* Astronomy

Blobrana · L

RE: Ingredients for life

Blobrana · L

Scientists have discovered that a 3.6-billion-year-old meteorite that fell to Earth in Australia nearly 40 years ago contains two molecules that are key ingredients for genes supporting the idea that the molecules of life could have been brought to primordial Earth from space. Other experiments suggest that simple molecules already on Earth, such as ammonia and methane, could have reacted together to create simple biomolecules. But what Frankel is more interested in is the next step along the road to life: how did these molecules spontaneously assemble themselves into the complicated biochemicals capable of kick-starting life?

One of the leading researchers in protocells is Professor Jack Szostak of the Howard Hughes Medical Institute in Chevy Chase, Maryland.

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Steranes are a class of 4-cyclic compounds derived from steroids or sterols via diagenetic and catagenetic degradation and saturation. They are sometimes used as biomarkers for the presence of eukaryotic cells.

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Blobrana · L

One of the greatest mysteries in science is how life began. Now one group of researchers says diamonds may have been life's best friend.
Scientists have long theorised that life on Earth got going in a primordial soup of precursor chemicals. But nobody knows how these simple amino acids, known to be the building blocks of life, were assembled into complex polymers needed as a platform for genesis.

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Blobrana · L

Scientists have confirmed for the first time that an important component of early genetic material which has been found in meteorite fragments is extraterrestrial in origin, in a paper published on 15 June 2008.
The finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.
The scientists, from Europe and the USA, say that their research, published in the journal Earth and Planetary Science Letters, provides evidence that lifes raw materials came from sources beyond the Earth.

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Blobrana · L

Well over 100 different amino acids have been detected in meteorites, and its probable that they originally formed on the asteroids that spawned these space rocks. Amino acids are the building blocks of living organisms, and quite a bit of research has gone into discovering how they may have formed.
Chief among the possibilities is a hydrothermal process chemical reactions stimulated by heat in the presence of water, a process that occurs on Earth in areas like deep-sea hydrothermal vents. Because asteroids may be heated by radioactive decay, hydrothermal formation may also have occurred on these rocky, sub-planetary bodies.

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Blobrana · L

The National Grid Service in the UK and the TeraGrid in the U.S. have joined forces to help University College London (UCL) scientists shed light on how life on Earth may have originated.
Deep ocean hydrothermal vents have long been suggested as possible sources of biological molecules, such as RNA and DNA, but it was unclear how they could survive the high temperatures and pressures that occur round these vents.
Peter Coveney and colleagues at the UCL Centre for Computational Science have used computer simulation to provide insight into the structure and stability of DNA while inserted into layered minerals. Their results were recently published in the Journal of the American Chemical Society.

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Blobrana · L

Left-handed amino acids

Blobrana · L

RE: Ingredients for life

Blobrana · L

Title: Indigenous amino acids in primitive CR meteorites
Authors: Z.Martins, C.M.O'D.Alexander, G.E.Orzechowska, M.L.Fogel, P.Ehrenfreund
(Version v2)

CR meteorites are among the most primitive meteorites. In this paper, we report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. EET92042, GRA95229 and GRO95577 were analysed for their amino acid content using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatographymass spectrometry (GC-MS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analysed, with total amino acid concentrations ranging from 180 parts-per-million (ppm) to 249 ppm. GRO95577, however, is depleted in amino acids. The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the alpha-amino acids glycine, isovaline, alpha-aminoisobutyric acid (alpha-AIB), and alanine, with delta13C values ranging from +31.6per mil to +50.5per mil. The carbon isotope results together with racemic enantiomeric ratios determined for most amino acids strongly indicate an extraterrestrial origin of these compounds. In addition, the relative abundances of alpha-AIB and beta-alanine in the Antarctic CR meteorites analysed appear to correspond to the degree of aqueous alteration on their respective parent body.

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Blobrana · L

An important discovery has been made with respect to the mystery of handedness in biomolecules. Researchers led by Sandra Pizzarello, a research professor at Arizona State University, found that some of the possible abiotic precursors to the origin of life on Earth have been shown to carry handedness in a larger number than previously thought.
The work is being published in this weeks Proceedings of the National Academy of Sciences (PNAS). The paper is titled, Molecular asymmetry in extraterrestrial chemistry: Insights from a pristine meteorite, and is co-authored by Pizzarello and Yongsong Huang and Marcelo Alexandre, of Brown University.

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