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Make a Toxic Site Bloom


There's a glorious garden growing at a landfill south of Detroit owned by Ford. Tiny lavender monkey flowers, purple and yellow New England asters, and blue-stem prairie grass are thriving between two mounds of refuse blanketed with scrub grass and cattails. But what really has scientists and engineers excited is what's going on underground. Microbes in the soil are receiving nutrients from the roots of these and some 20 other plants and shrubs, helping them to break down complex toxins known as polyaromatic hydrocarbons (PAHs).

If the experiment works as expected, Ford wants to use the same method, called phytoremediation, on a contaminated 30-acre site within its Rouge manufacturing complex that must be cleaned up within five years. So far, the results are encouraging. The soil is contaminated with a carcinogenic hydrocarbon residue--a by-product of the big coke ovens Ford used for decades to process coal. Working with agricultural researchers at Michigan State University, Ford removed some of the poisoned dirt from the Rouge site and used it to create three test plots at the landfill. Now, as the first growing season comes to a close, there's no doubt that the soil is cleaner. While scientists are still analyzing and comparing soil samples taken in May, July, and September, "there is very strong support of the removal of contaminants," says MSU Professor Clayton L. Rugh, who is heading up the project. "The plants are growing very aggressively." Each year, 5.5 million people in the U.S. are infected with human papilloma virus (HPV), which can cause cervical cancer. But not all of the women affected develop tumors, and it's almost impossible to tell from a Pap test which ones will. That means millions end up back in their gynecologists' offices for painful surgical tests--many of which reveal no cause for concern.

To address this, Ventana Medical Systems has developed Inform HPV, the first automated, slide-based test for damage caused by the virus. While the dominant HPV test, Digene's Hybrid Capture, measures the amount of virus in a tissue sample, Inform allows lab pathologists to distinguish visually between the HPV cells that have invaded healthy tissue--the primary cause of cervical cancer--and those that are harmless.

Still, Ventana faces an uphill struggle. Since 1999, when the Food & Drug Administration approved Hybrid Capture for HPV testing in women with borderline abnormal Pap tests, Digene has grabbed about 25% of the $70 million market. On Oct. 2, Digene applied for FDA approval of Hybrid Capture as a primary HPV screen for all women over 30--a potential $500 million market. Ventana, meanwhile, won't file for FDA approval for at least six months. Efforts to defend against germ warfare are getting a boost from researchers studying two of the most feared weapons in the biological arsenal: bubonic plague and anthrax.

In the Oct. 4 issue of Nature, Julian Parkhill and colleagues at the Sanger Centre in Cambridge, England, have decoded the entire genetic blueprint of Yersinia pestis, the bacterium that causes plague. There they have found signs of a stormy evolutionary past: lots of gene recombination and decay and many genes apparently absorbed from other bacteria and viruses. The discovery should one day enable researchers to find ways to disable and defend against the plague bacterium, which since the 6th century has caused three pandemics that killed 200 million people.

In a separate discovery, researchers at Harvard Medical School report in the October Current Biology that they have found a gene that makes mice naturally resistant to anthrax. The discovery could lead to the identification of people unlikely to be infected by anthrax and perhaps provide clues to help others resist infection. The finding may also point to better treatments for an illness that is now often fatal. -- The Dutch team that crafted the world's first functioning transistor from a single carbon nanotube in 1998 has taken another major step in molecular electronics. In the Oct. 5 issue of Science, researchers at Delft University of Technology report that they have deposited multiple nanotube transistors on a silicon chip, connected them with gold wires, and performed rudimentary computer functions. IBM announced a similar breakthrough in August, but the Delft team's chip is the first one to demonstrate that such devices can perform multiple logic operations of the sort carried out by conventional computer circuits. The development is bound to raise the expectations riding on nanotubes--supertough, elongated carbon molecules measuring just 1/100,000th the thickness of a human hair. Semiconductors incorporating such elements would likely deliver huge increases in computing speed.

-- A protein responsible for photosynthesis in spinach leaves might someday be transplanted into human eyes to stave off retinitis pigmentosa, a leading cause of blindness. When this disease strikes, the photoreceptor rods in the retina deteriorate to the point where they can no longer capture light or convert it into electrical signals that the brain interprets as images. In spinach, the protein called Photosystem I behaves almost like a rod, according to researchers at Oak Ridge National Laboratory and the University of Southern California: It captures photons and releases a small electrical voltage. The scientists have embedded the protein in an artificial membrane that mimics living cells but they have yet to start animal trials.


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