22 July 2007

Snail venom: Boo

Following up on the last post, the darker side of snail venom:

Powerful New Poison found in Deadly Sea Snails
By Aaron Rowe EmailJuly 11, 2007 | 8:00:00 AMCategories: Biology, Medicine & Medical Procedures

Conusparius Spies with a penchant for exotic poisons can add a new one to their list – snail venom.

For more than 23 years, Professor Baldomero M. Olivera has been studying snail venom. This week, his team at the University of Utah reported their discovery of a completely unique neurotoxin in Conus parius, a mollusk that hunts along the coast in the Philippines.

Some sea snails produce poisonous darts to hunt small fish and defend themselves. For the past 35 years, scientists have been studying these powerful neurotoxins. All of them are peptides, short strings of amino acids that make up miniature proteins.

Cone snail venoms are more than an elaborate tool for assassination. In 2004, one of those toxins was approved by the FDA to treat chronic pain. Some day, they may be used to treat a variety of neurological disorders including Alzheimer's and Parkinson's.

In the journal Biochemistry, Baldomero and his colleagues Russell Teichert and Elsie Jimenez compared this new poison to the others that have been identified in the past two decades. All of them impair the function of neuromuscular nicotinic acetylcholine receptors. In other words, they inactivate a protein found in the nerve cells that control muscle movement.

To identify the unique neurotoxin, the biologists cut out the venom ducts from several snails, froze them, pulverized them, and then extracted the peptides from the pulp with a mixture of water and the solvent acetonitrile. They purified the peptide and used a machine to determine its amino acid sequence. Later, they injected mice and goldfish with the purified peptide to prove that it is in fact the deadly poison. They were right. A tiny amount would kill goldfish within ten minutes and mice within thirty.

Perhaps this new poison will also find its way into the hospital -- or at least the next James Bond film.

HT: Slashdot

19 July 2007

Snail venom: Yay

A bit old and a topic I've posted on before, but relevant:

Dr Jon-Paul Bingham, of Clarkson University, has an unusual note on his file at the local hospital in New York State.

If he is admitted unconscious, they are to check to see whether he has been harpooned by a deadly snail.

Every week, he milks lethal marine molluscs called cone shells for their venom, using a condom, barbecue tongs and a fish. If anything goes wrong, though, it is no laughing matter.

Cone shells look like a seaside souvenir from the tropics. You find them in places like the Great Barrier Reef or Hawaii. The shells themselves are sometimes two to three inches long, often with striking patterns which make them collectable.

These snails will produce millions of changes in their toxins that they use to kill their prey
Dr Jon-Paul Bingham, Clarkson University
The snails inside are not all poisonous but the fish-eating ones are right up there with snakes and scorpions in the danger stakes. If you get stung by one of them, there will be enough venom in your system to kill up to 15 people; but it is not entirely hopeless.

"Get on a life support system. There have been cases where people have survived," Jon-Paul says helpfully.

Biological 'kit bag'

It is quite an overkill for a little marine animal whose usual dinner is no bigger than a goldfish, but what grips scientists is not the potency of its venom but the complexity.

Cone snail (Clarkson)
On a par with snakes and scorpions
"These snails will produce millions of changes in their toxins that they use to kill their prey," Jon-Paul tells the BBC Radio 4 programme Danger! Venomous Snails.

"If they don't make these changes, they can be at an evolutionary disadvantage, so the snails have become good pharmaceutical chemists. It is these compounds that we are trying to harness to use as specific medicines."

One of these compounds is already at work. Just over a year ago, the US Federal Drug Agency approved the first of a new type of painkiller - Prialt® - which can work in cases where ordinary drugs fail. The drug has also been approved for use in Europe.

It blocks a particular channel in nerves which communicates pain signals to the brain. The original toxin behind the drug was discovered in the lab of Professor Baldomero Olivera, at the University of Utah, and he's excited about the future.

In close-up: The cone snail's harpoon
"There's an explosion of data about neuroscience and what can go wrong," he says.

"We'd like to understand and affect many different molecules in the normal brain. Using very specific toxins that wipe out the function of just one thing in the nervous system, lets us do that.

"We see applications in epilepsy, stroke and cardiovascular conditions. Some are in development and one has reached clinical trials."

Just the beginning

Another way of stopping strokes and heart attacks is to cut down on smoking. Snail toxins might help here, too.

Professor Bruce Livett, of the University of Melbourne, Australia, is looking at how they affect the nicotinic receptor - the very thing that gets a hit when you puff on a cigarette.

A drug to inhibit that might help you stop smoking, but this research is already tackling severe pain in diabetic patients.

Some species are threatened because of the actions of collectors
There could even be applications in Alzheimer's or Parkinson's disease, says Bruce, but one thing bothers him: we should take time to get to know the snail, not just its venom.

"There's a whole world of invertebrate biology out there far more advanced than our own mammalian biology," he says.

That is where Jon-Paul Bingham's work has been important. By developing his way of milking the snails, Jon-Paul keeps the animals alive in his lab and learns more about them.

He does not need to dissect the "goose that lays the golden egg" to study its venom. He analyses their venoms and then synthesises the compounds he finds for further work.

His hope is to set up a library of venoms to help other researchers get access to this field. He sees potential for snail toxins to be used in everything from agriculture to anti-fouling paints against marine worms.

Cone shells research appears to be advancing much more quickly than your average snail.

Danger! Venomous Snails was broadcast on BBC Radio 4 on Monday 27 March. It can still be heard at the Listen again page.


16 July 2007

Balkan et al. on toture

The legal blog Balkanization has compiled a list of all their posts on torture here. Definitely worth checking out.

13 July 2007

Mirror-touch synethesia

From The Week (not online so no link)
They feel your pain
Some people can feel others' pain --literally. When those with a rare condition called mirror-touch synethesia see another person being touched or hurt, they actually feel the sensation themselves. There are several types of synesthesia, a neurological syndrome that causes senses to cross paths in the brain. For some synesthetes, for instance, specific colors create distinctive sounds in their head. Experts had heard only ancedotal accounts of mirror-touch synethesia until neuroscientist Sarah-Jayne Blakemore discussed the phenomenon at a seminar in 2003. "There was a woman in the audience who asked 'doesn't everyone experience that? Isn't that completely normal?" Blakemore tells Nature. Since then, Blakemore has studied 10 other mirror-touch synesthetes. All of them have overactive mirror neurons, which are the brain cells that allow us to see an action and comprehend it enough to be able to mimic it. "I have never been able to understand how people can enjoy looking at bloodthirsty films," says Alice, one of Blakemore's study subjects. "I can feel it."

Two comments:
(1) To some extent all of us do this. For example, one of my students tells me that once her boyfriend accidentally pulled her hair and yipped 'Ouch!' before she said anything. He claimed that it actually hurt him when he did it (I'm presuming that he doesn't have this condition).

(2) In general, I've always thought synesthesia is one of the coolest neurological conditions. A friend with perfect pitch tells me that he can tell if a note is off by its color --for example, A 440 seems red to him. That sounds very cool (though I'm not sure how much I'd like to have the version discussed here).

10 July 2007

Next up: Sharks with lasers

Following up on the previous post on non-lethal technology, the universe has decided to laugh at me.

Armed autonomous robots cause concern
10:32 07 July 2007

NewScientist.com news service

A MOVE to arm police robots with stun guns has been condemned by weapons researchers.

On 28 June, Taser International of Arizona announced plans to equip robots with stun guns. The US military already uses PackBot, made by iRobot of Massachusetts, to carry lethal weapons, but the new stun-capable robots could be used against civilians.

"The victim would have to receive shocks for longer, or repeatedly, to give police time to reach the scene and restrain them, which carries greater risk to their health," warns non-lethal weapons researcher Neil Davison, of the University of Bradford, UK.

"If someone is severely punished by an autonomous robot, who are you going to take to a tribunal?" asks Steve Wright, a security expert at Leeds Metropolitan University, UK.


And the kicker is that its made by iRobot, maker of my beloved Roomba. My cats have been telling me there's something evil about that thing for years.