A toxin (from Ancient Greek: τοξικόν, translit. toxikon)
is a poisonous substance produced within living cells or
organisms; synthetic toxicants created by artificial processes
are thus excluded. The term was first used by organic chemist Ludwig
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. Toxins vary greatly in their toxicity, ranging from usually
minor (such as a bee sting) to almost immediately deadly (such as
3 Environmental toxins
3.1 Finding information about toxins
3.2 Computational resources for prediction of toxic peptides and
4 Misuse of the term
5 See also
7 External links
Toxins are often distinguished from other chemical agents by their
method of production—the word toxin does not specify method of
delivery (compare with venom and the broader meaning of poison—all
substances that can also cause disturbances to organisms). It simply
means it is a biologically produced poison. There was an ongoing
terminological dispute between
NATO and the
Warsaw Pact over whether
to call a toxin a biological or chemical agent, in which the NATO
opted for biological agent, and the Warsaw Pact, like most other
countries in the world, for chemical agent.
According to an
International Committee of the Red Cross
International Committee of the Red Cross review of the
Biological Weapons Convention, "Toxins are poisonous products of
organisms; unlike biological agents, they are inanimate and not
capable of reproducing themselves", and "Since the signing of the
Constitution, there have been no disputes among the parties regarding
the definition of biological agents or toxins".
According to Title 18 of the United States Code, "... the term "toxin"
means the toxic material or product of plants, animals, microorganisms
(including, but not limited to, bacteria, viruses, fungi, rickettsiae
or protozoa), or infectious substances, or a recombinant or
synthesized molecule, whatever their origin and method of
A rather informal terminology of individual toxins relates them to the
anatomical location where their effects are most notable:
Hemotoxin, causes destruction of red blood cells (hemolysis)
Phototoxin, causes dangerous photosensitivity
On a broader scale, toxins may be classified as either exotoxins,
being excreted by an organism, or endotoxins, that are released mainly
when bacteria are lysed.
The term "biotoxin" is sometimes used to explicitly confirm the
biological origin. Biotoxins can be further classified, for
example, as fungal biotoxins, microbial biotoxins, plant biotoxins, or
Toxins produced by microorganisms are important virulence determinants
responsible for microbial pathogenicity and/or evasion of the host
Biotoxins vary greatly in purpose and mechanism, and can be highly
complex (the venom of the cone snail contains dozens of small
proteins, each targeting a specific nerve channel or receptor), or
relatively small protein.
Biotoxins in nature have two primary functions:
Predation, such as in the spider, snake, scorpion, jellyfish, and wasp
Defense as in the bee, ant, termite, honey bee, wasp, and poison dart
Some of the more well known types of biotoxins include:
Cyanotoxins, produced by cyanobacteria
Dinotoxins, produced by dinoflagellates
Necrotoxins cause necrosis (i.e., death) in the cells they encounter
and destroy all types of tissue. Necrotoxins spread
through the bloodstream. In humans, skin and muscle
tissues are most sensitive to necrotoxins. Organisms
that possess necrotoxins include:
The brown recluse or "fiddle back" spider
Most rattlesnakes and vipers produce phospholipase and various
trypsin-like serine proteases
Necrotizing fasciitis (caused by the "flesh eating" bacterium
Streptococcus pyogenes) - produces a pore forming toxin
Neurotoxins primarily affect the nervous systems of animals. The group
neurotoxins generally consists of ion channel toxins that disrupt ion
channel conductance. Organisms that possess neurotoxins include:
The black widow spider.
The box jellyfish
The cone snail
The Blue-ringed octopus
Various different types of algae, cyanobacteria and dinoflagellates
Myotoxins are small, basic peptides found in snake and lizard venoms,
They cause muscle tissue damage by a non enzymatic receptor based
mechanism. Organisms that possess myotoxins include:
eastern bearded dragon
Cytotoxins are toxic at the level of individual cells, either in a
non-specific fashion or only in certain types of living cells:
Ricin, from castor beans
Apitoxin, from honey bees
T-2 mycotoxin, from certain toxic mushrooms
The term "environmental toxin" can sometimes explicitly include
synthetic contaminants 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
Environmental toxins from food chains that may be dangerous to human
Paralytic shellfish poisoning (PSP)
Amnesic shellfish poisoning (ASP)
Diarrheal shellfish poisoning (DSP)
Neurotoxic shellfish poisoning (NSP)
Finding information about toxins
Toxicology and Environmental Health Information Program
(TEHIP) at the
United States National Library of Medicine
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. 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), 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
TOXMAP uses maps of the United States to help users visually
explore data from the United States Environmental Protection Agency's
Toxics Release Inventory
Toxics Release Inventory and Superfund Basic Research Programs.
Computational resources for prediction of toxic peptides and
One of the bottlenecks in peptide/protein-based therapy is their
toxicity. Recently, in silico models for predicting toxicity of
peptides and proteins, developed by Gajendra Pal Singh Raghava's
group, predict toxicity with reasonably good accuracy. The
prediction models are based on machine learning technique and
quantitative matrix using various properties of peptides. The
prediction tool is freely accessible to public in the form of web
Misuse of the term
When used non-technically, the term "toxin" is often applied to any
toxic substance, even though the term toxicant would be more
appropriate. Toxic substances not directly of biological origin are
also termed poisons and many non-technical and lifestyle journalists
follow this usage to refer to toxic substances in
In the context of quackery and alternative medicine, the term "toxin"
is used to refer to any substance alleged to cause ill health. This
could range from trace amounts of potentially dangerous pesticides, to
supposedly harmful substances produced in the body by intestinal
fermentation (auto-intoxication), to food ingredients such as table
sugar, monosodium glutamate (MSG), and aspartame.
Detoxification (alternative medicine)
List of fictional toxins
List of highly toxic gases
Toxicophore, feature or group within a molecule that is thought to be
responsible for its toxic properties.
^ "toxin" at Dorland's Medical Dictionary
^ "toxin - Definition from the Merriam-Webster Online Dictionary".
Retrieved 13 December 2008.
Biological Weapons Convention
Biological Weapons Convention - An overview". Retrieved 13
^ "U.S. Code". Archived from the original on 21 July 2011. Retrieved
13 December 2008.
^ "biotoxin - Definition from the Merriam-Webster Online Dictionary".
Retrieved 13 December 2008.
^ "biotoxin" at Dorland's Medical Dictionary
^ Proft T (editor) (2009). Microbial Toxins: Current Research and
Future Trends. Caister Academic Press.
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^ Vale, Carmen; Alfonso, Amparo; Vieytes, Mercedes R.; Romarís, Xosé
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Vitro and in Vivo Evaluation of Paralytic Shellfish Poisoning Toxin
Potency and the Influence of the pH of Extraction". Analytical
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Yutaka (2008). "Difference in the level of paralytic shellfish
poisoning toxin accumulation between the crabs Telmessus acutidens and
Charybdis japonica collected in Onahama, Fukushima Prefecture".
Fisheries Science. Springer. 73 (2): 395–403.
^ Abouabdellah, Rachid; Taleb, Hamid; Bennouna, Asmae; Erler, Katrin;
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poisoning toxin profile of mussels Perna perna from southern Atlantic
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^ Wang, Lin; Liang, Xu-Fang; Zhang, Wen-Bing; Mai, Kang-Sen; Huang,
Yan; Shen, Dan (2009). "
Amnesic shellfish poisoning toxin stimulates
the transcription of CYP1A possibly through AHR and ARNT in the liver
of red sea bream Pagrus major". Marine Pollution Bulletin. Elsevier.
58 (11): 1643–1648. doi:10.1016/j.marpolbul.2009.07.004.
^ Wang, Lin; Vaquero, E.; Leão, J. M.; Gogo-Martínez, A.; Rodríguez
Vázquez, J. A. (2001). "Optimization of conditions for the liquid
chromatographic-electrospray lonization-mass spectrometric analysis of
amnesic shellfish poisoning toxins". Chromatographia. Vieweg Verlag.
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^ Mouratidou, Theoni; Kaniou-Grigoriadou, I.; Samara, C.; Kouimtzis,
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^ Poli, Mark A.; Musser, Steven M.; Dickey, Robert W.; Eilers, Paul
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^ Morohashi, Akio; Satake, M.; Murata, K.; Naoki, H.; Kaspar, H.;
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^ Morohashi, Akio; Satake, Masayuki; Naoki, Hideo; Kaspar, Heinrich
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^ Sudheer Gupta, Pallavi Kapoor, Kumardeep Chaudhary, Ankur Gautam,
Rahul Kumar, Open Source Drug Discovery Consortium, Gajendra P. S.
Raghava (2013). "In Silico Approach for Predicting
Peptides and Proteins". PLOS ONE. 8: e73957.
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^ ""Detoxification" Schemes and Scams". Quackwatch.
T3DB: Toxin-target database
Animal toxin database
Society of Toxicology
The Journal of Venomous Animals and Toxins including Tropical Diseases
ToxSeek: Meta-search engine in toxicology and environmental health
Website on Models & Ecotoxicology
Staphylococcus aureus alpha/beta/delta
Toxic shock syndrome toxin
Enterotoxin B (SEB)
Verotoxin/shiga-like toxin (E. coli)
E. coli heat-stable enterotoxin/enterotoxin
Extracellular adenylate cyclase
Bacillus thuringiensis delta endotoxin
Clumping factor A
Fibronectin binding protein A
Amatoxin (alpha-amanitin, beta-amanitin, gamma-amanitin,
Androctonus australis hector insect toxin
note: some toxins are produced by lower species and pass through
History of poison
In vitro toxicology
Acceptable daily intake
Fixed Dose Procedure
Whole bowel irrigation
1858 Bradford sweets poisoning
2007 pet food recalls
Niigata Minamata disease
Poisoning of Alexander Litvinenko
Consumption of Tide Pods
List of poisonings
List of extremely hazardous substances
Occupational safety and health