How poison octopuses

The poisonous legacy of the cephalopods

Melbourne - Blue-ringed octopuses are known to produce a potent neurotoxin that they inject through a bite. According to a researcher from the University of Melbourne, they are not alone: ​​Most cephalopods have poison, says Bryan Fry in the "Journal of Molecular Evolution". At least this applies to octopuses, cuttlefish and some species of squid - these are also summarized under the term "squid", while the primitive pearl boats separated from this line of development earlier.

Basis of the assumption: The genetic analysis of various cephalopod species shows that all octopus species descend from a poisonous ancestor. He passed his poison on to his descendants, even though they developed into very different species over the course of millions of years.

Toxic proteins

This finding is relevant for the pharmaceutical industry and could contribute to the development of new drugs, stresses research director Bryan Fry. "The poisons of the cephalopods are toxic proteins that have special functions such as paralysis of the nervous system. By understanding the structure and action of the poison proteins, we hope to be able to develop new drugs, for example for pain perception, allergies or cancer."

Tissue samples from cephalopods from Hong Kong, the Coral Sea, the Great Barrier Reef and Antarctica provided information about the toxicity. A comparison of their genes, which are responsible for poison production, showed the existence of a common poisonous ancestor. From this comes a set of poison proteins, to which other proteins have joined in the course of evolution. Further research is now to determine why such different types of poisonous animals have relied on the same composition of poison proteins for such a long time, and what physical or chemical properties made them susceptible to the use of poison.

Paralysis of mussels

Cephalopods use poison when hunting, for example to paralyze mussels, the shell of which can then be cracked more easily. However, only the blue-ringed octopus is actually dangerous for humans. When bitten, this mollusc releases the fast-acting neurotoxin tetrodotoxin, which leads to paralysis and respiratory failure within two hours. (pte / red)