Showing posts with label medical. Show all posts
Showing posts with label medical. Show all posts

Thursday, May 27, 2010

Its Alive!

It may not quite be "Frankenstein," but for the first time scientists have created an organism controlled by completely human-made DNA.

Using the tools of synthetic biology, scientists from the J. Craig Venter Institute installed a completely artificial genome inside a host cell without DNA. Like the bolt of lightning that awakened Frankenstein, the new genome invigorated the host cell, which began to grow and reproduce, albeit with a few problems.

The research marks a technical milestone in the synthesis and implantation of artificial DNA. Venter expects the research will lead to cheaper drugs, vaccines and biofuels in several years — and dozens of other companies and researchers are working toward the same goal.

It may not quite be "Frankenstein," but for the first time scientists have created an organism controlled by completely human-made DNA.

Using the tools of synthetic biology, scientists from the J. Craig Venter Institute installed a completely artificial genome inside a host cell without DNA. Like the bolt of lightning that awakened Frankenstein, the new genome invigorated the host cell, which began to grow and reproduce, albeit with a few problems.

The research marks a technical milestone in the synthesis and implantation of artificial DNA. Venter expects the research will lead to cheaper drugs, vaccines and biofuels in several years — and dozens of other companies and researchers are working toward the same goal.

No machine can turn out a single piece of DNA anywhere close to that long, however. Instead, Venter and his colleagues started with many relatively small pieces of DNA. Then the scientists transferred DNA pieces back and forth between a yeast cell and E. coli bacteria, turning the many short pieces into fewer but longer DNA segments.

Once the synthetic DNA segment reached the desired length the scientists injected it into a Mycoplasma bacterium that had had its own DNA removed earlier. Needless to say, the process of assembling such a lengthy piece of synthetic DNA was complicated.

"I hope the day comes when making genomes is something everyone can do," said Pamela Silver, a systems biologist at Harvard Medical School.

Some genes suffered glitches
The new, synthetic DNA "booted up" the bacterium, but not without a few problems: Several of the synthesized genes didn't work properly. And the genes that did work didn't do anything particularly useful, at least by human standards.


The Mycoplasma bacteria grew and reproduced, but that was about all. Within several years however, Venter and his colleagues hope to create more exciting bacteria that will speed up the production and drive down the costs of biofuels, vaccines and drugs.

Venter has teamed up with a major oil and gas company, and a pharmaceutical company, to help realize these goals.

Venter's work falls into a nascent field of science known as synthetic biology. Synthetic biology builds on the decades-old field of genetic engineering. Unlike genetic engineering, where scientists introduce a handful of new genes into an organism, synthetic biology aims to reprogram entire organisms, including bacteria and viruses.

The creation and insertion of a synthetic genome more than 1 million base pairs is a technical landmark, said Frances Arnold, a synthetic biologist at the California Institute of Technology in Pasadena. He said the feat showcases scientists' ability to precisely manipulate long sections of DNA.

But before consumers see any benefit several significant hurdles have to be solved. One of the biggest problems is that scientists are still searching for the specific genetic code to produce cheap drugs, biofuel and other products.

"We can write anything we want," said Arnold. "The problem is that we don't know what to write."

Wednesday, April 21, 2010

Foreign Language Syndrome


Sky News 2010

A woman from Devon has begun speaking with a Chinese accent after suffering severe migraines.

Thirty-five-year-old Sarah Colwill puts the startling change down to an extremely rare medical condition known as Foreign Accent Syndrome (FAS).

"I knew I sounded different but I didn't know how much and people said I sounded a bit Chinese.

"Then I had another attack and when the ambulance crew arrived they said I definitely sounded Chinese."

The rare disorder is thought to be caused by strokes and brain injuries and causes sufferers to lose the ability to talk in their native accent.

There have been an estimated 60 recorded cases of FAS since it was first identified in the 1940s.

Mrs Colwill, who lives in St Budeaux in Plymouth, Devon, with her husband Patrick said her accent change had been startling.

"I spoke to my stepdaughter on the phone from hospital and she didn't recognise who I was.

"She said I sounded Chinese. Since then I have had my friends hanging up on me because they think I'm a hoax caller."

After researching FAS on the internet Mrs Colwill has been in contact with doctors from Oxford University who are interested in studying her plight.

She is undergoing speech therapy to try to revert to her West Country accent.

"I am frustrated to sound like this. I just want my own voice back, but I don't know if I will get it back."

John Coleman, a professor of phonetics at Oxford University, said: "FAS is extremely diverse, almost certainly not 'one thing', not a well-defined medical phenomenon.

"It is not the kind of problem that there are any easy generalisations about."

Sufferers can develop an accent without ever having been exposed to it as it is the change in speech patterns from a brain injury which causes the lengthening of syllables, change in pitch or mispronunciation of sounds.

Experts believe FAS is triggered following a stroke or head injury, when tiny areas of the left side of the brain linked with language, pitch and speech patterns are damaged.

The result is often a drawing out or clipping of the vowels that mimic the accent of a particular country, even though the sufferer may have had limited exposure to that accent.

One of the first reported cases was in 1941 when a Norwegian woman developed a German accent after being hit by bomb shrapnel during an air raid.

As a result, she was shunned by her community, who falsely believed she was a German spy.

In 2006 Linda Walker, 60, woke from a stroke to find that her Geordie accent had been transformed into a Jamaican one.