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Ryanodine
Ryanodine is a poisonous diterpenoid found in the South American plant ''Ryania speciosa'' (Salicaceae). It was originally used as an insecticide. The compound has extremely high affinity to the open-form ryanodine receptor, a group of calcium channels found in skeletal muscle, smooth muscle, and heart muscle cells. It binds with such high affinity to the receptor that it was used as a label for the first purification of that class of ion channels and gave its name to it. At nanomolar concentrations, ryanodine locks the receptor in a half-open state, whereas it fully closes them at micromolar concentration. The effect of the nanomolar-level binding is that ryanodine causes release of calcium from calcium stores as the sarcoplasmic reticulum in the cytoplasm, leading to massive muscle contractions. The effect of micromolar-level binding is paralysis. This is true for both mammals and insects. See also * Diamide insecticides, a class of insecticides with the same mechanism of ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryanodine Receptor
Ryanodine receptors (RyR) make up a class of high-conductance, intracellular calcium channels present in various forms, such as animal muscles and neurons. There are three major isoforms of the ryanodine receptor, which are found in different tissues and participate in various signaling pathways involving calcium release from intracellular organelles. Structure Ryanodine receptors are multidomain homotetramers which regulate intracellular calcium ion release from the sarcoplasmic and endoplasmic reticula. They are the largest known ion channels, with weights exceeding 2 megadaltons, and their structural complexity enables a wide variety of allosteric regulation mechanisms. RyR1 cryo-EM structure revealed a large cytosolic assembly built on an extended Alpha solenoid, α-solenoid scaffold connecting key regulatory domains to the pore. The RyR1 pore architecture shares the general structure of the six-transmembrane ion channel superfamily. A unique domain inserted between the secon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoplasmic Reticulum
The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+). Calcium ion levels are kept relatively constant, with the concentration of calcium ions within a cell being 10,000 times smaller than the concentration of calcium ions outside the cell. This means that small increases in calcium ions within the cell are easily detected and can bring about important cellular changes (the calcium is said to be a second messenger). Calcium is used to make calcium carbonate (found in chalk) and calcium phosphate, two compounds that the body uses to make teeth and bones. This means that too much calcium within the cells can lead to hardening (calcification) of certain intracellular structures, including the mitochondria, leading to cell death. Therefore, it is vital that calcium ion levels are controlled tightly, and can be released int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamide Insecticides
Diamide insecticides are a class of insecticides, active mainly against lepidoptera (caterpillars), which act on the insect ryanodine receptor. They are diamides of either phthalic acid or anthranilic acid, with various appropriate further substitutions. Worldwide sales of diamides in 2018 were estimated at , which is 13% of the $18.4 billion insecticide market. History and examples The first diamide was flubendiamide. It was invented by Nihon Nohyaku and commercialised in 2007. It is a highly substituted diamide of phthalic acid and is highly active against lepidoptera (caterpillers). Later DuPont introduced chlorantraniliprole, which is more active against caterpillers and in addition active against other insect types. Cyanthraniliprole, introduced later, shows systemic activity and is also active against sucking pests such as aphids and whitefly. According to one review, the first species reported to show resistance to diamides was the diamondback moth in 2012. The follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Contraction
Muscle contraction is the activation of Tension (physics), tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state. For the contractions to happen, the muscle cells must rely on the change in action of two types of Myofilament, filaments: thin and thick filaments. The major constituent of thin filaments is a chain formed by helical coiling of two strands of actin, and thick filaments dominantly consist of chains of the Motor protein, motor-protein myosin. Together, these two filaments form myofibrils - the basic functional organelles in the skeletal muscle system. In vertebrates, Muscle cell#Muscle contraction in striated muscle, skele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyridine Channel
Cav1.1 also known as the calcium channel, voltage-dependent, L type, alpha 1S subunit, (CACNA1S), is a protein which in humans is encoded by the ''CACNA1S'' gene. It is also known as CACNL1A3 and the dihydropyridine receptor (DHPR, so named due to the blocking action DHP has on it). Function This gene encodes one of the five subunits of the slowly inactivating L-type voltage-dependent calcium channel in skeletal muscle cells. Mutations in this gene have been associated with hypokalemic periodic paralysis, thyrotoxic periodic paralysis and malignant hyperthermia susceptibility. Cav1.1 is a voltage-dependent calcium channel found in the transverse tubule of muscles. In skeletal muscle it associates with the ryanodine receptor RyR1 of the sarcoplasmic reticulum via a mechanical linkage. It senses the voltage change caused by the end-plate potential from nervous stimulation and propagated by sodium channels as action potentials to the T-tubules. It was previously thought that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insecticide
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, industrial buildings, for vector control, and control of insect parasites of animals and humans. Acaricides, which kill mites and ticks, are not strictly insecticides, but are usually classified together with insecticides. Some insecticides (including common bug sprays) are effective against other non-insect arthropods as well, such as scorpions, spiders, etc. Insecticides are distinct from insect repellents, which repel but do not kill. Sales In 2016 insecticides were estimated to account for 18% of worldwide pesticide sales. Worldwide sales of insecticides in 2018 were estimated as $ 18.4 billion, of which 25% were neonicotinoids, 17% were pyrethroids, 13% were diamides, and the rest were many other classes which sold for less th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insecticides
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, industrial buildings, for vector control, and control of insect parasites of animals and humans. Acaricides, which kill mites and ticks, are not strictly insecticides, but are usually classified together with insecticides. Some insecticides (including common bug sprays) are effective against other non-insect arthropods as well, such as scorpions, spiders, etc. Insecticides are distinct from insect repellents, which repel but do not kill. Sales In 2016 insecticides were estimated to account for 18% of worldwide pesticide sales. Worldwide sales of insecticides in 2018 were estimated as $ 18.4 billion, of which 25% were neonicotinoids, 17% were pyrethroids, 13% were diamides, and the rest were many other classes which sold for less tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrroles
Pyrrole is a heterocyclic, Aromaticity, aromatic, organic compound, a five-membered Ring (chemistry), ring with the chemical formula, formula . It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., ''N''-methylpyrrole, . Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme. Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme, the chlorins, bacteriochlorins, and chlorophylls. Properties, structure, bonding Pyrrole is a colorless volatility (chemistry), volatile liquid that darkens readily upon exposure to air, and is usually purified by distillation immediately before use. Pyrrole has a nutty odor. Pyrrole is a 5-membered aromatic heterocycle, like furan and thiophene. Unlike furan and thiophene, it has a dipole in which the positive end lies on the side of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryania Speciosa
''Ryania speciosa'' is a species of plant family, plant in the family Salicaceae. The species is significant partly because the alkaloid ryanodine was originally extracted from this South American plant. It is used as a piscicide. Variety (botany), Varieties The Catalogue of Life lists these varieties: * Ryania speciosa var. bicolor, ''R. s.'' var. ''bicolor'' * Ryania speciosa var. chocensis, ''R. s.'' var. ''chocoensis'' * Ryania speciosa var. minor, ''R. s.'' var. ''minor'' * Ryania speciosa var. mutisii, ''R. s.'' var. ''mutisii'' (extinct) * Ryania speciosa var. panamensis, ''R. s.'' var. ''panamensis'' * Ryania speciosa var. stipularis, ''R. s.'' var. ''stipularis'' * Ryania speciosa var. subuliflora, ''R. s.'' var. ''subuliflora'' * Ryania speciosa var. tomentella, ''R. s.'' var. ''tomentella'' * Ryania speciosa var. tomentosa, ''R. s.'' var. ''tomentosa'' References M. Vahl, 1797 ''In: Eclog. Am. 1: 51, t. 9 (1796) [1797]'' External links * * {{Taxo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpene Alkaloids
Diterpene alkaloids are natural products of the terpene alkaloid type. Occurrence Veatchine is found in the bark of '' Garrya veatchii'', a member of the Cup Catkins family. Aconitine is the main alkaloid in aconite Aconite may refer to: *''Aconitum'', a plant genus containing the monkshoods *Aconitine Aconitine is an alkaloid toxin produced by various plant species belonging to the genus ''Aconitum'' (family Ranunculaceae), commonly known by the names wo ....{{citation, author= Rudolf Hänsel, Otto Sticher, date=2007, edition=8, isbn=9783540265085, location=Heidelberg, pages=1466, publisher=Springer Medizin Verlag, title=Pharmakognosie Phytopharmazie Structure Diterpene alkaloids can be divided into two groups: The diterpene alkaloids, characterized by a C20 parent body, and the norditerpene alkaloids, which are based on a hexacyclic C19 parent body. Representatives Diterpene group Among the C20 alkaloids is the atisine-type (atisine, hetidine, hetisine) and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentanes
Cyclopentane (also called C pentane) is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It is a colorless liquid with a petrol-like odor. Its freezing point is −94 °C and its boiling point is 49 °C. Cyclopentane is in the class of cycloalkanes, being alkanes that have one or more carbon rings. It is formed by cracking cyclohexane in the presence of alumina at a high temperature and pressure. It was first prepared in 1893 by the German chemist Johannes Wislicenus. Production, occurrence and use Cycloalkanes are formed by catalytic reforming. For example, when passed over a hot platinum surface, 2-methylbutane converts into cyclopentane. Cyclopentane is principally used as a blowing agent in the manufacture of polyurethane insulating foam, replacing ozone-depleting agents such as CFC-11 and HCFC-141b. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
