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This Gene Seems To Have A Green Thumb


Developments to Watch

This Gene Seems to Have a Green Thumb

Now that scientists have finished sequencing the human genome, they turn to a weightier matter: What gives domesticated tomatoes their tremendous girth and plumpness? New research, reported in the July 7 issue of Science, partially answers the question. Scientists at Cornell University have identified one of the more than 20 genes involved in determining the size of tomatoes. Surprisingly, the gene, called ORF-X, encodes a protein similar to one involved in human cancers. The finding suggests that the same genetic mechanism that spurs cancer growth is involved in creating plump and juicy vegetables.

Wild tomatoes are often no bigger than raspberries. Farmers have created the supersize domestic versions by crossing different varieties and selecting the offspring with the biggest tomatoes. Those plants turn out to contain mutations in nearly two dozen genes that contribute to growth--among them ORF-X. Plant biologist Steven D. Tanksley, who led the study, estimates that alterations in ORF-X can increase fruit size by 30%.

Tanksley has a theory about how the gene leads to bigger fruit. Using a powerful computer program that matches up DNA sequences to a catalog of known three-dimensional protein structures, Tanksley found that the ORF-X protein appears to fold up just like a protein that controls cell growth in humans. Based on this similarity, Tanksley believes ORF-X may play a similar role in plants.Edited by Ellen LickingReturn to top

Take a Hike--and Charge Up Your Cell Phone

These boots are made for walking--and talking. Trevor Baylis, co-founder of Electric Shoe Co., based in the British town of Leicester, has invented a nifty device, embedded in the heel of a shoe, that harnesses a person's walking power to charge small batteries such as those used in cell phones. The gadget should prove convenient for chronic cell-phone users, who know all too well the awful silence wrought by a dead battery. This "smart footwear" won't be on the fashion runways for several years, but Baylis and colleagues have already taken the technology for a dry run--in the Namib Desert.

Baylis began a charity walk through the dunes of Namibia on June 24. At the end of the 10-day trip, Baylis placed a call to Sir Richard Branson, chairman of Virgin Atlantic Airlines. The sole purpose of the call was to test whether or not the device had charged batteries enough to power an intercontinental phone call. The test was a success--the call went through.

Baylis developed the charger with Britain's Defense Evaluation & Research Agency. With each step, the gadget is squeezed, generating electricity that runs along wires to a battery placed on the side of the shoe. Electric Shoe Co. says a person wearing the boots must walk three to four hours to charge the battery fully--not necessarily in the Namib desert.By Mary Ann Saadi; Edited by Ellen LickingReturn to top

These Tiny Robots Go to Work in Your Bloodstream

Isaac Asimov's novel Fantastic Voyage, in which a microscopic submarine enters a patient's bloodstream on a repair mission, may be coming closer to reality. Edwin Jager, a graduate student at Sweden's Linkopings University, has created the smallest submersible robots ever. Each is shorter than this dash--and no wider than the following period. Yet each has an elbow, a wrist, a hand, and two to four fingers. Biologists see many applications for these microrobots and the even smaller robots yet to come. The future includes programmable machines that would travel in the blood and aid the immune system, "cell-herding" machines to stimulate rapid healing and tissue reconstruction, and cell-repair machines to ferry materials in and out of cells.

Unlike some other tiny robots, the Swedish-made microrobots function perfectly in salty broth, blood, and urine. Most microrobots contain silicon, which, when exposed to water, oxidizes and stops working. Jager's robots use silicon covered by "micromuscles" of gold and plastic that shrink and swell in response to electrical signals. The muscles protect the silicon and enable the robots to carry out their tiny tasks.By Mary Ann Saadi; Edited by Ellen LickingReturn to top


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