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Did learning to fly give bats super-immunity?
GREG WOOD/AFP/Getty Images
IN BRIEF Antarctic ice sheets warming fast
Evolution of flight gave bats super-immunity NOT content with echolocation, when bats learned to fly they gained another superpower: immunity to some of the world’s deadliest diseases. Bats can harbour many diseases, including SARS and Ebola – but very few actually make them sick. Christopher Cowled from the CSIRO Australian Animal Health Laboratory in Geelong, Victoria, thinks this incredible immunity may have evolved in response to the extra stresses of flying. Bats use about 20 times more energy than other mammals of the same size during an average day to fuel
their flights. As a result, they generate large quantities of molecules called reactive oxygen species. These damage DNA by ripping off its hydrogen atoms. Cowled figured that to avoid the cancer these DNA-smashing molecules would normally cause, bats must have evolved a damage-avoidance strategy. Comparing the genomes of two very different bat species, Cowled and colleagues found that the genes that detect and respond to DNA damage changed 88 million years ago, when bats’ ancestors first took to the skies. They think the changes not only left bats better able to handle DNA damage but also to initiate a frontline antiviral immune response. “We believe that flight was the initial trigger that led to improvement in the [immune] systems,” Cowled says (Science, doi.org/j34).
Bird flu virus is blowing in the wind POTENTIALLY fatal bird flu viruses can spread on the wind, a hitherto suspected but unproven route of transmission. Usually, people catch bird flu through close physical contact with each other or, much more commonly, with infected poultry. The newly identified capacity for wind to spread it opens up a potential route by which the viruses can spread between farms. 12 | NewScientist | 5 January 2013
The finding came about after Dutch researchers studied an outbreak of the avian flu strain H7N7 in poultry on Dutch farms in 2003, which resulted in 89 confirmed human infections including one death. Computer models showed that wind patterns at the time of the outbreak explain how different genetic variants of H7N7 ended up on different farms (Journal of
Infectious Diseases, doi.org/j3b). H5N1 is the most harmful strain of avian flu, having killed 360 of 610 infected people since it was discovered in 2003. The fact that a related strain can travel on the wind suggests that H5N1 can too, says Marion Koopmans of the Dutch National Institute for Public Health and the Environment in Bilthoven, who coordinated the research project. “You must assume that this same potential is there for H5N1,” she says.
THE ice sheets of West Antarctica are warming much faster than we thought, suggesting swathes of it could melt and send global sea levels soaring. Climatologists have struggled to work out whether Antarctica is warming, and how quickly, because it has few weather stations and the records from some are incomplete. David Bromwich of Ohio State University in Columbus and his colleagues filled in the gaps for one key station using statistics and data from a climate model. They conclude that temperatures since 1958 have risen about 0.46 °C per decade – more than twice as fast as previously thought (Nature Geoscience, doi.org/j351). But Michael Mann at Penn State University in University Park says that warmer ocean water flooding in underneath the sheet poses a greater threat.
White dwarf wears a black hole mask A WHITE dwarf caught mimicking a black hole may be the first in a new class of stellar objects. A short, ultra-bright X-ray flare spotted in November 2011 seemed to match bursts of radiation from a black hole swallowing matter. But the temperature of the flare was unusually low, so Phil Charles of the University of Southampton, UK, and colleagues made more observations and ran computer simulations. They found that the flare was best explained by a white dwarf burning off mass sucked from a much bigger, hotter companion – a pairing that has never been seen before (The Astrophysical Journal, doi.org/j3c). Charles says there may be many more such binary stars misidentified as black holes.
IN BRIEF Antarctic ice sheets warming fast
Evolution of flight gave bats super-immunity NOT content with echolocation, when bats learned to fly they gained another superpower: immunity to some of the world’s deadliest diseases. Bats can harbour many diseases, including SARS and Ebola – but very few actually make them sick. Christopher Cowled from the CSIRO Australian Animal Health Laboratory in Geelong, Victoria, thinks this incredible immunity may have evolved in response to the extra stresses of flying. Bats use about 20 times more energy than other mammals of the same size during an average day to fuel
their flights. As a result, they generate large quantities of molecules called reactive oxygen species. These damage DNA by ripping off its hydrogen atoms. Cowled figured that to avoid the cancer these DNA-smashing molecules would normally cause, bats must have evolved a damage-avoidance strategy. Comparing the genomes of two very different bat species, Cowled and colleagues found that the genes that detect and respond to DNA damage changed 88 million years ago, when bats’ ancestors first took to the skies. They think the changes not only left bats better able to handle DNA damage but also to initiate a frontline antiviral immune response. “We believe that flight was the initial trigger that led to improvement in the [immune] systems,” Cowled says (Science, doi.org/j34).
Bird flu virus is blowing in the wind POTENTIALLY fatal bird flu viruses can spread on the wind, a hitherto suspected but unproven route of transmission. Usually, people catch bird flu through close physical contact with each other or, much more commonly, with infected poultry. The newly identified capacity for wind to spread it opens up a potential route by which the viruses can spread between farms. 12 | NewScientist | 5 January 2013
The finding came about after Dutch researchers studied an outbreak of the avian flu strain H7N7 in poultry on Dutch farms in 2003, which resulted in 89 confirmed human infections including one death. Computer models showed that wind patterns at the time of the outbreak explain how different genetic variants of H7N7 ended up on different farms (Journal of
Infectious Diseases, doi.org/j3b). H5N1 is the most harmful strain of avian flu, having killed 360 of 610 infected people since it was discovered in 2003. The fact that a related strain can travel on the wind suggests that H5N1 can too, says Marion Koopmans of the Dutch National Institute for Public Health and the Environment in Bilthoven, who coordinated the research project. “You must assume that this same potential is there for H5N1,” she says.
THE ice sheets of West Antarctica are warming much faster than we thought, suggesting swathes of it could melt and send global sea levels soaring. Climatologists have struggled to work out whether Antarctica is warming, and how quickly, because it has few weather stations and the records from some are incomplete. David Bromwich of Ohio State University in Columbus and his colleagues filled in the gaps for one key station using statistics and data from a climate model. They conclude that temperatures since 1958 have risen about 0.46 °C per decade – more than twice as fast as previously thought (Nature Geoscience, doi.org/j351). But Michael Mann at Penn State University in University Park says that warmer ocean water flooding in underneath the sheet poses a greater threat.
White dwarf wears a black hole mask A WHITE dwarf caught mimicking a black hole may be the first in a new class of stellar objects. A short, ultra-bright X-ray flare spotted in November 2011 seemed to match bursts of radiation from a black hole swallowing matter. But the temperature of the flare was unusually low, so Phil Charles of the University of Southampton, UK, and colleagues made more observations and ran computer simulations. They found that the flare was best explained by a white dwarf burning off mass sucked from a much bigger, hotter companion – a pairing that has never been seen before (The Astrophysical Journal, doi.org/j3c). Charles says there may be many more such binary stars misidentified as black holes.