Tentacles of venom: New
study reveals all octopuses are venomous
Wednesday, April 15,
2009
Once thought to be only the realm of the blue-ringed octopus,
researchers have now shown that all octopuses and cuttlefish, and
some squid are venomous. The work indicates that they all share a
common, ancient venomous ancestor and highlights new avenues for
drug discovery.
Conducted by scientists from the University of Melbourne,
University of Brussels and Museum Victoria, the study was published
in the Journal of Molecular Evolution.
Dr Bryan Fry from the Department of Biochemistry at the Bio21
Institute, University of Melbourne said that while the blue-ringed
octopus species remain the only group that aredangerous to humans,
the other species have been quietly using their venom for
predation, such as paralysing a clam into opening its shell.
"Venoms are toxic proteins with specialised functions such as
paralysing the nervous system" he said.
"We hope that by understanding the structure and mode of action of
venom proteins we can benefit drug design for a range of conditions
such as pain management, allergies and cancer."
While many creatures have been examined as a basis for drug
development, cephalopods (octopuses, cuttlefish and squid) remain
an untapped resource and their venom may represent a unique class
of compounds.
Dr Fry obtained tissue samples from cephalopods ranging from Hong
Kong, the Coral Sea, the Great Barrier Reef and Antarctica.
The team then analysed the genes for venom production from the
different species and found that a venomous ancestor produced one
set of venom proteins, but over time additional proteins were added
to the chemical arsenal.
The origin of these genes also sheds light on the fundamentals of
evolution, presenting a prime example of convergent evolution where
species independently develop similar traits.
The team will now work on understanding why very different types of
venomous animals seem to consistently settle on the similar venom
protein composition, and which physical or chemical properties make
them predisposed to be useful as toxin.
"Not only will this allow us to understand how these animals have
assembled their arsenals, but it will also allow us to better
exploit them in the development of new drugs from venoms," said Dr
Fry.
"It does not seem a coincidence that some of the same protein types
have been recruited for use as toxins across the animal
kingdom."
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University of Melbourne
Thanks to University of Melbourne
for this article.
