The term "biotoxin" is sometimes used to explicitly confirm the biological origin as opposed to environmental or anthropogenic origins. 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). 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 can contain over 100 unique
peptides, which target specific nerve channels or receptors). 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,
poison dart frog and
plants producing toxins • The toxins used as defense in species among the
poison dart frog can also be used for medicinal purposes 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. 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
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. • 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 •
Mexican beaded lizard •
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 •
Cardiotoxin III, from
Chinese cobra •
Hemotoxin, from
vipers
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. As biotoxins act quickly, and are highly toxic even at low doses, they can be more efficient than chemical agents. ==Environmental==