Plants talk to each other chemically to warn of attacks by organisms such as viruses, according to a team at Rutgers University in New Jersey. Tobacco plants infected with the tobacco mosaic virus release a gas, methyl salicylate, that seems to help neighbouring, uninfected plants to resist the virus. The result came while the team was investigating the role of salicylic acid - the active ingredient of aspirin - in virus resistance. As reported in the latest Nature, Ilya Raskin and colleagues separated infected and uninfected plants by airways, and found that uninfected plants were resistant to the virus even without inoculation, where they had had air contact with an infected plant. Raskin said this was the first instance of a sick plant signalling in a way that can confer resistance.
Brain damage? Keep cool, says a team at the University of Pittsburgh Medical Center. Victims of severe brain injuries can recover more quickly and perhaps more fully if their bodies are chilled to below 31.1 C for a day, according to a study of 82 patients who were in comas after various traumas. Half were cooled for 24 hours, starting on average 10 hours after the injury, from the normal body temperature of 37 C. The treatment, reported in the New England Journal of Medicine, did not help those who were almost brain dead, but patients who already moved their limbs in response to pain during their comas did benefit. Six months later, 73 per cent of those who had been cooled were able to live independently, against 35 per cent of the others.
Notice that unusual smell when you walk into a room? Why, then, can't you notice it 10 minutes later? According to a team drawn from Japan and Italy, the "adaptation" to an unusual odour takes place at the level of a single sensory receptor, which controls the passage of charged chloride ions. In Nature, the team explains that at the basic, biochemical level, the receptor is turned on by a substance called cyclic AMP binding to it, and begins signalling odour detection. That causes calcium ions to accumulate in the receptor's cell. But the level of the receptor's output is reduced by its cell's internal calcium concentration - an effective feedback loop that allows a rapid response to a new smell, but switches it off after a few minutes.
Forget Mars. The really interesting place to go to look for extraterrestrial life right now in our solar system is Europa, an icy moon of Jupiter, according to a team of geologists and exobiologists. "If I really had to choose a place to look, and it was between going to Mars or to Europa, I would say Europa," says Professor Eugene Shoemaker, of comet-spotting (but also geology) fame. Planetary scientists at Last week's American Association for the Advancement of Science (AAAS) agreed that, though life may once have existed on Mars, it is now most likely to exist in volcanic vents at the bottom of a water ocean, below an ice crust 10 kilometres thick. Last week the Galileo spacecraft passed into Europa's atmosphere, beginning a four-day fly-past to take detailed pictures of Europa's surface and study the atmosphere - known to contain small amounts of oxygen - and ionosphere. The results will take up to a month to arrive back on Earth, but could be useful in planning a mission to study Europa in detailReuse content