Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Origins of Life

19.06.2002


Were the first macromolecules created on a primitive beach?



In order for life to emerge both peptides and nucleic acids must have appeared under "prebiotic" conditions. Despite numerous efforts, the formation of these macromolecules without the help of modern synthetic reagents has not been achieved in a laboratory. Now for the first time researchers have proposed a mechanism by which the formation of peptides could have occurred under prebiotic conditions. Reporting their findings in the July issue of the SCI journal Polymer International, they describe a molecular engine mechanism which could have taken place on primitive beaches in the Hadean age.

The molecular engine (the primary pump) relies on a reaction cycle made up of several successive steps, fed by amino acids, and fueled by NOx species. French researchers repeatedly cycled through the reaction steps using models of the primitive ocean, and each time peptides were formed, showing that the primary pump works at ambient temperatures and it continuously generates, elongates and complexifies sequential peptides.


Only a few of all the possible peptide sequences were formed, demonstrating that the primary pump should be able to select particular peptide sequences. Further, the primary pump should be able to drive the peptide pool towards homochirality through the amplifcation from a starting small enantiomeric excess.

For the proposed mechanism to work it assumes that there was a buffered ocean, emerged land and a nitrosating atmosphere. The researchers show that the primitive Earth during the Hadean may have satisfied all these requirements.

The Hadean began approximately 4.6 billion years ago with the creation of the Earth and ended 3.8 billion years ago. It was during the Hadean that the Earth surface cooled and solidified. The oldest terrestrial rocks are from this age and their chemical character demonstrates that a stable continental crust existed. Analysis has also shown that huge volumes of liquid water must have been available on the surface of the primitive Earth, and as the moon was already formed this would have tidal properties. According to lead researcher Auguste Commeyras, of the University of Montpellier, "The primary pump could have worked as soon as the pH of the oceans rose to 4-5. We consider it reasonable to postulate that the primitive ocean was initially acidic due to the presence of large amounts of CO2, and that its pH gradually increased to its current level through extraction of alkaline materials from reductive rocks."

The most recent works on the primitive atmosphere of the Earth suggest that its main components were CO2 and N2. Calculations show that sufficient NOx would have been available to supply the primary pump and act as a driving force to the mechanism. "The role of NO in the metabolisms of current living organisms might be a remnant of such a prebiotic chemistry," said Commeyras.

In conclusion Commeyras says, "Our primary pump scenario appears to be the first that is capable of supplying sequential peptides under realistic prebiotic conditions. Maintained out of thermodynamic equilibrium this system had the ability to recycle its reagents and to cause the products to evolve and increase in complexity. The emerging peptides would quickly have begun to act as catalysts, which may have helped the emergence of autoreplicant systems."

Joanna Gibson | alfa

More articles from Life Sciences:

nachricht Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>