the-BA : Science News Digest

Representation of egg and sperm (image copyright: istockphoto.com)

In the news this week: fertility treatment breakthroughs offer young cancer patients a chance of motherhood, piranhas show their nervous disposition and Cassini reveals Saturn’s spongy satellite. Plus, men are ‘just as chatty as women’…

A 1.2 mile-long ice core taken from Greenland’s ice cap has yielded the world’s oldest authenticated DNA samples and revealed that before the area became a frozen desert it was teeming with forest flora and fauna.

Fragments of DNA estimated to be 450,000-900,000 years old were extracted from a rich variety of insects and plant-life from muddy sediments at the base of the core, reported the Independent.

According to Professor Eske Willerslev, who led the study, the genetic material found indicated the landscape was similar to the eastern Canadian and Swedish forests of today. The particular trees identified indicated the temperature would have been significantly warmer than previously believed.

The finding also appears to disprove the theory that Greenland was ice-free around 125,000 years ago when the global climate was roughly five degrees Celcius warmer than at present; the ice core suggests continuous ice coverage for at least 450,000 years.

In last week’s Science News Digest, we reported new evidence that suggests cats have been our close companions longer than dogs, living alongside humans for 10,000-130,000 years. But it seems that these days the association is having a far greater impact on our health than previously thought. According to new research, cats can trigger allergic reactions in more than a quarter of the population.

Scientists studied 1,1884 volunteers from across Europe, who were picked to be representative of the general population. Samples of dust from their houses were analysed for levels of cat allergen, grass allergen, mould and dust mites and the allergic responses and lung function of the volunteers were monitored. More than one in four were found to have at least one allergy and their lung function was worse the higher the levels of cat allergen found in their home.

‘Our study suggests that all allergenic individuals have signs of asthmatic responses if exposed to cat allergen, even if blood tests show they are not allergic to cats,’ Dr Susan Chinn from Imperial College London told the Guardian. She suggested that people might want to think twice before choosing the animal as a pet.

Scientists have discovered a gene that is a powerful predictor of childhood asthma, raising the risk of developing the disorder by between 60 and 70 per cent. The new gene ORMDL3 was found to be expressed at a higher level in children with asthma (meaning more of the protein was produced) as a result of a DNA sequence that differed between asthmatics and non-asthmatics.

Scientists involved in the research emphasized that the finding helps to build up the ‘gene-environment jigsaw’ that contributes to the complex disease and will potentially lead to better understanding, diagnosis and treatment. This is particularly pressing since asthma is one of the fastest-growing childhood illnesses in Britain, and over a million children in the UK currently receive treatment. It is thought that exposure to various environmental factors, such as house dust, mites or air pollutants, are involved in triggering asthma attacks in people who are genetically predisposed.

Professor William Cookson from the National Heart and Lung Institute at Imperial College London said: ‘Our results have found the strongest genetic effect on asthma so far.’

The Independent reported that, although its role in asthma is still unclear, the existence of a similar gene in primitive organisms suggests it is a component of an ancient immune mechanism.

Scientists are also working to develop a test that could be used to confirm cases of vCJD (the human equivalent of ‘mad cow disease’), reported BBC News. Currently this can only be done by examining the brain post mortem. 161 people have died from the disease since it was identified in early 1990.

The technique, known as protein misfolding cyclic amplification, works to boost the amount of defective prion protein so that it is more easily detectable in test samples. A team of researchers from the University of Edinburgh have now shown that it is possible to use the technique to amplify the number of vCJD prions in infected human brain tissue extracts by using normal platelets (blood cells) to drive the reaction. Further research would be needed to show whether the technique would also work on other tissues, such as blood.

'The ethical dilemma remains over screening and testing for a disease for which there is no cure,' said Prof James Ironside, of the National CJD Surveillance Unit, in the Daily Telegraph.

However, according Roger Tomkins, of the CJD Network, which offers support and advice, earlier diagnosis would be preferable, saving a lot of ‘unnecessary and regretful treatment’.

The meeting of the European Society of Human Reproduction and Embryology took place in Lyon this week, and as a result there were several IVF and fertility-related news items.

The Guardian reported that in a year-long study conducted by psychologists, infertile women who supplemented their IVF treatment with complementary therapies such as herbal medicines, reflexology and acupuncture, were at least 30 per cent less likely to get pregnant that those who didn’t.

However, while the researchers involved in the study suggested that complementary medicines could be interfering with the drugs and hormones used in fertility treatment, it was also acknowledged that use of complementary medicine might indicate stress and health problems which could lead to lower conception success, since persistent failure to become pregnant using conventional treatment might encourage women to try alternative therapies.

In related news, the Times reported that research into the breeding habits of the African naked mole-rat is being conducted in the hope of shedding light on how stress leads to reduced fertility in humans.

Only the dominant ‘queen’ mole-rat in a colony breeds. She ensures the other females and males remain reproductively inactive by bullying them – the stress caused by her actions appears to suppress key fertility hormones in females and lowers the levels of testosterone and sperm production in non-breeding males.

Dr Chris Faulkes, of Queen Mary, University of London, said: ‘Social suppression of reproduction in marmoset monkeys is very similar to that in naked mole-rats, and as these are primates the applications to understanding human stress-related infertility aren’t so far-fetched.’

The Times also reported the case of a seven year old Canadian girl who ‘could one day give birth to her biological half brother or half sister’.

The girl has Turner syndrome, a condition in which one of the two X chromosomes is missing, which almost always causes infertility. Women with the condition can, however, conceive using donated eggs. Since there is a shortage of donated eggs in most countries, the girl’s mother has opted to freeze her eggs so that her daughter has the option to use them in the future.

The team from McGill University in Montreal that treated the mother referred the case to an independent ethics committee before agreeing to the procedure. Approval from another ethics committee would have to be obtained before the daughter could use the eggs, should she wish to.

In another Times article, it was revealed that a medical team in Israel has successfully removed and ‘ripened’ immature eggs from the ovaries of girls as young as five, before freezing and storing them.

The achievement means that prepubescent girls with cancer could still have the chance to start a family even after receiving chemotherapy treatment that would normally leave them sterile. The technique could also be used on older women with cancer who are unable to receive hormone treatment to stimulate their ovaries before egg collection.

In a related story, the Independent announced that a woman has given birth to the first baby to be conceived using an egg that had been ripened in the laboratory, frozen and then fertilised by IVF.

Dr Hananel Holzer of McGill University’s Reproductive Centre in Montreal said: ‘We have demonstrated for the first time that it is possible to do this and, so far, we have achieved four successful pregnancies, one of which has resulted in a live birth. The other three pregnancies are ongoing.’

In other news, high-resolution images of Saturn’s eighth-largest moon, Hyperion, have revealed it has an unusual sponge-like appearance. The irregularly shaped satellite has the unusual dimensions of 204 by 162 by 132 miles and it tumbles chaotically. It is also highly porous, which may enhance the preservation of the numerous craters observed by the Cassini spacecraft.

'Of special interest is the presence on Hyperion of hydrocarbons – combinations of carbon and hydrogen atoms that are found in comets, meteorites, and the dust in our galaxy,’ Dale Cruikshank of NASA’s Ames Research Centre told the Daily Telegraph.

'The molecules, when embedded in ice and exposed to ultraviolet light, form new molecules of biological significance. This doesn’t mean that we have found life, but it is a further indication that the basic chemistry needed for life is widespread in the universe.’

The view from Cassini was obtained in late 2005 and the results have now been described in the journal Nature. More recently, in June the spacecraft completed flybys of Saturn’s moons Tethys and Titan.

The flight of the huge prehistoric bird Argentavis magnificens has prompted decades of speculation by scientists. It was the size of a modern light aircraft and yet had relatively little muscle to enable it to flap its a seven-metre wingspan. Now, American scientists have analysed its aerodynamic secrets using software originally designed for helicopters and reveal how it took off, remained aloft and landed.

It seems the bird lacked the muscle power to enable it to remain in flight purely by flapping its wings. Instead, it relied on updrafts or thermals to provide sufficient lift, using gliding methods similar to the eagles, condors and storks of today.

The largest modern flying bird, the Great Kori Bustard, which can weigh up to 40-pounds, has to run along like a taxiing aircraft in order to take flight. Likewise, the 150-pound Argentavis would not have been able to take off from standing and ‘probably used some of the techniques used by hang-glider pilots such as running on sloping ground to get thrust or energy, or running with a headwind behind it’.

Professor Sankar Chatterjee of the Museum of Texas Tech University said: ‘Think about a super-sized bald eagle with a 21-foot wingspan. It would darken the sky. It’s almost like a tale from the “Arabian Nights”. It was a very aggressive bird that flew over the pampas of Argentina to sweep down from the sky and seize large prey with a formidable beak.’

The team estimated it would have been able to cruise for up to 200 miles at speeds of just over 40 mph, reported the Daily Telegraph.

According to the Guardian, it seems the press that piranhas get for being ferocious, blood-lusting pack hunters is a bit unfair. Conservationists working in the Amazonian wetlands have uncovered evidence that instead suggests they are rather nervous fish that form large shoals primarily to defend themselves from large predators.

Researchers, led by Anne Magurran of the University of St Andrews mimicked airborne attacks on different shoal sizes using giant water tanks and models of birds of prey, whilst observing a structure near the gills which quivers quickly when piranhas are stressed. They discovered that the fish in smaller shoals were more distressed and took longer to calm down.

Water levels in the Amazon vary widely throughout the year. The researchers found that in shallows, piranhas formed large shoals. The mature fish of a reproductive age placed themselves towards the centre of the shoals, where they were more protected. Younger fish remained at the edges, where they were more exposed but had the benefit of first access to food.

The research was demonstrated at the Royal Society’s summer science exhibition.

Other news in brief:

Ian Pearson has been named as the new UK science minister, taking up his post in the newly-created Department for Innovation, Universities and Skills (DIUS). He is MP for Dudley South and previously held a climate change brief in the Department for Environment, Food and Rural Affairs (Defra).
(BBC News)

An Ipsos MORI poll of 2,032 adults found that 56 per cent believe scientists are still questioning climate change. In response, the Royal Society said that most climate change scientists believe humans are having an ‘unprecedented’ effect on the climate, and emphasized the need for all of us to do as much as possible to help avoid the worst consequences of climate change. The survey indicated that terrorism, graffiti and crime are of more public concern.
(BBC News)

The Energy Saving Trust warned that the growing popularity of hi-tech devices, in particular flat screen TVs and digital radios, are threatening efforts to save energy. The organisation estimated that gadgets will account for about 45 per cent of households’ electricity usage by 2020.
(BBC News)

A Stone Age diet of fruit, nuts, root vegetables and lean meat or fish could help combat diabetes, according to a recent study. It was more effective at lowering blood sugar in a group of glucose-intolerant heart patients than a Mediterranean diet.
(Daily Telegraph)

Scientists in Spain celebrated the discovery of the oldest human fossil found in western Europe – a tooth from a distant human ancestor more than one million years old.
(The Independent)

Orangutans demonstrated their impressive problem-solving skills by becoming the first great ape to use water as a tool.
(Daily Telegraph)

And finally...

Contrary to popular belief, men are just as talkative as women. In the book the Female Brain, it was reported that woman used about 20,000 words a day while men used only 7,000. However, a new study, conducted over six years, has revealed that there is no statistically significant difference between the conversational ability of the two sexes, with both men and women speaking around 16,000 words a day.

Close to 400 American and Mexican students were monitored during the course of the research, reported the Guardian. Electronically activated recorders worn by the students captured 30 seconds of talk every 12.5 minutes. While no significant difference was found between the amount that men and women spoke (women had a daily average of 16,215, versus 15,669 for the men), there were huge differences observed between individuals – with some speaking 45,000 words a day and others only 500.

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