Random Science News Thread
Posted: Wed Sep 26, 2007 6:01 pm
Official Discussion Forum for the works of Stephen R. Donaldson
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--AGene-Altered Plant, Tree Can Suck Up Toxins
John Roach
for National Geographic News
October 15, 2007
Two types of genetically modified plants can remove toxic compounds from the environment, according to research by a pair of independent groups.
One group developed Arabidopsis plants—small plants related to cabbage and mustard—that can clean up soil contaminated with cyclonite, or RDX. The widely used explosive is highly toxic and carcinogenic.
The other team modified a poplar tree to soak up a host of cancer-causing compounds from soil, groundwater, and air.
The contaminants are then broken down into harmless compounds in a process called phytoremediation.
"It is our hope that by developing trees that can remove carcinogens from the water and air in a fast and economical way, people will be more likely to use [the land] than abandon the property as too expensive to clean up," Sharon Doty, of the University of Washington, said in an email.
Doty is the lead author of a paper on the modified poplar tree that appears this week in the journal Proceedings of the National Academy of Sciences.
"There is more research left to be done before we reach that stage, but that is the ultimate goal."
But outside experts cautioned that the risks of using genetically engineered plants are unknown and require rigorous testing.
"I think we're playing to some extent a game of roulette here," said Doug Gurian-Sherman with the Union of Concerned Scientists in Washington, D.C.
He noted that both Arabidopsis and poplars spread naturally in the wild, which heightens the risk of an engineered gene spreading unchecked.
"If they do [escape and] cause problems," he said, "we're pretty much going to be stuck with them."
Neil Bruce at the University of York in the U.K. co-authored a paper on the explosive-slurping Arabidopsis plant, which also appears this week in PNAS.
This microbe has since been found at RDX-contaminated sites around the world.
"But whilst you can find these microorganisms there, they clearly aren't breaking down the explosive fast enough before it migrates through the soil and contaminates groundwater," Bruce said.
Plants are well known for soaking up certain chemicals from soil, air, and groundwater and breaking them down into harmless components, he said. But no known plant naturally breaks down RDX.
So Bruce and colleagues combined the enzyme system from the soil microbes with Arabidopsis, a model plant for scientific studies because its genetic changes are easily observed (get a genetics overview).
Their first successful attempt was published in the January 2006 issue of the journal Nature Biotechnology. The new research published this week in PNAS documents the plants' superior performance.
"We've managed to identify the complete systems that allow this enzyme to work, and we've got both components of this enzyme system successfully expressed and working in Arabidopsis," Bruce said.
His team is now collaborating with researchers at the University of Washington in Seattle to develop grasses and trees more suited to removing RDX from contaminated soils at military bases around the world.
Stuart Strand, a research professor in the College of Forest Resources at the University of Washington, leads the collaboration with Bruce's team and is also a co-author of the paper on transgenic poplar trees.
That study used a similar technique to enhance the ability of poplar trees to remove a host of carcinogens from the environment.
In this case, the team inserted a gene that produces a contaminant-cleaning enzyme found in rabbit livers into the poplar trees.
Although poplars already naturally remove contaminants from the environment, the rabbit liver enzyme speeds up the process.
For example, the altered poplars removed trichloroethylene—a heavily used industrial degreaser—53 times faster than nonaltered trees, lead study author Doty noted.
The trees also more quickly removed carcinogens such as chloroform and vinyl chloride from the ground and benzene from the air.
And while control plants removed none of the industrial solvent trichloroethylene from the air, the altered trees removed 79 percent of the chemical during a week-long experiment.
Doty added that poplars grow for several years before flowering, and fallen branches do not take root in soil. As such, the trees could be harvested before their seeds germinate and spread their genes.
But Jane Rissler, of the Union of Concerned Scientists, cautioned that promises of safe bioremediation techniques seldom come to fruition.
"There have been so many promises in the past 20 years and so few products," she said, "and phytoremediation is another promise that hasn't been met."
Team Creates Rat Heart Using Cells of Baby RatsThe agency is not requiring labeling or any other additional measures for food from cattle, swine, and goat clones, or their offspring because food derived from these sources is no different from food derived from conventionally bred animals. Should a producer express a desire for voluntary labeling (e.g., "this product is clone-free"), it will be considered on a case-by-case basis to ensure compliance with statutory requirements that labeling be truthful and not misleading.
video linkA growing number of police departments across the country are using a new type of siren that can not only be heard, it can be felt.
I want one of those.Esmer wrote:that's some scary awesome stuff there Syl.
in other news:video linkA growing number of police departments across the country are using a new type of siren that can not only be heard, it can be felt.
He cannot yet make all metals into all colors but says he believes that it is only a matter of trial-and-error to find the right recipe for each permutation.
With his black metal finding, Dr. Guo suggested the possibility of black gold rings. He was surprised when jewelers started calling. “They are actually indeed interested in making colored jewelry,” he said.
On my one hand, a White Gold Ring.Syl wrote:Laser Makes Other Metals Look Like GoldHe cannot yet make all metals into all colors but says he believes that it is only a matter of trial-and-error to find the right recipe for each permutation.
With his black metal finding, Dr. Guo suggested the possibility of black gold rings. He was surprised when jewelers started calling. “They are actually indeed interested in making colored jewelry,” he said.
A material that is able to self-repair even when it is sliced in two has been invented by French researchers.
--AExtra-Solar PLanets Turn Theory Upside Down
A dominant theory about planets has been challenged by the discovery of nine worlds transiting distant stars, astronomers reported on Tuesday.
The belief that planets always orbit their sun in the same direction, imitating the rotation of the star itself, has been turned upside down, they said.
"This is a real bomb we are dropping into the field of exoplanets," said Geneva Observatory astronomer Amaury Triaud, referring to planets outside our solar system.
Triaud's team are to report their findings at a meeting this week of the Royal Astronomical Society (RAS) in Glasgow, Scotland.
Their revolutionary notion is based on the discovery of nine exoplanets, which bring the tally of these phenomena to a grand 452 since they first came to light in 1995.
Information
The latest planets are especially useful, as they were not discovered indirectly - by calculating their gravitational pull on the star's light - but because they passed directly in front of the sun.
These rarely-captured "transit" events are especially coveted, for they can yield much more information about the planet.
After combining the new results with previous observations of transiting exoplanets, Triaud and fellow astronomers Andrew Cameron and veteran exoplanet hunter Didier Queloz were stunned.
Six of 27 exoplanets they sampled were found to orbit in the opposite direction of their host star.
The big hypothesis about planets is that they coalesce from a disc of dust and gas orbiting a young star and move in the same direction as the star's own rotation.
"The new results really challenge the conventional wisdom that planets should always orbit in the same direction as their stars spin," said Cameron, of the University of St Andrews, Edinburgh.
The transiting planets are so-called "hot Jupiters", or planets with a mass similar to or greater than Jupiter.
Goldilocks zone
Unlike our Jupiter, which circles the Sun at a great distance, hot Jupiters are found very close to their star, sometimes scorchingly so.
Until now, hot Jupiters were believed to form from material far from the host star and then gradually migrate to a closer orbit as a result of gravitational interaction between the star and the proto-disc of planetary dust.
How the "renegade" hot Jupiters came to exist dents this theory, too.
It could be that, in their infant stage, these planets became caught up in a "gravitational tug-of-war" with distant planets or even nearby stars, the astronomers suggest in a press release.
As a result, the exoplanet would have been hauled into a tilted or elongated orbit. Eventually, due to a phenomenon called tidal friction, it would have been snared by the star, parked in a weird, randomly tilted orbit close by.
Another question is what this means about hopes for finding another Earth - a small, rocky planet that is in the "Goldilocks zone", where it is neither too hot nor too cold but just right so that water can exist in liquid form.
Killers
The Jupiter in our solar system is believed to play a protective role, its huge mass taking the hit from rogue comets or asteroids that could smack into the small, vulnerably rocky planets nearer to the Sun, including Earth.
But the new retrograde hot Jupiters would be killers, not guardians.
Essentially, they would be like a giant ball in a game of space billiards, wiping out any smaller planet in the vicinity as they lurched around.
"A dramatic side-effect of this process is that it would wipe out any other smaller Earth-like planet in these systems," said Queloz, also of the Geneva Observatory.
The discoveries, made using the European Southern Observatory's giant 3.6m telescope in La Silla, Chile, have been submitted to peer-reviewed journals for publication, ESO said.
- AFP