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JEREMY THOMAS
THEY wouldn’t wow a karaoke club, but parasitic caterpillars belt out a convincing cover version of a tune irresistible to red ants. The discovery may explain why duped ants treat the larvae “as if they were the holiest of holiest, the pinnacle of power, the queen ant”, says Jeremy Thomas at the University of Oxford. Young Maculinea rebeli caterpillars gorge on leaves. Before their metamorphosis, they drop to the forest floor and secrete ant-like chemicals which trick worker ants into treating it like one of them. The ants ferry the fattening larva to their colony and start bringing it food. Not convinced that chemicals alone could explain the caterpillars’ royal treatment, Thomas’s team recorded the sounds of the ants and the larvae. They found the sounds shared qualities, such as frequency. Worker ants listening to recordings of their own songs “tapped [the speakers] with their antennae with interest”, says Thomas. But both their queen’s song and that of a larva made them crowd around the speaker and refuse to budge (Science, DOI: 10.1126/science.1163583). “This potentially solves the mystery of how they mimic the queen, even though they don’t smell like the queen,” says David Nash at the University of Copenhagen in Denmark.
Injection boosts memory in animals with Alzheimer’s A PROTEIN that supports the growth and upkeep of brain cells has boosted memory and learning in rodents and primates with animal versions of Alzheimer’s. A team led by Mark Tuszynski of the University of California, San Diego, injected brain-derived neurotrophic factor (BDNF) into the entorhinal cortex and the hippocampus, the parts of the brain where memories are formed and consolidated, and where Alzheimer’s strikes first. Afterwards, all the animals, which included mice with a
version of Alzheimer’s, elderly rats and monkeys with natural degeneration, and rats and monkeys given brain lesions similar to those of Alzheimer’s, improved their performance on memory and learning tests (Nature Medicine, DOI: 10.1038/nm.1912). The injections also reduced the rate of brain cell death and increased by 25 per cent the number of connections between neurons, a crucial aspect of memory formation. Interestingly, these benefits arose even in animals whose brains had
developed the protein plaques typical of Alzheimer’s and often blamed for its symptoms. Some animals received BDNF directly, but the best results were in those injected with a harmless virus carrying the BDNF gene, which continued to make the protein. Tuszynski says that trials in people could start in as soon as two years. Charles Harrington of TauRx Therapeutics, a company in Aberdeen, UK, developing a drug for Alzheimer’s, questions whether brain injections in people would be safe or practical. MEDICALRF.COM/SPL
Caterpillars sing ant-queen’s hits
High anxiety over east coast sea level WATCH out, Washington DC: if the West Antarctic ice sheet melts, sea levels around the US coast will rise to much greater heights than expected because the meltwater will spread out unevenly. Previous climate models predict a 5-metre rise in global sea levels due to the melting ice sheet but Jerry Mitrovica and colleagues at the University of Toronto in Canada think some regions will get more water than others. In their model, the shrinking ice sheet exerts less of a gravitational pull on surrounding oceans, meaning water will dissipate northwards. On top of that, a lighter ice sheet will cause land beneath the ice to rise, displacing water elsewhere. Perhaps the most significant effect the team included is the possibility that redistributing such a large mass would alter the Earth’s spin axis. Centrifugal forces create bulges in oceans between the equator and the poles, but if the axis shifts, these bulges would move. The model shows the US east coast would bear the brunt of such a shift to the tune of an extra 1 or 2 metres in sea level rise (Science, DOI: 10.1126/science.1166510).
Blood booster is a breath of fresh air HOW do you transform mice with damaged hearts from couch potatoes into treadmill tearaways? A compound that prompts blood to release more oxygen does the trick, raising hopes it could help people weakened by heart attacks. Inadequate oxygen delivery to heart tissue causes many of the symptoms of heart failure, but previous attempts to rectify this have had limited success. Instead, Jean-Marie Lehn of the University of Strasbourg in France tried a new approach: getting haemoglobin in blood to release more oxygen to cells.
To do this, Lehn gave mice with heart problems a substance called myo-inositol trispyrophosphate (ITPP). Normally, haemoglobin releases only 25 per cent of its oxygen cargo, but if it binds to ITPP it releases much more, says Lehn. Drinking ITPP dissolved in water boosted exercise levels in the mice by 35 per cent, while injecting it caused a 60 per cent rise (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0812381106). Athletes should not see ITPP as a performance enhancer, not least because it is detectable, says Lehn.
14 February 2009 | NewScientist | 17
JEREMY THOMAS
THEY wouldn’t wow a karaoke club, but parasitic caterpillars belt out a convincing cover version of a tune irresistible to red ants. The discovery may explain why duped ants treat the larvae “as if they were the holiest of holiest, the pinnacle of power, the queen ant”, says Jeremy Thomas at the University of Oxford. Young Maculinea rebeli caterpillars gorge on leaves. Before their metamorphosis, they drop to the forest floor and secrete ant-like chemicals which trick worker ants into treating it like one of them. The ants ferry the fattening larva to their colony and start bringing it food. Not convinced that chemicals alone could explain the caterpillars’ royal treatment, Thomas’s team recorded the sounds of the ants and the larvae. They found the sounds shared qualities, such as frequency. Worker ants listening to recordings of their own songs “tapped [the speakers] with their antennae with interest”, says Thomas. But both their queen’s song and that of a larva made them crowd around the speaker and refuse to budge (Science, DOI: 10.1126/science.1163583). “This potentially solves the mystery of how they mimic the queen, even though they don’t smell like the queen,” says David Nash at the University of Copenhagen in Denmark.
Injection boosts memory in animals with Alzheimer’s A PROTEIN that supports the growth and upkeep of brain cells has boosted memory and learning in rodents and primates with animal versions of Alzheimer’s. A team led by Mark Tuszynski of the University of California, San Diego, injected brain-derived neurotrophic factor (BDNF) into the entorhinal cortex and the hippocampus, the parts of the brain where memories are formed and consolidated, and where Alzheimer’s strikes first. Afterwards, all the animals, which included mice with a
version of Alzheimer’s, elderly rats and monkeys with natural degeneration, and rats and monkeys given brain lesions similar to those of Alzheimer’s, improved their performance on memory and learning tests (Nature Medicine, DOI: 10.1038/nm.1912). The injections also reduced the rate of brain cell death and increased by 25 per cent the number of connections between neurons, a crucial aspect of memory formation. Interestingly, these benefits arose even in animals whose brains had
developed the protein plaques typical of Alzheimer’s and often blamed for its symptoms. Some animals received BDNF directly, but the best results were in those injected with a harmless virus carrying the BDNF gene, which continued to make the protein. Tuszynski says that trials in people could start in as soon as two years. Charles Harrington of TauRx Therapeutics, a company in Aberdeen, UK, developing a drug for Alzheimer’s, questions whether brain injections in people would be safe or practical. MEDICALRF.COM/SPL
Caterpillars sing ant-queen’s hits
High anxiety over east coast sea level WATCH out, Washington DC: if the West Antarctic ice sheet melts, sea levels around the US coast will rise to much greater heights than expected because the meltwater will spread out unevenly. Previous climate models predict a 5-metre rise in global sea levels due to the melting ice sheet but Jerry Mitrovica and colleagues at the University of Toronto in Canada think some regions will get more water than others. In their model, the shrinking ice sheet exerts less of a gravitational pull on surrounding oceans, meaning water will dissipate northwards. On top of that, a lighter ice sheet will cause land beneath the ice to rise, displacing water elsewhere. Perhaps the most significant effect the team included is the possibility that redistributing such a large mass would alter the Earth’s spin axis. Centrifugal forces create bulges in oceans between the equator and the poles, but if the axis shifts, these bulges would move. The model shows the US east coast would bear the brunt of such a shift to the tune of an extra 1 or 2 metres in sea level rise (Science, DOI: 10.1126/science.1166510).
Blood booster is a breath of fresh air HOW do you transform mice with damaged hearts from couch potatoes into treadmill tearaways? A compound that prompts blood to release more oxygen does the trick, raising hopes it could help people weakened by heart attacks. Inadequate oxygen delivery to heart tissue causes many of the symptoms of heart failure, but previous attempts to rectify this have had limited success. Instead, Jean-Marie Lehn of the University of Strasbourg in France tried a new approach: getting haemoglobin in blood to release more oxygen to cells.
To do this, Lehn gave mice with heart problems a substance called myo-inositol trispyrophosphate (ITPP). Normally, haemoglobin releases only 25 per cent of its oxygen cargo, but if it binds to ITPP it releases much more, says Lehn. Drinking ITPP dissolved in water boosted exercise levels in the mice by 35 per cent, while injecting it caused a 60 per cent rise (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0812381106). Athletes should not see ITPP as a performance enhancer, not least because it is detectable, says Lehn.
14 February 2009 | NewScientist | 17