美国科学60秒 SSS 2015-01-08（在线收听）

 This is scientific American 60 seconds science. I'm *, got a minute ?Genetically engineered bacteria already proves some products are commercial interests or biometical importance such as insulin. And coaxing the organism to do so can be done with a cleaner setup and produce fewer environmentally problematic by-products than other production methods. But the baceria approach is still limited to just a few products due to not efficient. Now, a research team at Harvard's Wyss institute for biologically inspired engineering says they've deleloped a system to get microbes to produce chemicals dramatically faster and more efficently. The technique uses Dr. william principles of multiple itrations what they call rounds of evolution. The study isn't the proceedings of the national academy of sciences. The researchers introduced mutations in specific genes related to their expression of the desired molecule. It then tweeted the bacteria so that genes for anti-biotic resistance only become active when the cells make some of softer product. When the anti-biotic present, cells died and do not produce enough of the product because those cells also do not have the life-saving resistance to the anti-biotics. The surviving cells however show promise. The system takes the cells through this evolutionary cycle repeatedly eliminating and product bacteria each time. And as a result, microbes that sypathize the chemical interests with 30 times the output of current compound production systems and up to the 1,000 times faster. The researchers say their programe could work to a efficiently produce a wide variety of useful compounds which might make vats of modified bacteria tomorrow's leaders and commercial chemical manufacturing.