Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, lungs, and the central nervous system. Neural AQP-1 are regulated by vasopressin AVPR1A receptor activity. Function Aquaporins are a family of small integral membrane proteins related to the major intrinsic protein ( MIP or AQP0). This gene encodes an aquaporin which functions as both a molecular water channel protein and as a non-selective cation channel gated by cyclic guanosine monophosphate (cGMP). It is a homotetramer with six bilayer spanning domains and N-glycosylation sites. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Agre
Peter Agre (; born January 30, 1949) is Nobel Laureate American physician, molecular biologist, Bloomberg Distinguished Professorships, Bloomberg Distinguished Professor at the Johns Hopkins Bloomberg School of Public Health and Johns Hopkins School of Medicine, and director of the Johns Hopkins Malaria Research Institute. In 2003, Agre and Roderick MacKinnon shared the 2003 Nobel Prize in Chemistry for "discoveries concerning channels in cell membranes." Agre was recognized for his discovery of aquaporin water channels. Aquaporins are water-channel proteins that move water molecules through the cell membrane. In 2009, Agre was elected president of the American Association for the Advancement of Science (AAAS) and became active in science diplomacy. Biography Agre is the second of six children born in Northfield, Minnesota, to parents of Norwegian people, Norwegian and Swedes, Swedish descent. Agre is a Lutheran. Fascinated by international travel after a high school camping trip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diabetes Insipidus
Diabetes insipidus (DI) is a condition characterized by large amounts of dilute urine and increased thirst. The amount of urine produced can be nearly 20 liters per day. Reduction of fluid has little effect on the concentration of the urine. Complications may include dehydration or seizures. There are four types of DI, each with a different set of causes. # Central DI (CDI), now known as arginine vasopressin deficiency (AVP-D), is due to a lack of vasopressin (antidiuretic hormone) production. This can be due to injury to the hypothalamus or pituitary gland or due to genetics. # Nephrogenic DI (NDI), also known as arginine vasopressin resistance (AVP-R), occurs when the kidneys do not respond properly to vasopressin. # Dipsogenic DI is a result of excessive fluid intake due to damage to the hypothalamic thirst mechanism. It occurs more often in those with certain psychiatric disorders or on certain medications. # Gestational DI occurs only during pregnancy. Diagnosis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johns Hopkins University
The Johns Hopkins University (often abbreviated as Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland, United States. Founded in 1876 based on the European research institution model, Johns Hopkins is considered to be the first research university in the U.S. The university was named for its first benefactor, the American entrepreneur and Quakers, Quaker philanthropist Johns Hopkins. Hopkins's $7 million bequest (equivalent to $ in ) to establish the university was the largest Philanthropy, philanthropic gift in U.S. history up to that time. Daniel Coit Gilman, who was inaugurated as :Presidents of Johns Hopkins University, Johns Hopkins's first president on February 22, 1876, led the university to revolutionize higher education in the U.S. by integrating teaching and research. In 1900, Johns Hopkins became a founding member of the Association of American Universities. The university has led all Higher education in the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmosis
Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively permeable membrane, selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of higher solute concentration), in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do Work (physics), work. Osmotic pressure is defined as the external pressure required to prevent net movement of solvent across the membrane. Osmotic pressure is a colligative properties, colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity. Osmosis is a vital process in biology, bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Diffusion
Molecular diffusion is the motion of atoms, molecules, or other particles of a gas or liquid at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid, size and density (or their product, mass) of the particles. This type of diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules. The result of diffusion is a gradual mixing of material such that the distribution of molecules is uniform. Since the molecules are still in motion, but an equilibrium has been established, the result of molecular diffusion is called a "dynamic equilibrium". In a phase with uniform temperature, absent external net forces act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercomputer
A supercomputer is a type of computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second (FLOPS) instead of million instructions per second (MIPS). Since 2022, supercomputers have existed which can perform over 1018 FLOPS, so called Exascale computing, exascale supercomputers. For comparison, a desktop computer has performance in the range of hundreds of gigaFLOPS (1011) to tens of teraFLOPS (1013). Since November 2017, all of the TOP500, world's fastest 500 supercomputers run on Linux-based operating systems. Additional research is being conducted in the United States, the European Union, Taiwan, Japan, and China to build faster, more powerful and technologically superior exascale supercomputers. Supercomputers play an important role in the field of computational science, and are used for a wide range of computationally intensive tasks in various fields, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelial Cells
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of many internal organs, the corresponding inner surfaces of body cavities, and the inner surfaces of blood vessels. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either simple squamous, simple columnar, or simple cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. 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 non-coding genes. During gene expression (the synthesis of Gene product, RNA or protein from a gene), DNA is first transcription (biology), copied into RNA. RNA can be non-coding RNA, directly functional or be the intermediate protein biosynthesis, template for the synthesis of a protein. The transmission of genes to an organism's offspring, is the basis of the inheritance of phenotypic traits from one generation to the next. These genes make up different DNA sequences, together called a genotype, that is specific to every given individual, within the gene pool of the population (biology), population of a given species. The genotype, along with environmental and developmental factors, ultimately determines the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
