NEWS OF THE WEEK
INVENTIONS WITH IMPACT LEMELSON-MIT AWARDS: Polymers
for chemical sensing and a process for alternative fuels reap prizes
T Swager demonstrates a handheld monitor that checks people, clothing, and automobiles for trace explosives.
WO RESEARCHERS whose inventions are making—or have the potential to make—a broad impact on society are being recognized with prestigious awards from the Lemelson-MIT Program. Timothy M. Swager, the John D. MacArthur Professor of Chemistry and head of the chemistry department at MIT, is the winner of this year's $500,000 LemelsonMIT Prize. The award recognizes S wager's development of highly sensitive semiconducting fluorescent polymers that can detect traces of chemicals found in explosives. Swager's invention is widely used by American soldiers in Iraq to detect explosives. Specifically, it is being used in handheld monitors to check people, clothing, and automobiles for trace TNT. Swager is also working on electrical resistance-based polymers that can detect changes in the levels of nitric oxide, an important indicator of a person's health.
GIVING BACTERIA A ONE-TWO PUNCH ANTIBIOTICS: Drug combo stymies development of resistant bacteria
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SING THE RIGHT COMBINATION of antibiotics could curtail the development of drug-resistant bacteria, a new study shows. Systems biology assistant professor Roy Kishony and grad students Remy Chait and Allison Craney at Harvard Medical School demonstrate that certain combinations of doxycycline and ciprofloxacin favor the growth of doxycycline-sensitive bacteria over doxycycline-resistant ones (Nature 2007,446, 668). The combination is "suppressive," meaning that its bacteria-killing effect is weaker than that of the individual drugs. The researchers tested the combinations against Escherichia coli strains that differ only in the presence or absence of a tetracycline efflux pump, which provides a common mechanism of resistance to tetracycline, doxycycline, and related antibiotics. In assays that measured selection for the gene responsible for this resistance, they found strong selection for doxycycline-resistant strains when they WWW.CEN-0NLINE.ORG
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These sensors could be used by doctors, for example, as an early diagnostic of a respiratory infection. "The future of chemistry relies a lot on our inventing things," Swager says. "Hopefully, this work can inspire other people to be entrepreneurial and take their inventions to the marketplace. It is absolutely critical that people seek innovative applications of their science." The Lemelson-MIT Program also bestowed another honor, this one for the first time: The $100,000 Lemelson-MIT Award for Sustainability went to Lee Lynd, a professor of engineering and adjunct professor of biology at Dartmouth College. Lynd, who cofounded biofuels start-up company Mascoma Corp., is pioneering a cost-effective, one-step approach to biologically converting cellulosic biomass, such as grass, wood, wheat, and rice straw, into ethanol that can be used for fuel. Known as consolidated bioprocessing, this approach is a potential breakthrough for processing cellulosic biomass at low cost. Lynd points out that although the work is still in progress, he is optimistic that it can be advanced rapidly and will improve the quality of life for future generations. The Lemelson-MIT Program, named after prolific inventor Jerome H. Lemelson, aims to recognize outstanding inventors, encourage sustainable solutions to real-world problems, and inspire young people to pursue creative lives and careers through invention.— LINDA WANG
treated bacteria with doxycycline alone or in combination with erythromycin, which has a synergistic effect with doxycycline. In contrast, the doxycycline-ciprofloxacin combination selects against the doxycycline-resistant bacteria at some concentrations. The resulting persistence of doxycycline-sensitive strains is counterintuitive. "The selection against resistance stems from the interaction between the antibiotics and is therefore largely independent of the underlying mechanistic way by which the bacteria become resistant," Chait says. The observed effects work against only doxycycline-resistant bacteria. The authors suggest that such a strategy will work best with combinations of drugs where each one suppresses the other. The clinical relevance of the findings is still uncertain. The current work involves antibiotic doses below therapeutic levels. "The suppressive condition that allowed for the observation of the effect is never used clinically," says Shahriar Mobashery, an antibiotic expert at the University of Notre Dame. Nevertheless, the study is "interesting conceptually," he says, and the phenomena "deserve further study and explanation." Kishony's group plans to study higher drug concentrations that fully inhibit both the sensitive and resistant bacteria. "We hope that these findings may suggest avenues of research into new treatment strategies employing antimicrobial combinations with improved selection against resistance," Chait says.—CELIA ARNAUD
APRIL9.2007
