Threat To Cone Shells And The Potential Drugs They Contain

23 November 2003


Scientists from the UK and America have warned this week that we might be loosing the most promising source of new drugs because of habitat loss and overexploitation. Cone snails are very pretty-looking sea-shells that live in the warm, shallow tropical seas, but are not to be played with, since they have a deadly sting that they inject prey with through a hollow, harpoon-like tooth. Each species of cone shell has it's own distinct cocktail of around 100 so called conotoxins which, like a gourmet chef, they mix in constantly changing proportions, preventing the evolution of resistance to the poison in their prey. Now it's these conotoxins that have been found to be a potentially incredibly important source of new medicines, because they are exquisitely selective in their cell receptor binding sites, that's the lock-and-key type mechanism on the surface of every cell that play crucial roles in all sorts of diseases. One discovery so far has been of a conotoxin that by blocking key neurological pathways is very effective in early detection and treatment of small cell lung cancer, one of the most devastating human cancers. Another has been found to have potent anti-epileptic properties. The problem is, that just as researchers are starting to appreciate the incredible pharmaceutical potential of cone shell toxins, these animals are coming under intense pressure in the wild. Cone shells live on coral reefs and mangroves, two habitats that are under massive threat throughout the tropics from coastal development, pollution, destructive fishing and global climate change. We've already lost half of the worlds mangroves and a quarter of the worlds coral reef are already seriously damaged. Cone shells are also being increasingly harvested for the ornamental shell trade, with millions of shells sold each year. Researchers are calling for increased planning for habitat protection and for the sustainable collection of the shells for ornaments as well as for biomedical research. There may be up 50 thousand conotoxins, so with such massive potential the extinction of cone shells could represent untold lost opportunities for modern medicine.


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