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Leiurus Hebraeus
''Leiurus hebraeus'', the Hebrew deathstalker, is a species of scorpion, a member of the family Buthidae. It is also known as the Palestinian yellow scorpion, It was once considered as a subspecies of '' Leiurus quinquestriatus'' but recently it was elevated to the rank of a species. It is currently known from Israel, but it may live in other countries in the Middle East. Other species of the genus ''Leiurus'' are also often referred to as "deathstalkers". Description ''Leiurus hebraeus'' is yellow, and long, with an average of . Geographic range ''Leiurus hebraeus'' can be found in desert and scrubland habitats in the Middle East. Its range covers Israel and its neighboring countries. Since it was declared as a species only recently, further research is needed to determine its range. Venom Neurotoxins in ''L. quinquestriatus'' venom include: * Chlorotoxin * Charybdotoxin * Scyllatoxin * Agitoxins types one, two and three Hazards The deathstalker is one of the most dangerou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charybdotoxin
Charybdotoxin (CTX) is a 37 amino acid neurotoxin from the venom of the scorpion '' Leiurus quinquestriatus hebraeus'' (''deathstalker'') that blocks calcium-activated potassium channels. This blockade causes hyperexcitability of the nervous system. It is a close homologue of agitoxin and both toxins come from ''Leiurus quinquestriatus hebraeus''. It is named after Charybdis, a sea monster from Greek myth. Chemical properties Family The Charybdotoxin family of scorpion toxins is a group of small peptides that has many family members, such as the pandinotoxin, derived from the venom of scorpion Pandinus imperator. Structure Scorpions such as the deathstalker paralyze their prey by injecting a potent mix of peptide toxins. Charybdotoxin, a 37 amino acid, 4 kDa neurotoxin with the molecular formula C176H277N57O55S7, is one of the peptide toxins that can be extracted from the venom of the scorpion. Its structure is very similar to that of margatoxin. Charybdotoxin contains three d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scorpion
Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always ending with a stinger. The evolutionary history of scorpions goes back 435 million years. They mainly live in deserts but have adapted to a wide range of environmental conditions, and can be found on all continents except Antarctica. There are over 2,500 described species, with 22 extant (living) families recognized to date. Their taxonomy is being revised to account for 21st-century genomic studies. Scorpions primarily prey on insects and other invertebrates, but some species hunt vertebrates. They use their pincers to restrain and kill prey, or to prevent their own predation. The venomous sting is used for offense and defense. During courtship, the male and female grasp each other's pincers and dance while he tries to move her onto his s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorotoxin
Chlorotoxin is a 36-amino acid peptide found in the venom of the deathstalker scorpion (''Leiurus quinquestriatus'') which blocks small-conductance chloride channels. The fact that chlorotoxin binds preferentially to glioma cells has allowed the development of methods for the treatment and diagnosis of several types of cancer. Sources Chlorotoxin can be purified from crude leiurus, which belongs to the scorpion toxin protein superfamily. Chemistry Chlorotoxin is a small toxin and at pH 7 is highly positively charged. It is a peptide consisting of 36 amino acids, with 8 cysteines forming 4 disulfide bonds. Chlorotoxin has a considerable sequence homology to the class of small insectotoxins. Target Chlorotoxin is the first reported high-affinity peptide ligand for Cl− channels and it blocks small conductance chloride channels. Each chloride channel can be closed by only one ligand molecule. Using a recombinant chlorotoxin it was demonstrated that chlorotoxin specifical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sahara
, photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , country2 = , country3 = , country4 = , country5 = , country6 = , country7 = , country8 = , country9 = , country10 = ( disputed) , region = , state = , district = , city = , relief = , label = , label_position = , coordinates = , coordinates_ref = , elevation = , elevation_m = , elevation_ft = , elevation_ref = , length = , length_mi = , length_km = 4,800 , length_orientation = , length_note = , width = , width_mi = , width ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Hemprich
Wilhelm Friedrich Hemprich (24 June 1796 – 30 June 1825) was a German naturalist and explorer. Hemprich was born in Glatz (Kłodzko), Prussian Silesia, and studied medicine at Breslau and Berlin. It was in Berlin that he became friends with Christian Gottfried Ehrenberg, the two men sharing an interest in natural history. Hemprich lectured at Berlin University on comparative physiology, and wrote ''Grundriss der Naturgeschichte'' (Compendium of Natural History) (1820). In his spare time he studied reptiles and amphibians at the zoological museum under Hinrich Lichtenstein. In 1820 Hemprich and Ehrenberg were invited to serve as naturalists on a primarily archeological expedition to Egypt, led by Prussian General von Minutoli. The two naturalists were sponsored by the Berlin Academy. In March 1821 they separated from the main party and travelled up the river Nile to Dongola, the capital of Nubia. They spent the next two years studying the natural history of that part of Egy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbekistan to the south, and Turkmenistan to the southwest, with a coastline along the Caspian Sea. Its capital is Astana, known as Nur-Sultan from 2019 to 2022. Almaty, Kazakhstan's largest city, was the country's capital until 1997. Kazakhstan is the world's largest landlocked country, the largest and northernmost Muslim-majority country by land area, and the ninth-largest country in the world. It has a population of 19 million people, and one of the lowest population densities in the world, at fewer than 6 people per square kilometre (15 people per square mile). The country dominates Central Asia economically and politically, generating 60 percent of the region's GDP, primarily through its oil and gas industry; it also has vast mineral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L Quinquestriatus2
L, or l, is the twelfth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''el'' (pronounced ), plural ''els''. History Lamedh may have come from a pictogram of an ox goad or cattle prod. Some have suggested a shepherd's staff. Use in writing systems Phonetic and phonemic transcription In phonetic and phonemic transcription, the International Phonetic Alphabet uses to represent the lateral alveolar approximant. English In English orthography, usually represents the phoneme , which can have several sound values, depending on the speaker's accent, and whether it occurs before or after a vowel. The alveolar lateral approximant (the sound represented in IPA by lowercase ) occurs before a vowel, as in ''lip'' or ''blend'', while the velarized alveolar lateral approximant (IPA ) occurs in ''bell'' and ''milk''. This velarization does not occur in many European langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scyllatoxin
Scyllatoxin (also leiurotoxin I) is a toxin, from the scorpion '' Leiurus quinquestriatus hebraeus'', which blocks small-conductance Ca2+-activated K+ channels. It is named after Scylla, a sea monster from Greek mythology. Charybdotoxin is also found in the venom from the same species of scorpion, and is named after the sea monster Charybdis. In Greek mythology, Scylla and Charybdis lived on rocks on opposing sides of a narrow strait of water. Sources Scyllatoxin is one of the components of the venom of the Israeli scorpion ''‘Leiurus quinquestriatus hebraeus’''. It consists of only 0.02% of the total protein in crude venom. Chemistry Leiurotoxin I is a 31-residue peptide (sequence AFCNLRMCQLSCRSLGLLGKCIGDKCECVKH-NH2), with a helix and a short antiparallel β-sheet. This toxin is stabilized by disulfide bonds: Cys8-Cys26 and Cys12-Cys28 is bound to the β-sheet, while Cys3-Cys21 is bound to an N-terminal segment preceding the helix. Leiurotoxin adopts the ά/β motif. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium-activated Potassium Channel
Calcium-activated potassium channels are potassium channels gated by calcium, or that are structurally or phylogenetically related to calcium gated channels. They were first discovered in 1958 by Gardos who saw that calcium levels inside of a cell could affect the permeability of potassium through that cell membrane. Then in 1970, Meech was the first to observe that intracellular calcium could trigger potassium currents. In humans they are divided into three subtypes: BK channel, large conductance or BK channels, which have very high conductance which range from 100 to 300 pS, intermediate conductance or IK channels, with intermediate conductance ranging from 25 to 100 pS, and small conductance or SK channels with small conductances from 2-25 pS. This family of ion channels is, for the most part, activated by intracellular Ca2+ and contains 8 members in the human genome. However, some of these channels (the KCa4 and KCa5 channels) are responsive instead to other intracellular ligan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia Minor
Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The region is bounded by the Turkish Straits to the northwest, the Black Sea to the north, the Armenian Highlands to the east, the Mediterranean Sea to the south, and the Aegean Sea to the west. The Sea of Marmara forms a connection between the Black and Aegean seas through the Bosporus and Dardanelles straits and separates Anatolia from Thrace on the Balkan peninsula of Southeast Europe. The eastern border of Anatolia has been held to be a line between the Gulf of Alexandretta and the Black Sea, bounded by the Armenian Highlands to the east and Mesopotamia to the southeast. By this definition Anatolia comprises approximately the western two-thirds of the Asian part of Turkey. Today, Anatolia is sometimes considered to be synonymous with Asia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
