Phosphatidylserine
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Phosphatidylserine
Phosphatidylserine (abbreviated Ptd-L-Ser or PS) is a phospholipid and is a component of the cell membrane. It plays a key role in cell cycle signaling, specifically in relation to apoptosis. It is a key pathway for viruses to enter cells via apoptotic mimicry. Its exposure on the outer surface of a membrane marks the cell for destruction via apoptosis. Structure Phosphatidylserine is a phospholipid—more specifically a glycerophospholipid—which consists of two fatty acids attached in ester linkage to the first and second carbon of glycerol and serine attached through a phosphodiester linkage to the third carbon of the glycerol. Phosphatidylserine sourced from plants differs in fatty acid composition from that sourced from animals. It is commonly found in the inner (cytoplasmic) leaflet of biological membranes. It is almost entirely found in the inner monolayer of the membrane with only less than 10% of it in the outer monolayer. Introduction Phosphatidylserine (PS) is ...
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Phosphatidylethanolamine
Phosphatidylethanolamine (PE) is a class of phospholipids found in biological membranes. They are synthesized by the addition of cytidine diphosphate- ethanolamine to diglycerides, releasing cytidine monophosphate. ''S''-Adenosyl methionine can subsequently methylate the amine of phosphatidylethanolamines to yield phosphatidylcholines. Function In cells Phosphatidylethanolamines are found in all living cells, composing 25% of all phospholipids. In human physiology, they are found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord, where they make up 45% of all phospholipids. Phosphatidylethanolamines play a role in membrane fusion and in disassembly of the contractile ring during cytokinesis in cell division. Additionally, it is thought that phosphatidylethanolamine regulates membrane curvature. Phosphatidylethanolamine is an important precursor, substrate, or donor in several biological pathways. As a polar head gr ...
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CDP-diacylglycerol—serine O-phosphatidyltransferase
In enzymology, a CDP-diacylglycerol—serine O-phosphatidyltransferase () is an enzyme that catalyzes the chemical reaction :CDP-diacylglycerol + L-serine \rightleftharpoons CMP + (3-sn-phosphatidyl)-L-serine Thus, the two substrates of this enzyme are CDP-diacylglycerol and L-serine, whereas its two products are CMP and (3-sn-phosphatidyl)-L-serine. This enzyme belongs to the family of transferases, specifically those transferring non-standard substituted phosphate groups. The systematic name of this enzyme class is CDP-diacylglycerol:L-serine 3-sn-phosphatidyltransferase. Other names in common use include phosphatidylserine synthase, CDPdiglyceride-serine O-phosphatidyltransferase, PS synthase, cytidine 5'-diphospho-1,2-diacyl-sn-glycerol, (CDPdiglyceride):L-serine O-phosphatidyltransferase, phosphatidylserine synthetase, CDP-diacylglycerol-L-serine O-phosphatidyltransferase, cytidine diphosphoglyceride-serine O-phosphatidyltransferase, CDP-diglyceride-L-serine phosphatidyl ...
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Apoptosis
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes ( morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA fragmentation, and mRNA decay. The average adult human loses between 50 and 70 billion cells each day due to apoptosis. For an average human child between eight and fourteen years old, approximately twenty to thirty billion cells die per day. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo occurs because cells between the digits undergo apoptosis. Unlike necrosis, apoptosis produces cell fragments called apop ...
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Glycerophospholipid
Glycerophospholipids or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes. Two major classes are known: those for bacteria and eukaryotes and a separate family for archaea. Structures The term glycerophospholipid signifies any derivative of glycerophosphoric acid that contains at least one ''O''- acyl, or ''O''-alkyl, or ''O''-alk-1'-enyl residue attached to the glycerol moiety. The phosphate group forms an ester linkage to the glycerol. The long-chained hydrocarbons are typically attached through ester linkages in bacteria/eucaryotes and by ether linkages in archaea. In bacteria and procaryotes, the lipids consist of diesters commonly of C16 or C18 fatty acids. These acids are straight-chained and, especially for the C18 members, can be unsaturated. For archaea, the hydrocarbon chains have chain lengths of C10, C15, C20 etc. since they are derived from isoprene units. These chains are branched, with one methyl substit ...
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Molecular Mimicry
Molecular mimicry is defined as the theoretical possibility that sequence similarities between foreign and self-peptides are sufficient to result in the cross-activation of autoreactive T or B cells by pathogen-derived peptides. Despite the prevalence of several peptide sequences which can be both foreign and self in nature, a single antibody or TCR (T cell receptor) can be activated by just a few crucial residues which stresses the importance of structural homology in the theory of molecular mimicry. Upon the activation of B or T cells, it is believed that these "peptide mimic" specific T or B cells can cross-react with self-epitopes, thus leading to tissue pathology (autoimmunity). Molecular mimicry is a phenomenon that has been just recently discovered as one of several ways in which autoimmunity can be evoked. A molecular mimicking event is, however, more than an epiphenomenon despite its low statistical probability of occurring and these events have serious implications in th ...
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Common Bean
''Phaseolus vulgaris'', the common bean, is a herbaceous annual plant grown worldwide for its edible dry seeds or green, unripe pods. Its leaf is also occasionally used as a vegetable and the straw as fodder. Its botanical classification, along with other ''Phaseolus'' species, is as a member of the legume family Fabaceae. Like most members of this family, common beans acquire the nitrogen they require through an association with rhizobia, which are nitrogen-fixing bacteria. The common bean has a long history of cultivation. All wild members of the species have a climbing habit, but many cultivars are classified either as ''bush beans'' or ''climbing beans'', depending on their style of growth. Best-known cultivar groups include the kidney bean, the navy bean, the pinto bean, and the wax bean. The other major types of commercially grown beans are the runner bean ('' Phaseolus coccineus'') and the broad bean ('' Vicia faba''). Beans are grown on every continent except Antarct ...
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Choline
Choline is an essential nutrient for humans and many other animals. Choline occurs as a cation that forms various salts (X− in the depicted formula is an undefined counteranion). Humans are capable of some ''de novo synthesis'' of choline but require additional choline in the diet to maintain health. Dietary requirements can be met by choline per se or in the form of choline phospholipids, such as phosphatidylcholine. Choline is not formally classified as a vitamin despite being an essential nutrient with an amino acid–like structure and metabolism. In most animals, choline phospholipids are necessary components in cell membranes, in the membranes of cell organelles, and in very low-density lipoproteins. Choline is required to produce acetylcholine – a neurotransmitter – and ''S''-adenosylmethionine (SAM), a universal methyl donor. Upon methylation SAM is transformed into homocysteine. Symptomatic choline deficiency causes non-alcoholic fatty liver disease and muscl ...
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Soft-shell Clam
Soft-shell clams (American English) or sand gaper (British English/Europe), scientific name ''Mya arenaria'', popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams" are a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae. Habitat and distribution These clams live buried in the sediment on tidal flats. While they are common in muddy areas, their name "arenaria" means sandy and they prefer a combination of sandy and muddy areas. They are well known as a food item on the coast of New England in the Western Atlantic Ocean; however, the range extends much farther north to Canada and south to the Southern states. They are also found in the Eastern Atlantic Ocean, for example in the UK, as well as in the North Sea's Wadden Sea (where they are the dominant large clam). This species has become invasive on the Pacific Coast of North America, including Alaska, Canada and the continental United States. However ''M. aren ...
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Mullet (fish)
The mullets or grey mullets are a family (Mugilidae) of ray-finned fish found worldwide in coastal temperate and tropical waters, and some species in fresh water. Mullets have served as an important source of food in Mediterranean Europe since Roman times. The family includes about 78 species in 20 genera. Mullets are distinguished by the presence of two separate dorsal fins, small triangular mouths, and the absence of a lateral line organ. They feed on detritus, and most species have unusually muscular stomachs and a complex pharynx to help in digestion. Classification and naming Taxonomically, the family is currently treated as the sole member of the order Mugiliformes, but as Nelson says, "there has been much disagreement concerning the relationships" of this family. The presence of fin spines clearly indicates membership in the superorder Acanthopterygii, and in the 1960s, they were classed as primitive perciforms, while others have grouped them in Atheriniformes. They ...
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Veal
Veal is the meat of calves, in contrast to the beef from older cattle. Veal can be produced from a calf of either sex and any breed, however most veal comes from young male calves of dairy breeds which are not used for breeding. Generally, veal is more expensive by weight than beef from older cattle. Veal production is a way to add value to dairy bull calves and to utilize whey solids, a byproduct from the manufacturing of cheese. Definitions and types There are several types of veal, and terminology varies by country. Similar terms are used in the US, including calf, bob, intermediate, milk-fed, and special-fed. Culinary uses In Italian, French and other Mediterranean cuisines, veal is often in the form of cutlets, such as the Italian '' cotoletta'' or the famous Austrian dish Wiener Schnitzel. Some classic French veal dishes include fried '' escalopes'', fried veal ''Grenadines'' (small, thick fillet steaks), stuffed '' paupiettes'', roast joints, and ...
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Phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science. The first phospholipid identified in 1847 as such in biological tissues wa ...
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Beef
Beef is the culinary name for meat from cattle (''Bos taurus''). In prehistoric times, humankind hunted aurochs and later domesticated them. Since that time, numerous breeds of cattle have been bred specifically for the quality or quantity of their meat. Today, beef is the third most widely consumed meat in the world, after pork and poultry. As of 2018, the United States, Brazil, and China were the largest producers of beef. Beef can be prepared in various ways; cuts are often used for steak, which can be cooked to varying degrees of doneness, while trimmings are often ground or minced, as found in most hamburgers. Beef contains protein, iron, and vitamin B12. Along with other kinds of red meat, high consumption is associated with an increased risk of colorectal cancer and coronary heart disease, especially when processed. Beef has a high environmental impact, being a primary driver of deforestation with the highest greenhouse gas emissions of any agricultural product ...
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