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Allopumiliotoxin
Allopumiliotoxins are a structural division in the pumiliotoxin-A class of alkaloids. The compounds of the pumiliotoxin-A class are primarily found in the skins of frogs, toads, and other amphibians and are used as a chemical defense mechanism to ward off predators, microorganisms, and ectoparasites. The compounds were originally discovered in neotropical dendrobatid frogs, but are also found in the mantellid frogs of Madagascar, myobatrachid frogs of Australia, and bufonid toad of South America. Frogs possessing this defense mechanism have aposematic coloring.Jain, P.; Garraffo, H. M.; Spande, T. F.; Yeh, H. J. C.; Daly, J. W. J. Nat. Prod. 1995, 58, 100-104. Biological activity The poison-dart frog family Dendrobatidae has yielded many different alkaloids categorized into several different classes, almost all of which have shown high pharmacological activity on muscle and nerve cells.Aoyagi, S.; Wang, T. C.; Kibayashi, C. J. Am. Chem. Soc. 1993, 115, 11393-11409. The pumili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allopumiliotoxin 267A
Allopumiliotoxin 267A is a toxin found in the skin of several poison frogs of the family ''Dendrobates''. It is a member of the class of compounds known as allopumiliotoxins. The frogs produce the toxin by modifying the original version, pumiliotoxin 251D. It has been tested on mice and found to be five times more potent than the former version. It has been produced synthetically through a variety of different routes. See also * Pumiliotoxin * Allopumiliotoxin Allopumiliotoxins are a structural division in the pumiliotoxin-A class of alkaloids. The compounds of the pumiliotoxin-A class are primarily found in the skins of frogs, toads, and other amphibians and are used as a chemical defense mechanism to ... References {{Poison frog alkaloids Vertebrate toxins Alkaloids Ion channel toxins Vicinal diols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumiliotoxin
Pumiliotoxins (PTXs), are one of several toxins found in the skin of poison dart frogs. The frog species, P. bibronii also produces PTXs to deter predators. Closely related, though more toxic, are allopumiliotoxins, (aPTXs). Other toxins found in the skin of poison frogs include decahydroquinolines (DHQs), izidines, coccinellines, and spiropyrrolizidine alkaloids. Pumiliotoxins are very poisonous in high concentrations. Pumiliotoxins are much weaker than batrachotoxins, ranging between 100 and 1000 times less poisonous. There are three different types of this toxin: A, B and C, of which toxins A and B are more toxic than C. Pumiliotoxins interfere with muscle contraction by affecting calcium channels, causing partial paralysis, difficulty moving, hyperactivity, or death. The median lethal dose of pumiliotoxins A and B is 50 µg / mouse, 20 µg / mouse respectively, while the amount of pumiliotoxin is 200 µg / frog.http://wiredspace.wits.ac.za/bitstream/handle/1053 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumiliotoxin
Pumiliotoxins (PTXs), are one of several toxins found in the skin of poison dart frogs. The frog species, P. bibronii also produces PTXs to deter predators. Closely related, though more toxic, are allopumiliotoxins, (aPTXs). Other toxins found in the skin of poison frogs include decahydroquinolines (DHQs), izidines, coccinellines, and spiropyrrolizidine alkaloids. Pumiliotoxins are very poisonous in high concentrations. Pumiliotoxins are much weaker than batrachotoxins, ranging between 100 and 1000 times less poisonous. There are three different types of this toxin: A, B and C, of which toxins A and B are more toxic than C. Pumiliotoxins interfere with muscle contraction by affecting calcium channels, causing partial paralysis, difficulty moving, hyperactivity, or death. The median lethal dose of pumiliotoxins A and B is 50 µg / mouse, 20 µg / mouse respectively, while the amount of pumiliotoxin is 200 µg / frog.http://wiredspace.wits.ac.za/bitstream/handle/1053 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indolizidine
Indolizidine is a heterocyclic chemical compound that forms the central core of the indolizidine alkaloids such as swainsonine and castanospermine. See also * Indole * Indolizine * Tryptophan * Tryptamine Tryptamine is an indolamine metabolite of the essential amino acid, tryptophan. The chemical structure is defined by an indole ─ a fused benzene and pyrrole ring, and a 2-aminoethyl group at the second carbon (third aromatic atom, with the f ... References Indolizidines {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chirality (chemistry)
In chemistry, a molecule or ion is called chiral () if it cannot be superposed on its mirror image by any combination of rotation (geometry), rotations, translation (geometry), translations, and some Conformational isomerism, conformational changes. This geometric property is called chirality (). The terms are derived from Ancient Greek χείρ (''cheir'') 'hand'; which is the canonical example of an object with this property. A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right-handed" or "left-handed" by their absolute configuration or some other criterion. The two enantiomers have the same chemical properties, except when reacting with other chiral compounds. They also have the same physics, physical properties, except that they often have opposite optical activity, optical activities. A homogeneous mixture of the two enantiomers in equal parts is said to be racemic mixtu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wittig
Wittig is a surname, and may refer to: * Burghardt Wittig (born 1947), German biochemist * Curt Wittig, American chemist * David Wittig (born 1955), American executive * Edward Wittig (1879–1941), Polish sculptor * Ferdinand Wittig (1851-1909), American politician * Georg Wittig (1897–1987), German chemist * Iris Wittig (1928-1978), German military pilot * Johnnie Wittig (1914–1999), former Major League pitcher * Martin C. Wittig (born 1964), German CEO * Michael Wittig (born 1976), American musician * Monique Wittig (1935–2003), French author and feminist theorist * Peter Wittig (born 1954), German diplomat * Rüdiger Wittig (born 1946), German professor of geobotany and ecology * Sigmar Wittig (born 1940), German Chair of the European Space Agency * Susan Wittig Albert (born 1940), American mystery writer See also * Wittich * Wittig River * 1,2-Wittig rearrangement * 2,3-Wittig rearrangement * Wittig reaction The Wittig reaction or Wittig olefination is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereochemistry
Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on the relationships between stereoisomers, which by definition have the same molecular formula and sequence of bonded atoms (constitution), but differ in structural formula (the three-dimensional orientations of their atoms in space). For this reason, it is also known as 3D chemistry—the prefix "stereo-" means "three-dimensionality". Stereochemistry spans the entire spectrum of organic, inorganic, biological, physical and especially supramolecular chemistry. Stereochemistry includes methods for determining and describing these relationships; the effect on the physical or biological properties these relationships impart upon the molecules in question, and the manner in which these relationships influence the reactivity of the molecules in question ( dynamic stereochemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaloids
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.Chemical Encyclopedia: alkaloids xumuk.ru Alkaloids are produced by a large variety of organisms including , , |
Dendrobates Auratus
The green-and-black poison dart frog (''Dendrobates auratus''), also known as the green-and-black poison arrow frog and green poison frog (among others), is a brightly colored member of the order Anura native to Central America and northwestern parts of South America. This species has also been introduced to Hawaii. It is one of the most variable of all poison dart frogs next to ''Dendrobates tinctorius'' and some ''Oophaga'' spp. It is considered to be of least concern from a conservation standpoint by the International Union for Conservation of Nature. Description The green-and-black poison dart frog has the typical appearance of the members of its family. Males average , while females are slightly larger, averaging an inch or longer. The green-and-black poison frog typically has mint-green coloration; however, this pigment can also be forest, lime, emerald green, turquoise, or even cobalt blue or pale yellow. Mixed with this typically green are splotches of dark color, ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrobates
''Dendrobates'' is a genus of poison dart frogs native to Central and South America. It once contained numerous species, but most originally placed in this genus have been split off into other genera such as ''Adelphobates'', '' Ameerega'', '' Andinobates'', ''Epipedobates'', '' Excidobates'', ''Oophaga'', ''Phyllobates ''Phyllobates'' is a genus of poison dart frogs native to Central and South America, from Nicaragua to Colombia. There are 3 different Colombian species of ''Phyllobates'', considered highly toxic species due to the poison they contain in the w ...'' and ''Ranitomeya'' (essentially all the brightly marked poison dart frogs; i.e. excluding the duller genera in the family like ''Colostethus'' and ''Hyloxalus''), leaving only five large to medium-sized species in the genus ''Dendrobates''. All the other genera used to be grouped in with ''Dendrobates'' because it was previously thought that all brightly colored poison dart frogs came from the same ancestor but t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trituration
Trituration (Latin, ''grinding'') is the name of several different methods used to process materials. In one sense, it is a form of comminution (reducing the particle size of a substance). In another sense, it is the production of a homogeneous powdered material by mixing and grinding component materials thoroughly. For example, a dental amalgam is formed by combining particles of a metal, usually gold or silver, with mercury. *In organic chemistry, trituration is a process used to purify crude chemical compounds containing soluble impurities. A solvent is chosen in which the desired product is insoluble and the undesired by-products are very soluble or vice versa. For example, when the impurities are soluble and the desired product is not, the crude material is washed with the solvent and filtered, leaving the purified product in solid form and any impurities in solution. If mixed solvents are used, target compound and impurities are first dissolved in small amount of solvent, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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