exotoxin


exotoxin
A specific, soluble, antigenic, usually heat labile, injurious substance elaborated by certain Gram-positive or Gram-negative bacteria; it is formed within the cell, but is released into the environment where it is rapidly active in extremely small amounts; most exotoxins are protein in nature (MW 70,000–900,000) and can have the toxic portion of the molecule destroyed by heat, prolonged storage, or chemicals; the nontoxic but antigenic form is a toxoid. SYN: ectotoxin, extracellular toxin.

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exo·tox·in .ek-sō-'täk-sən n a soluble poisonous substance produced during growth of a microorganism and released into the surrounding medium <tetanus \exotoxin> compare ENDOTOXIN
exo·tox·ic -'täk-sik adj

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n.
a highly potent poison, often harmful to only a limited range of tissues, that is produced by a bacterial cell and secreted into its surrounding medium. It is generally unstable, being rendered inactive by heat, light, and chemicals. Exotoxins are produced by such bacteria as those causing botulism, diphtheria, and tetanus. Compare endotoxin.

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exo·tox·in (ekґso-tok″sin) [exo- + toxin] a toxic substance that is formed by species of certain bacteria, such as Bacillus, Bordetella, Clostridium, Corynebacterium, Escherichia, Pseudomonas, Salmonella, Shigella, Staphylococcus, Streptococcus, Vibrio, and Yersinia, and is found either on the outside of the bacterial cell or free in the culture medium. Exotoxins are protein in nature and heat-labile; they are detoxified with retention of antigenicity by treatment with formaldehyde (formol toxoid), and are the most poisonous substances known to humans. The LD50 of crystalline botulinum type A toxin for the mouse is 4.5 Ч 10−9 mg.

Medical dictionary. 2011.

Look at other dictionaries:

  • Exotoxin A — Exotoxin A (Pseudomonas aeruginosa) Bändermodell nach PDB  …   Deutsch Wikipedia

  • exotoxin — exotoxin. См. экзотоксин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • exotoxin — [eks′ō täk΄sin] n. [ EXO + TOXIN] Bacteriology a protein toxin, as tetanus or diphtheria, secreted by bacteria …   English World dictionary

  • Exotoxin — An exotoxin is a soluble protein excreted by a microrganism, including bacteria, fungi, algae, and protozoa. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. Both gram negative and gram… …   Wikipedia

  • Exotoxin — egzotoksinas statusas T sritis ekologija ir aplinkotyra apibrėžtis Nuodingasis baltymas, kurį gamina ir išskiria į aplinką tam tikros bakterijos. atitikmenys: angl. exotoxin vok. Exotoxin, n rus. экзотоксин, m …   Ekologijos terminų aiškinamasis žodynas

  • exotoxin — egzotoksinas statusas T sritis ekologija ir aplinkotyra apibrėžtis Nuodingasis baltymas, kurį gamina ir išskiria į aplinką tam tikros bakterijos. atitikmenys: angl. exotoxin vok. Exotoxin, n rus. экзотоксин, m …   Ekologijos terminų aiškinamasis žodynas

  • Exotoxin — Ektotoxine (auch Exotoxine) sind von Bakterien abgesonderte Giftstoffe, gegen die der Wirtskörper Gegengifte (Antitoxine) bilden kann. Der Begriff leitet sich vom griechischen ekto = außen und toxin = Gift ab, das Gift „verlässt“ also das… …   Deutsch Wikipedia

  • exotoxin — egzotoksinas statusas T sritis chemija apibrėžtis Nuodingasis baltymas, kurį gamina ir išskiria į aplinką tam tikros bakterijos. atitikmenys: angl. exotoxin rus. экзотоксин …   Chemijos terminų aiškinamasis žodynas

  • exotoxin — noun Etymology: International Scientific Vocabulary Date: 1920 a soluble poisonous substance produced during growth of a microorganism and released into the surrounding medium …   New Collegiate Dictionary

  • exotoxin — (ek so tok sin) A heat labile, toxic protein produced by a bacterium as a result of its normal metabolism or because of the acquisition of a plasmid or prophage that redirects its metabolism. It is usually released into the bacterium s… …   Dictionary of microbiology


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