A TOXIN (from
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 botulinum toxin ).
* 1 Terminology * 2 Biotoxins
* 3 Environmental toxins
* 3.1 Finding information about toxins * 3.2 Computational resources for prediction of toxic peptides and proteins
* 4 Misuse of the term * 5 See also * 6 References * 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
According to an
International Committee of the Red Cross
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 production..."
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 , 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 are further classified into fungal biotoxins, or short mycotoxins , microbial biotoxins, plant biotoxins, short phytotoxins and animal biotoxins.
Toxins produced by microorganisms are important virulence determinants responsible for microbial pathogenicity and/or evasion of the host immune response .
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 in the spider , snake , scorpion , jellyfish , wasp * Defense in the bee , ant , termite , honeybee , wasp , poison dart frog
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
* Puff Adder
Necrotizing fasciitis (caused by the "flesh eating" bacterium
* 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. * Most scorpions * The box jellyfish * Elapid snakes * The cone snail * The Blue-ringed octopus * Venomous fish * Frogs * Palythoa coral * 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:
* rattlesnakes * 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:
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 contexts.
Environmental toxins from food chains that may be dangerous to human health include:
FINDING INFORMATION ABOUT TOXINS
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
COMPUTATIONAL RESOURCES FOR PREDICTION OF TOXIC PEPTIDES AND PROTEINS
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 server.
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 general.
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 .
* ArachnoServer * Brevetoxin * Cangitoxin * Detoxification (alternative medicine) * Excitotoxicity * Insect toxins * List of fictional toxins * List of highly toxic gases * Microbial toxins * Mycotoxin * Toxicophore , feature or group within a molecule that is thought to be responsible for its toxic properties. * Toxin-antitoxin system
* ^ "toxin" at Dorland\'s Medical Dictionary
* ^ "toxin - Definition from the Merriam-Webster Online
Dictionary". Retrieved 13 December 2008.
* ^ https://books.google.com/books?id=oWhqhK1cE-gC&pg=PA6
* ^ "The
Biological Weapons Convention - An overview". Retrieved 13
* ^ "U.S. Code". 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. ISBN 978-1-904455-44-8 . CS1
maint: Extra text: authors list (link )
* ^ Grigg J (March 2004). "Environmental toxins; their impact on
children\'s health". Arch. Dis. Child. 89 (3): 244–50. PMC 1719840
. PMID 14977703 . doi :10.1136/adc.2002.022202 .
* ^ Vale, Carmen; Alfonso, Amparo; Vieytes, Mercedes R.; Romarís,
Xosé Manuel; Arévalo, Fabiola; Botana, Ana M.; Botana, Luis M.
(2008). "In Vitro and in Vivo Evaluation of Paralytic Shellfish
Toxin Potency and the Influence of the pH of Extraction".
Analytical Chemistry .
American Chemical Society
* T3DB: Toxin-target