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Friday, 21 May 2010
Scientists in the US have succeeded in developing the first living cell to be controlled entirely by synthetic DNA.
The researchers constructed a bacterium's "genetic software" and transplanted it into a host cell.
The resulting microbe then looked and behaved like the species "dictated" by the synthetic DNA.
The advance, published in Science, has been hailed as a scientific landmark, but critics say there are dangers posed by synthetic organisms.
Some also suggest that the potential benefits of the technology have been over-stated.
But the researchers hope eventually to design bacterial cells that will produce medicines and fuels and even absorb greenhouse gases.
The team was led by Dr Craig Venter of the J Craig Venter Institute (JCVI) in Maryland and California.
Craig Venter defends the synthetic living cell
He and his colleagues had previously made a synthetic bacterial genome, and transplanted the genome of one bacterium into another.
Now, the scientists have put both methods together, to create what they call a "synthetic cell", although only its genome is truly synthetic.
Dr Venter likened the advance to making new software for the cell.
The researchers copied an existing bacterial genome. They sequenced its genetic code and then used "synthesis machines" to chemically construct a copy.
HOW A SYNTHETIC CELL
WAS CREATED
The scientists "decoded" the chromosome of an existing bacterial cell - using a computer to read each of the letters of genetic code.
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Dr Venter told BBC News: "We've now been able to take our synthetic chromosome and transplant it into a recipient cell - a different organism.
"As soon as this new software goes into the cell, the cell reads [it] and converts into the species specified in that genetic code."
The new bacteria replicated over a billion times, producing copies that contained and were controlled by the constructed, synthetic DNA.
"This is the first time any synthetic DNA has been in complete control of a cell," said Dr Venter.
'New industrial revolution'
Dr Venter and his colleagues hope eventually to design and build new bacteria that will perform useful functions.
"I think they're going to potentially create a new industrial revolution," he said.
"If we can really get cells to do the production that we want, they could help wean us off oil and reverse some of the damage to the environment by capturing carbon dioxide."
WATTS WHAT...
Continue reading the main story
Even some scientists worry we lack the means to weigh up the risks such novel organisms might represent, once set loose
Susan Watts
BBC Newsnight science editor
Read Susan Watts's thoughts
Send us your comments
Dr Venter and his colleagues are already collaborating with pharmaceutical and fuel companies to design and develop chromosomes for bacteria that would produce useful fuels and new vaccines.
But critics say that the potential benefits of synthetic organisms have been overstated.
Dr Helen Wallace from Genewatch UK, an organisation that monitors developments in genetic technologies, told BBC News that synthetic bacteria could be dangerous.
"If you release new organisms into the environment, you can do more harm than good," she said.
"By releasing them into areas of pollution, [with the aim of cleaning it up], you're actually releasing a new kind of pollution.
"We don't know how these organisms will behave in the environment."
Continue reading the main story
The risks are unparalleled, we need safety evaluation for this kind of radical research and protections from military or terrorist misuse
Julian Savulescu
Oxford University ethics professor
Profile: Craig Venter
Q&A: The meaning of synthetic life
Ethics concern over synthetic cell
Dr Wallace accused Dr Venter of playing down the potential drawbacks.
"He isn't God," she said, "he's actually being very human; trying to get money invested in his technology and avoid regulation that would restrict its use."
But Dr Venter said that he was "driving the discussions" about the regulations governing this relatively new scientific field and about the ethical implications of the work.
He said: "In 2003, when we made the first synthetic virus, it underwent an extensive ethical review that went all the way up to the level of the White House.
"And there have been extensive reviews including from the National Academy of Sciences, which has done a comprehensive report on this new field.
"We think these are important issues and we urge continued discussion that we want to take part in."
Ethical discussions
Dr Gos Micklem, a geneticist from the University of Cambridge, said that the advance was "undoubtedly a landmark" study.
But, he said, "there is already a wealth of simple, cheap, powerful and mature techniques for genetically engineering a range of organisms. Therefore, for the time being, this approach is unlikely to supplant existing methods for genetic engineering".
The ethical discussions surrounding the creation of synthetic or artificial life are set to continue.
Professor Julian Savulescu, from the Oxford Uehiro Centre for Practical Ethics at the University of Oxford, said the potential of this science was "in the far future, but real and significant".
"But the risks are also unparalleled," he continued. "We need new standards of safety evaluation for this kind of radical research and protections from military or terrorist misuse and abuse.
"These could be used in the future to make the most powerful bioweapons imaginable. The challenge is to eat the fruit without the worm."
The advance did not pose a danger in the form of bio-terrorism, Dr Venter said.
"That was reviewed extensively in the US in a report from Massachusetts Institute of Technology (MIT) and a Washington defence think tank, indicating that there were very small new dangers from this.
"Most people are in agreement that there is a slight increase in the potential for harm. But there's an exponential increase in the potential benefit to society," he told BBC's Newsnight.
"The flu vaccine you'll get next year could be developed by these processes," he added.
Thursday, 20 May 2010
New Device Adapts to Brain’s Surface
In people with epilepsy, the device could be used to detect when seizures first begin, and deliver pulses to shut the seizures down. In people with spinal cord injuries, the technology has promise for reading complex signals in the brain that direct movement, and routing those signals to healthy muscles or prosthetic devices.
"The focus of our study was to make ultrathin arrays that conform to the complex shape of the brain, and limit the amount of tissue damage and inflammation," said Brian Litt, an author on the study. The new silk-based implants can hug the brain like shrink wrap, collapsing into its grooves and stretching over its rounded surfaces, according to the researchers. The study shows that the thin flexible implants can record brain activity more faithfully than thicker implants embedded with similar electronics.
The implants contain metal electrodes that are 500 microns thick, or about five times the thickness of a human hair. The absence of sharp electrodes and rigid surfaces should improve safety, with less damage to tissue. Also, the implants' ability to mold to the brain's surface could provide better stability; the brain sometimes shifts in the skull and the implant could move with it. Finally, by spreading across the brain, the implants have the potential to capture the activity of large networks of brain cells, Litt said.
Besides its flexibility, silk was chosen as the base material because it is durable enough to undergo patterning of thin metal traces for electrodes and other electronics. It can also be engineered to avoid inflammatory reactions, and to dissolve at controlled time points, from almost immediately after implantation to years later. The electrode arrays can be printed onto layers of polyimide (a type of plastic) and silk, which can then be positioned on the brain.
The researchers tested the ability of these implants in animals. By recording signals from the brain's visual center in response to visual stimulation, they found that the thin polyimide-silk arrays captured more robust signals compared to thicker implants.
MEDICA.de
"The focus of our study was to make ultrathin arrays that conform to the complex shape of the brain, and limit the amount of tissue damage and inflammation," said Brian Litt, an author on the study. The new silk-based implants can hug the brain like shrink wrap, collapsing into its grooves and stretching over its rounded surfaces, according to the researchers. The study shows that the thin flexible implants can record brain activity more faithfully than thicker implants embedded with similar electronics.
The implants contain metal electrodes that are 500 microns thick, or about five times the thickness of a human hair. The absence of sharp electrodes and rigid surfaces should improve safety, with less damage to tissue. Also, the implants' ability to mold to the brain's surface could provide better stability; the brain sometimes shifts in the skull and the implant could move with it. Finally, by spreading across the brain, the implants have the potential to capture the activity of large networks of brain cells, Litt said.
Besides its flexibility, silk was chosen as the base material because it is durable enough to undergo patterning of thin metal traces for electrodes and other electronics. It can also be engineered to avoid inflammatory reactions, and to dissolve at controlled time points, from almost immediately after implantation to years later. The electrode arrays can be printed onto layers of polyimide (a type of plastic) and silk, which can then be positioned on the brain.
The researchers tested the ability of these implants in animals. By recording signals from the brain's visual center in response to visual stimulation, they found that the thin polyimide-silk arrays captured more robust signals compared to thicker implants.
MEDICA.de
Smoking could protect against Parkinson
The link is not however 100% clear, as some smokers develop the illness nevertheless. The hypothesis is that there is a genetic predisposition that, in combination with environmental factors, can trigger the disease. Taking this as its starting point, a team from the Mayo Clinic in Rochester, MN (USA) has carried out a study on a sample of 1228 subjects.
The researchers hypothesized that the variation may be due to pharmacogenetic effects and that nicotine might have neuroprotective properties for certain individuals.
“We asked the interviewees to tell us about their relationship with smoking and then compared this data with the presence or absence of variations in the gene CYP2A6, which encodes the enzyme responsible for metabolising nicotine”, says EURAC researcher Maurizio Facheris, neurologist at the Department of Neurology of Bozen/Bolzano Central Hospital and main author of the study.
From an analysis of the data, it emerges that the presence of a particular variant of the gene, when combined with smoking, considerably reduces the risk of contracting Parkinson’s disease. It remains to be clarified whether the protection against the disease is provided by the particular variant of gene CYP2A6 or by the presence of cotinine, the substance into which nicotine is transformed through the action of the gene. “If this second hypothesis is confirmed, producing a cotinine-based drug would be a means to reduce exposure to the disease”, explains Maurizio Facheris.
The study opens up interesting scenarios in the field of pharmacogenetics, a discipline that holds that variations in different patients’ response to pharmacological treatment depends on genetic factors. Under this view, analysing the patients’ DNA will allow us to predict their reaction to a particular drug and thus enable the development of personalised medicines.
The study was presented at Toronto on the occasion of the annual convention of the American Academy of Neurology, and was selected as among the top 5% of over 2,000 articles received. It was the first study of its kind to be presented.
MEDICA.de;
The researchers hypothesized that the variation may be due to pharmacogenetic effects and that nicotine might have neuroprotective properties for certain individuals.
“We asked the interviewees to tell us about their relationship with smoking and then compared this data with the presence or absence of variations in the gene CYP2A6, which encodes the enzyme responsible for metabolising nicotine”, says EURAC researcher Maurizio Facheris, neurologist at the Department of Neurology of Bozen/Bolzano Central Hospital and main author of the study.
From an analysis of the data, it emerges that the presence of a particular variant of the gene, when combined with smoking, considerably reduces the risk of contracting Parkinson’s disease. It remains to be clarified whether the protection against the disease is provided by the particular variant of gene CYP2A6 or by the presence of cotinine, the substance into which nicotine is transformed through the action of the gene. “If this second hypothesis is confirmed, producing a cotinine-based drug would be a means to reduce exposure to the disease”, explains Maurizio Facheris.
The study opens up interesting scenarios in the field of pharmacogenetics, a discipline that holds that variations in different patients’ response to pharmacological treatment depends on genetic factors. Under this view, analysing the patients’ DNA will allow us to predict their reaction to a particular drug and thus enable the development of personalised medicines.
The study was presented at Toronto on the occasion of the annual convention of the American Academy of Neurology, and was selected as among the top 5% of over 2,000 articles received. It was the first study of its kind to be presented.
MEDICA.de;
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