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3 December 2011 | NewScientist | 21 A NEURON transplant has rewired damaged brain areas in mice, raising hopes that such transplants might one day help to treat spinal- cord injuries, Parkinson’s disease and other brain conditions. Jeffrey Macklis at Harvard University and his colleagues took healthy neurons that had been labelled with a green fluorescent protein from mouse embryos. They then transplanted them into mice that were born with damage to a brain circuit involved in the regulation of food intake and body weight in response to the hormone leptin. Without intervention such mice become dangerously overweight. The fluorescent neurons integrated into the brain circuit, and differentiated into mature neurons that could communicate with existing neurons and On your marks, get set… hatch! TALK about egging your siblings on. Baby turtles communicate before hatching to coordinate their arrival into the world. Australian river turtles (Emydura macquarii) lay eggs in a hole in a sandy riverbank. Eggs at the cooler base of the nest develop more slowly and should hatch later than their warmer brethren at the top, says Ricky-John Spencer at the University of Western Sydney, Australia – but all eggs apparently hatch together. To confirm this, Spencer took eggs from the same clutch and held half at a low and half at a high temperature for two-thirds of the incubation period. When he reunited the eggs for the final third, the formerly cooler eggs used the time to play catch-up so that all eggs hatched together (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2011.2074). The eggs might communicate using chemical cues, says Spencer. The pigeon: less flying rat, more living helicopter THE humble pigeon could provide the unlikely inspiration for a flock of small military drones that can navigate enclosed spaces. It turns out the common birds can redirect their flight path with the agility of a helicopter. Ivo Ros of Harvard University and colleagues let three pigeons loose in a corridor that incorporated a sharp 90-degree turn. They placed 16 markers on each pigeon’s body and set up nine synchronised high-speed cameras along the corridor to track the birds’ position as they flew around the bend. The experiment revealed that the flying pigeons S.A. COMBES IN BRIEF Neuron transplant reverses obesity respond to leptin, insulin and glucose, suggesting that they had repaired the damaged circuit. The treated mice went on to weigh 30 per cent less than their untreated counterparts. Macklis hopes similar transplanted neurons could rewire other complex brain circuits, which could help treat brain injury or diseases that depend on signals coming from other neurons rather than signals coming from the blood. produce forces in a surprisingly consistent direction relative to the body, which means that when the pigeon wants to turn it has to roll and rotate its body. “We didn’t expect the forces to change direction relative to the body this little – as little as is observed in helicopters,” says Ros (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1107519108). It’s not clear yet whether the same applies to all flying animals or just to pigeons, says Ros. Adrian Thomas at the University of Oxford, who was not involved in the study, says that the information could help in the design of surveillance drones for flying inside buildings. Using pigeons as a model instead of choppers might offer a way to avoid dealing with the complex gyroscopic forces real helicopters face, he suggests. MICE can survive a dose of radiation that should have killed them when given a double-drug therapy – even if they get the drug cocktail 24 hours after exposure. Radiation damages rapidly dividing cells in the intestine, allowing harmful bacteria to leak into the bloodstream. Eva Guinan at Harvard Medical School found that boosting levels of a protein involved in the immune response against the bacteria – while simultaneously giving an antibiotic – helped 80 per cent of mice survive (Science Translational Medicine, DOI: 10.1126/scitranslmed.3003126). The protein and antibiotic are both safe to use in people, and could be stockpiled in case of a nuclear accident, says Guinan. How to survive a fatal radiation dose
