Biology:Toxin

From HandWiki
Short description: Naturally occurring organic poison
The Amanita muscaria mushroom, an iconic toxic mushroom.

A toxin is a naturally occurring organic[dubious ] poison[1] produced by metabolic activities of living cells or organisms.[2] They occur especially as proteins, often conjugated.[3] The term was first used by organic chemist Ludwig Brieger (1849–1919)[4] and is derived from the word "toxic".

Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. They vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin).[5][6]

Terminology

Toxins are often distinguished from other chemical agents strictly based on their biological origin.[7]

Less strict understandings embrace naturally occurring inorganic toxins, such as arsenic.[8][9][10] Other understandings embrace synthetic analogs of naturally occurring organic poisons as toxins,[11] and may[12] or may not[13] embrace naturally occurring inorganic poisons. It is important to confirm usage if a common understanding is critical.

Toxins are a subset of toxicants. The term toxicant is preferred when the poison is man-made and therefore artificial.[14] The human and scientific genetic assembly of a natural-based toxin should be considered a toxin as it is identical to its natural counterpart.[15] The debate is one of linguistic semantics.

The word toxin does not specify method of delivery (as opposed to venom, a toxin delivered via a bite, sting, etc.). Poison is a related but broader term that encompasses both toxins and toxicants; poisons may enter the body through any means - typically inhalation, ingestion, or skin absorption. Toxin, toxicant, and poison are often used interchangeably despite these subtle differences in definition. The term toxungen has also been proposed to refer to toxins that are delivered onto the body surface of another organism without an accompanying wound.[16]

A rather informal terminology of individual toxins relates them to the anatomical location where their effects are most notable:

On a broader scale, toxins may be classified as either exotoxins, excreted by an organism, or endotoxins, which are released mainly when bacteria are lysed.

Biological

The term "biotoxin" is sometimes used to explicitly confirm the biological origin as opposed to environmental or anthropogenic origins.[17][18] Biotoxins can be classified by their mechanism of delivery as poisons (passively transferred via ingestion, inhalation, or absorption across the skin), toxungens (actively transferred to the target's surface by spitting, spraying, or smearing), or venoms (delivered through a wound generated by a bite, sting, or other such action).[16] They can also be classified by their source, such as fungal biotoxins, microbial toxins, plant biotoxins, or animal biotoxins.[19][20]

Toxins produced by microorganisms are important virulence determinants responsible for microbial pathogenicity and/or evasion of the host immune response.[21]

Biotoxins vary greatly in purpose and mechanism, and can be highly complex (the venom of the cone snail can contain over 100 unique peptides, which target specific nerve channels or receptors).[22]

Biotoxins in nature have two primary functions:

Some of the more well known types of biotoxins include:

Weaponry

Many living organisms employ toxins offensively or defensively. A relatively small number of toxins are known to have the potential to cause widespread sickness or casualties. They are often inexpensive and easily available, and in some cases it is possible to refine them outside the laboratory.[24] As biotoxins act quickly, and are highly toxic even at low doses, they can be more efficient than chemical agents.[24] Due to these factors, it is vital to raise awareness of the clinical symptoms of biotoxin poisoning, and to develop effective countermeasures including rapid investigation, response, and treatment.[19][25][24]

Environmental

The term "environmental toxin" can sometimes explicitly include synthetic contaminants[26] such as industrial pollutants and other artificially made toxic substances. As this contradicts most formal definitions of the term "toxin", it is important to confirm what the researcher means when encountering the term outside of microbiological contexts.

Environmental toxins from food chains that may be dangerous to human health include:

Research

In general, when scientists determine the amount of a substance that may be hazardous for humans, animals and/or the environment they determine the amount of the substance likely to trigger effects and if possible establish a safe level. In Europe, the European Food Safety Authority produced risk assessments for more than 4,000 substances in over 1,600 scientific opinions and they provide open access summaries of human health, animal health and ecological hazard assessments in their OpenFoodTox[37] database.[38][39] The OpenFoodTox database can be used to screen potential new foods for toxicity.[40]

The Toxicology and Environmental Health Information Program (TEHIP)[41] at the United States National Library of Medicine (NLM) maintains a comprehensive toxicology and environmental health web site that includes access to toxins-related resources produced by TEHIP and by other government agencies and organizations.[42] This web site includes links to databases, bibliographies, tutorials, and other scientific and consumer-oriented resources. TEHIP also is responsible for the Toxicology Data Network (TOXNET),[43] an integrated system of toxicology and environmental health databases that are available free of charge on the web.

TOXMAP is a Geographic Information System (GIS) that is part of TOXNET.[44] TOXMAP uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic Research Programs.

See also


References

  1. Harper, Douglas. "toxin". Online Etymology Dictionary. https://www.etymonline.com/?term=toxin. 
  2. "toxin – Definition from the Merriam-Webster Online Dictionary". http://www.merriam-webster.com/dictionary/toxin. 
  3. "toxin" at Dorland's Medical Dictionary
  4. Brade, Helmut (1999). Endotoxin in Health and Disease. CRC Press. ISBN 9780824719449. OCLC 41299257. https://books.google.com/books?id=oWhqhK1cE-gC&pg=PA6. 
  5. Gupta, PK (2018). Illustrated Toxicology with Study Questions. Elsevier Inc.. ISBN 978-0-12-813213-5. https://www.sciencedirect.com/book/9780128132135/illustrated-toxicology. 
  6. "Diagnosis and Treatment | Botulism" (in en-us). 2021-06-01. https://www.cdc.gov/botulism/testing-treatment.html. 
  7. Bennett, Joan W; Inamdar, Arati A (2015). "Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?". Toxins (Basel) 7 (9): 3785–3804. doi:10.3390/toxins7093785. PMID 26402705. 
  8. Goodman, Brenda. "Arsenic in Food: FAQ". WebMD. https://www.webmd.com/diet/features/arsenic-food-faq. 
  9. "Arsenic in your food - Our findings show a real need for federal standards for this toxin". Consumer Reports. 2012. https://www.consumerreports.org/cro/magazine/2012/11/arsenic-in-your-food/index.htm. 
  10. Beans, Carolyn (2021). "Keeping arsenic out of rice". Proceedings of the National Academy of Sciences 118 (33). doi:10.1073/pnas.2113071118. PMID 34380741. Bibcode2021PNAS..11813071B. 
  11. "U.S. Code". https://www.law.cornell.edu/uscode/text/18/178. "the term "toxin" means the toxic material or product of plants, animals, microorganisms ...or a recombinant or synthesized molecule..." 
  12. "Module 1: Introduction to Toxicology". Agency for Toxic Substances and Disease Registry. https://www.atsdr.cdc.gov/es/training/toxicology_curriculum/modules/1/module-1.pdf. "arsenic, a toxic metal, may occur as a natural contaminant ... or ... as a by-product of industrial activities. If the second case is true, such toxic substances are referred to as toxicants, rather than toxins." 
  13. Goldblat, Jozef (30 June 1997). "The Biological Weapons Convention – An overview". http://www.icrc.org/en/doc/resources/documents/article/other/57jnpa.htm. ""The Convention applies to all natural or artificially created toxins, "whatever their origin or method of production" (Article I). It thus covers toxins produced biologically, as well as those produced by chemical synthesis"" 
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  18. "biotoxin" at Dorland's Medical Dictionary
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  20. "Biotoxins: What are Biotoxins?". https://www.biosciences-labs.bham.ac.uk/exhibit/whatare.html. 
  21. Microbial Toxins: Current Research and Future Trends. Caister Academic Press. 2009. ISBN 978-1-904455-44-8. 
  22. Robinson, Samuel D; Norton, Raymond S (17 December 2014). "Conotoxin Gene Superfamilies". Marine Drugs 12 (12): 6058–6101. doi:10.3390/md12126058. PMID 25522317. 
  23. Dorland's Illustrated Medical Dictionary (32nd ed.). Philadelphia, PA: Saunders/Elsevier. 2012. p. 1236. ISBN 978-1-4160-6257-8. 
  24. 24.0 24.1 24.2 Janik, Edyta; Ceremuga, Michal; Saluk-Bijak, Joanna; Bijak, Michal (2019-03-08). "Biological Toxins as the Potential Tools for Bioterrorism". International Journal of Molecular Sciences 20 (5): 1181. doi:10.3390/ijms20051181. ISSN 1422-0067. PMID 30857127. 
  25. Płusa, Tadeusz (September 2015). "[Toxins as a biological weapon"]. Polski Merkuriusz Lekarski 39 (231): 131–133. ISSN 1426-9686. PMID 26449572. https://pubmed.ncbi.nlm.nih.gov/26449572/#:~:text=Toxins%20list%20is%20extensive,%20but,include%20tetrodotoxin,%20brevetoxin%20and%20saxitoxin.. 
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  32. "Detection of the marine toxin okadaic acid in mussels during a diarrhetic shellfish poisoning (DSP) episode in Thermaikos Gulf, Greece, using biological, chemical and immunological methods". The Science of the Total Environment 366 (2–3): 894–904. August 2006. doi:10.1016/j.scitotenv.2005.03.002. PMID 16815531. Bibcode2006ScTEn.366..894M. 
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  35. "Brevetoxin B3, a new brevetoxin nalog isolated from the greenshell mussel perna canaliculus involved in neurotoxic shellfish poisoning in new zealand". Tetrahedron Letters 36 (49): 8995–98. 1995. doi:10.1016/0040-4039(95)01969-O. 
  36. "Brevetoxin B4 isolated from greenshell mussels Perna canaliculus, the major toxin involved in neurotoxic shellfish poisoning in New Zealand". Natural Toxins 7 (2): 45–8. 1999. doi:10.1002/(SICI)1522-7189(199903/04)7:2<45::AID-NT34>3.0.CO;2-H. PMID 10495465. 
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External links