the-BA : Science News Digest

An American Bullfrog - source of a compound with activity against MRSA (Image copyright: istockphoto.com)

In the science news this week: the Intergovernmental Panel on Climate Change meet to discuss strategies to mitigate climate change, a genetic clue to longevity is revealed and pioneering gene therapy to restore sight gets underway. Plus, the electronic nose that's not to be sniffed at...

The Intergovernmental Panel on Climate Change (IPCC) held its third summit this year in Bangkok. At least 400 scientists and experts from approximately 120 countries met to discuss ways of curbing greenhouse gas emissions, taking economic impacts into account. The two earlier reports established the science and potential consequences of global climate change. As the UN’s leading body on climate change, the IPCC’s final report will be used to help set national and international strategies of how to mitigate climate change.

According to BBC News, a major sticking point in the negotiations has been regarding the safe limit at which atmospheric carbon dioxide can be stabilised to avoid risking dramatic impacts. The majority of economic research focuses on a level of 550ppm, whereas more recent scientific studies indicate a limit of 450ppm would be necessary. Chinese delegates were keen to downplay scenarios that could adversely affect China’s short-term economic growth and resisted a new emphasis towards the lower level figure. Big developing nations were also keen to emphasize that the major responsibility for cumulative emissions in the atmosphere rests with rich countries.

Impacts on the global economy were assessed for a range of atmospheric concentration levels of greenhouse gases. The meeting concluded that it will be possible to stabilise greenhouse gas emissions at a reasonable economic cost. Keeping carbon dioxide concentration levels to between 445 and 535ppm, could cost up to 3 per cent of global GDP by 2030. An important consideration is the time available in which to implement changes. The report suggests that the trend of rising emission levels needs to be reversed within one or two decades.

Solutions to mitigate climate change described in the report include shifting to renewable energy forms and reducing deforestation. The building sector was singled out as a major contributor – the report concluded that making buildings more energy-efficient could result in significant cuts, particularly in the developing world.
(BBC News article 1, article 2, article 3)

In related news, a study published in the journal Geophysical Research Letters has added to those suggesting that the IPCC’s latest major global climate analysis is too conservative. Scientists assessed Arctic ice melting for the periods 1953-2006 and 1979-2006, comparing actual data to figures calculated using a number of computer models used by the IPCC to predict future climate scenarios. The researchers observed that the models generated a melting rate that is on average less than half the rate actually observed.
(BBC News)

The Prince of Wales held a May Day Business Summit on Climate Change in which he called on business leaders to take firm action to cut their carbon emissions over the coming 12 months. He stressed the urgency of the issue. Over 1,000 companies made pledges to reduce their carbon footprint by working with employees, suppliers and customers.
(BBC News)

In another BBC News story, one of their correspondents toured a new commercial solar thermal power plant in Spain. The first of it’s kind in Europe, the plant uses the Sun’s energy to convert water into steam which drives turbines to generate power. A dazzling array of 600 mirrors focus the Sun’s rays on water pipes in a 40 storey-high tower. Currently the power is three times more costly than that generated by a conventional source, and the plant can only function for an hour after sundown. However, the director of the company that owns the plant, believes that both the generating capacity and cost could improve as the technology develops.

In other news, the Times reported the results of a small-scale study in which maggots were applied to the MRSA-contaminated foot ulcers of 13 diabetics. In all but one of the patients, the sterile bottle fly larvae successfully cleared the wound of both dead tissue and bacteria, leaving healthy tissue to heal. The treatment was able to cure the wound much more quickly than conventional treatment – taking a mean period of three weeks, compared to the usual 28 weeks.

Professor Andrew Boulton, who published the results, said: “This is very exciting. If confirmed in a randomised controlled trial, larval treatment would offer the first non-invasive and risk-free treatment of this problem.”

Another potential cure for drug-resistant MRSA has been uncovered by a group of researchers from St Andrew’s University. The scientists have developed a treatment which combines two antimicrobial compounds and has an inhibitory effect on the bacterium, reported BBC News. One of the key ingredients is ranalexin – a natural molecule produced by American bullfrogs as a defence against disease-causing pathogens. By combining compounds, the chance of a resistant strain emerging is reduced. It is thought the new treatment could represent a potentially novel and effective way to combat MRSA via surface treatment or impregnation of wound dressings.

The Independent reported that scientists have discovered a gene critical for extending the lifespan of animals on calorie-restricted diets. Nearly all animals put on such a diet live longer lives, but the explanation has eluded researchers. Now scientists have uncovered a gene common to nematode worms, mice and humans, that plays a central role in longevity.

Blocking the activity of the gene known as PHA-4 in nematode worms was found to counteract the benefits of a calorie-restricted diet and the worms lived shorter lives. Likewise, stimulating the activity of PHA-4 in worms not on a special diet, led to increased longevity that almost matched those on a calorie-restricted diet.

Dr Andrew Dillin, one of the scientists who identified the gene, said: ”After 72 years of not knowing how calorie restriction works, we finally have genetic evidence to unravel the underlying molecular programme required for increased longevity in response to calorie restriction. It’s likely to play a role in the human condition, although we still don’t know whether calorie restriction works in humans. Studies in primates suggest it does.”

The discovery could lead to the development of pharmacological agents that could help extend lifespan of humans without the need for rigorous dieting. However, scientists generally believe that it is unlikely that humans could live beyond about 125 years.

Two independent groups of researchers have identified a stretch of genes that dramatically increases the risk of coronary heart disease and early-onset heart attacks, the Guardian reported. Up to a quarter of Caucasian populations carry the high-risk versions of the genes and have a 40 per cent higher chance of developing heart disease. The length of DNA is believed to be the most important genetic factor for heart disease yet found. It boosts the lifetime risk of a heart attack by 60 percent and doubles the chances of men under 50 and women under 60 suffering a heart attack.

The genetic variants were identified after the entire genomes of more than 40,000 people were compared. One of the teams of scientists works at a biotech company, and they hope to have a genetic test to identify those who are at risk available by the end of the year.

Another possible ramification of rising levels of diabetes could be an increased incidence of male infertility, according to a new research published in the journal Human Reproduction. So far there is no proof that the condition reduces fertility, reported the Guardian, but the results of a small-scale study indicate that men with diabetes are more likely to have damaged sperm cells.

Research by scientists from King’s College London has demonstrated how cannabis may trigger or exacerbate psychotic illnesses such as schizophrenia, reported BBC News. Healthy adult male volunteers who had not previously abused cannabis were given capsules that contained either tetrahydrocannabinol (THC), cannabidiol (CBD) or were a placebo. THC and CBD are both active ingredients in cannabis, but whereas THC has been shown to worsen psychotic symptoms, CBD has the potential to dampen them.

The volunteers underwent tests and brain scans. These revealed that those who took THC had reduced activity in the area of the brain that keeps inappropriate thoughts and behaviour, such as swearing and paranoia, in check.

Experts are worried that the average THC content is increasing. It is believed to have risen from six to 12 percent in recent years. And since THC and CBD have competing biochemical activity, this is overruling any positive effect due to CBD.

A cutting-edge technique is underway to try to use gene therapy to treat blindness caused by a genetic sight disorder, reported the Daily Telegraph. In Leber’s congenital amaurosis, which occurs in 1 in 100,000 babies, a gene called RPE65 stops the retina from working. Sight can deteriorate so badly that many sufferers go blind as adults.

In the new pioneering trial at Moorfield’s Eye Hospital in London – the world’s first attempt to transplant genes into the eye – normal genes are inserted into the retina of individuals using a harmless virus. This infects the cells to get the working copies of the gene in. The retina has to be detached to allow the virus access to infect the cells, and so the procedure requires great precision. It will be months before researchers know if the technique has worked. However, lab and animal tests have been very successful. In one, sight in dogs that had the disorder was restored to such a degree that they were able to navigate a maze alone.

Scientists have been able to simulate the slow brain waves typical of deep sleep by sending a harmless magnetic pulse through the brains of sleeping volunteers. This type of brain wave activity is thought to be important for learning, thinking and remembering and may be important in sleep’s restorative powers. The new research could eventually lead to an induced ‘power nap’ that carries the same benefit as a full night’s sleep. It may also lead to treatments for insomnia.

The technique used transcranial magnetic stimulation (TMS), in which an electromagnetic coil is placed closed to the head, to induce tiny electrical currents in the brain. By placing the coil above a particular area of the brain, a single magnetic field was able to evoke a wave that travelled through every part of the brain and looked identical to the normal slow wave observed during sleep. It did not induce sleep, but made the sleep of someone who was already napping deeper. Researchers will now study whether these artificial slow waves have restorative benefits, reported the Daily Telegraph.

The concept of ‘financial pain’ has biological justification, according to a new study reported in the Times. The experience of losing money, or anticipating a loss, causes a very similar pattern of activity in the striatum (a region of the brain involved in processing reward, pain and fear) to that seen when people experience actual physical pain. It seems that the brain’s pre-existing pain system has evolved a second use to help people learn to avoid risky financial decisions, like they would avoid injury.

New research reported in the Proceedings of the National Academy of Sciences supports the theory that human language evolved from gesturing. A team of scientists from Emory University, Atlanta, studied 13 bonobos and 34 chimpanzees. They monitored hundreds of gestures and sounds. But whereas the vocal signals and facial expressions of both species were almost identical and had fixed meaning, hand gestures were much more flexibly interpreted – their meaning dependent on the social context. For example, both humans and chimps hold out an open hand to beg, but it can be used to ask for help as well as for food.

In addition to humans, chimpanzees and bonobos, orangutans and gorillas also gesture, but no monkeys do.

Professor Frans de Waal told the Daily Telegraph: "The thinking is that we started evolving language not by speaking but by gesturing. For example, human babies can learn gestures before they learn words.”

The Times revealed that, according to a new study, average walking speeds around the globe have increased by about 10 percent since the early 1990s. Richard Wiseman, professor of psychology at the University of Hertfordshire, repeated a 1994 experiment to monitor how quickly pedestrians in 32 different cities walk, and found that people all over the world are walking faster. London was the fastest-paced city in Britain, and pedestrians in Singapore were the fastest overall – walking between 20 and 30 percent faster than previously recorded.

According to Professor Wiseman, the results are significant because walking speed is a good indicator of the pace of life. Other studies have also shown that as people walk faster, they are less likely to help others. A faster pace is also linked with higher incidences of coronary heart disease.

“While the effect of stress itself is actually quite small, what happens is that as people get more stressed and hurried they spend less time with their friends, they don’t have time to exercise, they eat poorly, and they drink and smoke more,” said Professor Wiseman. “It’s these factors that build up to cause the risk.”

And finally…

It may seem like a disgusting gloopy substance to be suffered during times of colds, but according to the Daily Telegraph, two new studies have revealed that we have much to thank snot for.

Rather than simply functioning to capture particles in our nose and keep our lungs clean, it seems that snot plays an important role in our ability to smell.

In the first study, artificial snot greatly enhanced the detecting capabilities of an ‘electronic nose’. These devices are used in quality control in the food industry, as well as a number of other commercial settings. Like the human nose, they have specialised sensors to detect particular aroma molecules. However, they have a mere 50 sensors, or fewer, compared to the 100 million specialised receptors of a natural nose.

In the natural nose, a layer of mucus dissolves scents. The individual odour molecules then reach the receptors at different speeds and times and the brain uses this information to help it distinguish different smells. Fake snot was found to improve the odour discrimination ability of an electronic nose – enabling it to tell smells apart that it had previously had trouble distinguishing, such as milk and banana.

In the second study, a scientist identified a nasal mucus problem in patients with congenital smell loss.

Normal mucus contains ‘death factors’ to kill ageing receptor cells. The patients suffering from the congenital inability to smell odours were found to have five to 10 times the normal concentration of these factors. By inhibiting their secretion, the American researcher was able to restore a sense of smell, enabling the patients to smell something for the first time in their lives.