環(huán)球英語 — 750：Steps Forward in Science
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Hello, and welcome to Spotlight. I'm Steve Myersco. This programme uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.
The world of science never seems to stand still! Scientists are continually testing, researching, experimenting. They have a desire for knowledge about how the world works. And their aim is to reduce the limits of that knowledge - to open doors to greater understanding. In today's Spotlight programme, we look at two developments in biology and medicine. And, we discuss what effects these discoveries may have on our future. Here are Marina Santee and Ruby Jones with our first story - a plant that produces fuel.
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People say that money does not grow on trees. But does fuel? A scientist from Montana State University believes that maybe it does! Gary Strobel is a professor of plant sciences and plant pathology. He travels around the world, looking for unusual plants. He then examines them to find if they contain any bacteria that may be useful to humans.
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In 2002, Professor Strobel visited the Patagonian rainforest. This rich, fertile area covers parts of two South American countries: Argentina and Chile. Strobel collected many cuttings from different plants and trees growing in the rainforest. He then returned home and examined them closely some time later. One of the cuttings came from an ancient family of trees called "ulmo".
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Strobel and his team of helpers found an organism growing on the ulmo's leaves. It was a fungus - a growth that lives by feeding off another organism. The scientists investigated some more. They discovered that the fungus was naturally producing a mix of chemicals. And they found that this chemical mix was very similar to diesel fuel! Strobel named the mix, "Mycodiesel." He stated that the discovery was the first of its kind. They were the first people to find an organism that could produce this mix of fuel substances. And in his opinion, the mix was ready for use in any diesel fuel engine - no need for any changes!
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Other scientific experts have welcomed this new discovery. However, producing fuel from crops - biofuel - still causes many arguments. It may be a more friendly kind of fuel for the environment. But people need large amounts of crops, such as corn, to produce it. This increases crop prices. And people who depend on these crops to survive often do not have the money to pay for them. So Strobel's discovery is creating hope. The mycodiesel provides a natural way of supplying biofuel - without using up much-needed crops!
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However, Professor Strobel still has a lot of work to do. The next step will be to produce purer versions of the mycodiesel. To do this, the professor needs to find a way to make the fungus grow more quickly - and in larger amounts! Then, it will be time to test the mycodiesel outside the laboratory. Only time will tell if we will one day fill our tanks with fuel from the ulmo tree fungus. But Professor Strobel and his team are sure that they will succeed!
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And now, an exciting development from the medical world. Here are Christy Van Aragon and Adam Navis to tell us about it.
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Doctors perform organ transplant operations often these days. People receive new lungs, new kidneys - and even new hearts. Usually these organs come from especially kept dead bodies. These organs often save patients' lives. But, there are risks involved. It is possible for the body to reject its new organ. So, patients have to take a number of different medicines for the rest of their lives.
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However, in June 2008, doctors in Spain achieved a new kind of transplant success! For the first time ever they used an organ grown from cells from the patient's own body! The name of the patient was Claudia Castillo. And she was suffering from tuberculosis. The tuberculosis had damaged her wind-pipe - the airway going from her nose and mouth to her lungs. This made her breathing difficult. Even a little exercise left Claudia weak. Because of the damage to her wind-pipe, she was in danger of losing her left lung. So, doctors decided to replace the damaged part of Claudia's wind-pipe.
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Doctors cut a piece of wind-pipe from a dead body. Then they ‘washed' it in strong chemicals. They did this to destroy all the cells belonging to the owner of the wind-pipe. This cleaning process left the doctors with the basic structure of the piece of wind-pipe: like a tent without its protective cover! Doctors then took two different kinds of cells from Mrs Castillo. One kind of cell was from her wind-pipe. The other cells were young adult stem cells from her hip bone. The body's stem cells are able to grow into any kind of specialized cell. The doctors mixed the two kinds of cells together. And the stem cells grew into new wind-pipe cells.
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Doctors in the United Kingdom helped with this process. And they managed to grow enough cells to cover the old piece of wind-pipe. They flew the new cells back to Spain. And there, doctors covered the wind-pipe with them. All that remained for them to do was to replace the damaged piece of wind-pipe in Mrs Castillo!
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It was a very tense event. Professor Paolo Macchiarini performed the operation. And he admitted that he was very afraid. However, the doctors had managed to trick Mrs Castillo's body. The new cells covering the wind-pipe made her body believe that this new wind-pipe was part of itself - not a strange new organ. Mrs Castillo has recovered well. And she will not have to take any extra medicine to stay healthy.
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Professor Martin Birchall was one of the United Kingdom doctors who helped grow the new cells. He believes that this process marks a huge step forward in this kind of organ transplant. It reduces the chances of a body rejecting the new organ. And, it may also reduce the amount of time that patients have to wait for a transplant. Professor Birchall estimates that in twenty years' time, doctors could make almost any transplant organ in this way.
