Bacteria 'linked' to Parkinson's

22 May 2011 Last updated at 23:03 GMT Could this bacterium cause Parkinson's disease? The bacteria responsible for stomach ulcers have been linked to Parkinson's disease, according to researchers in the US.

Mice infected with Helicobacter pylori went onto develop Parkinson's like symptoms.

The study, presented at a meeting of the American Society for Microbiology, argues that infection could play "a significant role".

The charity Parkinson's UK said the results should be treated with caution.

Parkinson's disease affects the brain and results in slow movements and a tremor.

Middle-aged mice, the equivalent of being between 55 and 65 in humans, were infected. Six months later they showed symptoms related to Parkinson's, such as reduced movement and decreased levels of a chemical, dopamine, in the brain.

These changes were not noticed in younger mice.

Toxic

Dr Traci Testerman, from the Louisiana State University Health Sciences Center, said: "Our findings suggest that H. pylori infection could play a significant role in the development of Parkinson's disease in humans.

"The results were far more dramatic in aged mice than in young mice, demonstrating that normal ageing increases susceptibility to Parkinsonian changes in mice, as is seen in humans."

The researchers believe the bacteria are producing chemicals which are toxic to the brain.

They said H. pylori was able to "steal" cholesterol from the body and process it by adding a sugar group.

The bacteria responsible for stomach ulcers may have a role in Parkinson's say researchers.

Dr Testerman said this new chemical was almost identical to one found in seeds from the cycad plant, which had been shown to trigger a Parkinson's-like disease among people in Guam.

She told the BBC: "H. pylori eradication in late stage Parkinson's disease is unlikely to result in significant improvement.

"Certain neurons are killed before symptoms begin, and more are killed as the disease progresses. Those neurons will not grow back."

Dr Kieran Breen, director of research at Parkinson's UK, said: "We believe Parkinson's is most likely caused by a combination of environmental factors together with an individual's genetic susceptibility to developing the condition.

He said there was some evidence that bacteria can prevent the main drug to treat Parkinson's, levodopa, being absorbed, but there was no strong evidence that people who have H. pylori in their gut are actually more likely to develop Parkinson's.

He added: "The current study is interesting and suggests that the bacteria may release a toxin that could kill nerve cells.

"However, the results should be treated with caution. The research was carried out in mice that were infected with relatively high doses of the bacterium or its extract.

"While they developed movement problems, we don't know whether this was actually due to the death of nerve cells. Further research needs to be carried out".

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Bacteria 'abound in hailstones'

25 May 2011 Last updated at 07:45 GMT By Jason Palmer Science and technology reporter, BBC News The layers representing the build-up of hailstones can be seen in cross-section A study of hailstones has found large numbers of bacteria at their cores.

The find lends credence to the "bio-precipitation" idea, which suggests that bacteria are actively involved in stimulating precipitation.

The bacteria have protein coatings that cause water to freeze at relatively warm temperatures.

Researchers at the American Society for Microbiology meeting suggest bacteria may have evolved to use the water cycle to facilitate their own dispersal.

The micro-organisms that can be found in precipitation such as snow have been studied since the 1960s.

One bacterium that has appeared in many contexts is Pseudomonas syringae, which expresses a protein on its surface that encourages an orderly arrangement of water molecules.

That in turn acts as a "nucleation" site, stimulating the formation of ice at temperatures far higher than those normally required.

So effective is P. syringae at the task that it is used in a commercially-available mixture for snow machines.

In nature, the ice that P. syringae stimulates can damage the walls of plant cells, allowing the bacterium to feed on the cells' interiors.

Only in recent years, however, has a wider role for the bacterium's strategy started to become more clear.

In 2008, Brent Christner of Louisiana State University reported finding significant numbers of bacteria in snow found around the world.

'Intriguing'

Now, Alexander Michaud of Montana State University has added to the idea, having collected hailstones on the university campus following a major hailstorm in 2010.

P syringae bacteria are well-known "catalysts" for ice formation

He analysed the hailstones' multi-layer structure, finding that while their outer layers had relatively few bacteria, the cores contained high concentrations.

"You have a high concentration of 'culturable' bacteria in the centres, on the order of thousands per millilitre of meltwater," he told the meeting.

The bacteria are known to gather together in "biofilms" on the plant surfaces and can form bacteria-rich aerosols in forest canopies - aerosols that can rise on updraughts, eventually stimulating precipitation in clouds at temperatures far higher than would be required if soot or dust served as the nucleation sites.

Dr Christner, also present at the meeting, said the result was another in favour of the bio-precipitation idea - that the bacteria's rise into clouds, stimulation of precipitation, and return to ground level may have evolved as a dispersal mechanism.

"It's an interesting idea that's been thrown around for decades but only recently has the data accumulated to support it," he told the meeting.

"As a microbiologist, this idea that... an organism could piggy-back on the water cycle I find just intriguing.

"We know that biology influences climate in some way, but directly in such a way as this is not only fascinating but also very important."

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