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Vanishing methane on Mars bodes ill for alien life
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PAUL ANDREW LAWRENCE/ALAMY
WHICHEVER way you look at it, events in the Arctic bode ill for the global climate. The ice is disappearing, melting permafrost threatens to belch methane, and now comes a warning that vast regions of tundra could singe. When that happens, it will start emitting carbon far faster then healthy tundra soaks it up. Adrian Rocha of the Marine Biological Laboratory in Woods Hole, Massachusetts, and colleagues placed sensors across the 1000-square-kilometre fire scar left by a blaze in 2007 on the Brooks mountain range in northern Alaska. They found that in the following year the most severely burnt tundra emitted twice as much carbon as tundra normally stores away. The fire itself is estimated to have released 1.3 billion tonnes of carbon dioxide. What’s more, the burnt region absorbed 71 per cent more solar radiation than normal, melting 5 to 10 centimetres of its permafrost layer. In results to be presented at the annual meeting of the Ecological Society of America in Albuquerque, New Mexico, Rocha warns that such fires will become worse. Tundra only burns once certain thresholds are crossed. Drier conditions, more thunderstorms and warming in the Arctic over the coming century, he says, will make this more likely.
Open a tumour’s supply channels, then send in the troops BELIEVE it or not, boosting the blood supply to cancers can make them easier to kill. Cancers often develop very poor blood supplies that leave parts of the tumour hypoxic, or starved of oxygen. This creates internal pressures that prevent anti-cancer drugs penetrating deeply enough to take effect. “We have identified a way of using drugs to soften up cancers for subsequent treatment,” says Gillies McKenna at the University of Oxford, who led the research.
McKenna and his team have identified four different drugs – including the anti-HIV drug nelfinavir – that can disrupt the process by which hypoxia occurs, restoring proper blood flow to the tumours and making them more vulnerable to chemotherapy (Cancer Research, DOI: 10.1158/ 0008-5472.can-09-0657). The strategy has already been demonstrated in people with advanced pancreatic cancer. Tumours in six out of 10 patients treated shrank to a size where they could be cut out, compared
with an expectation of 1 in 10 under conventional treatment. Now, a larger trial with about 50 people is under way, again using nelfinavir to open up the tumours to attack prior to chemotherapy. McKenna says the findings do not undermine the rationale for using other drugs to block the blood supply to cancers. If anything, he says, the two approaches are complementary, as tumours softened up and then shrunk by chemotherapy could be finished off with bloodvessel blockers. JEAN-PAUL FERRERO/AUSCAPE
Burning tundra’s global threat
Vanishing methane blow to Mars life HOPES that we will find life on Mars have been dented by the claim that something is quickly destroying methane. This suggests conditions on the planet are much harsher than we thought. In 2003, a telescope survey observed pockets of methane on Mars. This was a surprise, because the gas should have spread evenly around the planet, so Franck Lefevre and François Forget of the Pierre and Marie Curie University in Paris, France, created a climate model to explain how such concentrations might form. The pair found that to recreate the observations, a big source of methane is required and the gas must be destroyed within 200 terrestrial days – 600 times faster than on Earth (Nature, DOI: 10.1038/nature08228). Since methane is the simplest organic molecule, other more complex organic molecules would probably suffer the same fate, they argue. The cause of the destruction is unknown. Dust storms could play a part, or the gas could be reacting with minerals in the planet’s soil. In the latter case, Lefevre calculates that a molecule of methane could be destroyed in as little as 1 hour.
Crows even smarter than we thought? NEW Caledonian crows may be smart, but are they schemers? A series of tests designed by Joanna Wimpenny and Alex Kacelnik at the University of Oxford shows the corvids can upgrade tools in succession to obtain an otherwise unreachable snack. But Kacelnik cautions against jumping to the conclusion that the birds can plan two steps ahead. Wimpenny and Kacelnik tempted seven crows with a bit of pig heart trapped down a clear tube. To snag the treat, the birds had to use a short stick to ferret an intermediate stick out of a tube. They then had to use
this stick to obtain a third one long enough to reach the food (PLoS ONE, DOI: 10.1371/journal.pone.0006471). In each step, they had to choose the right stick from a selection on offer. Four crows solved the task with varying degrees of success. Analysing the way the birds selected each stick showed this was not a random process: more often than not they chose a better tool each time. Still, Kacelnik says it is impossible to prove they had formulated step-by-step plans to complete the task. “We want to be very cautious in making that conclusion,” he says.
8 August 2009 | NewScientist | 15
PAUL ANDREW LAWRENCE/ALAMY
WHICHEVER way you look at it, events in the Arctic bode ill for the global climate. The ice is disappearing, melting permafrost threatens to belch methane, and now comes a warning that vast regions of tundra could singe. When that happens, it will start emitting carbon far faster then healthy tundra soaks it up. Adrian Rocha of the Marine Biological Laboratory in Woods Hole, Massachusetts, and colleagues placed sensors across the 1000-square-kilometre fire scar left by a blaze in 2007 on the Brooks mountain range in northern Alaska. They found that in the following year the most severely burnt tundra emitted twice as much carbon as tundra normally stores away. The fire itself is estimated to have released 1.3 billion tonnes of carbon dioxide. What’s more, the burnt region absorbed 71 per cent more solar radiation than normal, melting 5 to 10 centimetres of its permafrost layer. In results to be presented at the annual meeting of the Ecological Society of America in Albuquerque, New Mexico, Rocha warns that such fires will become worse. Tundra only burns once certain thresholds are crossed. Drier conditions, more thunderstorms and warming in the Arctic over the coming century, he says, will make this more likely.
Open a tumour’s supply channels, then send in the troops BELIEVE it or not, boosting the blood supply to cancers can make them easier to kill. Cancers often develop very poor blood supplies that leave parts of the tumour hypoxic, or starved of oxygen. This creates internal pressures that prevent anti-cancer drugs penetrating deeply enough to take effect. “We have identified a way of using drugs to soften up cancers for subsequent treatment,” says Gillies McKenna at the University of Oxford, who led the research.
McKenna and his team have identified four different drugs – including the anti-HIV drug nelfinavir – that can disrupt the process by which hypoxia occurs, restoring proper blood flow to the tumours and making them more vulnerable to chemotherapy (Cancer Research, DOI: 10.1158/ 0008-5472.can-09-0657). The strategy has already been demonstrated in people with advanced pancreatic cancer. Tumours in six out of 10 patients treated shrank to a size where they could be cut out, compared
with an expectation of 1 in 10 under conventional treatment. Now, a larger trial with about 50 people is under way, again using nelfinavir to open up the tumours to attack prior to chemotherapy. McKenna says the findings do not undermine the rationale for using other drugs to block the blood supply to cancers. If anything, he says, the two approaches are complementary, as tumours softened up and then shrunk by chemotherapy could be finished off with bloodvessel blockers. JEAN-PAUL FERRERO/AUSCAPE
Burning tundra’s global threat
Vanishing methane blow to Mars life HOPES that we will find life on Mars have been dented by the claim that something is quickly destroying methane. This suggests conditions on the planet are much harsher than we thought. In 2003, a telescope survey observed pockets of methane on Mars. This was a surprise, because the gas should have spread evenly around the planet, so Franck Lefevre and François Forget of the Pierre and Marie Curie University in Paris, France, created a climate model to explain how such concentrations might form. The pair found that to recreate the observations, a big source of methane is required and the gas must be destroyed within 200 terrestrial days – 600 times faster than on Earth (Nature, DOI: 10.1038/nature08228). Since methane is the simplest organic molecule, other more complex organic molecules would probably suffer the same fate, they argue. The cause of the destruction is unknown. Dust storms could play a part, or the gas could be reacting with minerals in the planet’s soil. In the latter case, Lefevre calculates that a molecule of methane could be destroyed in as little as 1 hour.
Crows even smarter than we thought? NEW Caledonian crows may be smart, but are they schemers? A series of tests designed by Joanna Wimpenny and Alex Kacelnik at the University of Oxford shows the corvids can upgrade tools in succession to obtain an otherwise unreachable snack. But Kacelnik cautions against jumping to the conclusion that the birds can plan two steps ahead. Wimpenny and Kacelnik tempted seven crows with a bit of pig heart trapped down a clear tube. To snag the treat, the birds had to use a short stick to ferret an intermediate stick out of a tube. They then had to use
this stick to obtain a third one long enough to reach the food (PLoS ONE, DOI: 10.1371/journal.pone.0006471). In each step, they had to choose the right stick from a selection on offer. Four crows solved the task with varying degrees of success. Analysing the way the birds selected each stick showed this was not a random process: more often than not they chose a better tool each time. Still, Kacelnik says it is impossible to prove they had formulated step-by-step plans to complete the task. “We want to be very cautious in making that conclusion,” he says.
8 August 2009 | NewScientist | 15