News from Space: “Life” Molecules Detected in Space!

SagitariusB2The secret to the creation to life in our universe appears to be seeding – the proper elements in the right mix in the right places to form the right kind of molecules. Only then can these molecules evolve chemically into more and more complex structures, thus following a general pathway toward biology. The pathway for life as we know it starts with carbon, but one which is specific organized and structured.

Recently, a team of astronomers  at the ALMA Observatory reported the discovery of this very element while probing distant galaxies. What they found was not just interstellar carbon, but a form of carbon with a branched structure. The discovery was made in the gaseous-star forming region known as Sagittarius B2 – a giant molecular cloud of gas and dust that is located about 390 light years from the center of the Milky Way.

radio-wave-dishesSimple carbon chains aren’t particularly unusual in the cosmos, but complex carbon is a different matter. It is what the researchers, based at Cornell University and the Max Planck Institute, describe as finding a molecular needle in a cosmic haystack. The actual molecule in question is isopropyl cyanide, and it was discerned thanks to the miracle known as radio astronomy.

Within clouds of interstellar dust and gas, elements find themselves shielded from the harsh radiation of open space and are, thus, free to form into more complex arrangements. These molecules don’t just sit there, but instead move around within their cloud-homes and bump into each other. The result of this activity are radio signals which can be detected light-years away – in this case, by radio telescopes here on Earth.

MaxPlanckIns_radiowavepulseEvery molecule has a different radio signal, so it’s possible to pick apart the contents of interstellar junk by examining a cloud’s frequency spectra. NASA, via the Ames Research Center, even maintains a radio-emission frequency database to aid in the tracking of polycyclic aromatic hydrocarbons, a form of molecule thought to contain much of the universe’s carbon stockpiles.

The branching carbon structure of isopropyle cyanide is of particular interest because it’s thought that this arrangement is a step on the way to the production of amino acids, the building blocks of proteins, and hence organic life. The discovery gives weight to the increasingly popular notion that life, or at least many of the key steps leading toward life, actually occurs off-planet.

alien-worldLife on Earth may have been well on its way while the planet was still just space dust waiting to come together into our rock-home. What’s more, the molecules discovered by the ALMA team probably aren’t alone.  As the authors, led by astronomer Arnaud Belloche, wrote:

[Isopropyle cyanide’s] detection therefore bodes well for the presence in the [interstellar medium] (ISM) of amino acids, for which such side-chain structure is a key characteristic… This detection suggests that branched carbon-chain molecules may be generally abundant in the [interstellar medium].

The discovery follows a general progression in recent years adding more and more life-ingredients to our picture of the ISM. A 2011 study revealed that complex organic matter should be created in large volumes from stars, while a 2012 report study found that conditions within the ISM are uniquely suited to the creation of increasingly complex molecules, “step[s] along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively.”

sugar-in-space-molecules_58724_990x742Also in 2012, astronomers working for ALMA found basic sugar molecules hanging out in the gas cloud around IRAS 16293-2422 – a young star located some 400 light-years from Earth. The particular form, glycoaldehyde, is thought to be a key component of the reaction behind the creation of DNA. Indeed, more and more, the universe is looking less and less like a harsh environment in which life must struggle to emerge, to a life factory.


First Ever Organism with “Alien” DNA

alien-dna-640x353Normal DNA, which is characterized by the double helix and its the four bases that bond it together – known as T, G, A, and C – is at the heart of all living organisms. While permutations and differences exist between species, this basic structure has existed unchanged for billions of years. That is, until now. This past May, researchers announced that they had created the first ever organism with synthetic DNA that has two new bases – X and Y. Mary Shelley and H.G. Wells must be turning over in their graves, as scientists are officially playing God now!

This landmark study, 15 years in the making, was carried out by scientists at the Scripps Research Institute and published in Nature today under the title “A semi-synthetic organism with an expanded genetic alphabet”. In normal DNA, the four bases combine in predictable ways. A always bonds with T, and C always bonds with G, creating a fairly simple “language” of base pairs — ATCGAAATGCC, etc. Combine a few dozen base pairs together in a long strand of DNA and you then have a gene, which tells the organism how to produce a certain protein.

DNA-MicroarrayIf you know the sequence of letters down one strand of the helix, you always know what other letter is. This “complementarity” is the fundamental reason why a DNA helix can be split down the middle, and then have the other half perfectly recreated. In this new study, the Scripps scientists found a method of inserting a new base pair into the DNA of an e. coli bacterium. These two new bases are represented by the letters X and Y, but the actual chemicals are described as “d5SICS” and “dNaM.”

A previous in vitro (test tube) study had shown that these two chemicals were compatible with the enzymes that split and copy DNA. For the purposes of this study, the scientists began by genetically engineering an e. coli bacterium to allow the new chemicals (d5SICS and dNaM) through the cell membrane. Then they inserted a DNA plasmid (a small loop of DNA) that contained a single XY base pair into the bacterium.

dnaheadAs long as the new chemicals were available, the bacterium continued to reproduce normally, copying and passing on the new DNA, alien plasmid and all, and continued to carry on flawlessly for almost a week. For now, the XY base pair does nothing; it just sits there in the DNA, waiting to be copied. In this form, it could be used as biological data storage which, as a new form of biocomputing, could result in hundreds of terabytes of data being stored in a single gram of synthetic, alien DNA. 

Floyd Romesberg, who led the research, has much grander plans:

If you read a book that was written with four letters, you’re not going to be able to tell many interesting stories. If you’re given more letters, you can invent new words, you can find new ways to use those words and you can probably tell more interesting stories.

Now his target is to find a way of getting the alien DNA to actually do something, such as producing amino acids (and thus proteins) that aren’t found in nature. If Romesberg and his colleagues can crack that nut, then it will suddenly become possible to engineer cells that produce proteins that target cancer cells, or special amino acids that help with fluorescent microscopy, or new drugs/gene therapies that do weird and wonderful things.

dna_cancerUltimately it may even be possible to create a wholly synthetic organism with DNA that contains dozens (or hundreds) of different base pairs that can produce an almost infinitely complex library of amino acids and proteins. At that point, we’d basically be rewriting some four billion years of evolution. The organisms and creatures that would arise would be unrecognizable, and be capable of just about anything that a researcher (or mad scientist) could dream up.

In the future, this breakthrough should allow for the creation of highly customized organisms – bacteria, animals, humans – that behave in weird and wonderful ways that mundane four-base DNA would never allow. At the same time, it raises ethical dilemmas and fears that may be well founded. But such is the nature of breakthroughs. The potential for harm and good are always presumably equal when they are firts conceived.