Sequestration of toxins

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Glaucus atlanticus , a nudibranch , feeds on the Portuguese galley ( Physalia physalis ) and stores its nettle cells in the tissue
Strawberry frog ( Oophaga pumilio ), a poison dart frog from Costa Rica, feeds on u. a. of scale ants of the genera Brachymyrmex and Paratrechina and stores their pumiliotoxins under the skin.
Spurge goose ( Plectropterus gambensis ) from Africa, feeds u. a. of oil beetles (Meloidae) and stores their cantharidin in the muscle tissue.

Sequestration of toxins ( late Latin sequestrare 'secrete, separate') refers to the uptake, storage and accumulation of toxins ( poisonous substances from living beings) from the natural environment by animals , for "disposal" or for their protection against parasites and predators . The poisonous starting products can come from all kingdoms of organisms . When incorporating it is necessary that protective mechanisms are in place to avoid toxic effects. It is often stored in certain organs such as a poisonous bladder or the skin. Only animals that are not capable of direct biosynthesis of toxic substances are able to sequester poisons . Metabolic changes to the poison molecules are sometimes possible.

The Toxinology , a portion of the toxicology , deals u. a. with sequestered toxins .

Sequestering animals

The poison-sequestering animals are often known as the "real" poison carriers. Many of these poisonous animals practice aposematism , that is, they wear warning coloring . Often the process of sequestration and the mechanisms to tolerate the ingested amount of poison are not well understood.

Birds

Some Pitohui from New Guinea are known as poisonous birds , such as the two-color pitohui ( Pitohui dichrous ), Pitohui ferrugineus and Mohrenpitohui ( Pitohui nigrescens ), as well as blue-capped flute ( Ifrita kowaldi ), which probably obtain the insect venom batrachotoxin from the skin of beetles of the genus Chores and sequester plumage.

The barnacles get their body poison cantharidin from oil beetles (Meloidae). This enriches them in their tissues, so that consuming the spurge, depending on the amount of beetles ingested, is poisonous for predators and humans.

frogs

Among the poisonous amphibians , some can synthesize their own amphibian poisons . Frogs cannot do this. Poison dart frogs are particularly noticeable as sequestering poison . They store the toxins, mostly from insects or horn mites , in or under their skin. Poison dart frogs are very often aposematic. Contaminated with their skin toxins, e.g. B. through injuries, poison dart frogs can suffer poisoning.

fishes

By eating cyanobacteria or dinoflagellates, plankton- eating fish can accumulate their toxins in the body and become poisonous for humans or predators. Through sequestration through the food chain , even predatory fish can become potent carriers of poison and mediate fish poisoning .

Molluscs

Some nudibranch snails ( suborder Nudibranchia) that feed on polyps of cnidarians can store the stinging cells in the skin of their abdomen, where they can lead to unpleasant experiences in predators. The stinging cells pass through the digestive tract undamaged and are brought to the appropriate places in the abdomen through special intestinal protuberances. The nudibranch themselves have developed defense mechanisms against the nettle attack by the polyps. Special cells with large vacuoles in the skin probably play a role here. Venom-sequestering nudibranchs are often aposematic.

Mussels can consume large amounts of poisonous dinoflagellates or cyanobacteria through plankton filtration, so that their mussel meat e.g. B. becomes neurotoxic by saxitoxin .

insects

Although many insects to be able to produce even various poisons sequester some butterflies of the tensioner (eg. B. Arichanna gaschkevitchii and arichanna melanaria ) Widderchen and ermine moth plant toxins (for. Example, diterpenoids). Butterflies that sequester plant toxins are often aposematic. Also locusts can quinones , phenols store and other vegetable poisons in their bodies, for example Romalea microptera .

The pyrrolizidine alkaloid accumulation in some butterflies and grasshoppers is based on the sequestration of these vegetable toxins.

Sources of poison

Bacterial toxins

Toxins from cyanobacteria can accumulate in mussels and fish via the food chain. The best known are the microcystins from representatives of the blue-green algae Microcystis . The neurotoxic amino acid β-methylamino-alanine (BMAA) also occurs.

Poisons from single cells

Poisonous dinoflagellates can appear in large quantities, which means that plankton eaters such as fish and mussels, as long as they are not poisoned themselves, become carriers of poison, the consumption of which can also have life-threatening effects on humans. The disease Ciguatera , a type of fish poisoning, is caused by metabolic products of the dinoflagellate species Gambierdiscus toxicus . The dinoflagellate toxins ciguatoxin and maitotoxin find their way into fish via the food chain , which are also highly toxic.

Mycotoxins

Mycotoxins are mostly accumulated through the food chain.

Herbal poisons

Many poisonous invertebrates get their toxins from their feeding plants. Since young parts of plants often contain higher concentrations of poison, the herbivores can influence the amount of poison absorbed.

Poisonous secondary metabolites like dipertene or pyrrolizidine alkaloids are ingested by some butterflies and grasshoppers.

The use of milkweed plants with poisonous milky sap was named after some groups of butterflies, such as milkweed hawks , milkweed bark owl , milkweed wolf and milkweed ring moth .

Animal poisons

Insect venom and poisons from arachnids such as horn mites are used by both venom-sequestering frogs and birds.

Poisonous cnidarians serve as a source of poison for nudibranchs.

Countermeasures

The most important countermeasure is knowing and avoiding poisonous animals. A sequestration of toxins through the food chain occurs especially in mussels and fish. In slaughtered meat and cow's milk z. B. the accumulation of mycotoxins can take place from the feed, which is then countered with specific adsorbents .

Individual evidence

  1. ↑ Duden: sequester , accessed on July 8, 2015.
  2. ↑ Alan H. Savitzky, Akira Mori, Deborah A. Hutchinson, Ralph A. Saporito, Gordon M. Burghardt, Harvey B. Lillywhite, Jerrold Meinwald: Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies. In: Chemoecology. Volume 22, No. 3, September 2012, pp. 141-158, doi: 10.1007 / s00049-012-0112-z
  3. ^ John Tidwell: The intoxicating birds of New Guinea. (PDF). In: ZooGoer. Volume 30, No. 2, 2001.
  4. ↑ Stephanie Greenman Stone, Pat Kilduff: New Research Shows that Toxic Birds and Poison-dart Frogs Likely Acquire their Toxins from Beetles. ( Memento of December 3, 2012 in the Internet Archive ) Newsroom of the California Academy of Sciences, article dated October 12, 2004.
  5. ↑ John P. Dumbacher, Avit Wako, Scott R. Derrickson, Allan Samuelson, Thomas F. Spande, John W. Daly: Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds . (PDF). In: PNAS 101, No. 45, 2004, pp. 15857–15860, doi: 10.1073 / pnas.0407197101 .
  6. ↑ Bethany Halford: Birds and beetles: A toxic trail. In: Chemical & Engineering News 82, No. 45, 2004, p. 17.
  7. ^ Stefan Bartram, Wilhelm Boland: Chemistry and ecology of toxic birds. In: ChemBioChem. 2, No. 11, November 2001, pp. 809-811, doi : 10.1002 / 1439-7633 (20011105) 2:11 <809 :: AID-CBIC809> 3.0.CO; 2-C .
  8. ↑ Karem Ghoneim: Cantharidin toxicosis to animal and human in the world: A review.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. @1@ 2Template: Dead Link / www.standresjournals.org   In: Standard Res. J. Toxicol. Environ. Health Sci. 1, 2013, pp. 001-022.
  9. ↑ Alan H. Savitzky, Akira Mori, Deborah A. Hutchinson, Ralph A. Saporito, Gordon M. Burghardt, Harvey B. Lillywhite, Jerrold Meinwald: Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies. In: Chemoecology. Volume 22, No. 3, September 2012, pp. 141-158, doi: 10.1007 / s00049-012-0112-z
  10. ^ Ritsuo Nishida: Sequestration of plant secondary compounds by butterflies and moths. In: Chemoecology. Vol. 5-6, No. 3-4, 1994/95, pp. 127-138, doi: 10.1007 / BF01240597 .
  11. ↑ James T. Costa: The other insect societies. Harvard University Press, 2006, ISBN 0-674-02163-0 , p. 82 ff.
  12. ↑ GVP Reddy, A. Guerrero: Interactions of insect pheromones and plant semiochemicals. In: TRENDS in Plant Science. Volume 5, No. 5, 2004, pp. 253-261, doi: 10.1016 / j.tplants.2004.03.009 .
  13. ↑ M. Boppré, OW Fischer: Harlequin terrors (Orthoptera: Zonocerus) - harmful insects of a special kind. In: Healthy plants. 51, 1999, pp. 141-149.
  14. ↑ Gadi VP Reddy, Angel Guerrero: Interactions of insect pheromones and plant semiochemicals. In: Trends in Plant Science. 9, 2004, pp. 253-261, doi: 10.1016 / j.tplants.2004.03.009 .
  15. ↑ A. Swift, T. Swift: Ciguatera. In: J Toxicol Clin Toxicol . 31, 1993, pp. 1-29. ( Abstract )
  16. ^ AD Higginson, MP Speed, GD Ruxton: Effects of anti-predator defense through toxin sequestration on use of alternative food microhabitats by small herbivores. In: J Theor Biol. Volume 300, May 7, 2012, pp. 368-375, doi: 10.1016 / j.jtbi.2012.01.020 .
  17. ^ DE Diaz, TK Smith: Mycotoxin sequestering agents: practical tools for the neutralization of mycotoxins. The mycotoxin blue book, 2005, pp. 323-339.
  18. ↑ N. Aoudia et al .: Effectiveness of mycotoxin sequestration activity of micronized wheat fibers on distribution of ochratoxin A in plasma, liver and kidney of piglets fed a naturally contaminated diet. In: Food and Chemical Toxicology. 47, No. 7, 2009, pp. 1485-1489.
  19. ↑ Maurizio Moschini et al: The effects of rumen fluid on the in vitro aflatoxin binding capacity of different sequestering agents and in vivo release of the sequestered toxin. In: Animal Feed Science and Technology. 147, No. 4, 2008, pp. 292-309.