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Massive stars avoid the single life
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R. Hanus
OLD-AGED termites go out with a bang, taking enemies with them. Jan Šobotník from the Academy of Sciences of the Czech Republic and Thomas Bourguignon from the Free University of Brussels in Belgium were surprised to find pale blue spots on the abdomens of older termites (Neocapriterme taracua). But the real shock came when the pair picked up the insects – they exploded in their hands. To investigate whether the suicides might be part of a defence strategy, Šobotník, Bourguignon and their colleagues pitted spotted and younger non-spotted termites against two rival species of termite that are known to compete with the others for land and food. When the spotted termites were physically unable to defend themselves with their jaws, they would burst a pouch on their backs, releasing a liquid that paralysed and killed any termites it touched. Younger termites were less likely to self-detonate, and their liquid was far less toxic (Science, DOI: 10.1126/ science.1219129). The lethal brew is thought to be a mixture of the spots’ blue crystals and the insects’ saliva and haemolymph – a blood-like fluid. The team thinks the insects develop their spotted toxicity to remain useful to the colony once they’re too old to forage for food.
Meteorite’s left-handed molecules a blow to ET search NEVER touted as easy, hunting for aliens just got a little bit harder. It seems an excess of “lefthanded” molecules, long assumed to be a signature of life, can be created inside asteroids through a non-biological process. That puts a damper on missions that intended to look for this chemical signature as evidence of biological activity on other worlds. Molecules have handedness, or chirality, if their mirror-images cannot be superimposed upon each other, rather like your right and left hands. Life on Earth is
built almost exclusively on lefthanded amino acids, so scientists have assumed that a strong lefthanded bias is a fundamental part of biochemistry. Instruments on the European Space Agency’s ExoMars and Rosetta missions were designed to search for left-handed molecules as a trace of life. But a team led by Daniel Glavin of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, found that meteorites collected from Canada’s Tagish Lake also have a large amount of left-handed
amino acids that are common in terrestrial life (Meteoritics & Planetary Science, DOI: 10.1111/j.1945-5100.2012.01400.x). The researchers think liquid water in asteroids caused the acids to dissolve and then crystallise with a heavy chiral bias. “As evidence mounts that [lefthanded] excess occurs naturally across bodies in the solar system, any strategies designed to search for life based on looking for this excess require serious rethinking,” says Alberto Fairen of the SETI Institute in California. L. Calçada/S. E. de Mink/ESO
Suicidal termites spew toxic brew
Gene fusion behind lethal brain cancer TREATMENT for a lethal form of brain cancer could be on the horizon after the discovery that it forms as a result of genes fusing. Anna Lasorella at the Institute for Cancer Genetics at Columbia University in New York and colleagues found that about 3 per cent of glioblastoma tumours that they studied were caused by the fusing of two genes. When fused, the two wreak havoc during cell division. The protein that the fused genes code for latches onto the spindles that pull freshly replicated chromosomes into two new cells during cell division. The interference means that instead of an even division, the cells end up with different numbers of chromosomes – a well-known hallmark of cancer. After the team injected the protein into the brains of healthy mice, 90 per cent went on to develop glioblastomas. They then administered a drug that blocked the activity of the protein. In doing so, they were able to double the mice’s survival time (Science, DOI: 10.1126/science.1220834). The protein is specific to the cancer cells, so the team predicts that drugs that target it would cause little damage to healthy cells.
Massive stars avoid the single life MOST people don’t like to be alone, and the same goes for massive stars. Now it seems that pairing up is the norm among the universe’s most influential stars. Massive stars seed the universe with heavier elements, such as iron and oxygen. Only in these stars is there enough heat and pressure for the fusion reactions needed to create these larger atoms. Astronomers had thought most large stars were single, and based their models of galactic evolution on this assumption. But when Hugues Sana of the University of Amsterdam in the
Netherlands and colleagues looked at 71 stars with masses greater than 15 times that of our sun, they found that more than 70 per cent revolve with a companion in a binary system (Science, doi.org/h4k). This new view is improving our interpretations of stellar evolution. In about 50 per cent of the team’s sample, the companion star is a “vampire” that siphons material off its mate. As the stripped star often ends up unusually hydrogen-poor, massive stellar pairings could explain why a third of supernovae have surprisingly little hydrogen.
4 August 2012 | NewScientist | 17
R. Hanus
OLD-AGED termites go out with a bang, taking enemies with them. Jan Šobotník from the Academy of Sciences of the Czech Republic and Thomas Bourguignon from the Free University of Brussels in Belgium were surprised to find pale blue spots on the abdomens of older termites (Neocapriterme taracua). But the real shock came when the pair picked up the insects – they exploded in their hands. To investigate whether the suicides might be part of a defence strategy, Šobotník, Bourguignon and their colleagues pitted spotted and younger non-spotted termites against two rival species of termite that are known to compete with the others for land and food. When the spotted termites were physically unable to defend themselves with their jaws, they would burst a pouch on their backs, releasing a liquid that paralysed and killed any termites it touched. Younger termites were less likely to self-detonate, and their liquid was far less toxic (Science, DOI: 10.1126/ science.1219129). The lethal brew is thought to be a mixture of the spots’ blue crystals and the insects’ saliva and haemolymph – a blood-like fluid. The team thinks the insects develop their spotted toxicity to remain useful to the colony once they’re too old to forage for food.
Meteorite’s left-handed molecules a blow to ET search NEVER touted as easy, hunting for aliens just got a little bit harder. It seems an excess of “lefthanded” molecules, long assumed to be a signature of life, can be created inside asteroids through a non-biological process. That puts a damper on missions that intended to look for this chemical signature as evidence of biological activity on other worlds. Molecules have handedness, or chirality, if their mirror-images cannot be superimposed upon each other, rather like your right and left hands. Life on Earth is
built almost exclusively on lefthanded amino acids, so scientists have assumed that a strong lefthanded bias is a fundamental part of biochemistry. Instruments on the European Space Agency’s ExoMars and Rosetta missions were designed to search for left-handed molecules as a trace of life. But a team led by Daniel Glavin of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, found that meteorites collected from Canada’s Tagish Lake also have a large amount of left-handed
amino acids that are common in terrestrial life (Meteoritics & Planetary Science, DOI: 10.1111/j.1945-5100.2012.01400.x). The researchers think liquid water in asteroids caused the acids to dissolve and then crystallise with a heavy chiral bias. “As evidence mounts that [lefthanded] excess occurs naturally across bodies in the solar system, any strategies designed to search for life based on looking for this excess require serious rethinking,” says Alberto Fairen of the SETI Institute in California. L. Calçada/S. E. de Mink/ESO
Suicidal termites spew toxic brew
Gene fusion behind lethal brain cancer TREATMENT for a lethal form of brain cancer could be on the horizon after the discovery that it forms as a result of genes fusing. Anna Lasorella at the Institute for Cancer Genetics at Columbia University in New York and colleagues found that about 3 per cent of glioblastoma tumours that they studied were caused by the fusing of two genes. When fused, the two wreak havoc during cell division. The protein that the fused genes code for latches onto the spindles that pull freshly replicated chromosomes into two new cells during cell division. The interference means that instead of an even division, the cells end up with different numbers of chromosomes – a well-known hallmark of cancer. After the team injected the protein into the brains of healthy mice, 90 per cent went on to develop glioblastomas. They then administered a drug that blocked the activity of the protein. In doing so, they were able to double the mice’s survival time (Science, DOI: 10.1126/science.1220834). The protein is specific to the cancer cells, so the team predicts that drugs that target it would cause little damage to healthy cells.
Massive stars avoid the single life MOST people don’t like to be alone, and the same goes for massive stars. Now it seems that pairing up is the norm among the universe’s most influential stars. Massive stars seed the universe with heavier elements, such as iron and oxygen. Only in these stars is there enough heat and pressure for the fusion reactions needed to create these larger atoms. Astronomers had thought most large stars were single, and based their models of galactic evolution on this assumption. But when Hugues Sana of the University of Amsterdam in the
Netherlands and colleagues looked at 71 stars with masses greater than 15 times that of our sun, they found that more than 70 per cent revolve with a companion in a binary system (Science, doi.org/h4k). This new view is improving our interpretations of stellar evolution. In about 50 per cent of the team’s sample, the companion star is a “vampire” that siphons material off its mate. As the stripped star often ends up unusually hydrogen-poor, massive stellar pairings could explain why a third of supernovae have surprisingly little hydrogen.
4 August 2012 | NewScientist | 17