Passage 2 Knockout blow a breakthrough in understanding how tuberculosis(TB)lies low in the body could lead to a fast and effective cure for the disease TB is a growing threat as drug- resistant forms emerge. At present, a course of antibiotics lasting between 6 and 12 months is needed to cure tB. It takes this long because the existing drugs target rapidly dividing bacteria, rather than the slow-growing ones responsible for persistent infections But when John McKinney, who is now at the rockefeller University in New York, reviewed research done in the 1950s, he was intrigued by a study of bacteria taken from long-infected lung tissue. Unlike Mycobacterium tuberculosis grown in the lab, these bacteria got their energy from fatty acids, not sugars McKinney and his colleagues then targeted the pathway bacteria use to break down fatty acids. They genetically engineered TB bacteria that lacked a key enzyme called isocitrate lyase. When they infected mice with these mutant bacteria, a normal infection developed but the animals immune systems were able to clear the bacteri The results suggest that the m. tuberculosis bacterium alters its metabolism to counter the immune system's attack. McKinney and his collaborators are now studying the structure of the enzyme and are developing drugs to inhibit it. They hope to begin animal trials by the end of the year 2000 If all goes well, TB patients could soon get the drugs that target rapidly growing bacteria along with another one that targets persistent bugs. This one-two punch could eliminate the bacteria in weeks instead of months, McKinney says It would be wonderful to imagine that we could treat tuberculosis like any other bacterial infection, says James Sacchettini, one of McKinney's collaborators at Texas A&M University in College Station. If we could treat tuberculosis in two to three weeks, I think we'd have a really good chance of eradicating the disease Vocabulary tuberculosis n.肺结核 emerge v.出现,形成 screen 1:筛选 persistent a.持续久]的,持久的 ntrigue vt.激起…兴趣 isocitrate lyase异柠檬酸(裂合)酶 metabolism n新陈代谢 inhibit 1:抑制 target 1:瞄准:把.作为目标[对象 eliminate y消除,排除 eradicate 1:.根除Passage 2 Knockout Blow A breakthrough in understanding how tuberculosis (TB) lies low in the body could lead to a fast and effective cure for the disease. TB is a growing threat as drug-resistant forms emerge. At present, a course of antibiotics lasting between 6 and 12 months is needed to cure TB. It takes this long because the existing drugs target rapidly dividing bacteria, rather than the slow-growing ones responsible for persistent infections. But when John McKinney, who is now at the Rockefeller University in New York, reviewed research done in the 1950s, he was intrigued by a study of bacteria taken from long-infected lung tissue. Unlike Mycobacterium tuberculosis grown in the lab, these bacteria got their energy from fatty acids, not sugars. McKinney and his colleagues then targeted the pathway bacteria use to break down fatty acids. They genetically engineered TB bacteria that lacked a key enzyme called isocitrate lyase. When they infected mice with these mutant bacteria, a normal infection developed but the animals’ immune systems were able to clear the bacteria. The results suggest that the M. tuberculosis bacterium alters its metabolism to counter the immune system’s attack. McKinney and his collaborators are now studying the structure of the enzyme and are developing drugs to inhibit it. They hope to begin animal trials by the end of the year 2000. If all goes well, TB patients could soon get the drugs that target rapidly growing bacteria along with another one that targets persistent bugs. This one-two punch could eliminate the bacteria in weeks instead of months,4 McKinney says. “It would be wonderful to imagine that we could treat tuberculosis like any other bacterial infection,” says James Sacchettini, one of McKinney’s collaborators at Texas A&M University in College Station. “If we could treat tuberculosis in two to three weeks, I think we’d have a really good chance of eradicating the disease.” Vocabulary tuberculosis n. 肺结核 emerge vi. 出现，形成 screen v. 筛选 persistent a. 持续久]的，持久的 intrigue vt. 激起…兴趣 isocitrate lyase 异柠檬酸(裂合)酶 metabolism n. 新陈代谢 inhibit v. 抑制 target v. 瞄准； 把...作为目标[对象] eliminate v. 消除，排除 eradicate v. 根除