Sunday, February 17, 2013

Diamond to shine light on infections

The UK's national synchrotron facility - the Diamond Light Source near Oxford - is to become a world centre for studying the structure of viruses and bacteria that cause serious disease.

Diamond uses intense X-rays to reveal the molecular and atomic make-up of objects and materials.

It will now use this capability to image Containment Level 3 pathogens.

These are responsible for illnesses such as Aids, hepatitis and some types of flu.

Level 3 is one step down from the most dangerous types of infectious agent, such as Ebola, which can only be handled in the most secure government facilities.

"Viruses, as you know, are sort of tiny nanomachines and you can't see them in a normal microscope.

"But with the crystallography and X-ray techniques we use, we are able to get about 10,000 times the resolution of the normal light microscope," explained Dave Stuart, the life sciences director at Diamond and a professor of structural biology at Oxford University.

"This takes us from the regime of not being able to see them to being able to see individual atoms.

"And if we can look at 'live' viruses and get an atomic-level description of them, it opens up the possibility of using modern drug-design techniques to produce new pharmaceuticals."

Prof Stuart was speaking in Boston at the annual meeting for the American Association for the Advancement of Science (AAAS).

Diamond has been working for some time to get its "Crystal Lab" ready for Level 3 work, and the Oxford researcher used the US conference to announce that the preparation was now complete.

Synchrotrons work by accelerating electrons in a giant magnetic ring to near light-speeds.

As the particles turn around the circle, they lose energy in the form of exceptionally intense X-rays.

This light is channelled down "beamlines" where it hits targets put in its path.

The way the X-rays scatter off the atoms in these targets reveals their arrangement. This allows scientists to glimpse the shape of virus and bacteria components and get some insight into how they function.

Diamond has already been studying pathogens at lower levels of containment.

A good recent example, says Prof Stuart, is the Human Enterovirus 71 (EV71) that causes hand-foot-and-mouth disease.

The infection is relatively common in infants and children, especially across the Asia-Pacific region, and is characterised by fever, painful sores in the mouth, and unpleasant blisters on the hands, feet and buttocks. There is currently no vaccine or anti-viral treatment available.

A joint UK and Chinese team working at Diamond solved the structure of EV71 last year.

This allowed the researchers to see a kind of breathing motion in the virus that it uses to initiate the infection process. Evident also was the small molecule it picks up from the body's cells to shift itself from one state to another.

"That molecule must be lost to cause an infection, but now that we can see in atomic detail what that molecule looks like, we can try to design a synthetic version that will attach more strongly," Prof Stuart told BBC News.

"That would stop the breathing and stop the infection process."

The British synchrotron's new status makes it now one of only two such facilities in the world where Level 3 study is undertaken; the other being in the US.

This means it will be a major draw for scientists across the world.

Prof Stuart stressed the operations at Diamond would pose no risk to others working on the Harwell site or in the immediate Oxfordshire area.

The pathogens will be brought to the synchrotron in crystal form in double-sealed containers that are not opened during their time at the facility.

They are manipulated robotically inside the Light Source and, what is more, they are destroyed in the very act of shining X-rays on them.

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos

Source: http://www.bbc.co.uk/news/science-environment-21481223#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa

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