the-BA : Science News Digest

Squirrel (Image copyright: istockphoto.com)

In the science news this week: scientists rebuild a beating heart, a fossil of a rat the size of a car is unearthed and experts blame Columbus for bringing syphilis to Europe. Plus, why we’re suckers for expensive wine...

US scientists made an exciting breakthrough that offers hope it will one day be possible to build ‘reconditioned’ organs for patients using their own stem cells. The researchers rebuilt a rat heart, using immature heart cells to repopulate an empty scaffold of connective tissue that had been created by dissolving the muscle cells of a dead rat’s heart. After several days in culture the cells started beating rhythmically and, to the astonishment of the team, a few days later the heart began pumping blood again.

‘We used immature heart cells in this version, as a proof of concept. We pretty much figured heart cells in a heart matrix had to work,’ said Professor Doris Taylor of the University of Minnesota. ‘Going forward, our goal is to use a patient’s stem cells to build a new heart. It opens a door to this notion that you can make any organ – kidney, liver, lung or pancreas.’
(Read more in the Independent)
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It is thought a fertility doctor has become the first human to clone himself. He created early-stage embryos with help from colleagues, using DNA from his and another man’s skin cells to replace the genetic material in donated eggs.

’This is a key advance in the development of patient-specific stem cell lines for therapeutic and drug development purposes,’ said Dr Miodrag Stojkovic, co-editor of the journal Stem Cells, which published the research.

Dr Stephen Minger, a stem cell expert at King’s College London, commented: ‘This is academically interesting research that shows that another group have managed to create clone human embryos using nuclear transfer. Disappointingly the researchers did not go on to do the next step – to create embryonic stem cell lines from cloned embryos. The community is waiting with baited breath to see if anyone can do both steps together.’
(Read more in the Telegraph)
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In other news, Dr Minger expressed delight that the Human Fertilisation and Embryology Authority (HFEA) has finally granted approval to his group to create embryos known as cytoplasmic hybrids, where human DNA will be injected into empty cow eggs. Another one-year licence was issued to a team from the University of Newcastle.

The decision brought an end to more than a year of uncertainty for the researchers. Permission was first sought in autumn 2006, but the HFEA deferred its decision and began a public consultation on the issue. In September 2007, they reported that the public was broadly supportive, but they again delayed their decision because of concerns relating to procedures for obtaining consent from the human DNA donors. During this process, the Government proposed a ban on the human-animal embryos but backed down after scientists strongly defended the need for the work.

Lyle Armstrong, who heads the Newcastle group, said: ‘Finding better ways to make human embryonic stem cells is the long-term objective of our work and understanding reprogramming is central to this. Cow eggs seem to be every bit as good at doing this job as human eggs so it makes sense to use them since they are much more readily available, but it is important to stress that we will only use them as a scientific tool and we need not worry about cells derived from them ever being used to treat human diseases.’
(Read more in the Times and Guardian)
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Paleotologists have uncovered the fossilised skull of a one-tonne rat that lived between two and four million years ago. The huge rodent would have been about the size of a car, reported the Times.

The discovery was made in rock deposits in Uruguay and was nearly whole. Previous finds of giant South American rodents had been limited to bone fragments.

While researchers concluded that it most-likely lived off soft vegetation since teeth in the skull were too small to have allowed it to chew food well, its incisors were a massive 30cm long (of which 10cm would have been exposed). Dr Ernesto Blanco, part of the team who discovered the fossil, suggests that the rat may have used its huge teeth like to fell trees like a beaver does, or in courtship rituals or to fight predators.
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Scientists have discovered that squirrels mistrust fellow acorn-hiders, pretending to bury their food in order to protect it from would-be thieves. Researchers observed eastern grey squirrels in two American states and found that they used the strategy of pretend burying around 10 to 20 per cent of the time. This behaviour increased in autumn and when other squirrels were less than 20 metres away.

In other experiments, the scientists raided the squirrel’s stores. This led to a higher frequency of false burying and also to the squirrels digging stores in more hidden locations.

The research of Dr Michael Steele and colleagues was highlighted in New Scientist magazine. He told the Telegraph that their work was the first to offer behavioural deception by a scatter-hoarding rodent.
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NASA’s Messenger spacecraft has captured images of the previously unseen ‘dark side’ of Mercury. Since the same hemisphere was in sunlight during each flyby of the Mariner 10 probe in 1974, only that side of the planet was photographed.

The latest pictures show features as small as six mile across and colour differences in craters and basins compared to surrounding regions suggest they may have different compositions.
(The Times)
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Also in the Times: researchers have provided the strongest evidence to date that Christopher Columbus’s crew was responsible for bringing syphilis to Europe from the Americas.

The feared venereal disease that plagued many well-known figures, including Henry VII, Abraham Lincoln and Vincent van Gogh, is caused by a sexually transmitted treponeme pathogen. The first recorded epidemic in Europe was recorded in 1495 among French Soldiers fighting in Italy, supporting the explanation that Columbus’s crew brought it back with them after their 1492 voyage to the New World. However, bone damage characteristic of syphilis has also been found in much older skeletons from several European sites, leading some to argue that syphilis did not originate from South America.

A team of scientists, led by Dr Kristin Harper of Atlanta’s Emory University, sought to clarify the origins of the disease by comparing the DNA of 26 strains of treponeme that cause syphilis and similar diseases.

They found that Treponema pallidum, the sexually transmitted strain responsible for syphilis, is most closely related to South American treponemes that cause a different disease known as yaws. Their work also suggests that an older strain of non-sexually transmitted treponeme may have evolved in Africa and become endemic in Europe long before Columbus made his monumental journey, and that this related disease could have caused the bone damage seen in the 13th, 14th and 15th century skeletons.

’[This genetic data] supports the hypothesis that syphilis – or some progenitor – came from the New World,’ said Dr Harper. ‘When this...is combined with extensive documentary evidence that syphilis appeared in Europe for the first time around 1495...the Columbian hypothesis for syphilis’s origin gains new strength.’
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And finally…

Restaurants may be helping our enjoyment of wines by raising the prices, it seems. The Times reported that research has shown that if a wine has a higher price people enjoy it more, even if it is not actually of a better quality.

The brains of 20 people were observed using functional magnetic imaging while they were given the same Cabernet Sauvignon and told it cost anything from £2.50 to £45 per bottle. As well as verbal reports from most people that the ‘higher-priced’ wine was more enjoyable to drink, researchers observed greater activation in response to the ‘expensive’ wines compared to the ‘cheaper’ ones in a part of the brain that plays a central role in many types of pleasure – showing the increased pleasure was real even though the wines were identical.

Some scientists pointed out that the pleasure the subjects derived from drinking the wine they believed to be expensive may have been decreased had they had to pay for it.

’In a study of 13,000 people it emerged that 15 per cent were spendthrifts to whom spending gave pleasure and 25 per cent were tight-wads to whom it gave pain,’ added Scott Rick, a researcher in neuroeconomics at Carnegie Mellon University in Pennsylvania. ‘The remaining 60 per cent fell in between the two.’

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