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Welcome. Science.

And that is the same physics, medicine, nature, or space, time, the brain, life, the universe.

Hello, this week, the Naked Scientist Sense Month continues with a look at the science of smell,

including how we can learn smells in our sleep, and the dogs that can smell

when their owners are having a nightmare.

Plus, a marathon-running physiologist, plastic-munching bacteria, and how an oversized spleen helps a group of divers to hold their

breath for longer. I'm Georgia Mills. I'm Chris Smith and this is the

Naked Scientist. The Naked Scientists podcast is powered by UKfast.co. UK.

Plastics are incredible materials which have arguably transformed the quality of modern life,

but they come at a huge cost, which is that because they're chemically unnatural,

nature hasn't evolved an efficient way to deal with them so they

accumulate and damage the environment.

However, there are some plastic-like chemicals that are used in nature, including by plants

to protect their leaves.

So some bacteria do carry enzymes, which are biological catalysts,

that are capable of attacking these substances.

And a couple of years ago, scientists in Japan discovered bacteria carrying a mutated form of one of these enzymes that was enabling them to degrade PET, which is one of the communist forms of man-made plastic.

Now, John Magean at the University of Portsmouth has assembled a 3D model of this mutant

eating enzyme to understand how it works and to help him to discover how to make it work even better.

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