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Ringside view of change at Uranus
Only the good have Alzheimer’s plaques dissolve after gene therapy social power
MOVIESTORE COLLECTION
www.newscientist.com
COULD gene therapy provide a means of busting the plaques that cause Alzheimer’s disease? Alzheimer’s occurs when a protein called amyloid-beta (Aß) accumulates in the regions of the brain concerned with memory and thought. Existing therapies treat the symptoms of the disease but do nothing to target this underlying cause. Now, Matthew Hemming and his colleagues at Harvard Medical School in Boston have used gene therapy to boost levels of an enzyme called neprilysin in
mice with the equivalent of Alzheimer’s. Neprilysin was already known to degrade the amyloid protein and its levels are reduced in people with Alzheimer’s. Hemming’s team took fibroblast cells from the skin of the mice and engineered them to contain the gene for neprilysin. When they injected these cells into the hippocampus, nearby plaques disappeared. Crucially, plaques further away also diminished. This is because the gene had been altered to create a form of neprilysin that can travel
through the body instead of remaining bound to cell membranes. “It allows the enzyme to go to the sites of Aß accumulation rather than just sitting on the cell,” says Hemming (PLoS Medicine, DOI: 10.1371/ journal.pmed.0040262). The researchers now plan to inject the cells into other parts of the body, to see if neprilysin can still reach the brain. The ultimate goal is to incorporate the cells into a small implant that could be placed anywhere under the skin, says Hemming. ENVISION/CORBIS
PITY the villains of the Marvel comics – they never had a chance against superheroes like Spider-Man. An analysis of the social webs within the fictional Marvel universe reveals that villains were banished to the periphery of society, while the superheroes were well connected. Physicist Pablo Gleiser of the National Council for Scientific and Technical Research in Buenos Aires, Argentina, studied the social web within the fictional universe of Marvel comics, comprising 6486 characters in 12,942 issues. Taking two characters to be linked if they appeared in the same issue, he found a superficially realistic social network. A small fraction of characters – notably the superheroes themselves – had far more links than most others, acting as key social hubs. “The Marvel universe looks almost like a real social network,” says Gleiser (www.arxiv.org/ abs/0708.2410). However, even prominent arch-villains always played marginal social roles at the periphery of the network, says Gleiser. He suggests that this may reflect the restrictions on comic writers laid down by the rules of the Comics Magazine Association of America. One reads: “Criminals shall not be presented so as to be rendered glamorous or to occupy a position which creates the desire for emulation.” No wonder the superheroes always win.
Ringside view of change at Uranus A RARE edge-on alignment of Uranus’s rings as seen from Earth has revealed extensive changes since the Voyager 2 probe observed them in 1986. Voyager 2 photographed Uranus’s major rings, thought to be made of chunks of rock, along with some wispy dust rings. In 2003, the Hubble Space Telescope revealed two new dust rings. Imke de Pater of the University of California, Berkeley, and her team have now taken infrared images of the dust rings using the 10-metre Keck II telescope on Mauna Kea, Hawaii. They found that one dust ring seen by Voyager 2, called the zeta ring, seems to have disappeared altogether, while a new one has appeared in a zone that had previously looked empty (Science, DOI: 10.1126/science.1148103). The changes reinforce the emerging view that ring systems are much more dynamic than previously thought. “We used to think it was like studying geology,” says team member Mark Showalter of the SETI Institute in Mountain View, California. “Now we’re learning that studying them is more like studying weather.”
Women are still the best gatherers MEN hunted, women gathered. That is how the division of labour between the sexes is supposed to have been in the distant past. According to a new study, an echo of these abilities can still be found today. Max Krasnow and colleagues at the University of California, Santa Barbara, have discovered that modern women are better than men at remembering the location of food such as fruit and veg in a market. The researchers led 86 adults to certain stalls in Santa Barbara’s large Saturday farmer’s market, then back to a location in the centre of the market
from where the stalls could not be seen. They were then asked to point to each stall’s location. This requires dead reckoning – a skill that men may once have used to return from hunting, and one that men today still usually perform better than women in experiments. Despite this, the women performed 27 per cent better than men at locating the food (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2007.0826). They were also consistently better at locating high-calorie foods such as olive oil and honey than low-calorie foods such as cucumbers, regardless of whether they liked the stall or the food. Observations of modern tribes suggest that foragers need to preferentially remember where such high-value foods are, the researchers say.
1 September 2007 | NewScientist | 21
MOVIESTORE COLLECTION
www.newscientist.com
COULD gene therapy provide a means of busting the plaques that cause Alzheimer’s disease? Alzheimer’s occurs when a protein called amyloid-beta (Aß) accumulates in the regions of the brain concerned with memory and thought. Existing therapies treat the symptoms of the disease but do nothing to target this underlying cause. Now, Matthew Hemming and his colleagues at Harvard Medical School in Boston have used gene therapy to boost levels of an enzyme called neprilysin in
mice with the equivalent of Alzheimer’s. Neprilysin was already known to degrade the amyloid protein and its levels are reduced in people with Alzheimer’s. Hemming’s team took fibroblast cells from the skin of the mice and engineered them to contain the gene for neprilysin. When they injected these cells into the hippocampus, nearby plaques disappeared. Crucially, plaques further away also diminished. This is because the gene had been altered to create a form of neprilysin that can travel
through the body instead of remaining bound to cell membranes. “It allows the enzyme to go to the sites of Aß accumulation rather than just sitting on the cell,” says Hemming (PLoS Medicine, DOI: 10.1371/ journal.pmed.0040262). The researchers now plan to inject the cells into other parts of the body, to see if neprilysin can still reach the brain. The ultimate goal is to incorporate the cells into a small implant that could be placed anywhere under the skin, says Hemming. ENVISION/CORBIS
PITY the villains of the Marvel comics – they never had a chance against superheroes like Spider-Man. An analysis of the social webs within the fictional Marvel universe reveals that villains were banished to the periphery of society, while the superheroes were well connected. Physicist Pablo Gleiser of the National Council for Scientific and Technical Research in Buenos Aires, Argentina, studied the social web within the fictional universe of Marvel comics, comprising 6486 characters in 12,942 issues. Taking two characters to be linked if they appeared in the same issue, he found a superficially realistic social network. A small fraction of characters – notably the superheroes themselves – had far more links than most others, acting as key social hubs. “The Marvel universe looks almost like a real social network,” says Gleiser (www.arxiv.org/ abs/0708.2410). However, even prominent arch-villains always played marginal social roles at the periphery of the network, says Gleiser. He suggests that this may reflect the restrictions on comic writers laid down by the rules of the Comics Magazine Association of America. One reads: “Criminals shall not be presented so as to be rendered glamorous or to occupy a position which creates the desire for emulation.” No wonder the superheroes always win.
Ringside view of change at Uranus A RARE edge-on alignment of Uranus’s rings as seen from Earth has revealed extensive changes since the Voyager 2 probe observed them in 1986. Voyager 2 photographed Uranus’s major rings, thought to be made of chunks of rock, along with some wispy dust rings. In 2003, the Hubble Space Telescope revealed two new dust rings. Imke de Pater of the University of California, Berkeley, and her team have now taken infrared images of the dust rings using the 10-metre Keck II telescope on Mauna Kea, Hawaii. They found that one dust ring seen by Voyager 2, called the zeta ring, seems to have disappeared altogether, while a new one has appeared in a zone that had previously looked empty (Science, DOI: 10.1126/science.1148103). The changes reinforce the emerging view that ring systems are much more dynamic than previously thought. “We used to think it was like studying geology,” says team member Mark Showalter of the SETI Institute in Mountain View, California. “Now we’re learning that studying them is more like studying weather.”
Women are still the best gatherers MEN hunted, women gathered. That is how the division of labour between the sexes is supposed to have been in the distant past. According to a new study, an echo of these abilities can still be found today. Max Krasnow and colleagues at the University of California, Santa Barbara, have discovered that modern women are better than men at remembering the location of food such as fruit and veg in a market. The researchers led 86 adults to certain stalls in Santa Barbara’s large Saturday farmer’s market, then back to a location in the centre of the market
from where the stalls could not be seen. They were then asked to point to each stall’s location. This requires dead reckoning – a skill that men may once have used to return from hunting, and one that men today still usually perform better than women in experiments. Despite this, the women performed 27 per cent better than men at locating the food (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2007.0826). They were also consistently better at locating high-calorie foods such as olive oil and honey than low-calorie foods such as cucumbers, regardless of whether they liked the stall or the food. Observations of modern tribes suggest that foragers need to preferentially remember where such high-value foods are, the researchers say.
1 September 2007 | NewScientist | 21