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Venus flytrap counts prey's steps to dissolve them alive
Chris Mattison/naturepl.com
in Brief Latest prime champ smashes record
Venus flytrap counts prey’s steps to dissolve them alive IT’S as easy as one, two, three… Venus flytraps count the number of steps their insect prey make to trigger key stages in catching and digesting them. We knew that brushing the sensitive trigger hairs on a flytrap twice closes the trap in a tenth of a second. The first touch causes molecules to build up in the trap’s sensory hairs and the second pushes their concentration across a threshold, resulting in an electrical impulse that activates the trap. This led Rainer Hedrich of the University of Würzburg in Germany and his team to feed crickets to flytraps and investigate what happened next.
They found that after the third touch, the plant begins to make digestive enzymes. And after five touches, it kicks off digestion in earnest, releasing enzymes and turning on pumps that suck sodium into the plant as its meal turns to liquid (Current Biology, doi.org/bbzp). The number of touches after five – with the crickets averaging 63 within an hour of capture – leads to a proportional response. “It measures the touches to see what type of visitor it is,” Hedrich says. Bigger insects take longer to subdue, and their struggling summons more enzymes. This means the plant avoids releasing more digestive juices than it needs to. “Effectively, it’s counting,” says Wayne Fagerberg at the University of New Hampshire in Durham. “It’s just not thinking about it.”
Gene test can tell if you need antibiotics IS YOUR runny nose the work of a virus, or a symptom of a bacterial infection that could lead to pneumonia? A gene test could help family doctors decide what to prescribe. Coughs and colds are one of the most common reasons for seeing a doctor, and viruses are usually the cause. But in the US, 73 per cent of people with cold symptoms are given antibiotics, which are
useless against viruses. Worse, such overprescription makes microbes resistant to drugs. It would be clearer if you could work out what a person’s immune system was trying to fight. Chris Woods and his team at Duke University in Durham, North Carolina, created such a test by looking at gene expression patterns in 317 blood samples. They identified signatures that
could distinguish between viral and bacterial infections, and non-infectious illnesses, with an accuracy of 87 per cent. “We’re very happy with that performance,” says Woods. “This type of tool should help reduce inappropriate antibiotic use.” One drawback is that the test requires up to 10 hours of lab analysis. The team is trying to adapt it to give results in an hour (Science Translational Medicine, doi.org/bbzr).
IT’S time for a new prime to shine. The largest known prime number is now 274,207,281 − 1, beating the previous candidate by nearly 5 million digits. The 22,338,618-digit monster was discovered by Curtis Cooper, at the University of Central Missouri in Warrensburg, as part of the Great Internet Mersenne Prime Search (GIMPS). It pools computing power online to test whether numbers are prime: divisible only by themselves and 1. GIMPS only checks for Mersenne primes, which take the special form 2p − 1, where p is also prime. Only 49 are known, and GIMPS has discovered the last 15. The new record prime turned up on 17 September last year, but a bug meant the GIMPS software failed to tell anyone, so it went unnoticed until revealed by routine maintenance. Curtis also found the previous record holder, 257,885,161 − 1, in February 2013.
Size matters in animal cleverness IT’S a no-brainer: animals with bigger brains are better problemsolvers. But there has been little evidence for the idea. Sarah Benson-Amram at the University of Wyoming in Laramie and colleagues have now tested it using puzzle boxes baited with food. When they presented these to 140 carnivores from 39 species in North American zoos, they found that those with larger brains relative to body mass, such as river otters and bears, were better at opening the boxes (PNAS, DOI: 10.1073/pnas.1505913113). Problem-solving is linked to cognitive ability, says BensonAmram, although intelligence is so broad that “it would be difficult, if not impossible, to measure”, she adds. 30 January 2016 | NewScientist | 17
in Brief Latest prime champ smashes record
Venus flytrap counts prey’s steps to dissolve them alive IT’S as easy as one, two, three… Venus flytraps count the number of steps their insect prey make to trigger key stages in catching and digesting them. We knew that brushing the sensitive trigger hairs on a flytrap twice closes the trap in a tenth of a second. The first touch causes molecules to build up in the trap’s sensory hairs and the second pushes their concentration across a threshold, resulting in an electrical impulse that activates the trap. This led Rainer Hedrich of the University of Würzburg in Germany and his team to feed crickets to flytraps and investigate what happened next.
They found that after the third touch, the plant begins to make digestive enzymes. And after five touches, it kicks off digestion in earnest, releasing enzymes and turning on pumps that suck sodium into the plant as its meal turns to liquid (Current Biology, doi.org/bbzp). The number of touches after five – with the crickets averaging 63 within an hour of capture – leads to a proportional response. “It measures the touches to see what type of visitor it is,” Hedrich says. Bigger insects take longer to subdue, and their struggling summons more enzymes. This means the plant avoids releasing more digestive juices than it needs to. “Effectively, it’s counting,” says Wayne Fagerberg at the University of New Hampshire in Durham. “It’s just not thinking about it.”
Gene test can tell if you need antibiotics IS YOUR runny nose the work of a virus, or a symptom of a bacterial infection that could lead to pneumonia? A gene test could help family doctors decide what to prescribe. Coughs and colds are one of the most common reasons for seeing a doctor, and viruses are usually the cause. But in the US, 73 per cent of people with cold symptoms are given antibiotics, which are
useless against viruses. Worse, such overprescription makes microbes resistant to drugs. It would be clearer if you could work out what a person’s immune system was trying to fight. Chris Woods and his team at Duke University in Durham, North Carolina, created such a test by looking at gene expression patterns in 317 blood samples. They identified signatures that
could distinguish between viral and bacterial infections, and non-infectious illnesses, with an accuracy of 87 per cent. “We’re very happy with that performance,” says Woods. “This type of tool should help reduce inappropriate antibiotic use.” One drawback is that the test requires up to 10 hours of lab analysis. The team is trying to adapt it to give results in an hour (Science Translational Medicine, doi.org/bbzr).
IT’S time for a new prime to shine. The largest known prime number is now 274,207,281 − 1, beating the previous candidate by nearly 5 million digits. The 22,338,618-digit monster was discovered by Curtis Cooper, at the University of Central Missouri in Warrensburg, as part of the Great Internet Mersenne Prime Search (GIMPS). It pools computing power online to test whether numbers are prime: divisible only by themselves and 1. GIMPS only checks for Mersenne primes, which take the special form 2p − 1, where p is also prime. Only 49 are known, and GIMPS has discovered the last 15. The new record prime turned up on 17 September last year, but a bug meant the GIMPS software failed to tell anyone, so it went unnoticed until revealed by routine maintenance. Curtis also found the previous record holder, 257,885,161 − 1, in February 2013.
Size matters in animal cleverness IT’S a no-brainer: animals with bigger brains are better problemsolvers. But there has been little evidence for the idea. Sarah Benson-Amram at the University of Wyoming in Laramie and colleagues have now tested it using puzzle boxes baited with food. When they presented these to 140 carnivores from 39 species in North American zoos, they found that those with larger brains relative to body mass, such as river otters and bears, were better at opening the boxes (PNAS, DOI: 10.1073/pnas.1505913113). Problem-solving is linked to cognitive ability, says BensonAmram, although intelligence is so broad that “it would be difficult, if not impossible, to measure”, she adds. 30 January 2016 | NewScientist | 17