A snake's intended prey might affect the type and evolution of toxins in their venom, research published in the online open access journal BMC Evolutionary Biology shows.
In snakes, venom composition varies both between species and within a particular species. Land snakes feed on a range of animals and birds, so scientists think that these snakes need a diverse array of toxins in their venom. Sea snakes, on the other hand, tend to have a more restricted diet, feeding only on fish. The toxins in these snakes have now been shown to be less diverse than those in terrestrial snakes.
Professor R Manjunatha Kini and colleagues from the National University of Singapore examined two kinds of sea snakes. They constructed complementary DNA libraries from the venom glands of the reptiles, representing only the stretches of DNA that code for venom gland proteins, and studied two types of protein toxins. The three-finger toxins (3FTx) and the phospholipase A2 (PLA2) enzymes are the main components of sea snake venom.
Although the sea snakes studied lived in very different aquatic environments, the toxins examined were similar in both and the genes encoding the toxins were highly conserved. By contrast, the same toxins in land snakes and sea kraits (which fall between land and sea snakes) showed much greater diversity. The researchers suggest that the toxin genes in sea snakes have remained relatively unchanged because of sea snakes share the same kind of feeding behaviour and diet.
"We examine toxin genes of snakes to identify new toxins, some of which will be useful in developing new therapeutic strategies to treat human diseases," says Prof Kini from the Department of Biological Sciences, National University of Singapore. "A new anticoagulant or a hypotensive toxin may help us develop new cardiovascular drugs to block unwanted clot formation or to lower the blood pressure."
Article:
Expression pattern of three-finger toxin and phospholipase A2 genes in the venom glands of two sea snakes, Lapemis curtus and Acalyptophis peronii: comparison of evolution of these toxins in land snakes, sea kraits and sea snakes
Susanta Pahari, David Bickford, Bryan G Fry and R Manjunatha Kini
BMC Evolutionary Biology (in press)
During embargo, article available at: http://www.biomedcentral.com/imedia/8328408441407682_article.pdf?random=265430
After the embargo, article available from the journal website at: http://www.biomedcentral.com/bmcevolbiol/
Article citation and URL available on request at press@biomedcentral.com on the day of publication
Please quote the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central's Open Access policy.
Author contact:
Wong Ching Yee (Media Relations Officer, National University of Singapore)
Phone +0065 651 61517
Email: ocrwcy@nus.edu.sg
Journal
BMC Evolutionary Biology