酶使DNA与外部细胞交换信息

时间：2013-03-22 07:02:56

（单词翻译:单击）

The discovery of the Rosetta Stone resolved a longstanding puzzle, permitting the translation of Egyptian hieroglyphs1（象形文字） into Ancient Greek. John Chaput, a researcher at Arizona State University's Biodesign Institute has been hunting for a biological Rosetta Stone -- an enzyme2 allowing DNA3's 4-letter language to be written into a simpler (and potentially more ancient) molecule4 that may have existed as a genetic5 pathway to DNA and RNA in the prebiotic（生命起源以前的） world.
 
Research results, which recently appeared in the Journal of the American Chemical Society, demonstrate that DNA sequences can be transcribed6 into a molecule known as TNA and reverse transcribed back into DNA, with the aid of commercially available enzymes7.
 
The significance of the research is three-fold: 
It offers tantalizing8（撩人的） clues about how DNA and RNA -- which encode the building plans for all earthly life -- may have arisen from more primitive9 information-carrying molecules10
Contributes to the field of exobiology（外空生物学） -- the search for alternative life forms elsewhere in the universe
Points to possible applications for TNA and other unusual nucleic acid molecules (known as xenonucleic acids or XNAs) in molecular11 medicine.
 
In the case of biomedical applications, XNAs may be developed into aptamers -- molecular structures that can mimic12 the properties of naturally occurring polymers, folding into a variety of 3-dimensional forms and binding13 with selected targets. Aptamers are useful for a range of clinical applications including the development of macromolecular drugs.
 
"TNA is resistant14 to nuclease degradation15, making it an ideal molecule for many therapeutic16 and diagnostic applications," Chaput says.
 
The structural17 plans for organisms ranging from bacteria to primates18 (including humans) are encrypted in DNA using an alphabetic19 code consisting of just A, C, T & G, which represent the 4 nucleic acids. In addition to their information-carrying role, DNA and RNA possess two defining properties: heredity, (which allows them to propagate their genetic sequences to subsequent generations) and evolution, (which allows successive sequences to be modified over time and to respond to selective pressure).
 
The chemical complexity20 of DNA has convinced most biologists that it almost certainly did not arise spontaneously from the prebiotic soup existing early in earth's history. According to one hypothesis, the simpler RNA molecule may at one time have held dominion21 as the sole transmitter of the genetic code. RNA is also capable of acting22 as an enzyme and may have catalyzed23 important chemical reactions leading eventually to the first cellular24 life.

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1 hieroglyphs d786aaeff706af6b7c986fbf102e0c8a     
n.象形字（如古埃及等所用的）( hieroglyph的名词复数 )；秘密的或另有含意的书写符号
参考例句：
  • Hieroglyphs are carved into the walls of the temple. 寺庙的墙壁上刻着象形文字。 来自辞典例句
  • This paper discusses the fundamental distinctions between the hieroglyphs andforerunner of writing. 英汉象形文字的比较是建立在象形文字具体内涵的基础上。 来自互联网
2 enzyme cPozF     
n.酵素，酶
参考例句：
  • Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
  • An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。
3 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句：
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
4 molecule Y6Tzn     
n.分子，克分子
参考例句：
  • A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈?f婘??妈?成的。
  • This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
5 genetic PgIxp     
adj.遗传的，遗传学的
参考例句：
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
6 transcribed 2f9e3c34adbe5528ff14427d7ed17557     
（用不同的录音手段）转录( transcribe的过去式和过去分词 )； 改编（乐曲）（以适应他种乐器或声部）； 抄写； 用音标标出（声音）
参考例句：
  • He transcribed two paragraphs from the book into his notebook. 他把书中的两段抄在笔记本上。
  • Every telephone conversation will be recorded and transcribed. 所有电话交谈都将被录音并作全文转写。
7 enzymes 7881ad8ce9c83424f7874e70266ed2d8     
n. 酶，酵素
参考例句：
  • It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
  • Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。
8 tantalizing 3gnzn9     
adj.逗人的；惹弄人的；撩人的；煽情的v.逗弄，引诱，折磨( tantalize的现在分词 )
参考例句：
  • This was my first tantalizing glimpse of the islands. 这是我第一眼看见的这些岛屿的动人美景。 来自《简明英汉词典》
  • We have only vague and tantalizing glimpses of his power. 我们只能隐隐约约地领略他的威力，的确有一种可望不可及的感觉。 来自英汉非文学 - 历史
9 primitive vSwz0     
adj.原始的；简单的；n.原(始)人，原始事物
参考例句：
  • It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
  • His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。
10 molecules 187c25e49d45ad10b2f266c1fa7a8d49     
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。
11 molecular mE9xh     
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。
12 mimic PD2xc     
v.模仿，戏弄；n.模仿他人言行的人
参考例句：
  • A parrot can mimic a person's voice.鹦鹉能学人的声音。
  • He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。
13 binding 2yEzWb     
有约束力的，有效的，应遵守的
参考例句：
  • The contract was not signed and has no binding force. 合同没有签署因而没有约束力。
  • Both sides have agreed that the arbitration will be binding. 双方都赞同仲裁具有约束力。
14 resistant 7Wvxh     
adj.(to)抵抗的，有抵抗力的
参考例句：
  • Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
  • They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
15 degradation QxKxL     
n.降级；低落；退化；陵削；降解；衰变
参考例句：
  • There are serious problems of land degradation in some arid zones.在一些干旱地带存在严重的土地退化问题。
  • Gambling is always coupled with degradation.赌博总是与堕落相联系。
16 therapeutic sI8zL     
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。
17 structural itXw5     
adj.构造的，组织的，建筑（用）的
参考例句：
  • The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
18 primates 9536f12c27d026e37c108bd6fc53dbba     
primate的复数
参考例句：
  • Primates are alert, inquisitive animals. 灵长目动物是机灵、好奇的动物。
  • Consciousness or cerebration has been said to have emerged in the evolution of higher primates. 据说意识或思考在较高级灵长类的进化中已出现。
19 alphabetic zz6z0m     
adj.照字母次序的，字母的
参考例句：
  • A generic name for a device that can store and process numeric and alphabetic in formation. 能存储和处理数字与字母信息的设备的总称。 来自辞典例句
  • A coded character set whose character set is an alphabetic character set. 一种编码字符集，它的字符集是一种字母字符集。 来自互联网
20 complexity KO9z3     
n.复杂(性)，复杂的事物
参考例句：
  • Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
  • The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。
21 dominion FmQy1     
n.统治，管辖，支配权；领土，版图
参考例句：
  • Alexander held dominion over a vast area.亚历山大曾统治过辽阔的地域。
  • In the affluent society,the authorities are hardly forced to justify their dominion.在富裕社会里，当局几乎无需证明其统治之合理。
22 acting czRzoc     
n.演戏，行为，假装；adj.代理的，临时的，演出用的
参考例句：
  • Ignore her,she's just acting.别理她，她只是假装的。
  • During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。
23 catalyzed 064244d5918af26ff76d42aea2003d91     
v.催化，促进( catalyze的过去式和过去分词 )
参考例句：
  • Modern technology catalyzed tremendous economic growth in China. 现代技术促成了中国经济的巨大发展。 来自辞典例句
  • The mechanisms of sorption-catalyzed organophosphate hydrolysis are not well understood. 吸附催化水解有机磷的机制还不太清楚。 来自辞典例句
24 cellular aU1yo     
adj.移动的；细胞的，由细胞组成的
参考例句：
  • She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
  • Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

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