[Science Report]:Designer Antibiotics


This is the VOA SpecialEnglish SCIENCE REPORT.

Researchers in La Jolla, California, have taken steps towarddeveloping effective new antibiotic drugs. M. Reza Ghadiri and otherresearchers from the Scripps Research Institute have developedstructures called "nanotubes." Nanotubes are molecules of amino acidthat can build themselves into tubes that are smaller than a cell.

Mister Ghadiri's team recently reported its findings in thepublication, NATURE. The researchers said the nanotubes killed anumber of bacteria in animals and in laboratory tests. They alsoreported that the structures helped mice recover from normallydeadly bacterial attacks. These same bacteria resisted a traditionalantibiotic drug used to kill harmful bacteria.

The team said the central structure of the nanotubes containsrings called cyclic peptides. These circular structures are made ofeither six or eight amino acids. The researchers chose the aminoacids because their molecules form themselves into tubes only in thecorrect chemical environment.

During their experiments the researchers placed the rings insidethe covering of bacteria. The rings lined up to form tubes that areempty in the middle. The tubes killed the bacteria by making holesin them. The bacteria died when the material inside them leaked out.

In test-tube experiments the team found nanotubes formed inbacteria but did not form in red blood cells. The amino acidnanotubes also protected animals sick with Staphylococcus Aureus.This disease affects more than two-million hospital patients in theUnited States every year.

Current antibiotic drugs often attack one special molecule withinbacteria. Bacteria can develop resistance to such drugs over time.They do this by changing the shape of the targeted molecule. Or,they may keep the drugs away from their molecular target.

Mister Ghadiri says he hopes nanotubes have a long life. Thiswould force bacteria to make more changes to resist treatment. Hesays changing amino acids in the peptide rings could create manydifferent versions of the nanotubes.

Mister Ghadiri's team has given mice the drugs by forcing themthrough the skin. But he believes these new kinds of antibiotics cansome day be produced to take by mouth, in pill form.

This VOA Special English Science Report was written by JerilynWatson.

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