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5th Aug 2007
Venoms and Toxins - Nature's Chemical Arsenal
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This week, mind reading children, scientists find a new gene in the lung cancer cocktail, and satnav or map-nav - what's greener? Plus we become biological weapons inspectors and explore nature's arsenal of venoms, poisons and toxins, including a scorpion's sting that can highlight cancer, how funnel web spiders are helping farmers fight off insect pests, the marine cone snail that harbours a painkiller ten thousand times more powerful than morphine, and how a snake bite can help to prevent a heart attack. Meanwhile, in Kitchen Science, Ben samples a more everyday toxin - by making stinging nettle tea.
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Interviews
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Jim Olsen, Fred Hutchinson Cancer Research Centre
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Susanne Bard & Bob Hirshon, AAAS
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Bruce Livett, University of Melbourne
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Gavin Laing, Liverpool School of Tropical Medicine
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Glenn King, University of Queensland
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Dr Beverley Glover, University of Cambridge
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Question of the Week
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How does an Octopus keep track of all eight arms? Does it have one brain for each arm?
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Welcome to the forum!...
- Karen W. - 1st Oct 07
I was really fascinated with spider venom used as a natural pesticide that has to be the way to go....
- Lazy_Genius - 1st Oct 07
Although just because it is natural doesn't mean that it is going to be environmentally harmless. Each chemical should be taken on its merits whe...
- daveshorts - 1st Oct 07
yes thats true, The guy seemed a little fuzzy on how it would effect friendly species too...
- Lazy_Genius - 1st Oct 07
Whole Thread | Post Reply | Science News
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As a new dad, Dr Chris may feel like his baby can read his mind. And now researchers in Italy have shown that he may actually be right.
One of the unique characteristics that makes us human is our ab... |
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What's best for the environment, a well thumbed map and some common sense, or a satnav? To find out, Tiawanese researchers Wen-Chen Lee and Bar-Wen Cheng from the National Yunlin University of Science... |
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Lung cancer has a very poor survival rate, which is often due to the fact that the disease isn’t diagnosed until it has spread around the body, making treatment difficult. Now a team of researchers in... |
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A cluster of new anti-AIDS drugs are expected to be approved for general use later this year, giving hope to patients who have developed drug-resistant forms of the virus. This is because the new agen... |
Questions
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We hear all the time about the 10s of thousands of chemicals in cigarettes, including things like formaldehyde, but why are they there? Would smoking straight tobacco be as harmful? If not, why aren’t cigarettes made that way? Is it the chemicals that smokers are addicted to or the tobacco?
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The main thing that smokers are addicted to is nicotine, which is a drug that your brain starts to crave after you’ve been exposed to it. There’s more than 4000 chemicals in cigarettes, and they come from a variety of sources. Some of them are in the tobacco plant itself, absorbed from the air by the plants including chemicals such as polonium. Some chemicals are produced when the tobacco is processed, some are added in when cigarettes are made. The most dangerous chemicals in tobacco are actually created when you burn a cigarette; the chemicals of burning are produced by the act of lighting a cigarette and inhaling something that is burning.
There are a few extra chemicals added during the process of making a cigarette, and so smoking straight tobacco would lack these, but the important chemicals are created by the simple act of burning the tobacco.
A lot more information is available from Cancer Research UK’s smoke is poison campaign, www.smokeispoison.com.
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What are the main components and causes of household dust?
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Dust is mainly human skin cells. The average person loses between 50-100 thousand skin cells every minute. Those flakes of skin accumulate in carpets and furnishings, dry out and then are lifted into the air by drafts or air currents.
Because dust mainly consists of skin cells, it’s nutritious and there are some things that will eat it. House dust mites are a microscopic organism which eat these skin cells –asthma sufferers are often allergic to their poo, which is carried into the air, and can irritate the lungs.
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I was wondering how they produce antibodies from venoms of snakes to make a anti-venom from it. And whether this is a long process or not.
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We put this question to Gavin Laing, of the Liverpool School of Tropical Medicine:
Okay, antivenom has been around for at least 100 years, but the techniques of producing antivenom have not really altered a lot in that time. What normally happens is a very large animal is immunised over a long time with very small amounts of snake venom, so it won’t harm the animal; traditionally they have used horses.
Chris: So what you would do is milk the snake, get some of its venom and then inject that into the horse.
Gavin: Yes, in very small quantities, so the horse will not be affected at all, it’s only a tiny amount. The horse will then raise antibodies against this antigen that’s been injected in the same way that humans immunised with smallpox would be raising antibodies against that.
Chris: So the horse gets antibodies in the bloodstream.
Gavin: That’s correct, and over a long period of time, say eight months or so, the horse will then become hyper-immune. Every so often, some serum is then drawn from the horse and immunoglobulins are purified from that, and from that you can split the immunoglobulins into smaller components such as the FAB or the FAB prime-2. And these would then be infused intravenously to a person who presents themselves in hospital who has been envenomed.
Chris: And so the antibodies would, in that victim, lock on to the venom and neutralise it?
Gavin: They would. They would seek out the circulating venom in the patient and immobilise it. They would form an immune complex and would be completely harmless and would then be flushed away normally.
You can read the whole interview with Gavin here, or listen to it as part of the podcast.
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| Venoms and Toxins - Nature's Chemical Arsenal - More about this podcast“You're toxic, I'm slipping under…”
This week on the Naked Scientists we’re heeding the words of the charming Ms Britney Spears and delving into the dangerous world of natural poisons, also known as biotoxins. We’ll be joined by snake venom expert Dr Gavin Laing, and we’ll find out from Dr Bruce Livett how the deadly cone snail could be a potent source of painkillers. Plus we hear from Dr Jim Olson about a tumour “paint” made from scorpion venom.
From deadly ricin produced by castor bean plants to the fatal venom of the Black Widow spider, a number of animals and plants produce some pretty nasty chemicals. Some of these are used for defence, to protect an animal or plant against being eaten. But sometimes they are used for attack, with dramatic results. For example, box jellyfish have the most deadly venom in the animal kingdom, and use it to stun or kill their prey before scoffing it. But they can also kill unwary humans who stray into their path - will we make it through the show in one piece?
Snakes in the grass
Dr Gavin Laing from the Liverpool School of Tropical Medicine is the expert who’ll carefully guide us through the world of deadly snakes, which kill around 125,000 people every year around the world. He is studying the biological mechanisms that underlie the poisonous effects of snake bites, and trying to turn this to medical advantage through the development of anti-venoms and new drugs.
For example, Dr Laing and his team have found a new type of receptor protein on the surface of platelet cells – responsible for blood clotting – by studying the actions of snake venom on the cells. This work revealed a whole new signalling pathway in platelets – perhaps this could one day lead to new ways to treat blood diseases.
Dr Laing is also working on anti-venoms, which can help to treat people who have been bitten. In particular these treatments are vitally important in places such as Africa, where many people die of snake bites every year. He is working on new ways to create and test anti-venoms that could save many lives. And of course, Gavin will be on hand to answer any venom-related questions, so email us now.
From killer to healer?
But not all venoms spell bad news for humans. We’ll be hearing from Dr Jim Olson from the Fred Hutchinson Cancer Research Centre in Seattle. He’s been developing a “tumour paint”, based on a molecule found in scorpion venom. When injected into the body, the paint sticks to cancer cells within minutes and causes them to glow, but doesn’t bind to healthy tissues. The technique could help surgeons to remove tumours more accurately.
We’ll also hear from Glenn King at the University of Queensland, who is investigating whether toxins from poisonous spiders could be used to make the next generation of pesticides. Harmless to humans but fatal for the insects that eat our food, we find out if spider venom could lead to cleaner, greener farming in the future.
And finally, Dr Bruce Livett from the University of Melbourne works on cone snails found in tropical seas. These crawling critters produce a potent venom that can kill humans. But Dr Livett has found that they also make a painkilling protein that is a thousand times more powerful than morphine, and he has now found the gene responsible for making it. Could the future of pain relief be snail shaped? Find out more on the Naked Scientists this week. |
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