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Toxin




Part of a series on
Toxicology and poison
Toxicology (Forensic) - Toxinology
History of poison
(ICD-10 T36-T65, ICD-9 960-989)
Concepts
Poison - Venom - Toxicant - Antidote
Acceptable daily intake - Acute toxicity
Bioaccumulation - Biomagnification
Fixed Dose Procedure - LD50 - Lethal dose
Toxic capacity - Toxicity Class
Toxins and venoms
Neurotoxin - Necrotoxin - Hemotoxin
Mycotoxin - Aflatoxin - Phototoxin
List of fictional toxins
Incidents
Bradford - Minamata - Niigata
Alexander Litvinenko - Bhopal
2007 pet food recalls
List of poisonings
Poisoning types
Elements
Toxic metal (Lead - Mercury - Cadmium - Antimony - Arsenic - Beryllium - Iron - Thallium) - Fluoride - Oxygen
Seafood
Shellfish (Paralytic - Diarrheal - Neurologic
Amnesic)
- Ciguatera - Scombroid
Tetrodotoxin
Other substances
Pesticide - Organophosphate - Food
Nicotine - Theobromine - Carbon monoxide - Vitamin - Medicines
Living organisms
Mushrooms - Plants - Animals
Related topics
Hazard symbol - Carcinogen
Mutagen - List of Extremely Hazardous Substances - Biological warfare

A toxin (Greek: τοξικόν, toxikon, lit. (poison) for use on arrows) is a poisonous substance produced by living cells or organisms that is active at very low concentrations. Toxins can be small molecules, peptides, or proteins and are capable of causing disease on contact or absorption with body tissues by interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their severity, ranging from usually minor and acute (as in a bee sting) to almost immediately deadly (as in botulinum toxin).

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.

Additional recommended knowledge

Contents

Use

Biotoxins in nature have two primary functions:

Some of the more well known types of biotoxins include:

  • Cyanotoxins, produced by cyanobacteria
  • Hemotoxins target and destroy red blood cells, and are transmitted through the bloodstream. Organisms that possess hemotoxins include:
  • Necrotoxins cause necrosis (i.e., death) in the cells they encounter and destroy all types of tissue. Necrotoxins spread through the bloodstream, but infect all tissues. In humans, skin and muscle tissues are most sensitive to necrotoxins. Organisms that possess necrotoxins include:
  • Neurotoxins primarily affect the nervous systems of animals. Organisms that possess neurotoxins include:

Ricinis is a plant toxin found in the castor bean plant.

Environmental toxins

Non-technical usage

When used non-technically, the term "toxin" is often applied to any toxic substances. Toxic substances not of biological origin are more properly termed poisons. Many non-technical and lifestyle journalists also follow this usage to refer to toxic substances in general, though some specialist journalists at publishers such as BBC and The Guardian maintain the distinction that toxins are only those produced by living organisms.

In the context of alternative medicine the term is often used nonspecifically to refer to any substance claimed to cause ill health, ranging anywhere from trace amounts of pesticides to common food items like refined sugar or additives like artificial sweeteners and MSG.[1]

See also

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Toxin". A list of authors is available in Wikipedia.
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