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

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.

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

Alzheimer’s plaques dissolve after gene therapy

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.”

Ringside view of change at Uranus

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.

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.

MOV

IEST

ORE C

OLLE

CTIO

N

ENVI

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/COR

BIS

Only the good have social power

Women are still the best gatherers

www.newscientist.com 1 September 2007 | NewScientist | 21

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