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Key enzyme makes farm kids healthier
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Joseph K H Koh
THIS spider has gone to town in making itself look like crap – literally. Bird-dung crab spiders spend a lot of time sitting motionless on leaves, using their gross looks to attract flies for dinner. Their trick is to mimic bird droppings in colour, shape, size and smell, deceiving predators and prey alike. “Birds, almost all with good eyesight, will not go for what appears to be their own turd for food,” says Joseph K. H. Koh of the Lee Kong Chian Natural History Museum in Singapore. The spider’s body has a glossy surface that gives it the “wet” look of fresh faeces. “The nodules on the body and rough-edges of the legs further reinforce the ‘shitty’ look – pardon the rudeness,” Koh says. Long Yu of Hubei University in China and his team exposed the spider to one of its predators – jumping spiders. They also added houseflies as prey. The team found that the camouflage helps these crab spiders (Phrynarachne ceylonica) repel more jumping spiders and attract more flies than those without camouflage. They presented their findings at the Behaviour 2015 meeting in Cairns, Australia, last month. Other spiders, such as orb weavers in the genus Celaenia, also look like bird droppings, but the foul smell makes bird-dung crab spiders unique.
Key enzyme makes farm kids healthier DIRT is good for you. Kids on farms are less likely to develop allergies and asthma than urban children. But the protective effects of friendly microbes also seem to depend on a person’s genetic make-up. The hygiene hypothesis says that a lack of exposure to dirt and microbes is to blame for increases in allergies and asthma. One explanation is that children today encounter less endotoxin, a bacterial protein found on the surface of many common species, including E. coli, that may be
important for damping down overactive immune systems. Children with gene mutations that disrupt the functioning of an enzyme called A20 are more likely to have asthma and allergies, so Bart Lambrecht of Ghent University in Belgium and his team wondered whether A20 may be involved in helping endotoxins train our immune systems. First they exposed mice to endotoxin, and saw they developed fewer allergies when later exposed to dust mites. But this effect wasn’t seen when the
experiment was repeated with mice that had been genetically engineered to lack A20 (Science, doi.org/7hf). Lambrecht and his team then turned to human lung cells and found that A20 was less active in adults who had asthma. “It’s important because it shows that endotoxin can’t work on its own,” says Erika von Mutius of the Ludwig Maximilian University in Munich, Germany, a proponent of the hygiene hypothesis. It is thought that about 5 per cent of people have a faulty version of the A20 enzyme. Alex Segre / Alamy Stock Photo
Crappy fashion keeps spider alive
Palaeolithic people ate carbs as well GOING on the palaeo diet? Don’t put down your porridge just yet. Hunter-gatherers ate oats as far back as 32,000 years ago – way before farming took root. This is the earliest known human consumption of oats, say Marta Mariotti Lippi at the University of Florence in Italy and her colleagues, who made the discovery after analysing starch grains on an ancient stone grinding tool from southern Italy (PNAS, DOI: 10.1073/ pnas.1505213112). The Palaeolithic people ground up the wild oats to form flour, which they may have boiled or baked into a simple flatbread, says Mariotti Lippi. They also seem to have heated the grains before grinding them, perhaps to dry them out in the colder climate of the time. Mariotti Lippi notes that this would also have made the grain easier to grind and longer-lasting. This multi-stage process would have been time consuming, but beneficial. The grain is nutritionally valuable, and turning it into flour would have been a good way to transport it, which was important for Palaeolithic nomads, she says.
Speedier trains can slow down roads READING this while stuck in traffic? Fast trains may be to blame. Slowing the London Underground could cut overall congestion in the city. Marc Barthelemy of the French Atomic Energy and Alternative Energies Commission in Gif-surYvette and colleagues mapped out the road and subway networks in London and New York City and simulated travel at different speeds. They found that the ratio of the average road and rail speeds can have a critical impact on congestion. If the subway speeds up while road speed stays fixed, for example,
more people on the outskirts will use trains. But these commuters often have to travel by road to do so, as suburban stations are thinly spread. The result is more congestion overall, as increased traffic at the outskirts outweighs smoother flow in the centre (arxiv.org/abs/1508.07265). “If you want to give more access to more people, then increasing the speed of the subway is not the best solution,” says Barthelemy – packing stations more closely is often better. New York City is an exception, however: congestion here is so bad that speeding up trains does help.
12 September 2015 | NewScientist | 17
Joseph K H Koh
THIS spider has gone to town in making itself look like crap – literally. Bird-dung crab spiders spend a lot of time sitting motionless on leaves, using their gross looks to attract flies for dinner. Their trick is to mimic bird droppings in colour, shape, size and smell, deceiving predators and prey alike. “Birds, almost all with good eyesight, will not go for what appears to be their own turd for food,” says Joseph K. H. Koh of the Lee Kong Chian Natural History Museum in Singapore. The spider’s body has a glossy surface that gives it the “wet” look of fresh faeces. “The nodules on the body and rough-edges of the legs further reinforce the ‘shitty’ look – pardon the rudeness,” Koh says. Long Yu of Hubei University in China and his team exposed the spider to one of its predators – jumping spiders. They also added houseflies as prey. The team found that the camouflage helps these crab spiders (Phrynarachne ceylonica) repel more jumping spiders and attract more flies than those without camouflage. They presented their findings at the Behaviour 2015 meeting in Cairns, Australia, last month. Other spiders, such as orb weavers in the genus Celaenia, also look like bird droppings, but the foul smell makes bird-dung crab spiders unique.
Key enzyme makes farm kids healthier DIRT is good for you. Kids on farms are less likely to develop allergies and asthma than urban children. But the protective effects of friendly microbes also seem to depend on a person’s genetic make-up. The hygiene hypothesis says that a lack of exposure to dirt and microbes is to blame for increases in allergies and asthma. One explanation is that children today encounter less endotoxin, a bacterial protein found on the surface of many common species, including E. coli, that may be
important for damping down overactive immune systems. Children with gene mutations that disrupt the functioning of an enzyme called A20 are more likely to have asthma and allergies, so Bart Lambrecht of Ghent University in Belgium and his team wondered whether A20 may be involved in helping endotoxins train our immune systems. First they exposed mice to endotoxin, and saw they developed fewer allergies when later exposed to dust mites. But this effect wasn’t seen when the
experiment was repeated with mice that had been genetically engineered to lack A20 (Science, doi.org/7hf). Lambrecht and his team then turned to human lung cells and found that A20 was less active in adults who had asthma. “It’s important because it shows that endotoxin can’t work on its own,” says Erika von Mutius of the Ludwig Maximilian University in Munich, Germany, a proponent of the hygiene hypothesis. It is thought that about 5 per cent of people have a faulty version of the A20 enzyme. Alex Segre / Alamy Stock Photo
Crappy fashion keeps spider alive
Palaeolithic people ate carbs as well GOING on the palaeo diet? Don’t put down your porridge just yet. Hunter-gatherers ate oats as far back as 32,000 years ago – way before farming took root. This is the earliest known human consumption of oats, say Marta Mariotti Lippi at the University of Florence in Italy and her colleagues, who made the discovery after analysing starch grains on an ancient stone grinding tool from southern Italy (PNAS, DOI: 10.1073/ pnas.1505213112). The Palaeolithic people ground up the wild oats to form flour, which they may have boiled or baked into a simple flatbread, says Mariotti Lippi. They also seem to have heated the grains before grinding them, perhaps to dry them out in the colder climate of the time. Mariotti Lippi notes that this would also have made the grain easier to grind and longer-lasting. This multi-stage process would have been time consuming, but beneficial. The grain is nutritionally valuable, and turning it into flour would have been a good way to transport it, which was important for Palaeolithic nomads, she says.
Speedier trains can slow down roads READING this while stuck in traffic? Fast trains may be to blame. Slowing the London Underground could cut overall congestion in the city. Marc Barthelemy of the French Atomic Energy and Alternative Energies Commission in Gif-surYvette and colleagues mapped out the road and subway networks in London and New York City and simulated travel at different speeds. They found that the ratio of the average road and rail speeds can have a critical impact on congestion. If the subway speeds up while road speed stays fixed, for example,
more people on the outskirts will use trains. But these commuters often have to travel by road to do so, as suburban stations are thinly spread. The result is more congestion overall, as increased traffic at the outskirts outweighs smoother flow in the centre (arxiv.org/abs/1508.07265). “If you want to give more access to more people, then increasing the speed of the subway is not the best solution,” says Barthelemy – packing stations more closely is often better. New York City is an exception, however: congestion here is so bad that speeding up trains does help.
12 September 2015 | NewScientist | 17