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Flesh-eating bacteria -

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HideRobyn Williams: We leap now to Oxford, investigating flesh eating bacteria, and another breakthrough involving genes and the structure of proteins. This is biochemist Mark Howarth.

Now, tell me, what is a flesh eating bacterium? What does it actually do to eat flesh?

Mark Howarth: There are a number of different species of bacteria which are able to cause this horrific disease, termed necrotising fasciitis, where the bacterium can cause loss of large amounts of issue. And the way it does this is through secreting enzymes which break down the connective tissue, and it also stimulates the immune system, and the immune system, rather than helping clear the infection actually contributes to the damage. So you can get very severe tissue degeneration, and unfortunately in many cases the surgeons can remove the infected area but sometimes it's so bad that amputation is the most effective treatment to actually avoid death.

Robyn Williams: So the flesh is almost dissolving.

Mark Howarth: It's quite horrific.

Robyn Williams: And does it occur quite commonly, this affliction?

Mark Howarth: It's not especially common. There was a period of hysteria in Britain in the '90s about this disease. It turned out that a lot of this was media driven. The number of cases that were found during that year were similar to the number of cases in previous years. But one of the strange things is that the origin is not very clear, that this bacterium, many people are carriers of it, and what happens to cause this condition is not clear. It's not like there's a particular strain which necessarily leads to it in every case.

Robyn Williams: Your work reminded me of looking for, if you like, the Higgs boson of microbiology, looking at how the glue works, just as the Higgs boson provides mass and to some extent binds small particles together, so similarly what you're looking at is a way that small creatures managed to somehow coalesce and have the glue within their systems.

Mark Howarth: Yes, that's a very interesting analogy, I hadn't thought of it like that. The Higgs boson is universal and relates to all matter. The features that we study are actually not at all universal, and that's why people have only discovered it in the last few years. They are very specific to a certain class of bacteria, and within those bacteria only a small proportion of the proteins actually contain this specific...what we might call a glue. But they are quite interesting because many of those bacteria are responsible for some very serious conditions like the flesh eating disease as we've discussed but also Staphylococcus aureus also has this glue within its proteins, and the causative agent of diphtheria, for example. So we can take this particular feature and apply it in new circumstances and create a kind of glue that hasn't been seen before and apply it for mammalian systems.

Robyn Williams: So what they're trying to this right? to latch on to parts of the body from which our general system is trying to expel them? So if they're rushing through the pipes they are trying to hang on and stay in the system. Is that right?

Mark Howarth: Yes, that's a part of it. So they are sending out these anchors which enabled them to latch on and attaching to the lining of your throat is one of the first crucial steps in the infection cycle, and it's important that they can produce a very strong stable anchors. And the way they do this is quite different to the way that most organisms produce strong protein structures, and part of this may relate to the fact that many of these bacteria survive very well under very low oxygen environments. And if you have oxygen around there are certain oxidising chemistry which you're able to do to lock your proteins together which these bacteria are unable to do. And so evolution has managed to come up with an alternative chemistry, an alternative glue to hold these proteins together.

Robyn Williams: And how are you making use of that?

Mark Howarth: What we've done is dissect these proteins. So rather than one half of the bacteria's protein sticking to the other half and the proteins become locked together, what we've done is split this protein into two parts. We can do this genetically, so that when the two parts come together then they form an irreversible lock. There is nothing you can do to break this linkage, which is quite different to the way that most interactions work in biology where things are tuned to be easy to put together, easy to pull apart because things are constantly changing in your cellular environment. And so we can create a lock which will never break, and that provides us with a new tool for targeting, which could be applied to drugs and other therapies, for example.

Robyn Williams: In what way will the flesh eating bacteria be an inspiration, if you like, for this?

Mark Howarth: This chemistry is actually very surprising. No one thought that this reaction would happen spontaneously. They are catalysing something which would be very hard to do in a test-tube. So learning from the chemistry that they are able to carry out and applying it in a new way, no one would have thought it possible until people started investigating the molecular details of how these bacteria function.

Robyn Williams: A way to subvert these killer bacteria by playing with their proteins. Mark Howarth lectures in biochemistry at Oxford and is a fellow of Worcester College where Rupert Murdoch once studied and displayed portraits of Lenin.