Instructions:In this section, there is one passage followed by a summary. Read the passage carefully and complete the summary below by choosing no more than three words from the passage. Remember to write the answers on the Answer Sheet.
　　Answers 1-5 are based on the following passage.
　　Insects entombed in fossilised amber for tens of millions of years have provided the key to creating a new generation of antibiotic drugs that could wage war on modern diseases. Scientists have isolated the antibiotics from microbes preserved either inside the intestines of the amber-encased insects or in soil particles trapped with them when they were caught by sticky tree resin up to 130 million years ago. Spores of the microbes have survived an unprecedented period of suspended animation, enabling scientists to revive them in the laboratory.
　　Research over the past two years has uncovered at least four antibiotics from the microbes and one has been able to kill modern drug-resistant bacteria that can cause potentially deadly diseases in humans. Present-day antibiotics have nearly all been isolated from micro-organisms that use them as a form of defence against their predators or competitors. But since the introduction of antibiotics into medicine 50 years ago, an alarming number have become ineffective because many bacteria have developed resistance to the drugs. The antibiotics that were in use millions of years ago may prove more deadly against drug-resistant modern strains of disease-causing bacteria.
　　Raul Cano, who has pioneered the research at the California Polytechnic State University at San Luis Obispo, said the ancient antibiotic had been successful in fighting drug-resistant strains of staphylococcus bacteria, a “superbug” that has threatened the health of patients in hospitals throughout the world. He now intends to establish whether the antibiotic might have harmful side effects. “The problem is how toxic it is to other cells and how easy it is to purify.” said Cano.
　　A biotechnology company, Ambergene, has been set up to develop the antibiotics into drugs. If any ancient microbes are revived that resemble present-day diseases, they will be destroyed in case they escape and cause new epidemics. Drug companies will be anxious to study the chemical structures of the prehistoric antibiotics to see how they differ from modern drugs. They hope that one ancient antibiotic molecule could be used as a basis to synthesise a range of drugs.
　　There have been several attempts to extract material such as DNA from fossilized life-forms, ranging from Egyptian mummies to dinosaurs, but many were subsequently shown to be unsuccessful. Cano’s findings have been hailed as a significant breakthrough by scientists. Edward Golenberg, an expert on extracting DNA from fossilized life-forms at Wayne State University in Detroit, said: “They appear to be verifiable, ancient spores. They do seem to be real.” Richard Lenski, professor of microbial ecology at Michigan State University, said the fight against antibiotic-resistant strains of bacteria, such as tuberculosis and staphylococcus, could be helped by the discovery.
　　However, even the discovery of ancient antibiotics may not halt the rise of drug- resistant bacteria. Stuart Levy, a micro-biologist at Tufts University in Boston, warned that the bacteria would eventually evolve to fight back against the new drugs. “There might also be an enzyme already out there that can degrade it. So the only way to keep the life of that antibiotic going is to use it sensibly and not excessively.” he said.
　　Summary
　　Microbes that may supply new antibiotic drugs have been　1　in the bodies of fossilised insects. The discovery may help destroy　2　bacteria. What needs to be done now is to find out how 　2　hey are to humans. It is thought that a single antibiotic molecule could lead to a whole series of new drugs. Other scientists who have tried to produce antibiotics in a similar way have been　3　Scientists think Cano’s findings are a　5　breakthrough in the fight against diseases.

发布日期：2021-10-09

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