Featured Research

from universities, journals, and other organizations

'Lost' Miller-Urey Experiment Created More Of Life's Building Blocks

Date:
October 17, 2008
Source:
Indiana University
Summary:
A classic experiment proving amino acids are created when inorganic molecules are exposed to electricity isn't the whole story, it turns out. The 1953 Miller-Urey Synthesis had two sibling studies, neither of which was published. Vials containing the products from those experiments were recently recovered and reanalyzed using modern technology. The results are reported in this week's Science.

The apparatus used for Miller's "second," initially unpublished experiment. Boiled water (1) creates airflow, driving steam and gases through a spark (2). A tapering of the glass apparatus (inlay) creates a spigot effect, increasing air flow. A cooling condenser (3) turns some steam back into liquid water, which drips down into the trap (4), where chemical products also settle.
Credit: Ned Shaw, Indiana University

A classic experiment proving amino acids are created when inorganic molecules are exposed to electricity isn't the whole story, it turns out. The 1953 Miller-Urey Synthesis had two sibling studies, neither of which was published. Vials containing the products from those experiments were recently recovered and reanalyzed using modern technology. The results are reported in this week's Science.

One of the unpublished experiments by American chemist Stanley Miller (under his University of Chicago mentor, Nobelist Harold Urey) actually produced a wider variety of organic molecules than the experiment that made Miller famous. The difference between the two experiments is small -- the unpublished experiment used a tapering glass "aspirator" that simply increased air flow through a hollow, air-tight glass device. Increased air flow creates a more dynamic reaction vessel, or "vapor-rich volcanic" conditions, according to the present report's authors.

"The apparatus Stanley Miller paid the least attention to gave the most exciting results," said Adam Johnson, lead author of the Science report. "We suspect part of the reason for this was that he did not have the analytical tools we have today, so he would have missed a lot."

Johnson is a doctoral student in IU Bloomington's Biochemistry Program. His advisor is biogeochemist Lisa Pratt, professor of geological sciences and the director of NASA's Indiana-Princeton-Tennessee Astrobiology Institute.

In his May 15, 1953, article in Science, "A Production of Amino Acids Under Possible Primitive Earth Conditions," Miller identified just five amino acids: aspartic acid, glycine, alpha-amino-butyric acid, and two versions of alanine. Aspartic acid, glycine and alanine are common constituents of natural proteins. Miller relied on a blotting technique to identify the organic molecules he'd created -- primitive laboratory conditions by today's standards. In a 1955 Journal of the American Chemical Society paper, Miller identified other compounds, such as carboxylic and hydroxy acids. But he would not have been able to identify anything present at very low levels.

Johnson, Scripps Institution of Oceanography marine chemist Jeffrey Bada (the present Science paper's principal investigator), National Autonomous University of Mexico biologist Antonio Lazcano, Carnegie Institution of Washington chemist James Cleaves, and NASA Goddard Space Flight Center astrobiologists Jason Dworkin and Daniel Glavin examined vials left over from Miller's experiments of the early 1950s. Vials associated with the original, published experiment contained far more organic molecules than Stanley Miller realized -- 14 amino acids and five amines. The 11 vials scientists recovered from the unpublished aspirator experiment, however, produced 22 amino acids and the same five amines at yields comparable to the original experiment.

"We believed there was more to be learned from Miller's original experiment," Bada said. "We found that in comparison to his design everyone is familiar with from textbooks, the volcanic apparatus produces a wider variety of compounds."

Johnson added, "Many of these other amino acids have hydroxyl groups attached to them, meaning they'd be more reactive and more likely to create totally new molecules, given enough time."

The results of the revisited experiment delight but also perplex.

What is driving the second experiment's molecular diversity? And why didn't Miller publish the results of the second experiment?

A possible answer to the first question may be the increased flow rate itself, Johnson explained. "Removing newly formed molecules from the spark by increasing flow rate seems crucial," he said. "It's possible the jet of steam pushes newly synthesized molecules out of the spark discharge before additional reactions turn them into something less interesting. Another thought is that simply having more water present in the reaction allows a wider variety of reactions to occur."

An answer to the second question is relegated to speculation -- Miller, still a hero to many scientists, succumbed to a weak heart in 2007. Johnson says he and Bada suspect Miller wasn't impressed with the experiment two's results, instead opting to report the results of a simpler experiment to the editors at Science.

Miller's third, also unpublished, experiment used an apparatus that had an aspirator but used a "silent" discharge. This third device appears to have produced a lower diversity of organic molecules.

Research on early planetary geochemistry and the origins of life isn't limited to Earth studies. As humans explore the Solar System, investigations of past or present extra-terrestrial life are inevitable. Recent speculations have centered on Mars, whose polar areas are now known to possess water ice, but other candidates include Jupiter's moon Europa and Saturn's moon Enceladus, both of which are covered in water ice. The NASA Astrobiology Institute, which supports these investigations, has taken a keen interest in the revisiting of the Miller-Urey Synthesis.

"This research is both a link to the experimental foundations of astrobiology as well as an exciting result leading toward greater understanding of how life might have arisen on Earth," said Carl Pilcher, director of the NASA Astrobiology Institute, headquartered at NASA Ames Research Center in Mountain View, Calif.

Henderson Cleaves (Carnegie Institution for Science) also contributed to the report. It was funded with grants from the NASA Astrobiology Institute, the Marine Biological Laboratory in Woods Hole, Mass., and Mexico's El Consejo Nacional de Ciencia y Tecnologia.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Adam P. Johnson, H. James Cleaves, Jason P. Dworkin, Daniel P. Glavin, Antonio Lazcano, and Jeffrey L. Bada. The Miller Volcanic Spark Discharge Experiment. Science, Vol. 322, Issue 5900

Cite This Page:

Indiana University. "'Lost' Miller-Urey Experiment Created More Of Life's Building Blocks." ScienceDaily. ScienceDaily, 17 October 2008. <www.sciencedaily.com/releases/2008/10/081016141411.htm>.
Indiana University. (2008, October 17). 'Lost' Miller-Urey Experiment Created More Of Life's Building Blocks. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2008/10/081016141411.htm
Indiana University. "'Lost' Miller-Urey Experiment Created More Of Life's Building Blocks." ScienceDaily. www.sciencedaily.com/releases/2008/10/081016141411.htm (accessed October 21, 2014).

Share This



More Fossils & Ruins News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Turns Out Jack The Ripper's True Identity Is Still Unknown

Turns Out Jack The Ripper's True Identity Is Still Unknown

Newsy (Oct. 20, 2014) After testing DNA from a shawl found near one of Jack the Ripper's victims, a scientist said he'd identified the killer. New reports refute the claim. Video provided by Newsy
Powered by NewsLook.com
Fish Fossil Shows First-Ever Sex Was Done Side By Side

Fish Fossil Shows First-Ever Sex Was Done Side By Side

Newsy (Oct. 19, 2014) A 380-million-year-old fish may be the first creature to have copulative sex - and it was side by side with arms linked, like square dancers. Video provided by Newsy
Powered by NewsLook.com
As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

Newsy (Oct. 19, 2014) With Sweden on the look-out for a suspected Russian sub, a lot of people are talking about the Cold War, but is it an apt comparison? Video provided by Newsy
Powered by NewsLook.com
So, Kangaroos Didn't Always Hop

So, Kangaroos Didn't Always Hop

Newsy (Oct. 16, 2014) Researchers believe an extinct kangaroo species weighed 500 pounds or more and couldn't hop. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins