18 | NewScientist | 10 September 2011

Old cells work best in young conditions

ADULT stem cells can be rejuvenated by growing them in a youthful environment – at least in mice. The discovery boosts hopes that adult human stem cells could be used to grow replacement tissue.

Mesenchymal stem cells (MSCs) are found in the bone marrow of adults, and have the potential to differentiate into a range of cell types. “These cells have big potential, but generally their quality and quantity decreases with age,” says Xiao-Dong Chen of the University of Texas Health Science Center in San Antonio.

Chen’s team took MSCs from 3-month and 18-month-old mice, and grew them on extracellular matrices (ECM) from 3-month or 18-month-old mice. Young and old cells showed a 16.1-fold and 17.1-fold expansion, respectively, when grown on an ECM from young mice, compared with a 4.1-fold and 3.8-fold expansion when grown on an old ECM. The results, given at the Strategies for Engineered Negligible Senescence meeting in Cambridge, UK, this week, open up the possibility of taking MSCs from older people and growing them on ECMs from younger people to produce replacement bone or organs.

Quantum computer chips pass key milestonesQUANTUM computer users may one day have to wrestle with their own version of the “PC or Mac?” question. A design based on superconducting circuits has performed two benchmark feats, suggesting it will be a competitor to set-ups using photons or ions.

“The number of runners in the [quantum] race has just gone up to three,” says Andrew White at the University of Queensland in Brisbane, Australia.

Quantum computers use quantum bits or qubits. Unlike ordinary bits, these can exist

in multiple states at once and can link their quantum states in a process called entanglement, allowing for multiple calculations to take place simultaneously.

Previously, set-ups using photons or trapped ions as qubits have made the most headway, factorising small numbers in a calculation known as Shor’s algorithm and using entangled qubits to create a simple piece of computer code called a Toffoli gate.

Now Matteo Mariantoni at the University of California, Santa Barbara, and colleagues have

THE ants of Borneo go out with a bang, thanks to a body built to blow up during a suicidal death grip.

They are known to grab enemy ants and expel a lethal sticky substance in a final act of altruistic defence of their colony which kills attacker and intruder. Now, Johan Billen of the Catholic University of Leuven (KUL), Belgium, and his team have shown just how much the ants invest in their suicide strategy – with the largest gland reservoirs yet known in ants.

All 10,000 species of ant have glands in their jaws to release

chemicals in alarm or defence. But Billen found that in the south-east Asian Camponotus cylindricus ants most of the body is given over to storing the deadly secretion. The insects operate on a hair-trigger; their abdomen walls ruptured even when researchers lightly touched them with forceps (Acta Zoologica, DOI: 10.1111/j.1463-6395.2011.00523.x).

“It’s too bad for the ant itself, but its nest mates will survive,” says Billen. “It makes perfect sense genetically,” agrees William Foster of the University of Cambridge. “Fight for your siblings, protect the nest.”

Kamikaze ants protect the colony

Ma

rk M

off

ett/

Min

den

Pic

ture

s/fL

Pa

boosted the computing power of a rival design that uses tiny, superconducting wires as qubits. Their set-up created a Toffoli gate and ran a central component of Shor’s algorithm (Science, DOI: 10.1126/science.1208517).

Mariantoni says the result is exciting because the wire loops were embedded in chips, which should be easier to scale up than delicate photon or ion systems. White agrees: “The beautiful thing about a solid circuit is that it’s something you can write using lithographic technology.”

African roots? Beware peanuts

IF YOU have recent African ancestors, you might be more prone to peanut allergies, geneticists warn.

To find out whether some ethnicities are more at risk than others, Rajesh Kumar’s team at the Children’s Memorial Hospital in Chicago looked for a link between ethnicity and peanut sensitivity in over 1000 American children.

The group screened their genomes for 150 known genetic markers of Asian, European and African ancestry. The team also looked for antibodies to peanuts in the children’s blood – high levels suggest the immune system has previously overreacted to peanuts.

The more markers for African ancestry that the children had, the higher their risk of having peanut antibodies at levels associated with allergy, says Kumar. This association remained irrespective of their ethnicity.

When the group tested for milk allergies, however, they found that children whose mothers identified them as black were more likely to be allergic to milk, regardless of their genetic ancestry (Pediatrics, DOI: 10.1542/peds.2011-0691).

Genetic factors appear to be important in peanut allergies, says Kumar, but milk sensitivity might result from cultural and lifestyle factors.

ka

ren

ka

sMau

ski/

corb

is

in brief For new stories every day, visit newscientist.com/news