Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

At that star, turn left!

17.10.2002


Our bodies contain proteins that are made of smaller molecules that can be either left- or right-handed, depending upon their structure. Regardless of which hand we use to write, however, all human beings are `left-handed` at the molecular level. Life on Earth uses the left-handed variety and no one knows how this preference crept into living systems. In 2012, ESA`s Rosetta lander will land on a comet to investigate, among other things, if the origin of this preference lies in the stars.



Living cells use tiny organic molecules (called amino acids) to build proteins in the same way as children build things out of Lego bricks. Most amino acids come in two mirror-image varieties, right- and left-handed. The arrangement of the thumb and four fingers on a left hand is the mirror image of the arrangement on the right. In amino acids, the arrangement of the atoms determines whether the molecule is left- or right-handed.

Uwe Meierhenrich, at the University of Bremen, Germany, thinks that the Earth`s early supply of amino acids came from space, carried by comets. He is part of a European team who reproduced the way organic molecules form in space, to try to understand what the Rosetta lander might find on Comet Wirtanen in 2012.


At a laboratory in Leiden, The Netherlands, they lowered the temperature of a chamber to -261°C, pumped out the air, and injected a rarefied mixture of molecules known to exist in space: water, ammonia, and simple carbon molecules. These molecules froze onto artificial dust grains inside the chamber. They then shone an ultraviolet lamp onto the samples, to simulate starlight. "Our aim was to simulate interstellar conditions as accurately as possible. We did not adapt the conditions to produce amino acids," says Meierhenrich.

Using a version of Rosetta`s Cometary Sampling and Composition (COSAC) experiment, they found newly formed right- and left-handed amino acids in equal quantities. Earthly life, however, uses only left-handed amino acids. Experiments during the 1950s showed that adding right-handed amino acids to proteins stopped the proteins from growing. Was Earth supplied with more left-handed amino acids than right-handed ones in the beginning, allowing life to begin? One famous study has suggested this. Meierhenrich says, "The excess (of left-handed amino acids) found in the Murcheson meteorite is really small and some of the analyses are controversial. Rosetta will give us a much clearer picture."

Some scientists think the key to creating an excess of left over right is in the type of ultraviolet light that shines on the amino acids. When ultraviolet starlight strikes dust grains, it can begin to twist - either clockwise or anticlockwise. Depending on the direction in which it is twisting, it destroys one handedness of amino acid more than the other. In 1998, an international group of astronomers discovered large amounts of `twisty` light occurring naturally in the dusty cocoons of some young stars, where planets might be forming. "I think this is the most probable origin of the excesses," says Meierhenrich who is now using a Paris Laboratory where scientists can twist ultraviolet light to recreate these conditions.

We may well find that Rosetta`s findings on Comet Wirtanen reliably indicate that our molecular left-handedness is indeed a legacy of the stars.

Monica Talevi | alfa
Further information:
http://www.esa.int

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>