the-BA : The BA Science News Digest

In the news this week: Lazy gardeners make the best bee keepers, mapping memory formation, a gel that can mop up toxic heavy metals and is mobile phone malaise all in the mind? Plus, the accidental discovery of the itchy gene…

If you want to help reverse the decline of our native bumblebee population, the best thing you can do is to let your garden run a bit wild. A report in the Applied Journal of Ecology published results of the National Bumblebee Nest Survey which found that gardens had more nests per hectare than many types of countryside. The average number of nests in your typical backyard is 36 per hectare whereas in grassland or woodland, the average is only 11 to 17, reported BBC News.

The results came from observations of over 700 volunteers who watched both a region of their garden and an area in the countryside for the tell tale sign of a nest, a steady stream of bees indicating an entrance nearby.

This is an important find as it should help ecologists understand and perhaps reverse the decrease in the species population. Recent years have seen the extinction of three of Britain’s 25 native populations and another nine are described as being of “special concern”.

The scientists think gardens are particularly attractive to bees as they offer lots of places to nest over a small area; compost heaps, bird boxes, garden sheds, fence lines are all ideal locations. Juliet Osborne, leader of the study said: ‘There is a lot people can do. They could just leave an area where the grass isn't mowed or grow bright scented flowers throughout March to September.’

For the first time, scientists have been able to observe the formation of memory. By taking high resolution images of the brains of rats that have learnt to navigate their way through a maze, the nerve pathway of the memory was tracked. This confirms what many brain scientists had assumed - that memory has a cellular basis, an idea that was first put forward over a century ago by the psychology historian, Theodore Ribot.
Researchers from the University of California, Irvine, analysed the hippocampus, or memory centre, of three groups of rats. One group was given half an hour to navigate their way through a maze, the second did the same but was given memory suppressant drugs and the third was a control. Using a technique known as restorative deconvolution microscopy and fluorescent antibodies, the team was able to see that out of one million synapses (the connections via which nerve cells communicate with each other) in the brains of the rats in the first group, one percent were enlarged and had formed stronger connection with neighbouring brain cells.

Professor Gary Lynch, who led the team, told the Guardian: ‘The larger consequence is that now we can see these, the route is open for us to map where memories are located. So much of our thinking about memories is intuited, and this may help answer questions such as “what is a memory”’.

It couldn’t have been more timely. As England recovers from some of the worst flooding in meteorological history, a report published in Nature has found what many of us already suspected – that rainfall levels can join air temperature, ocean temperature and sea level as the latest climate characteristic that humans have had a hand in changing. As global temperatures rise so does the average atmospheric pressure which in turn means more water vapour to form rain swelled clouds.

An international team of scientists has found that human activity has caused an increase in the annual average rainfall in the mid latitudes of the northern hemisphere while the southern hemisphere has seen drier conditions. Until now, computer models have been unable to show the extent of human activity on rainfall patterns conclusively. By comparing monthly precipitation data from 1925 to 1999 organised into latitude bands rather than the assumption of a global average, the team were able to compare the results of a programme set to include human factors against one based on nature alone. Unsurprisingly, the former most closely matched the actual observations.

Whilst some parts of the UK got their monthly quota of rainfall in a few hours this summer, it is actually the winter that is supposed to get the most extreme wet weather. The summers are predicted to get drier, Dr Peter Stott, co-author of the paper explained to the Daily Telegraph: ‘It is possible under climate change that there could be an increase of extreme rainfall even under general drying. Recent events are associated with unusual weather patterns that could be linked to the tropical oceans. The problem for the UK is that there is a lot of uncertainty about what will happen in future regarding extreme rainfall.’

Staying on global warming, new research says that we have been overlooking the effect of ozone as a potent greenhouse gas reported the Times. We are more used to hearing about the need to protect our ozone layer, the fragile blanket that protects us from the Sun’s radiation. However, ozone is only a benevolent gas if you’re in the stratosphere, closer to the ground it is a toxic greenhouse gas, capable of causing pulmonary damage and stunting plant growth. The latter is an important factor in the fight against climate change as small, weak plants cannot soak up as much carbon dioxide during photosynthesis, reducing their efficiency as carbon sinks. This means more carbon dioxide remains in the atmosphere, worsening global warming.

Ozone is produced when the oxygen in the air reacts with other polluting gases such as nitrous dioxide and methane, catalysed by sunshine. The Met Office has predicted that by the turn of the next century, this effect could have caused temperatures to rise by as much as 6.4 degrees Celsius.

Heavy metals, such as lead, mercury and cadmium, are well known for their damaging effects on our health. The toxic metal ions are found in the soil, water supply and air from the burning of fossil fuels and the manufacture of paper and chlorine, and they are notoriously difficult to capture. This might be about to change as a team from Northwestern University in Illinois have developed a new type of “aerogel” capable of mopping up these dangerous ions, reported BBC News.

The gel is a highly absorbent, low density, semi-conducting material whose liquid component has been replaced with gas. Its huge surface area - a few cubic centimeters could stretch across a football field - means that any particles that encounter it are bound to eventually reach its surface. If these particles are charged heavy metals, known as ions, then they will be absorbed, as the chemistry of the gel means that its atoms preferentially bond to these ions over any others. Previous aerogels have been oxides, a chemical group based on oxygen which only absorbs the small metal ions like zinc. The new type is based on a chemical group known as the chalcogenides, which includes the elements sulphur and selenium.

The gel has wide ranging potential applications; from use in environmental clean-up operations, to water decontamination, to hydrogen purification for carbon-free fuel cells, and perhaps even its semi-conducting properties could be exploited.

A study has found no link between so called “radio-sensitivity” and actual exposure to radio waves. About 4 per cent of the population claim to suffer from flu-like symptoms and nausea when exposed to radiation from mobile phone masts. New research shows that these people cannot actually tell whether or not the phone mast is active, leading scientists to suggest their symptoms are psychological, reported the Guardian.

A team from the University of Essex conducted a double blind test with 156 individuals, 44 of which claimed to be “radio-sensitive”. Double blind means that neither the scientists nor the volunteers knew whether the masts were on or not. Only two out of the 44 sensitive people and five out of the 114 controls correctly identified the presence of radiowaves in all of the six tests, the result expected by chance alone. Elaine Fox, author of the study, said, ‘Belief is very powerful. There are real, clinical effects.’ She advocated further research into the symptoms: ‘If people are convinced that they are suffering because of mobile phone masts they don't investigate other causes.’

The study is not without controversy. Whilst new technology has been blamed for an increase in these kinds of symptoms before, for example when microwaves and television sets were first in common use, it is the fact that this survey was half-funded by mobile phone companies that has got many anti-mast campaigners uncomfortable. Also, twelve electrosensitive people dropped out of the survey after the first double blind test. Whilst none of these could correctly judge when the mast was emitting radiowaves, just the reduction in numbers is enough to reduce the reliability of the results by perhaps 30 per cent, Professor Fox admitted.

Other news in brief:

Until now, it has been thought that children from low income families were most at risk of developing obesity. A new study contradicts this by showing that actually it is children from wealthier families with working mothers who tend to succumb. The “classic money-rich but time-poor” situation means that many mothers don’t find the time to ensure their children eat healthily enough and take plenty of exercise. Children in after-school care were at an even greater risk.
(The DailyTelegraph)

In related news, it has been found that weight fluctuations are socially contagious. Scientists from Harvard and the University of California looked at height and weight data collected over 32 years from 12,000 people and found that more patterns emerged following social connections rather than genetic ones. James Fowler, from the University of California said: 'This is about people's ideas about their bodies and their health. Consciously or unconsciously, people look to others when they are deciding how much to eat, how much to exercise and how much weight is too much.' Read more at the Independent.

People at risk of heart disease or strokes should stay inside when the pollution levels are high. That is the warning from a study conducted by the University of California, LA. The research shows that particles found in air pollution combine with the artery clogging type of cholesterol, known as low density lipoprotein fats, to exacerbate the problem. Dr Andre Nel from UCLA told the Daily Telegraph: ‘Their combination creates a dangerous synergy that wreaks cardiovascular havoc far beyond what's caused by the diesel or cholesterol alone.’

Genetically modified goats are producing large quantities of a drug that could act as an antidote to nerve gas toxins, such as sarin and VX, reported BBC News. The drug is an enzyme produced by the human body but until now it has only been possible to harvest it in very small amounts. This new approach involves the extracted human DNA code being inserted into a vector molecule and implanted into a goat embryo. This eventually grows into a goat which produces the enzyme in its milk. So far these "transgenic" goats have produced 15kg of the drug. It could be used as a prophylactic to protect people in case of attack or as an antidote after exposure.

And finally…

It is one of our most basic urges - scratching that irritating, persistent itch and now its genetic origin has been stumbled upon, the Guardian reported.

A team from Washington University were using mice to try to find the genes that allow us to sense pain. Frustratingly for the team, their genetically modified mice, bred minus a gene known as GRPR, acted in exactly the same way as normal mice to pain. However, when the researchers, on a whim, exposed them to substances that provoked itching, the GM mice hardly reacted whereas the normal mice went into a flurry of hind leg scratching.

A genetic understanding what makes us itch could help in the design of new treatments that tackle the underlying cause of conditions such as eczema rather than just alleviate its symptoms.

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