the-BA : Science News Digest

Elephant (Image copyright: istockphoto.com)

In the science news this week: the new stem technique proves its mettle, a breakthrough 3D cell image, and the dark stars that could litter the cosmos. Plus, the amazing memory feats of chimps and elephants…

Three young chimps have been showing humans up by performing much better at a numerical memory task. Researchers at the Primate Research Institute in Kyoto, Japan, set up computerised games in which the numbers 1 to 9 were scattered randomly across the screen. To complete them successfully, the chimps had to touch the numbers in order. The task was made more difficult by the absence of certain numbers – to complete it the apes had to realise that if the number 4 was missing, for example, the sequence continued with 5. Other variations included replacing the numbers with blank squares once the first number had been touched – the chimp then had to remember where the other numbers had been located.

Even when the time allotted to memorise the position of the numbers was reduced to just a fraction of a second, the chimps performed well. In fact, this was when the difference between the animals and human student volunteers was most noticeable. Ayumu, the best-performing chimp, successfully identified the number order 80 per cent of the time when the digits appeared on screen for just two tenths of a second. In comparison, humans were correct just 40 per cent of the time.

Their ability suggests Ayumu and the other young chimps have something akin to ‘eidetic imagery’ – the retention of detailed and accurate images of complex scenes or patterns. Some children have this ability, but it declines with age. When an older chimp, Ayumu’s mother, was tested, she performed worse than the humans.
(Watch chimps perform their memory feat at the Guardian)
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A ‘monster’ find of a dinosaur ‘mummy’ has provided new insights into the life and appearance of the hadrosaur, a plant-eating contemporary of the Tyrannosaurus rex. The fossil was of such a high quality, a stripey skin pattern can be discerned. Not only that, soft tissue is present. This is normally destroyed by microbes before fossilization takes place, and has only been preserved in a handful of specimens.

Dr Phil Manning, the Manchester University who led the investigation said: ‘When you get up close and look at the skin envelope it's beautiful. This is not a skin impression, it's fossilized skin. That's very, very different.’

The fossil has provided such exquisite detail that it has led paleontologists to revise their ideas of what the animal looked like and how it moved. One surprise was that its rump was 25 per cent larger than previously assumed, meaning more muscle power and greater acceleration. One of this year’s BA Festival of Science presenters, Dr Bill Sellers, calculates that it was able to outrun the T. rex.

The specimen also has bigger implications for the size of other dinosaurs. Curators generally display dinosaur vertebrae with no gaps. However, the detail in this fossil revealed that its vertebrae were separated by a centimetre thickness of soft tissue. This could mean that other dinosaurs were much longer/taller than estimated. For example, reports the Guardian, the gaps would make a specimen with 200 vertebrae two metres longer.
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Last month, scientists unveiled a new technique for producing stem cells without using embryos that worked by reprogramming human skin cells (see Science News Digest – 23 November 2007). This week, the first study showing that the technique can be used to cure disease was published in the journal Science.

Researchers reprogrammed mouse skin cells back to an embryonic state before programming them to develop into the precursors of bone marrow stem cells which produce blood cells. They then replaced a defective gene that was causing sickle cell anaemia in the animals. When the cells were injected back into the mice they reversed the symptoms of the disease, reported the Guardian.
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Scientists have finally achieved their long-standing goal of a 3D image of a cell with the publication in Nature of the first 3D image of human skin at molecular resolution.

At just 10 microns – one hundred thousandth of a metre – across, single cells are too small for their inner organelles and proteins to be visible using a conventional light microscope. Electron microscopes could cope with the scale, but aren’t suitable for viewing living cells because they require a vacuum and metal-coating of the sample. Instead, researchers from the European Molecular Biology Laboratory in Heidelberg, used Cryo-electron tomography to build up a 3D picture of a cell that was first frozen, and then scanned at multiple levels.

‘This is a real breakthrough in two respects,’ group leader Dr Achilleas Frangakis told the Daily Telegraph. ‘Never before has it been possible to look in three dimensions at a tissue so close to its native state at such a high resolution. We can now see details at the scale of a few millionths of a millimetre. In this way we have gained a new view on the interactions of molecules that underlie cell adhesion in tissues - a mechanism that has been disputed over decades.’

The team focused on a class of proteins called cadherins, which play a key role in cell-cell interactions. These important proteins are crucial for tissue integrity and play an important role in the spread of cancers, as the interactions must be overcome for tumour cells to become metastatic and spread throughout the body, which is the point at which many cancers become deadly.

The new method enabled the researchers to see the interaction between two cadherins directly.
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In other news, the Times reported that a UK Centre for Medical Research and Innovation in the centre of London has come a step closer to reality after the Government agreed to sell three acres of land next to St Pancras Station. The £500 million medical laboratory which is backed by the Medical Research Council, the Wellcome Trust, Cancer Research UK and University College London will house 1,500 experts researching cancer, stem cells and flu pandemics, as well as genetics, neuroscience and infectious diseases, among other things.

Sir Leszek Borysiewicz, the MRC chief executive, said: ‘The [hub] will help people to live longer, healthier lives – in London, the UK and across the world. By taking groundbreaking scientific discoveries right through to treatment, I expect that the 1,500 staff who will be part of this project will develop many of the cures, vaccines and drugs from which the NHS and its patients will benefit in years to come.’
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The launch of the Atlantis space shuttle was postponed due to faulty fuel gauges, delaying the mission to deliver Europe’s first permanent space laboratory to the International Space Station.
(BBC News)
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Scientists may have traced the source of solar wind – electrically charged gas that is propelled away from the Sun at great speeds that can interfere with electric power grids on Earth, along with terrestrial communication and navigation systems. The Hinode satellite’s high resolution X-ray telescope has provided the first direct evidence of Alfvén waves – magnetic waves rippling within the Sun’s plasma that are thought to be critical for driving the solar wind into space.

Researchers would like to be able to predict the incidence of space storms involving solar wind, so that they could plan for them and possibly reduce the disruption caused. As the Telegraph reports: there will be a solar maximum in 2011 or 2012 so the number of solar flares and eruptions will increase until then, and some predict that the next cycle will be the most intense for half a century.
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In other space-related news in the Telegraph, scientists in the US have proposed that the cosmos could be speckled with ‘dark stars’ that are 400 to 200,000 times wider than the Sun and powered by dark matter annihilation. They have calculated that these invisible stars that spew out gamma rays, heat and antimatter were the first stars in existence.

Researchers don’t know whether such stars still exist as they don’t know how long they could last for – this is a calculation they are now carrying out. But Prof Paolo Gondolo, who was involved in the study, suggests that, if they do, ‘they would most probably be found among old stars, for example in globular clusters, the bulges of spiral galaxies, or elliptical galaxies.’
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This week, as governments met in Bali for a key UN climate summit to discuss future greenhouse gas reduction measures, scientists reported that, according to five different strands of satellite evidence, the tropics have widened by between 2 and 4.8 degrees latitude since 1979, with important implications for ecosystems and human settlements. And in another study, computer models have projected a doubled frequency of weather conditions in which severe thunderstorms can occur.
(BBC News)

There were also a number of climate-related warnings:

More than 200 scientists signed a declaration urging politicians at the conference not to delay reaching an agreement on how to reduce greenhouse gas emissions, announced the Times. The declaration warned of the serious consequences faced if we fail to limit temperature rises and says: ‘Global greenhouse gas emissions need to be reduced by at least 50 per cent below their 1990 levels by the year 2050… In order to stay below 2C, global emissions must peak and decline in the next ten to fifteen years, so there is no time to lose.’

The WWF released a report warning that by 2030 almost 60 per cent of the Amazon rainforest could be destroyed or severely damaged as a result of climate change and deforestation. According to Dan Nepstead, the senior scientist who authored the report, the area is a key stabiliser of the global climate system, whose importance cannot be underplayed. And yet the ‘point of no return’ is just 15- 25 years away, says the report – much sooner than some models suggest. After this, the conservation prospects will be greatly reduced.
(The Guardian)

Another report, commisioned by the OECD, served to warn Governments that they must begin major flood defence projects now to prevent massive loss of life and assets in coastal floods caused by climate change. They assessed the risk to 136 port cities around the world with over a million inhabitants in scenarios where the global sea-level has risen by half a metre and wind strength and pattern have also changed due to climate change. All but three of the countries deemed to be at risk of catastrophic flooding are in developing countries.
(The Guardian)
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And finally…

It’s not just chimps that have been showing off this week. Female elephants have also been demonstrating their impressive memories. They can remember the locations of at least 17 family members simultaneously within in a constantly changing environment.

‘Elephants are keeping track of whether a member of the family is in the group they are in and whether they are in front or behind,’ said Professor Richard Byrne of the University of St Andrews. ‘That’s quite a challenge for any of us when you are talking about 20 to 30 individuals.’

African Elephants are able to identify one another from urine traces. To test the elephants’ memories, researchers collected samples of urine-soaked earth in the Amboseli National Park in Kenya, and placed them in areas where a herd of elephants was about to pass. They observed that elephants exhibited signs of surprise when they smelt the odour of a family member they knew was behind them and had not passed that patch of ground, reported the Times.

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