Lowering the defenses of bacteria.
Slipping genes that disarm those resistance mechanisms into bacteria makes the microorganisms again susceptible to antibiotics, Sidney Altman of Yale University and his colleagues report in the Aug. 5 Proceedings of the National Academy of Sciences.
The genes used by Altman's team encode small strands of RNA called external guide sequences. If designed correctly, these RNA strands can bind to the protein-coding RNA strands produced by the bacteria's normal genes. This union calls into action an enzyme that destroys the protein-coding RNA.
Altman's group designed its external guide sequences to join to the RNAs that code for bacterial enzymes that destroy or inactivate antibiotics. By eliminating these RNAs, the scientists deprived the bacteria of their drug resistance, as they proved by testing the drugs on the microbes.
"It's a very clever laboratory technique," says Stuart B. Levy of Tufts University School of Medicine in Boston, who also studies ways to interfere with bacterial resistance mechanisms. Yet Levy is skeptical that Altman's strategy will prove useful. He notes that delivering genes into bacteria is easy in test tubes but much more difficult when the microorganisms are inside people. Moreover, physicians would have to, ensure that both the external guide sequence genes and the antibiotics reached the bacteria. "That's no easy trick," says Levy.
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|Title Annotation:||Biology; researchers attempt to disrupt mechanisms in bacteria that enable them to resist drugs|
|Article Type:||Brief Article|
|Date:||Aug 23, 1997|
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