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A Designer Protein That Wards Off The Aids Virus

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A Designer Protein That Wards Off the AIDS Virus

In the mid-1990s, biologist Peter S. Kim discovered how the AIDS virus makes one key move during its deadly attack--and now he has come up with some promising defenses. In the Jan. 12 Science, he reports on findings that could result in new anti-HIV drugs, and even a possible vaccine.

Kim's work revealed that when HIV encounters a vulnerable cell, it shoots a molecular "harpoon" into the victim's membrane. The harpoon molecule, called GP41, then snaps back into a hairpin shape, drawing the virus into contact with the cell's membrane and allowing HIV's genes to enter the cell.

After elucidating the three-dimensional shape of the hairpin, Kim and his colleagues at Massachusetts Institute of Technology sought ways to block the virus' entry. One of their most promising schemes is reported in Science. The group has designed a protein, dubbed 5-Helix, that binds tightly to one end of GP41. As a result, it prevents the hairpin from forming--and blocks infection. It's effective against many strains of HIV, and at low concentrations. "We were pleased with how well it worked," says Kim, incoming vice-president for R&D at Merck & Co.

The findings also provide new strategies for vaccine development, says Kim. If people were immunized with the right bits of GP41, their immune systems might make antibodies that work just like the 5-Helix protein to prevent infection.By John Carey; Edited by Ellen LickingReturn to top

When You Have to Get to Mars in a Hurry...

Mars-bound astronauts may someday take the A train. A for americium, that is. Researchers at Israel's Ben-Gurion University figure an americium-fueled rocket could make it to the red planet in as little as two weeks, not the eight months or more that the 300-million-mile jaunt now takes.

There's a hitch, though: The americium needed is the 242m isotope, a rare and costly nuclear fuel. Moreover, nuclear-engine research has been shelved since the early '60s, in part due to the problem of lifting heavy uranium fuel, plus a radiation shield, into orbit. But with Am-242m, things could change dramatically, according to a team headed by Israeli nuclear engineer Yigal Ronen.

A nuclear-propulsion system using Am-242m could slash the weight of the fuel by as much as 99%. It could also eliminate the weight of a separate engine, like the one on NASA's Deep Space 1 probe, which uses solar panels to power an electric engine that spits out xenon ions. Because thin strips of Am-242m don't absorb the high-energy particles produced by fission, as fat uranium rods do, the particles themselves could be vented to provide thrust. Ronen admits there are many engineering hurdles ahead, but he's confident the A train will eventually make interplanetary stops.By Otis Port; Edited by Ellen LickingReturn to top

A Water-Treatment Plant for Every Office Building?

Halford House believes that every drop of water--even wastewater--is precious. So the water-quality specialist at North Carolina State University has built a self-contained water-treatment system that mimics the natural cleansing processes of wetlands and rain forests for an office building outside Raleigh.

Every day, the system, which occupies a 2,800-square-foot courtyard next to the office, purifies and recycles the roughly 900 gallons of wastewater generated by the building's 60 workers. Gallons of sewer water first flow through two wetlands, where a garden of microorganisms and plants work together to break down noxious contaminants such as nitrogen and phosphorus. Next, the water trickles into a greenhouse, where tropical plants convert any remaining nutrients into food. Before being piped back into the building, the water is disinfected with chlorine. Roughly a week after water enters the system it emerges sparkling and clean enough for use in toilets and to irrigate the lawn, says House. He notes that his recycled wastewater isn't potable, but could be made so with the addition of a few simple cleaning steps.Edited by Ellen LickingReturn to top

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