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Avermectin
The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by ''Streptomyces avermitilis'', a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin, and abamectin. Half of the 2015 Nobel Prize in Physiology or Medicine was awarded to William C. Campbell and Satoshi Ōmura for discovering avermectin, "the derivatives of which have radically lowered the incidence of river blindness and lymphatic filariasis, as well as showing efficacy against an expanding number of other parasitic diseases." History I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abamectin
Abamectin is a widely used insecticide and anthelmintic. Abamectin, is a member of the Avermectin family and is a natural fermentation product of soil dwelling actinomycete ''Streptomyces avermitilis''. Abamectin (also called Avermectin B1), differs from Ivermectin, the popular member of the Avermectin family, by double bond on C-22-25. Fermentation of ''Streptomyces avermitilis'' yields 8 closely related Avermectin homologues out of which B1 (a and b) forms the bulk of the fermentation. The non proprietary name, abamectin, is a combination of Bla (~ 80%) and B1b (~ 20%). Out of all the Avermectins, abamectin is the only one that is used both in agriculture and pharmaceuticals. Mode of Action Avermectins bind to the glutamate-gated chloride channels that are found in invertebrate nerve and muscle cells. They cause hyperpolarization of these cells resulting in paralysis and death. Mammals only possess glutamate-gated chloride channels in the brain and spinal cord and as the Avermec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avermectin Skeletal
The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by ''Streptomyces avermitilis'', a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin, and abamectin. Half of the 2015 Nobel Prize in Physiology or Medicine was awarded to William C. Campbell and Satoshi Ōmura for discovering avermectin, "the derivatives of which have radically lowered the incidence of river blindness and lymphatic filariasis, as well as showing efficacy against an expanding number of other parasitic diseases." History I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivermectin
Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat infestations including head lice, scabies, river blindness (onchocerciasis), strongyloidiasis, trichuriasis, ascariasis and lymphatic filariasis. It works through many mechanisms to kill the targeted parasites, and can be taken orally, or applied to the skin for external infestations. It belongs to the avermectin family of medications. William Campbell and Satoshi Ōmura won the 2015 Nobel Prize in Physiology or Medicine for its discovery and applications. It is on the World Health Organization's List of Essential Medicines, and is approved by the U.S. Food and Drug Administration as an antiparasitic agent. In 2018, it was the 420th most commonly prescribed medication in the United States, with more than 100,000 prescriptions. It is availab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces Avermitilis
''Streptomyces avermitilis'' is a species of bacteria in the genus ''Streptomyces''. This bacterium was discovered by Satoshi Ōmura in Shizuoka Prefecture, Japan. The first complete genome sequence of ''S. avermitilis'' was completed in 2003. The genome consists of a single chromosome with a linear structure, unlike most bacterial genomes, which exist in the form of circular chromosomes. Avermectins are industrially produced from ''S. avermitilis''. Avermectin itself was discovered by the Satoshi Ōmura group and first disclosed in Burg ''et al.'' 1979. One of the most widely employed drugs against nematode and arthropod infestations is the avermectin derivative ivermectin, as well as abamectin, a widely used insecticide and antihelmintic. See also * List of Streptomyces species, List of ''Streptomyces'' species References External links *Type strain of ''Streptomyces avermitilis'' at Bac''Dive'' - the Bacterial Diversity Metadatabase Streptomyces, avermitilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onchocerciasis
Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm ''Onchocerca volvulus''. Symptoms include severe itching, bumps under the skin, and blindness. It is the second-most common cause of blindness due to infection, after trachoma. The parasite worm is spread by the bites of a black fly of the ''Simulium'' type. Usually, many bites are required before infection occurs. These flies live near rivers, hence the common name of the disease. Once inside a person, the worms create larvae that make their way out to the skin, where they can infect the next black fly that bites the person. There are a number of ways to make the diagnosis, including: placing a biopsy of the skin in normal saline and watching for the larva to come out; looking in the eye for larvae; and looking within the bumps under the skin for adult worms. A vaccine against the disease does not exist. Prevention is by avoiding being bitten by flies. This may include the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satoshi Ōmura
is a Japanese biochemist. He is known for the discovery and development of hundreds of pharmaceuticals originally occurring in microorganisms. In 2015, he was awarded the Nobel Prize in Physiology or Medicine jointly with William C. Campbell for their role in the discovery of avermectins and ivermectin, the world's first endectocide and a safe and highly effective microfilaricide. It is believed that the large molecular size of ivermectin prevents it from crossing the blood/aqueous humour barrier, and renders the drug an important treatment of helminthically-derived blindness. Early life and education Satoshi Ōmura was born in Nirasaki, Yamanashi Japan in 1935, the second son of Ōmura family. After graduating from the University of Yamanashi in 1958, he was appointed to science teacher at Tokyo Metropolitan Sumida Tech High School. In 1960, he became an auditor of Koji Nakanishi’s course at Tokyo University of Education, one year later, he enrolled in the Tokyo Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthelmintic
Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host. They may also be called vermifuges (those that stun) or vermicides (those that kill). Anthelmintics are used to treat people who are infected by helminths, a condition called helminthiasis. These drugs are also used to treat infected animals. Pills containing anthelmintics are used in mass deworming campaigns of school-aged children in many developing countries. The drugs of choice for soil-transmitted helminths are mebendazole and albendazole; for schistosomiasis and tapeworms it is praziquantel. Types Antiparasitics that specifically target worms of the genus ''Ascaris'' are called ascaricides. * Benzimidazoles: ** Albendazole – effective against threadworms, roundworms, whipworms, tapeworms, hookworms ** Mebendazole – effective against v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insecticide
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain. Insecticides can be classified into two major groups: systemic insecticides, which have residual or long term activity; and contact insecticides, which have no residual activity. The mode of action describes how the pesticide kills or inactivates a pest. It provides another way of classifying insecticides. Mode of action can be important in understanding whether an insecticide will be toxic to unrelated species, such as fish, birds and mammals. Insecticides may be repellent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostome
Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's members, although the reverse is typically true of its sister clade, Deuterostomia. Well known examples of protostomes are arthropods, molluscs, annelids, flatworms and nematodes. They are also called schizocoelomates since schizocoely typically occurs in them. Together with the Deuterostomia and Xenacoelomorpha, these form the clade Bilateria, animals with bilateral symmetry, anteroposterior axis and three germ layers. Protostomy In animals at least as complex as earthworms, the first phase in gut development involves the embryo forming a dent on one side (the blastopore) which deepens to become its digestive tube (the archenteron). In the sister-clade, the deuterostomes (), the original dent becomes the anus while the gut eventually tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamate-gated Chloride Channel
Chloride channels are a superfamily of poorly understood ion channels specific for chloride. These channels may conduct many different ions, but are named for chloride because its concentration ''in vivo'' is much higher than other anions. Several families of voltage-gated channels and ligand-gated channels (e.g., the CaCC families) have been characterized in humans. Voltage-gated chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell proliferation and differentiation. Based on sequence homology the chloride channels can be subdivided into a number of groups. General functions Voltage-gated chloride channels are important for setting cell resting membrane potential and maintaining proper cell volume. These channels conduct or other anions such as . The structure of these channels are not like other known channels. The chloride channel subunits contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABA-ergic neurons. Its molecular formula is . Glutamic acid exists in three optically isomeric forms; the dextrorotatory -form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971. Its molecular structure could be idealized as HOOC−CH()−()2−COOH, with two carboxyl groups −COOH and one amino group −. However, in the solid state and mildly acidic water solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyene
In organic chemistry, polyenes are poly- unsaturated, organic compounds that contain at least three alternating double () and single () carbon–carbon bonds. These carbon–carbon double bonds interact in a process known as conjugation, resulting in some unusual optical properties. Related to polyenes are dienes, where there are only two alternating double and single bonds. The following polyenes are used as antibiotics for humans: amphotericin B, nystatin, candicidin, pimaricin, methyl partricin, and trichomycin. Optical properties Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon. Normally alkenes absorb in the ultraviolet region of a spectrum, but the absorption energy state of polyenes with numerous conjugated double bonds can be lowered such that they enter the visible region of the spectrum, resulting in compounds which are coloured (because they contain a chromophore). Thus many natural dyes contain linear polyenes. Chemical and electri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
