the-BA : Science News Digest - 15 November 2007

Modern chocolate drink (image copyright: istockphoto.com)

In the science news this week: successful creation of a cloned monkey embryo prompts hopes and fears for human cloning. Plus, the buzz that helps build up bone, a toothsome dino and our lengthy love affair with chocolate drinks...

The Times announced that scientists have successfully created embryonic stem cells from a cloned monkey embryo for the first time.

Lack of previous success with primates suggested it was too technically demanding and had prompted speculation that therapeutic cloning might always remain impractical, but now hopes have been raised that one day human embryonic stem cells could be created to help treat a multitude of diseases such as Parkinson’s and diabetes.

Professor Shoukhrat Mitalipov, of the Oregon National Primate Research Centre led the new research which has been published online by the journal Nature. Previous fraudulent claims by the South Korean scientist Woo Suk Hwang has increased scepticism in the field but the latest work has been confirmed by an independent group of scientists commissioned by Nature.

Professor Mitalipov transferred nuclei from an adult male rhesus macaque monkey’s skin cells into 304 eggs from 14 female monkeys, and two colonies of ES cells were successfully created from the resulting embryos. His success has been attributed to a new method for handling the eggs while the nuclei are transferred, which avoids the damage caused by the dye and UV light used in the conventional approach, says Nature online.

For the moment, the frequency of success is too low to make human cloning practical, but the progress made is likely to strengthen calls for an international ban on reproductive cloning.
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Scientists have come up with an intriguing new way to strengthen bones in elderly people that could even tackle obesity, reported the Telegraph.

Professor Clinton Rubin from the State University of New York, Stony Brook, discovered that when mice stood on a gently buzzing platform for 15 minutes a day, five days a week, they had 27 per cent less fat and correspondingly more bone than mice that didn’t. The US National Institutes of Health now plan to investigate the effects on bone and fat in elderly people in a large clinical trial.

The mice in the study were fed identical amounts of food, whether they were in the buzzed or control group, but critics cautioned that the act of staying on the platform could be burning extra calories. Professor Rubin thinks that the vibrations could simply boost the effects of diet and exercise in some people, but he also believes that the vibrations act on immature cells in bone marrow that have the potential to turn into either fat or bone.

‘The whole point of the mice study is that we keep the animals lean by slowing down the commitment of stem cells into fat cells... they are busy instead becoming bone cells. So you can't get fat if you don't have any fat cells to start with,’ he said.
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Brain implants could one day help paralysed patients who have lost the power of speech to communicate audibly. Scientists have taken the first steps towards this goal with the help of Eric Ramsey, who has been unable to speak since he was paralysed eight years ago in a car accident, despite being fully aware. Currently he can only communicate via eye movements.

The Times reported that Mr Ramsey is the first person to receive implants into the area of the brain that normally generates movement in the tongue and mouth during speech. To begin with, he has been asked to focus on imagining the vowel sounds ‘oh’, ‘ee’ and ‘oo’ while researchers analyse the brain activity recorded by the electrodes. The researchers believe they can correctly identify the sound he is thinking of 80 per cent of the time.

The results were presented at the Society for Neuroscience conference in San Diego by the lead researcher, Jonathan Brumberg of Boston University. The team now plans to use a computer to translate the electrodes’ recordings into sound, so that Mr Ramsey can provide direct feedback and help fine tune the accuracy of the system. They will then move onto other vowels and consonants.
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A global inventory of carbon dioxide emissions has pinpointed Australians as the worst emitters per capita.

A US think-tank, the Center for Global Development compiled the data for the Carbon Monitoring for Action website. The study, which focuses on power stations, shows that, overall, US power plants emit the most carbon dioxide, closely followed by China. However, if the number of people are taken into account, Australian plants are the least efficient – emitting 10 tonnes, compared to the US’s 8. 2 tonnes.

The website aims to provide people with information they did not previously have. A research assistant at the think-tank, Kevin Ummel, told BBC News that their website doesn’t push a particular agenda or outcome but that ‘the experience of people in the environmental field has been that supplying the public and markets with information that they did not have has often led to improvements in environmental quality.’
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Scientists are enlisting the help of bacteria to help provide a more environmentally friendly source of hydrogen – raising the possibility that it could become a viable, plentiful fuel that could help limit climate change.

Hydrogen itself produces only water when it is burnt, which is why many public transport systems are moving towards hydrogen-powered engines as a green alternative to petrol engines. However, currently most hydrogen is produced by burning polluting fossils fuels. A new ‘electrohydrogenesis’ process offers an alternative where ‘efficient and sustainable hydrogen production is possible from any type of biodegradable organic matter’.

The Telegraph reports that the method developed by scientists in America uses electron-generating bacteria, grown from soil or waste water, combined with a small electrical charge. The bacteria are grown in special ‘microbial electrolysis cells’ that increase bacterial growth and electrical current generation.

According to Prof Bruce Logan, one of the research team: ‘This process produces 288 per cent more energy in hydrogen than the electrical energy that is added to the process.’
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An observant PhD student from Portsmouth University has uncovered a previously unknown dinosaur species that lived 140 million years ago.

Mike Taylor was visiting London’s Natural History Museum’s sub-basement as part of his research when he came across a labelled spine fossil that struck him as wrong.

‘I was going through the cabinets looking for two particular specimens, but before I got to those, I found this thing lying on its side with a label calling it something that it clearly wasn't,’ he told the Guardian. ‘I was thinking it's like nothing I've seen. I took it over to the bench, laid it down gently on sandbags, and started turning it over, looking at it. I was thinking can it be this, can it be that, and the answer, over and over, was no.’

The specimen had been discovered by a fossil collector in the 1890s and was identified as coming from a sauropod species once common in what is now North America. While Taylor could see from bone features that it was a sauropod (such as large air holes that lightened the frame of the giants and made it easier for them to walk), other aspects differed.

Angela Milner, the museum’s keeper of paleontology, said other undiscovered species could exist in the collection: ‘Because the collections here are so large, it's bound to be the case that some specimens have not been reviewed in many, many years. When people look at things with modern techniques, it's not unusual to make new discoveries and that's why museum collections are so important. Things that did not appear too significant when they were first discovered can become important later on.’
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Another dinosaur that lived 110 million years ago was described in the Times after research into how it lived and ate was published in the journal Public Library of Science One.

The most striking aspect of the Nigersaurus taqueti dinosaur was its odd shovel-shaped mouth, packed with 50 columns of teeth. Computer scans have revealed that up to nine sets of replacements grew behind each tooth, meaning its mouth could have been packed with around 500.

‘Among dinosaurs, the Nigersaurus sets the Guinness record for tooth replacement,’ said Professor Paul Sereno, of the University of Chicago, who led the research team. Scientists believe it used these teeth to graze on vegetation.
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The President of the Institute of Systems Biology in Seattle, Dr Leroy Hood, has unveiled a powerful new approach to provide early warning of disease in any of the body’s organs. It involves analysis of proteins present in a blood sample by a specialised chip.

The Telegraph reported that, while the method is likely to take at least a decade to perfect, the chip can already monitor 20 or so proteins. Dr Hood proposes a hit list of 2500 proteins – 50 per organ/major tissue – that could provide tell tale signs of developing problems. He calls his new approach ‘systems medicine’, in which a collection of proteins provide a molecular fingerprint of the health of an organ.

His team has already found around ten protein markers of brain health that can distinguish between prion disease, such as Creutzfeldt-Jakob Disease (vCJD; the human form of BSE, Bovine Spongiform Encephalopathy), and glioblastoma, a common brain tumour. In mice, his method was able to accurately predict infection by prion proteins as early as six weeks – mice live up to 23 weeks after infection and don’t show symptoms until 18 weeks.

In humans, the early diagnosis of diseases such as vCJD which are currently incurable raises ethical issues. But in the meantime, the method could help analyse how well and quickly experimental drugs under study at the University of California work. The chips are also likely to lead to a test that detects BSE in cattle before symptoms develop, because the same set of proteins are found in cows. The patented idea could be tested within six months.
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Meanwhile, Professor John Collinge of University College London, described by the Telegraph as Britain’s leading expert on vCJD, said he continues to be worried that there are ‘a lot more cases in the pipeline’ as a result of the consumption of BSE contaminated beef between 1980 and 1996.

He is concerned, despite a declining incidence of vCJD in Britain, because he believes only people who are genetically susceptible have been affected so far and that it is possible for the disease to incubate in a symptom-free person for many decades. Such a possibility receives some weight from the fact that Kuru, a similar human disease caused by prion proteins, can incubate in a person for four decades.

Professor Collinge made his comments while outlining a new theory, published in the journal Science, about how prion diseases kill brain cells. In prion diseases, abnormal proteins cause normal proteins in the brain to become mis-shapen and form damaging clumps. The new theory identifies the smaller clumps of abnormal proteins as the toxic molecules that damage brain cells, rather than the relatively huge deposits.

‘This is a fundamental change of thinking and this model fits every piece of data we have got,’ said Professor Collinge. ‘Of course, now it is the job of other scientists to try to falsify this idea.’

If the theory is correct, it has implications for drug development, as attempts to disrupt huge deposits to treat the disease could, instead, produce more of the toxic fragments. Professor Collinge is at an early stage on research to develop drugs that instead prevent the initial formation of the toxic abnormal form of prion protein. Lab tests have so far proven promising.
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In other news, the highly-contagious H5N1 strain of bird flu was found in turkeys on a Suffolk farm last weekend. As a result, 6,500 birds were culled at the farm where the infection was discovered, with a further 22,000 turkeys being culled on four other premises as a precaution because the farms shared staff. Restricted and surveillance zones have been put in place by the Department for the Environment, Food and Rural Affairs (DEFRA). The source of the infection isn’t known, but wild birds are suspected.
(BBC News)
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And finally...

The ancient peoples of Central America were enjoying chocolate drinks at least 500 years earlier than previously thought, although they were probably alcoholic and didn’t actually have a chocolaty flavour.

Pottery fragments from vessels used as long ago as 1150BC were found to contain traces of theobromine, a chemical that occurs only in the cacao plant used to make chocolate, reported the Times.

John Henderson, Professor of Anthropology at Cornell University in New York State, suggests that the pottery was used to serve a primitive fermented drink made from cacao pulp and that the distinctive chocolate taste, which later featured in frothy beverages enjoyed by the later Aztec and Mayan people, was likely stumbled upon by the ancient brewers.

‘In the course of beer brewing, you discover that if you ferment the seeds of the plant you get this chocolate taste,’ he said. ‘It may be that the roots of the modern chocolate industry can be traced back to this primitive fermented drink.’

Even at this early date, the designs of the vessels reflect ‘cacao serving and drinking in ceremonies that took place at celebrations of marriages, births and other occasions.’