VOA标准英语2010年-Chemists Take First Steps in Making Ca

The drug Taxol is a powerful weapon in the fight against cancer, but it's very expensive and complicated to manufacture.

Now, scientists at Tufts University and the Massachusetts Institute of Technology (MIT) say they've taken the first steps to make the drug using a common bacterium¹.

Taxol was first found in the bark of the Pacific Yew² tree decades ago. Like many complex chemicals, it is the result of a series of steps that in this case all happen in the tree.

 

MIT chemical engineering professor Gregory Stephanopoulos and colleagues have begun the process of making Taxol in the lab, starting with a genetically³ engineered form of E. coli, a safe variety of the bacterium that's usually in the news in stories about food poisoning.

"It is the bacterium of choice for a lot of molecular⁴ biology," he explained, "so there are many, many tools available for working with E. coli, and these tools allow researchers to 'knock out' genes⁵ and introduce new genes into E. coli."

By genetically manipulating the microbe, the scientists were able to take the first chemical steps in the process that, in nature, eventually leads to Taxol.

"So E. coli, that little bacterium, acts as a little chemical factory. In this way it replaces an equivalent chemical process which may require high temperatures and pressures and expensive solvents⁶ and all of these things — all of that is replaced by a single bacterium that's been property engineered to do that," said Stephanopoulos.

Another advantage is that the intermediate chemical molecules⁷ can themselves be studied and tested for any possible therapeutic⁸ effects they might have.

Although the process, if perfected, may synthesize a drug found in tree bark, Stephanopoulos says it's important to remember that Taxol — and possibly other, undiscovered medicines — originate in nature.

"It relies on samples from plants from the rainforests, from different sources, because the diversity that exists in these habitats gives the opportunity for the production of many, many, many different types of molecules, some of which may have very potent⁹ therapeutic properties."

So he says it is important to continue prospecting¹⁰ in the natural world in the hopes of discovering pharmaceutical¹¹ molecules, even if they are eventually manufactured in ways different than how they are grown in nature.

MIT chemical engineering professor Gregory Stephanopoulos and his colleagues published their research in the journal Science.
 

1 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

2 yew   

n.紫杉属树木

参考例句：

• The leaves of yew trees are poisonous to cattle.紫杉树叶会令牛中毒。
• All parts of the yew tree are poisonous,including the berries.紫杉的各个部分都有毒，包括浆果。

3 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

4 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

5 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

6 solvents   

溶解的，溶剂

参考例句：

• It is resistant to borohydride reduction in alcoholic solvents. 在醇溶剂中，它不能被硼氢化物还原。
• Strains require special treatments for removal such as spotting with organic solvents. 要清除这些着色物质，需要特殊处理，例如：滴加有机溶剂。

7 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

8 therapeutic   

adj.治疗的，起治疗作用的；对身心健康有益的

参考例句：

• Therapeutic measures were selected to fit the patient.选择治疗措施以适应病人的需要。
• When I was sad,music had a therapeutic effect.我悲伤的时候，音乐有治疗效力。

9 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

10 prospecting   

n.探矿

参考例句：

• The prospecting team ploughed their way through the snow. 探险队排雪前进。
• The prospecting team has traversed the length and breadth of the land. 勘探队踏遍了祖国的山山水水。

11 pharmaceutical   

adj.药学的，药物的；药用的，药剂师的

参考例句：

• She has donated money to establish a pharmaceutical laboratory.她捐款成立了一个药剂实验室。
• We are engaged in a legal tussle with a large pharmaceutical company.我们正同一家大制药公司闹法律纠纷。