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Snake Venom
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom. The glands that secrete zootoxins are a modification of the parotid salivary glands found in other vertebrates and are usually located on each side of the head, below and behind the eye, and enclosed in a muscular sheath. The venom is stored in large glands called alveoli in which it's stored before being conveyed by a duct to the base of channeled or tubular fangs through which it's ejected. Venom contains more than 20 different compounds, which are mostly proteins and polypeptides. The complex mixture of proteins, enzymes, and various other substances has toxic and lethal properties. Venom serves to immobilize prey. Enzymes in venom play an important role in the digestion of prey, and various other substances ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vipera Berus - Venom Delivery Apparatus
''Vipera'' (; commonly known as the palaearctic vipersSpawls S, Branch B (1995). ''The Dangerous Snakes of Africa: Natural History, Species Directory, Venoms and Snakebite''. Sanibel Island, Florida: Ralph Curtis Books / Dubai: Oriental Press. 192 pp. . and Eurasian vipersMallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. ) is a genus of vipers. It has a very wide range, being found from North Africa to just within the Arctic Circle and from Great Britain to Pacific Asia. The Latin name ''vīpera'' is possibly derived from the Latin words ''vivus'' and ''pario'', meaning "alive" and "bear" or "bring forth"; likely a reference to the fact that most vipers bear live young.Gotch AF (1986). ''Reptiles – Their Latin Names Explained''. Poole, UK: Blandford Press. 176 pp. . Currently, 21 species are recognized. Like all other vipers, the members of this genus are venomous. De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elapid
Elapidae (, commonly known as elapids ; grc, ἔλλοψ ''éllops'' "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the white-lipped snake to the king cobra. Most species have neurotoxic venom which is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with some 360 species and over 170 subspecies. Description Terrestrial elapids look similar to the Colubridae; almost all have long, slender bodies with smooth scal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobratoxin
α-Cobratoxin is a substance of the venom of certain ''Naja'' cobras. It is a nicotinic acetylcholine receptor (nAChR) antagonist which causes paralysis by preventing the binding of acetylcholine to the nAChR. Sources α-Cobratoxin is a neurotoxin from the venom of certain ''Naja genus'', including the Thailand cobra, the Indo-Chinese spitting cobra (Naja siamensis) and the Chinese cobra (Naja atra). The cobras that produce the toxin live in tropical and subtropical regions of Africa and Asia. The venom, produced by these snakes, is a mixture of proteins, carbohydrates, and other substances. The venom is only used when the snake needs it for survival, because it costs a lot of effort to produce. If poisoning a subject is not necessary, it can bite without excreting the venom. When the snake does use it, it mostly tries to immobilize or kill its prey. Structure α-Cobratoxin forms three hairpin type loops with its polypeptide chain. The two minor loops are loop I (amino acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiotoxin
Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is the class of anthracyclines) treatment and/or radiotherapy; complications from anorexia nervosa; adverse effects of heavy metals intake; the long-term abuse of or ingestion at high doses of certain strong stimulants such as cocaine; or an incorrectly administered drug such as bupivacaine. One of the ways to detect cardiotoxicity at early stages when there is a subclinical dysfunction is by measuring changes in regional function of the heart using strains. See also * Cardiotoxin III * Batrachotoxin * Heart failure * Drug interaction Drug interactions occur when a drug's mechanism of action is disturbed by the concomitant administration of substances such as foods, beverages, or other drugs. The cause is often the inhibition of the sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytotoxin
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa''). Cell physiology Treating cells with the cytotoxic compound can result in a variety of cell fates. The cells may undergo necrosis, in which they lose membrane integrity and die rapidly as a result of cell lysis. The cells can stop actively growing and dividing (a decrease in cell viability), or the cells can activate a genetic program of controlled cell death (apoptosis). Cells undergoing necrosis typically exhibit rapid swelling, lose membrane integrity, shut down metabolism, and release their contents into the environment. Cells that undergo rapid necrosis in vitro do not have sufficient time or energy to activate apoptotic machinery and will not express apoptotic markers. Apoptosis is characterized by well defined cytological and molecular events including a cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelium
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells form the barrier between vessels and tissue and control the flow of substances and fluid into and out of a tissue. Endothelial cells in direct contact with blood are called vascular endothelial cells whereas those in direct contact with lymph are known as lymphatic endothelial cells. Vascular endothelial cells line the entire circulatory system, from the heart to the smallest capillaries. These cells have unique functions that include fluid filtration, such as in the glomerulus of the kidney, blood vessel tone, hemostasis, neutrophil recruitment, and hormone trafficking. Endothelium of the interior surfaces of the heart chambers is called endocardium. An impaired function can lead to serious health issues thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalloproteinases
A metalloproteinase, or metalloprotease, is any protease enzyme whose catalytic mechanism involves a metal. An example is ADAM12 which plays a significant role in the fusion of muscle cells during embryo development, in a process known as myogenesis. Most metalloproteases require zinc, but some use cobalt. The metal ion is coordinated to the protein via three ligands. The ligands coordinating the metal ion can vary with histidine, glutamate, aspartate, lysine, and arginine. The fourth coordination position is taken up by a labile water molecule. Treatment with chelating agents such as EDTA leads to complete inactivation. EDTA is a metal chelator that removes zinc, which is essential for activity. They are also inhibited by the chelator orthophenanthroline. Classification There are two subgroups of metalloproteinases: * Exopeptidases, metalloexopeptidases ( EC number: 3.4.17). * Endopeptidases, metalloendopeptidases (3.4.24). Well known metalloendopeptidases include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Proteases
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. Classification The MEROPS protease classification system counts 16 superfamilies (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. The majority belong to the S1 family of the PA clan (superfamily) of proteases. For superfamilies, P: superfamily, containing a mixture of nucleophile class families, S: purely serine proteases. superfamily. Within each superfamily, families are designated by their catalytic nucleophile, (S: serine proteases). Substrate specificity Serine pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kallikreins
Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins. In humans, plasma kallikrein (encoded by '' KLKB1 gene'') has no known paralogue, while tissue kallikrein-related peptidases (''KLKs'') encode a family of fifteen closely related serine proteases. These genes are localised to chromosome 19q13, forming the largest contiguous cluster of proteases within the human genome. Kallikreins are responsible for the coordination of various physiological functions including blood pressure, semen liquefaction and skin desquamation. Occurrence In 1934, Eugen Werle reported finding a substance in the pancreas of humans and various animals in such large amounts that the pancreas could be taken for its site of origin. He named it kallikrein, by derivation from the Greek word for pancreas. Since then, similar enzymes have been found in the biological fluids of humans and other mammals, as well as in some snake venoms. Venom The caterpillar know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombin
Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma-thrombin'') is a serine protease, an enzyme that, in humans, is encoded by the ''F2'' gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions. History After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872. Prothrombin was discovered by Pekelharing in 1894. Physiology Synthesis Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is great ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
