Date: March 14, 2017
Source: University of Queensland
A University of Queensland-led international study
has revealed how one of the world's most feared types of snakes -- cobras --
developed their potent venom.
Associate Professor Bryan Fry of UQ's School of
Biological Sciences said cobras were killers in Africa and Asia, and caused
crippling social and economic burdens through the number of survivors who
needed amputations due to the snake's flesh-eating venom.
"While we knew the results of their venom, how
the cobra's unique defensive venom evolved remained a mystery until now,"
he said.
"Our study discovered the evolutionary factors
shaping not only cobra venom, but also the ornate markings on their hoods, and
the extremely bright warning colourings present in some species.”
The research team studied 29 cobra species and
related snakes, finding that the flesh-destroying venom first evolved alongside
the broad hoods that make cobras so distinctive.
Dr Fry said further increases in the potency of the
toxins subsequently occurred parallel to their warning strategies such as hood
markings, body banding, red colouring and spitting.
"Their spectacular hoods and eye-catching
patterns evolved to warn off potential predators because unlike other snakes,
which use their venom purely for predation, cobras also use it in
defence," he said.
"For the longest time it was thought that only
spitting cobras had these defensive toxins in high amounts in their venoms,
however we've shown that they are widespread in cobras.
"These results show the fundamental importance
of studying basic evolution and how it relates to human health.”
Dr Fry said the next step in the team's research was
to conduct broad antivenom testing.
"Globally, snakebite is the most neglected of
all tropical diseases and antivenom manufacturers are leaving the market in
favour of products that are cheaper to produce and have a bigger market,"
he said.
"Antivenom is expensive to make, has a short
shelf life and a small market located in developing countries.
"Therefore, we need to do further research to
see how well those remaining antivenoms neutralise not only the toxins that
kill a person, but also those that would cause a severe injury.”
He said there may also be a benefit to this research
in cancer treatment.
"Any kind of compound that selectively kills
cells could be a good thing," Dr Fry said.
"These chemicals may lead to new cancer
treatments if we can find ones that are more potent to cancer cells than normal
healthy cells.
"Cobras are a rich resource of novel compounds
in this way so there may ultimately be a silver lining to this very dark cloud."
Story Source:
Materials provided by University
of Queensland. Note: Content may be edited for style and length.
/story_source
Journal Reference:
1 Nadya Panagides, Timothy
Jackson, Maria Ikonomopoulou, Kevin Arbuckle, Rudolf Pretzler, Daryl Yang, Syed
Ali, Ivan Koludarov, James Dobson, Brittany Sanker, Angelique Asselin, Renan
Santana, Iwan Hendrikx, Harold van der Ploeg, Jeremie Tai-A-Pin, Romilly van
den Bergh, Harald Kerkkamp, Freek Vonk, Arno Naude, Morné Strydom, Louis
Jacobsz, Nathan Dunstan, Marc Jaeger, Wayne Hodgson, John Miles, Bryan Fry. How
the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation
and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting. Toxins,
2017; 9 (3): 103 DOI: 10.3390/toxins9030103
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