米勒-尤里实验
此词条暂由Henry翻译。
The experiment
实验
The Miller–Urey experiment[1] (or Miller experiment)[2] was a chemical experiment that simulated the conditions thought at the time (1952) to be present on the early Earth and tested the chemical origin of life under those conditions. The experiment at the time supported Alexander Oparin's and J. B. S. Haldane's hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors. Considered to be the classic experiment investigating abiogenesis, it was performed in 1952 by Stanley Miller, supervised by Harold Urey at the University of Chicago, and published the following year.[3][4][5]
The Miller–Urey experiment (or Miller experiment) was a chemical experiment that simulated the conditions thought at the time (1952) to be present on the early Earth and tested the chemical origin of life under those conditions. The experiment at the time supported Alexander Oparin's and J. B. S. Haldane's hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors. Considered to be the classic experiment investigating abiogenesis, it was performed in 1952 by Stanley Miller, supervised by Harold Urey at the University of Chicago, and published the following year.
米勒尤里实验 Miller–Urey experiment(或称 Miller 实验)是一个化学实验,模拟了当时(1952年)认为存在于早期地球上的条件,并在这些条件下测试了生命的化学起源。当时的实验支持了亚历山大·奥帕林和J·B·s·霍尔丹的假设,即原始地球上假定的条件有利于化学反应,即从简单的无机前体合成更复杂的有机化合物。它被认为是研究自然发生的经典实验,1952年由斯坦利·米勒完成,由芝加哥大学的哈罗德·尤里监督,并于次年出版。
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different amino acids produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in the genetic code.[6] More recent evidence suggests that Earth's original atmosphere might have had a composition different from the gas used in the Miller experiment, but prebiotic experiments continue to produce racemic mixtures of simple-to-complex compounds under varying conditions.[7]
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different amino acids produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in the genetic code.
2007年米勒去世后,科学家们检查了从原始实验中保存下来的密封小瓶,发现实际上米勒原始实验中产生了超过20种不同的氨基酸。这大大超过了米勒最初报道的数量,也超过了遗传密码中自然产生的20种。
Experiment实验
Descriptive video of the experiment
实验的描述性视频
The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of water. The water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.
The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of water. The water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.
实验用水(H2O)、甲烷(CH4)、氨(NH3)和氢(H 2)。所有的化学物质都被密封在一个5升的无菌玻璃瓶里,这个玻璃瓶连接着一个500毫升的半满水的烧瓶。将小烧瓶中的水加热以诱导蒸发,使水蒸气进入大烧瓶。在电极之间连续地点燃电火花,以模拟水蒸气和气体混合物中的闪电,然后再次冷却模拟的大气,使水凝结并滴入装置底部的U形阱中。
After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.[3] The boiling flask was then removed, and mercuric chloride was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid, and evaporated to remove impurities. Using paper chromatography, Miller identified five amino acids present in the solution: glycine, α-alanine and β-alanine were positively identified, while aspartic acid and α-aminobutyric acid (AABA) were less certain, due to the spots being faint.[3]
After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.
一天之后,在诱捕器上收集到的溶液变成了粉红色,连续操作一周之后,溶液变成了深红色和混浊的液体。
In a 1996 interview, Stanley Miller recollected his lifelong experiments following his original work and stated: "Just turning on the spark in a basic pre-biotic experiment will yield 11 out of 20 amino acids."[8]
The original experiment remained in 2017 under the care of Miller and Urey's former student Jeffrey Bada, a professor at the UCSD, Scripps Institution of Oceanography. , the apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science.
最初的实验在2017年由 Miller 和 Urey以前的学生 Jeffrey Bada 负责,他是加州大学圣地亚哥分校斯克里普斯海洋研究所的教授。实验仪器在丹佛自然科学博物馆展出。
The original experiment remained in 2017 under the care of Miller and Urey's former student Jeffrey Bada, a professor at the UCSD, Scripps Institution of Oceanography.[9] 模板:Asof, the apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science.[10]模板:Update after
One-step reactions among the mixture components can produce hydrogen cyanide (HCN), formaldehyde (CH2O), and other active intermediate compounds (acetylene, cyanoacetylene, etc.):
混合组分之间的一步反应可以生成氰化氢、甲醛和其他活性中间体化合物(乙炔、氰乙炔等):
Chemistry of experiment实验化学
One-step reactions among the mixture components can produce hydrogen cyanide (HCN), formaldehyde (CH2O),[11][12] and other active intermediate compounds (acetylene, cyanoacetylene, etc.):[citation needed]
CO2 → CO + [O] (atomic oxygen)
CO < sub > 2 & rarr; CO + [ o ](原子氧)
CH4 + 2[O] → CH2O + H2O
CH < sub > 4 + 2[ o ] & rarr; CH < sub > 2 o + h < sub > 2 o
- CO2 → CO + [O] (atomic oxygen)
CO + NH3 → HCN + H2O
CO + NH < sub > 3 & rarr; HCN + h < sub > 2 o
- CH4 + 2[O] → CH2O + H2O
CH4 + NH3 → HCN + 3H2 (BMA process)
CH4 + NH3 → HCN + 3H2 (BMA process)
- CO + NH3 → HCN + H2O
- CH4 + NH3 → HCN + 3H2 (BMA process)
The formaldehyde, ammonia, and HCN then react by Strecker synthesis to form amino acids and other biomolecules:
然后,甲醛、氨和 HCN 通过 Strecker合成反应生成氨基酸和其他生物分子:
The formaldehyde, ammonia, and HCN then react by Strecker synthesis to form amino acids and other biomolecules:
CH2O + HCN + NH3 → NH2-CH2-CN + H2O
CH2O + HCN + NH3 → NH2-CH2-CN + H2O
NH2-CH2-CN + 2H2O → NH3 + NH2-CH2-COOH (glycine)
NH2-CH2-CN + 2H2O → NH3 + NH2-CH2-COOH (glycine)
- CH2O + HCN + NH3 → NH2-CH2-CN + H2O
- NH2-CH2-CN + 2H2O → NH3 + NH2-CH2-COOH (glycine)
Furthermore, water and formaldehyde can react, via Butlerov's reaction to produce various sugars like ribose.
此外,水和甲醛可以反应,通过巴特列罗夫的反应产生各种糖,如核糖。
Furthermore, water and formaldehyde can react, via Butlerov's reaction to produce various sugars like ribose.
The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.
实验表明,在添加能量的情况下,气体可以形成简单的有机化合物,由蛋白质和其他大分子组成 。
The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.
This experiment inspired many others. In 1961, Joan Oró found that the nucleotide base adenine could be made from hydrogen cyanide (HCN) and ammonia in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.
这个实验启发了许多其他人。1961年,Joan oró 发现,在水溶液中,由氰化氢和氨制成的核苷酸碱基腺嘌呤。他的实验产生了大量的腺嘌呤,其分子由5个HCN分子组成。
Other experiments其他实验
Also, many amino acids are formed from HCN and ammonia under these conditions.
此外,许多氨基酸是由 HCN 和氨在这些条件下形成。
This experiment inspired many others. In 1961, Joan Oró found that the nucleotide base adenine could be made from hydrogen cyanide (HCN) and ammonia in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.[13] 这个实验启发了许多其他人。1961年,Joan Oró发现核苷酸碱基腺嘌呤可以由氰化氢(HCN)和氨在水溶液中制成。他的实验产生了大量腺嘌呤,腺嘌呤分子由5个HCN分子组成。
Experiments conducted later showed that the other RNA and DNA nucleobases could be obtained through simulated prebiotic chemistry with a reducing atmosphere.
后来进行的实验表明,其他 RNA 和 DNA 碱基可以通过模拟生命前化学在还原气氛下获得。
Also, many amino acids are formed from HCN and ammonia under these conditions.[14] 此外,在这些条件下,许多氨基酸由HCN和氨形成 Experiments conducted later showed that the other RNA and DNA nucleobases could be obtained through simulated prebiotic chemistry with a reducing atmosphere.[15] 随后进行的实验表明,另一种 RNA和DNA碱基可以通过模拟益生元化学和还原气氛获得 There also had been similar electric discharge experiments related to the origin of life contemporaneous with Miller–Urey. An article in The New York Times (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at The Ohio State University, before the Miller Science paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis." The article describes other early earth experiments being done by MacNevin. It is not clear if he ever published any of these results in the primary scientific literature.
与米勒-尤里同时期也有过类似的与生命起源有关的放电实验。《纽约时报》(1953年3月8日:E9)上的一篇题为“回顾20亿年”的文章描述了1953年5月米勒科学论文发表之前,俄亥俄州立大学的沃尔曼(William)M.MacNevin的工作。麦克尼文通过甲烷和水蒸气产生10万伏特的火花,产生“树脂固体”,这些“树脂固体”过于复杂,无法分析。目前还不清楚他是否曾在原始科学文献中发表过这些结果。(不清楚是因为学者们已经对此进行了研究,不知何故无法判断,还是仅仅因为阅读了《纽约时报》的文章,维基百科的撰稿人就不清楚了?)
There also had been similar electric discharge experiments related to the origin of life contemporaneous with Miller–Urey. An article in The New York Times (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at The Ohio State University, before the Miller Science paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis." The article describes other early earth experiments being done by MacNevin. It is not clear if he ever published any of these results in the primary scientific literature.[16]
K. A. Wilde submitted a paper to Science on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953. Wilde used voltages up to only 600 V on a binary mixture of carbon dioxide (CO2) and water in a flow system. He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.
1952年12月15日,K·A· 王尔德向《科学》杂志提交了一篇论文,之后米勒又于1953年2月10日向同一杂志提交了他的论文。王尔德的论文发表于1953年7月10日。王尔德使用的电压只有600v 对二氧化碳(CO2)和流动系统中的水的二元混合物。他观察到只有少量的二氧化碳减少为一氧化碳,没有其他重要的还原产物或新形成的碳化合物。
Other researchers were studying UV-photolysis of water vapor with carbon monoxide. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.
其他研究人员正在研究水蒸气与一氧化碳的紫外光解反应。他们发现各种醇类、醛类和有机酸都是在反应混合物中合成的。
K. A. Wilde submitted a paper to Science on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953.[17] Wilde used voltages up to only 600 V on a binary mixture of carbon dioxide (CO2) and water in a flow system. He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.
Other researchers were studying UV-photolysis of water vapor with carbon monoxide. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.[18]
More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at Scripps Institution of Oceanography of the University of California, San Diego were similar to those performed by Miller. However, Bada noted that in current models of early Earth conditions, carbon dioxide and nitrogen (N2) create nitrites, which destroy amino acids as fast as they form. When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen.[19]
Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, hydrogen sulfide (H2S), and sulfur dioxide (SO2) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D enantiomers) and experiments since have shown that "in the lab the two versions are equally likely to appear"; however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.
一些证据表明,地球原始大气层中还原分子的含量可能比 Miller-Urey 实验时所认为的要少。有大量的证据表明,40亿年前的大型火山爆发会向大气中释放二氧化碳、氮、硫化氢(H2S)和二氧化硫(SO2)。除了最初的 Miller-Urey 实验中使用的气体之外,使用这些气体的实验已经产生了更多样化的分子。该实验创造了一种外消旋体(包含L和D对映体)的混合物,此后的实验表明,“在实验室中,这两种化合物出现的可能性相等” ; 然而,在自然界中,l 氨基酸占主导地位。后来的实验证实了不成比例的L或D取向对映异构体是可能的。
Earth's early atmosphere地球最早的大气层
Originally it was thought that the primitive secondary atmosphere contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO2 with perhaps some CO and the nitrogen mostly N2. In practice gas mixtures containing CO, CO2, N2, etc. give much the same products as those containing CH4 and NH3 so long as there is no O2. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, hydroxyacids, purines, pyrimidines, and sugars have been made in variants of the Miller experiment.
起初人们认为原始的二次大气主要含有氨和甲烷。但是,大气中的大部分碳可能是 CO2 ,也可能是一些 CO 和氮大部分是N2 。在实际应用中,含有 CO、 CO2 、 N2 等的混合气体。只要没有O 2 ,就可以给出与含 CH4和 NH3 相同的产品。氢原子主要来自水蒸气。事实上,为了在原始土壤条件下生成芳香族氨基酸,必须使用较少的富氢气体混合物。大多数天然氨基酸、羟基酸、嘌呤、嘧啶和糖都是米勒实验的变体。
Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, hydrogen sulfide (H2S), and sulfur dioxide (SO2) into the atmosphere.[20] Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D enantiomers) and experiments since have shown that "in the lab the two versions are equally likely to appear";[21] however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.[22]
More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature. One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.
最近的研究结果可能会质疑这些结论。滑铁卢大学和科罗拉多大学在2005年进行了模拟,结果表明地球早期大气中可能含有高达40%的氢,这意味着有利于形成益生元有机分子的环境更加有利。氢从地球大气层逃逸到太空的速度可能只有先前根据对高层大气温度的修正估计所相信的速率的百分之一。作者之一欧文·图恩指出:“在这个新的场景中,有机物可以在早期大气中高效地产生,这让我们回到海洋中富含有机物的汤的概念。。。我认为这项研究使米勒和其他人的实验再次具有相关性。“利用早期地球的球粒陨石模型进行放气计算,补充了滑铁卢/科罗拉多的结果,重新确立了米勒-乌雷实验的重要性 Originally it was thought that the primitive secondary atmosphere contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO2 with perhaps some CO and the nitrogen mostly N2. In practice gas mixtures containing CO, CO2, N2, etc. give much the same products as those containing CH4 and NH3 so long as there is no O2. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, hydroxyacids, purines, pyrimidines, and sugars have been made in variants of the Miller experiment.[7][23]
In contrast to the general notion of early earth's reducing atmosphere, researchers at the Rensselaer Polytechnic Institute in New York reported the possibility of oxygen available around 4.3 billion years ago. Their study reported in 2011 on the assessment of Hadean zircons from the earth's interior (magma) indicated the presence of oxygen traces similar to modern-day lavas. This study suggests that oxygen could have been released in the earth's atmosphere earlier than generally believed.
与早期地球还原大气层的普遍观点不同,纽约伦斯勒理工学院的研究人员在43亿年前报告了氧气的可能性。他们在2011年报告了对来自地球内部(岩浆)的哈迪恩锆石的评估研究,研究表明存在类似于现代熔岩的氧气痕迹。这项研究表明,氧气在地球大气中释放的时间可能比人们通常认为的要早。
More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature.[24] One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.[25]
In contrast to the general notion of early earth's reducing atmosphere, researchers at the Rensselaer Polytechnic Institute in New York reported the possibility of oxygen available around 4.3 billion years ago. Their study reported in 2011 on the assessment of Hadean zircons from the earth's interior (magma) indicated the presence of oxygen traces similar to modern-day lavas.[26] This study suggests that oxygen could have been released in the earth's atmosphere earlier than generally believed.[27]
Conditions similar to those of the Miller–Urey experiments are present in other regions of the solar system, often substituting ultraviolet light for lightning as the energy source for chemical reactions. The Murchison meteorite that fell near Murchison, Victoria, Australia in 1969 was found to contain over 90 different amino acids, nineteen of which are found in Earth life. Comets and other icy outer-solar-system bodies are thought to contain large amounts of complex carbon compounds (such as tholins) formed by these processes, darkening surfaces of these bodies. The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed. This has been used to infer an origin of life outside of Earth: the panspermia hypothesis.
类似 Miller-Urey 实验的条件在太阳系的其他区域也存在,常常以紫外线代替闪电作为化学反应的能源。1969年落在默奇森河附近的默奇森陨石被发现含有超过90种不同的氨基酸,其中十九种存在于地球生命中。彗星和其他太阳系外围冰冷的天体被认为含有大量复杂的碳化合物(例如塞林) ,这些碳化合物是由这些天体的暗化表面形成的。早期的地球被彗星大量撞击,可能提供了大量复杂的有机分子以及它们贡献的水和其他挥发物。这被用来推断地球以外生命的起源: 胚种说。
Extraterrestrial sources外星源
Conditions similar to those of the Miller–Urey experiments are present in other regions of the solar system, often substituting ultraviolet light for lightning as the energy source for chemical reactions.[28][29][30] The Murchison meteorite that fell near Murchison, Victoria, Australia in 1969 was found to contain over 90 different amino acids, nineteen of which are found in Earth life. Comets and other icy outer-solar-system bodies are thought to contain large amounts of complex carbon compounds (such as tholins) formed by these processes, darkening surfaces of these bodies.[31] The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed.[32] This has been used to infer an origin of life outside of Earth: the panspermia hypothesis.
In recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.
近年来,人们对“老”基因中“老”区域的产物的氨基酸组成进行了研究,“老”基因被定义为来自几个相距甚远的物种的生物体所共有的氨基酸组成,这些物种被认为在所有现存物种中只共享最后共同祖先。这些研究发现,这些区域的产物富含那些在 Miller-Urey 实验中也最容易产生的氨基酸。这表明,最初的遗传密码是基于比现在更少的氨基酸-只有那些在益生元性质-比目前的。
Jeffrey Bada, himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.
杰弗里·巴达(Jeffrey Bada)是米勒的学生,他在2007年米勒去世时继承了这项实验的原始设备。根据最初实验中的密封小瓶,科学家们已经能够证明,虽然米勒成功了,但在现有设备的情况下,米勒始终无法发现实验成功的全部程度。后来的研究人员已经能够分离出更多不同的氨基酸,总共25种。Bada估计,更精确的测量可以很容易地在非常低的浓度下提取出30或40种氨基酸,但是研究人员已经停止了这项测试。考虑到所有已知生命只使用20种不同的氨基酸,米勒的实验因此在从较简单的化学物质合成复杂有机分子方面取得了显著成功。
In recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.[33]
In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of Charles Darwin's envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of volcanic eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using high-performance liquid chromatography and mass spectrometry, the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 amines and many hydroxylated molecules, which could have been formed by hydroxyl radicals produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of carbonyl sulfide there could have helped these molecules form peptides.
2008年,一组科学家检查了米勒20世纪50年代早期实验遗留下来的11个小瓶。除了经典的实验(让人想起查尔斯·达尔文设想的“温暖的小池塘”)外,米勒还进行了更多的实验,其中一个实验的条件与火山爆发时相似。这个实验有一个喷嘴在火花放电处喷射蒸汽。通过使用高效液相色谱和质谱,研究小组发现了比米勒更多的有机分子。他们发现,类似火山的实验产生了最多的有机分子,22个氨基酸,5个胺和许多羟基化分子,这些分子可能是由通电蒸汽产生的羟基自由基形成的。研究小组认为,火山岛系统以这种方式富含有机分子,而羰基硫化物的存在可能有助于这些分子形成肽。 Jeffrey Bada, himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.[6]
The main problem of theories based around amino acids is the difficulty in obtaining spontaneous formation of peptides. Since John Desmond Bernal's suggestion that clay surfaces could have played a role in abiogenesis, scientific efforts have been dedicated to investigating clay-mediated peptide bond formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators suggested that peptides could form at the interlayers of layered double hydroxides such as green rust in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a ribosome-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.
以氨基酸为基础的理论的主要问题是很难获得肽的自发形成。自从约翰·德斯蒙德·伯纳尔提出粘土表面可能在自然发生中起作用以来,科学家致力于研究粘土介导的肽键的形成,但成效有限。形成的肽保护过度,没有遗传或新陈代谢的证据。2017年12月,Erastova和他的合作者开发的一个理论模型表明,在早期的地球条件下,多肽可以在层状双氢氧化物的中间层形成,例如绿锈。根据该模型,插层材料的干燥应提供能量和以核糖体样的方式形成肽键所需的共排列,而再湿润应允许活化新形成的肽和重新填充层与新的氨基酸。这一机制有望在15-20次洗涤过程中形成12 + 氨基酸长肽。研究人员还观察到对不同氨基酸的吸附偏好略有不同,并假定,如果与混合氨基酸的稀释溶液相结合,这种偏好可能导致排序。
In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of Charles Darwin's envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of volcanic eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using high-performance liquid chromatography and mass spectrometry, the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 amines and many hydroxylated molecules, which could have been formed by hydroxyl radicals produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of carbonyl sulfide there could have helped these molecules form peptides.[34][35]
In October 2018, researchers at McMaster University on behalf of the Origins Institute announced the development of a new technology, called a Planet Simulator, to help study the origin of life on planet Earth and beyond.
2018年10月,麦马士达大学的研究人员代表起源研究所宣布了一项名为行星模拟器的新技术的发展,以帮助研究行星地球及其他地方的生命起源。
The main problem of theories based around amino acids is the difficulty in obtaining spontaneous formation of peptides. Since John Desmond Bernal's suggestion that clay surfaces could have played a role in abiogenesis[36], scientific efforts have been dedicated to investigating clay-mediated peptide bond formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators [37][38] suggested that peptides could form at the interlayers of layered double hydroxides such as green rust in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a ribosome-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.
In October 2018, researchers at McMaster University on behalf of the Origins Institute announced the development of a new technology, called a Planet Simulator, to help study the origin of life on planet Earth and beyond.[39][40][41][42]
Amino acids identified氨基酸鉴定
Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as published by Miller in 1953, and the 2010 re-analysis of vials from the H2S-rich spark discharge experiment.
下面是由 Miller 在1953年发表的1952年“经典”实验中产生和鉴定的氨基酸表,以及2010年对H2S高密度火花放电实验中小瓶的重新分析。
Amino acid | 氨基酸
|
---|
| 模板:Na
| style="background:#9F9;vertical-align:middle;text-align:center;" class="table-yes"|Yes
|}
References参考
- ↑ Hill HG, Nuth JA (2003). "The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems". Astrobiology. 3 (2): 291–304. Bibcode:2003AsBio...3..291H. doi:10.1089/153110703769016389. PMID 14577878.
- ↑ Balm SP; Hare J.P.; Kroto HW (1991). "The analysis of comet mass spectrometric data". Space Science Reviews. 56 (1–2): 185–9. Bibcode:1991SSRv...56..185B. doi:10.1007/BF00178408.
- ↑ 3.0 3.1 3.2 3.3 Miller, Stanley L. (1953). "Production of Amino Acids Under Possible Primitive Earth Conditions" (PDF). Science. 117 (3046): 528–9. Bibcode:1953Sci...117..528M. doi:10.1126/science.117.3046.528. PMID 13056598. Archived from the original (PDF) on 2012-03-17. Retrieved 2011-01-17.
- ↑ Miller, Stanley L.; Harold C. Urey (1959). "Organic Compound Synthesis on the Primitive Earth". Science. 130 (3370): 245–51. Bibcode:1959Sci...130..245M. doi:10.1126/science.130.3370.245. PMID 13668555. Miller states that he made "A more complete analysis of the products" in the 1953 experiment, listing additional results.
- ↑ A. Lazcano; J. L. Bada (2004). "The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry". Origins of Life and Evolution of Biospheres. 33 (3): 235–242. Bibcode:2003OLEB...33..235L. doi:10.1023/A:1024807125069. PMID 14515862.
- ↑ 6.0 6.1 "The Spark of Life". BBC Four. 26 August 2009. Archived from the original on 2010-11-13. TV Documentary.
{{cite web}}
: CS1 maint: postscript (link) - ↑ 7.0 7.1 Bada, Jeffrey L. (2013). "New insights into prebiotic chemistry from Stanley Miller's spark discharge experiments". Chemical Society Reviews. 42 (5): 2186–96. doi:10.1039/c3cs35433d. PMID 23340907.
- ↑ "Exobiology: An Interview with Stanley L. Miller". Accessexcellence.org. Archived from the original on May 18, 2008. Retrieved 2009-08-20.
- ↑ Dreifus, Claudia (2010-05-17). "A Conversation With Jeffrey L. Bada: A Marine Chemist Studies How Life Began". nytimes.com. Archived from the original on 2017-01-18.
- ↑ "Astrobiology Collection: Miller-Urey Apparatus". Denver Museum of Nature & Science. Archived from the original on 2013-05-24.
- ↑ https://www.webcitation.org/query?url=http://www.geocities.com/capecanaveral/lab/2948/orgel.html&date=2009-10-25+16:53:26 Origin of Life on Earth by Leslie E. Orgel
- ↑ Council, National Research; Studies, Division on Earth Life; Technology, Board on Chemical Sciences and; Sciences, Division on Engineering Physical; Board, Space Studies; System, Task Group on Organic Environments in the Solar (2007). Read "Exploring Organic Environments in the Solar System" at NAP.edu. doi:10.17226/11860. ISBN 978-0-309-10235-3. Archived from the original on 2009-06-21. https://web.archive.org/web/20090621053626/http://books.nap.edu/openbook.php?record_id=11860&page=85. Retrieved 2008-10-25. Exploring Organic Environments in the Solar System (2007)
- ↑ Oró J, Kimball AP (August 1961). "Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide". Archives of Biochemistry and Biophysics. 94 (2): 217–27. doi:10.1016/0003-9861(61)90033-9. PMID 13731263.
- ↑ Oró J, Kamat SS (April 1961). "Amino-acid synthesis from hydrogen cyanide under possible primitive earth conditions". Nature. 190 (4774): 442–3. Bibcode:1961Natur.190..442O. doi:10.1038/190442a0. PMID 13731262.
- ↑ Oró J (1967). Fox SW. ed. Origins of Prebiological Systems and of Their Molecular Matrices. New York Academic Press. pp. 137.
- ↑ Krehl, Peter O. K. (2009). History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference. Springer-Verlag. pp. 603.
- ↑ Wilde, Kenneth A.; Zwolinski, Bruno J.; Parlin, Ransom B. (July 1953). "The Reaction Occurring in CO2, 2O Mixtures in a High-Frequency Electric Arc". Science. 118 (3054): 43–44. Bibcode:1953Sci...118...43W. doi:10.1126/science.118.3054.43-a. PMID 13076175.
- ↑ Synthesis of organic compounds from carbon monoxide and water by UV photolysis Origins of Life. December 1978, Volume 9, Issue 2, pp 93-101 其他研究人员正在研究水蒸气与一氧化碳的紫外线-光解。他们发现在反应混合物中可以合成各种醇、醛和有机酸 More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at Scripps Institution of Oceanography of the University of California, San Diego were similar to those performed by Miller. However, Bada noted that in current models of early Earth conditions, carbon dioxide and nitrogen (N2) create nitrites, which destroy amino acids as fast as they form. When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen. 米勒的研究生之一、化学家杰弗里·巴达和加州大学圣地亚哥斯克里普斯海洋学研究所的吉姆·克里夫斯最近的实验与米勒的实验相似。然而,Bada指出,在目前的早期地球条件模型中,二氧化碳和氮(N2)会产生亚硝酸盐,亚硝酸盐在氨基酸形成的同时也会被破坏。
External links外部链接
- A simulation of the Miller–Urey Experiment along with a video Interview with Stanley Miller by Scott Ellis from CalSpace (UCSD)
- Cairns-Smith, A.G. (1966). "The origin of life and the nature of the primitive gene". Journal of Theoretical Biology. 10 (1): 53–88. doi:10.1016/0022-5193(66)90178-0. PMID 5964688.
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