Scientists say they have reversed age-related degeneration in mice, resulting in an improvement in the rodents' fertility and the growth of new brain tissue. But it could be some time before the technique might be used in humans.

Fountain of youth

Scientists at Harvard University's Dana-Farber Cancer Institute in Boston report they were able to reverse signs of aging in mice by tweaking a gene that protects cells from the harmful, cumulative effects associated with growing old.

The gene is involved in the production of structures at the tips of DNA chromosomes called telomeres.

Telomeres are like the plastic caps on the ends of shoe laces that keep them from becoming frayed. In the case of chromosomes, the telomeres protect the strands of DNA from environmental assaults such as chemical and radiation exposure.

But every time a cell divides, its telemeres shorten, eventually leading to DNA damage and aging.

In studies with mice, researchers switched off the telomerase gene and watched the rodents rapidly develop age-related impairments.

Eternally young?

However, when they turned the genes back on on, the animals' declines reversed.

"Their fertility was restored. We also saw a big effect on the lining of the intestines and as well as in the brain, which was a little bit unexpected," says lead researcher Mariela Jaskelioff. "We actually saw a decrease in the size of the brains of these mice with premature aging. And we could reverse these by reactivating telomerase."

The mice in the study were at an age equivalent of an 80- or 90-year-old human. Researchers restored them to middle age by turning on the telomerase gene.

Despite the encouraging results, the genetic manipulation is not the secret to eternal youth for humans. Jaskelioff says the telomerase gene is involved in the growth of both normal and cancerous cells.

"The fear is that in humans, adult humans, we accumulate mutations all through our lifetimes," she says. "And if we were to reactivate telomerase in cells that have malignant mutations, then the propensity to develop cancer would probably be exacerbated."

However, according to Jaskelioff, it might be possible to stimulate the telomerase gene for short periods of time in people with a rare disorder which causes premature aging.

Scientists describe how they reversed aging in mice in an article published in the journal Nature Medicine.

Historians, anti-war activists and armchair observers of human nature have had plenty to mull over in recent years thanks to the online group WikiLeaks.

The Web site has published hundreds of thousands of stolen U.S. military and diplomatic documents from as recently as February of this year and as far back as the 1960s. The latest round of leaks, involving diplomatic cables, has renewed efforts by the U.S. government to tighten security on its computer systems. But cyber-security experts point out the leaks were less a breakdown of technology than of trust.

That fact now has the U.S. government scrambling to secure its computer networks. But Bruce Schneier, British Telecom's chief security technology officer, says even the most secure systems will still be vulnerable to human nature.

"You could take a computer, bury it in the ground, make sure you never turn it on," Schneier says. "Don't tell anybody where it is and it's probably pretty secure. But as soon as you turn it on and have people look at it, you have to trust the people."

Listen to Kate Woodsome's interview with Bruce Schneier


Tightening security

The U.S. Defense and State Departments say they are working to limit users' ability to download material onto removable media, like CDs and USB "thumb drives." And they are working to better track suspicious behavior.

"In general, I think reducing the capabilities of the hardware is probably not the way to go," Schneier says. "Although as a temporary measure after this has already happened, it’s seems like an okay, quick solution. But long-term, it seems kind of dumb."

He says a better solution would be to limit access to the diplomatic cables in the first place. "Make sure people who only need to know them have access to them. And make sure that people who read them, make sure an audit log record is kept."

But that wasn't the case when U.S. Army intelligence specialist Private Bradley Manning committed one of the biggest information breaches in U.S. history while listening to Lady Gaga's hit song "Telephone." Manning says he lip-synched the words to the song while downloading a quarter-million classified diplomatic cables from the Defense Department's data network onto a Lady Gaga CD.

If access was far more limited, as Schneier recommends, there's no way Private Manning and his Lady Gaga tunes could have touched the network and all the diplomatic cables it stored. But he did. Because at that time, government agencies were sharing more intelligence in the wake of the September 11 terrorist attacks in 2001.

This week, U.S. Defense Secretary Robert Gates told reporters the procedures spread information too widely.

Demystifying state secrets

Instead of rolling back information sharing, says Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists, the U.S. government instead should keep fewer secrets.

"If we kept less information classified, it would be an easier, more manageable task to protect that smaller volume of information," Aftergood says. "When you start getting into tens of millions of secrets being produced every year, you can easily swamp the system and lose control precisely of what you're trying to protect."

Listen to Kate Woodsome's interview with Steven Aftergood

The secrecy system now in place has its roots in the Cold War, when U.S. President Harry Truman signed an executive order in 1951 establishing standards to classify and control information in the name of national security.

But now the defense and intelligence bureaucracy is so massive that is has outgrown, and outdated, that Cold War-era system. "Information is produced and consumed and transferred in completely different ways from what was true 10, 20 or 30 years ago. And the classification system has not yet adapted to that," Aftergood says.

Overhauling the system

U.S. President Barack Obama says he recognizes the problem. Last year, he ordered an overhaul of how the government keeps its top secrets. In May this year, the government disclosed the size of its nuclear weapons arsenal for the first time. And in September, the director of National Intelligence and Defense Secretary Gates revealed the total intelligence budget.

Aftergood calls the changes "momentous."

"Government officials have resisted disclosure of this information literally for decades," he says. "And the fact that it is finally possible to get this information out into the open and do so as a standard practice means that the system is not totally calcified. It's not totally stuck in concrete."

Still, keeping fewer secrets will not stop hackers from trying to break into secure networks. For about 18 minutes in April, China Telecom rerouted about 15 percent of U.S. and foreign Internet traffic through Chinese servers. According to the U.S.-China Economic and Security Review Commission, that traffic included communications from the U.S. government and military in a breach far greater than WikiLeaks. It is not clear how the information was, or will be, used.

Man versus machine?

David Gewirtz, the director of the U.S. Strategic Perspective Institute, says cyber-war is inevitable because it is just too easy and effective to ignore.

"Cyber-terrorism is much more like a cancer. It just sort of eats at you from the inside as opposed to traditional terrorism, where you can actually see flames."

Listen to Kate Woodsome's interview with David Gewirtz

Gewirtz says the U.S. is now focused on improving its cyber-defense, but it is an uphill battle because of the sheer number of vulnerabilities. Government computer networks not only need to be protected against state-sponsored cyber attacks and rogue hackers, but also against internal threats such as Private Manning. Cheap consumer electronics like USB "thumb drives," cameras and mp3 players can turn any network user into a threat.

"Everybody has these things, and so we have a million points of weakness instead of just one or two."

Private Manning now sits in military custody where he faces charges of leaking classified documents. As he awaits trial, U.S. officials are left grappling with a security problem that technology alone cannot solve.

NASA scientists on Thursday announced they have found a new source of bacteria, made of something earlier thought impossible. The bacteria's DNA is not made of phosphorus but of arsenic. The scientific community can barely contain themselves about the findings. Within two hours of the announcement, more than 2,000 articles about it were found on the internet. Our correspondent explains how this could change what we know about life and the possibility of life outside of earth.

The picture NASA shows us looks like a bunch of white fingerling potatoes. But we are told, these microbes change everything. Here's NASA's director of Astrobiology, Mary Voytek.

"This is a huge deal," she said. "It's going to require at least some paragraphs in a textbook to be rewritten, perhaps. This is a big finding."

The real star of the NASA briefing is named GFAJ 1. It's a microbe that thrives on arsenic, an element that is normally poisonous. NASA's Felisa Wolfe-Simon discovered the bacterium with a team from Arizona State University.

"All life that we know of requires carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur," said Wolfe-Simon. "And it uses those six elements in critical pieces that I think we are all familiar with, including DNA and RNA. We've discovered an organism that can substitute one element for another in these major biomolecules."

The researchers found the bacteria in Mono Lake, a Northern California lake that has three times the salt of sea water and is full of arsenic. The team scraped the bacteria from the bottom of the lake, then grew it in a laboratory, where it incorporated arsenic - rather than phosphorus, which was previously thought to be the backbone of DNA and RNA. Wolfe-Simon says extra terrestial life could be possible.

"I was taught as a biochemist all life we know of is here so far, and if there's an organism doing something different, we've cracked open the door to what's possible for life elsewhere in the universe," she said.

But chemist Steven Benner, from the Foundation for Applied Molecular Evolution is cautious. He says arsenic molecules would be a weak link in a compound under stress.

"We know they are relatively unstable and they fall apart with half lives measured in the order of minutes, conveniently," said Benner. "When you try and put them into a DNA molecule, and you put them under stress they fall apart."

Wolfe-Simon points out that for every one of a human's cells, there are ten microbial cells. Therefore, she says this finding has implications in how our bodies work, in addition to how the planet works.

Meantime, this announcement dealt with a scientific discovery. Others will announce the practical implications of it -starting with the tiny GFAJ 1 and its fellow potato-looking microbes.