the-BA : Science News Digest

Flood (image copyright: istockphoto.com)

by Berwyn Jones

In the science news this week: scientists take the first step towards computerised bionic eyes, how HIV can be stopped in its tracks, and more rain is coming our way. Plus, police use flower power to tackle gun crime...

The Times reports on how an American woman has become the first paying customer to have her dog cloned.

Bernann McKinney, 57, received a quintet of puppies who were not only genetically identical to each other, but also to her late pitbull terrier Booger who died two years ago. South Korean biotechnologists used the frozen remains of Booger’s ear to produce the puppies in a process that cost over £25,000.

It has been over ten years since Dolly the sheep became the first cloned animal, but canine cloning has proven particularly difficult due to unpredictable ovulation cycles and difficulties in extracting a mature egg. However, RNL Bio, the company that undertook the cloning, has now declared itself open to international business, and has already been involved in cloning copies of the best South Korean sniffer dogs.
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Scientists have developed a digital camera closely modeled on the human eye, in what could prove the first step towards computerised bionic eyes.

It is the first time that scientists have built a curved light-sensitive surface for a digital device. Conventional cameras use a flat service for detecting light, but this involves complex lenses to ensure that light landing towards the outside of the surface is not distorted by the fact it is outside the focal plane of the lens. Scientists at the University of Illinois believe that a curved light detector would be much better suited for retinal implants and could be attached to the surface of an artificial eyeball.

It has taken scientists 20 years to build an effective curved light detector, and one of the reasons for their recent success was the ability to miniaturise photodetectors and elements of the circuits. The fact that they were smaller meant that they were not affected by the distortion of being built into a curved shape, much the same way as buildings are not distorted by the curvature of the Earth.

(Read more at the Independent)
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A recent study has shown that HIV can be stopped in its tracks by a technique that ‘silences’ genes, reports the Independent.

The technique, called RNA interference, ‘silences’ genes by means of a natural molecular switch in the cell and can prevent the HIV virus replicating. This could herald a new method of treating HIV that does not involve toxic anti-viral drugs.

The study by Harvard Medical School is the first to show that the method works in animal testing. However, further animal studies are needed before it can be trialed in humans.

Professor Premlata Shankar, who carried out the work, believes that ‘RNA interference has great potential as an antiviral treatment’. ‘We think it has real promise, but there is a lot more to be done,’ she said.
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Neanderthal DNA recovered from a 38,000 year-old fossilised leg bone has shed light on why the species disappeared.

Scientists read the complete sequence of DNA held in ‘cellular power plants’ called mitochondria, which provide energy for cells. Analysis of 13 genes from the Neanderthal mitochondria showed that they were distinctly different to modern humans and suggests that there was little or no inbreeding between the two species.

Further DNA analysis showed that there had been very little evolutionary change in the species, suggesting that they only existed in small numbers, with maybe as little as 10,000 Neanderthals existing at any one time.

‘This has implications for our picture of Neanderthals and perhaps the reasons for their extinction. If the population was teetering on the brink for hundreds of thousands of years, it maybe changes our impression of what it would have taken to make them go extinct rather than if there were millions of them,’ said Adrian Briggs, a molecular biologist who worked on the project.

The team has only read four per cent of the Neanderthals genetic code so far but hopes to have a complete reading by the end of the year.

(Read more at the Guardian)
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The Telegraph reports that the number of extreme rainstorms will rise by more than 10 per cent by 2050.

The prediction is based on a joint study between the University of Reading and the University of Miami that looked at 20 years worth of satellite observations. Scientists have believed that a warmer climate will lead to more powerful rainfall for some time, but the study is the first hard-evidence that this is the case. The research also showed that previous rainfall predictions may have been underestimated.

‘One of the most serious challenges that humanity will face in response to climate change is adapting to changes in extreme weather events. There is a major concern that heavy rainstorms will become more common and more intense in a warmer climate,’ said Dr Richard Allan from the University of Reading.

Researchers studied the natural climate pattern El Niño, which affects weather across the globe. By examining the relationship between tropical rainfall and changes in surface temperature and atmospheric moisture, scientists concluded that heavy rain increased during warmer periods and decreased during colder periods.
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On the opening day of the 2008 Olympic Games, BBC News reports on how the hot, humid Beijing conditions may benefit British competitors.

With temperatures over the coming days expected to be in the mid-30s celsius along with high humidity, many people may expect the British team to wilt under the extreme conditions. However, a team from Nottingham Trent University has shown that members of the GB hockey squad were better at decision-making in the heat.

Researchers put two members of the squad into an ‘Environmental Chamber’ that recreated the exact heat and humidity expected in Beijing. They were then made to run on a treadmill in a way that mimicked the exertions of a game. When scientists asked them to complete mental tasks, the players were able to complete the same number as in normal conditions but at a much quicker rate.

‘We've found that under extreme conditions, elite athletes are able to draw on cognitive reserves which allow them to counter the effects of heat stress,’ said Hannah Macleod from Nottingham Trent University. ‘Their mental acuity is actually seen to improve, a result that is of enormous benefit to competitors in field sports such as hockey. Our findings have been able to offer reassurance to the GB players that their brain functions will not be affected by heat stress.’
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A genetic-mutation in dachshunds could help scientists understand the cause of some forms of inherited blindness.

Cone-rod dystrophy is a rare form of human blindness caused by progressive cell loss in the retina, and dachshunds appear to be particularly prone to a similar type of blindness. Until recently, scientists were unsure why this was the case, but US and Norwegian researchers have now discovered an altered gene which they think may be responsible.

They discovered that part of a particular gene, called NPHP4, was not present in affected dachshunds. ‘This gene has been associated with a combination of kidney and eye disease in human patients,’ said Dr Frode Lingaas, who was involved in the research. ‘Here, we found a mutation which affects only the eyes, suggesting this gene might be a candidate for human patients with eye disease only.’

Scientists hope that research on the similar gene in humans might lead to new therapies.

(Read more at BBC News)
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And finally...

Scientists have developed a way of using lily pollen to tag bullets and help catch the perpetrators of gun crimes.

The nanotags, made up of microscopic pollen and a unique chemical signature, can be coated onto the surface of bullets in their thousands, and will cling on even after the bullet has been fired.

‘The tags primarily consist of naturally occurring pollen, a substance that evolution has provided with extraordinary adhesive properties,’ explains Professor Paul Sermon from the University of Surrey. ‘It has been given a unique chemical signature by coating it with titanium oxide, zirconia [zirconium dioxide], silica or a mixture of other oxides. The precise composition of this coating can be varied subtly from one batch of cartridges to another, enabling a firm connection to be made between a particular fired cartridge and its user.’

By giving each batch of bullets its own nanotag, police will be able to pinpoint when, where and by whom the bullets were bought. The pollen tags, which are invisible to the human eye, would also stick to hands and clothes and could help police prove that someone has been handling the bullets.

(Read more at the Guardian)