the-BA : Science News Digest

A bee - a talented communicator (image copyright: istockphoto.com)

In the latest science news: earthquake warnings could come from the Earth’s atmosphere, a vaccine hope for hayfever sufferers, and the discovery that honeybees can learn foreign ‘languages’. Plus, the wasp that casts a spell on caterpillars…

Nasa scientists believe they could be on the verge of a breakthrough in earthquake prediction after they spotted a close link between electrical disturbances in the ionosphere – a layer of the Earth’s atmosphere – and impending earthquakes. A previous study looking at earthquakes of magnitude 5.0 or larger in Taiwan found that of 100 earthquakes almost all of those at a depth of 35km or less were preceded by disturbances in the ionosphere. It’s also thought such a signal was observed prior to the recent devastating earthquake in China.

Minoru Freund, Director for Advanced Aerospace Materials and Devices at Nasa’s Ames Research Center in California, told BBC News: ‘I am cautiously optimistic that we have good scientific data, and we are designing a series of experiments to verify our data. I do believe that we will be able to establish a clear correlation between certain earthquakes and certain pre-earthquake signals, in an unbiased way.’

Researchers have now teamed up with UK-based experts at Surrey Satellite Technology Limited to investigate the potential of space-based early warning systems.
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BBC News also reported that astronomers have found the smallest planet yet orbiting a normal star. The planet, catchingly called MOA-2007-BLG-192Lb, is just 3.3 times the size of Earth. It was located by the new MOA-II telescope at the Mount John Observatory in New Zealand, using the gravitational microlensing technique. This method works on the basis that rays of light are bent as they pass close to massive objects such as stars.

The planet’s host star has such a low mass it may be a ‘failed star’, or brown dwarf, and as such it is likely to be between 3,000 to one million times fainter than the Sun. As a result, the top of the planet’s atmosphere is likely to be colder than Pluto. This doesn’t rule out the possibility of a liquid ocean, however, as a thick atmosphere could keep the surface warm enough.

Nicholas Rattenbury from Jodrell Bank, commented: ‘Our best ideas about how planets form suggests the planet could have quite a thick atmosphere. This atmosphere could act like a big blanket, keeping the planet warm. This has led to some speculation that there could, possibly, be a liquid ocean on the surface of the planet. The reason why that’s exciting, is one of the properties we’d like to have on a habitable planet is liquid water on the surface.’
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Research published this week suggests that stem cell injections might one day help treat many severe neurological diseases.

The work was carried out in ‘shiverer mice’ (named after the way they shake and wobble) that lack sufficient myelin – the fatty coating that protects brain cells like insulation on electrical wires and enables signals to reach their destination. Such a defect is also at the heart of a number of debilitating and ultimately fatal diseases that strike during childhood. Lorenzo Odone, whose story inspired the film Lorenzo’s Oil, suffered from one of these diseases, adrenoleukodystrophy. He passed away at the end of May.

In the latest work, researchers at the University of Rochester Medical Centre, New York, injected approximately 300,000 human glial stem cells into specific brain regions of 26 shiverer mice. Whereas the mutant mice usually die within 20 weeks of birth, six of the mice that received transplants lived far beyond their usual lifespan, and a further four appeared to be completely cured – a first for such mice. The one-off injection just after birth was able to repair defective wiring throughout the central nervous system.

More work is necessary before human clinical trials can proceed. However, Professor Steven Goldman who heads the research team told the Telegraph: ‘Preclinical work is now sufficiently compelling that I’d be relatively confident of an outcome that will justify the effort – which is to say provide real benefit – once we finally do get to trials.’
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Some positive news for hayfever sufferers: British scientists have developed a vaccine which has been shown in the world’s largest allergy vaccine trial to reduce symptoms such as sneezing, itchy eyes and a runny nose.

1,028 volunteers received one injection a week for four weeks during the hayfever season, and were asked to score the severity of their symptoms in an electronic diary. Compared with a placebo, an average improvement of 13 per cent was seen, reported the Guardian. However, those that kept a more complete record of their symptoms reported an even greater improvement of 27 per cent.

Existing vaccines against pollen allergies have needed to be given over a number of years, as doses must start very small and be built up very gradually since injecting pollen can trigger severe reactions. This problem has been overcome in the new vaccine by modifying the pollen so that it is less likely to overstimulate the immune system. In addition, a natural amino acid has been added to result in slow release of the pollen into the bloodstream, while inclusion of the fatty molecule MPL boosts the immune system’s response to the vaccine.
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‘A synthetic organism could be producing enough of a key malaria drug to treat the world within three years’, according to NewScientist.com.

Yeast had previously been engineered to produce artemisinic acid, a precursor to the anti-malarial drug artemisinin, by the insertion of around 12 genes copied from shrub species that naturally produce the compound. Extraction of artemisinin from the shrub itself is a relatively expensive process, and scientists believe that using yeast can make the process more efficient and cheaper, and ensure a steady supply.

Now, scientists have optimised the process and are in the process of scaling it up for industrial production in partnership with a drugs company. The approach differs from traditional genetic engineering approaches in that the genes have been specifically designed so that they look like yeast genes (rather than plant or bacteria genes) and are therefore easier for the yeast cells to read.
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A study conducted on behalf of the Food Standards Agency suggests that there is significant public reluctance regarding food derived from cloned animals and their offspring. The FSA is responsible for food safety and wanted to gauge public attitudes as it thinks there will eventually be an application to sell food such as meat, milk, cheese and eggs from cloned animals in Britain. Currently, the safety of such food has to be assessed and approved by all 27 EU member states before it can be sold, but there are no clear rules yet regarding the progeny of cloned animals.

The study, based on two three-hour workshops involving 70 people in Aberdeen, Aberystwyth, Belfast and Croydon, found consumers struggled ‘to identify any convincing benefits of the technique’ and were concerned about safety, ethics and animal welfare.
(Read more in the Guardian and the Telegraph)
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BBC News reported that scientists have shown for the first time that unborn animals are able to learn visual images.

Cuttlefish embryos that had crabs placed alongside them in a laboratory tank were found to prefer them as prey in later life, whereas those not exposed to crabs preferred shrimp. To ensure that the results were due only to visual cues before the cuttlefish hatched, and not smell or sound, the crabs were placed in a separate adjacent glass tank. The researchers from the University of Caen Basse-Normandy, France, who reported their work in the journal Animal Behaviour, found that the cuttlefish’s preference for hunting crabs was greater the clearer the view the embryos had of the crabs.

While it’s less likely that birds, reptiles and mammals could recognise visual images in the womb, the study reinforces the idea that some animals begin to learn before birth. Other studies have shown that embryos are able to pick up chemical and auditory cues. For example, unborn gulls learn the alarm calls of their parents, and salmon and frog embryos can recognise the chemical signatures of the water that surrounds them.
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In other animal-related news, bees have been found to be talented communicators who can learn various ‘bee dialects’.

The world’s nine species of honeybee separated about 30 million years ago and since then have developed their own dances that they use like languages, says the Guardian. Now, researchers have investigated whether European and Asian honeybees, the most geographically distant species, can interpret each other’s waggle dance – the dance used by foragers to signal to worker bees where to fly to find food.

High-speed footage was used to determine how the two species’ dances differed. Each used the same tactic to indicate direction, but danced for different amounts of time to indicate the same distance.

The scientists set up a mixed hive and trained European honeybees to fly to one of six feeding stations set 400, 500 and 600 metres in front of and behind the hive. Video footage showed that other bees watched the dance performed when the foragers returned and flew off in search of the food. Initially the Asian bees took a while but eventually found the right feeder.

The European bees were then trained to fly to a different feeder, again performing their dance at the hive. This time, the Asian bees quickly found the correct feeder. ‘They had learned that the distance was different in these dances and recalibrated how far they had to fly,’ says Jurgen Tautz one of the team whose work was published in the journal PLoS One.
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And finally…

To see ‘zombie caterpillars controlled by voodoo wasps’, as NewScientist.com put it, check out this video. It provides a striking example of a parasite manipulating the behaviour of its host to its own advantage.

The parasitoid wasp Glyptapanteles lays about 80 eggs at a time in young geometrid caterpillars. When they hatch, the larvae feed on the caterpillar’s body fluids, eating through its skin when they’re fully developed to attach themselves to a nearby branch and form a cocoon around themselves.

That’s the point at which the caterpillar seems to become possessed. Still alive, it stands protectively over the cocoon, remaining there without moving or feeding until the adult wasps hatch.

‘We don’t know exactly what kills the caterpillars, but it is fascinating that the moment of death seems to be tuned to the duration of the wasp’s pupal stage,’ commented Arne Janssen of the University of Amsterdam.

He and colleagues don’t know how the parasites effect the behavioural chance in the caterpillars, but since they find one or two larvae left behind when they dissect the caterpillars, they suspect that a few larvae in each brood may sacrifice themselves to help protect the remainder.