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A new capillary electrophoresis technique could be much more sensitive to the presence of amino acids on other worlds in our solar system:
A simple chemistry method could vastly enhance how scientists search for signs of life on other planets. The test uses a liquid-based technique known as capillary electrophoresis to separate a mixture of organic molecules into its components. It was designed specifically to analyze for amino acids, the structural building blocks of all life on Earth. The method is 10,000 times more sensitive than current methods employed by spacecraft like NASA's Mars Curiosity rover, according to a new study published in Analytical Chemistry [open, DOI: 10.1021/acs.analchem.6b04338] [DX]. The study was carried out by researchers from NASA's Jet Propulsion Laboratory, Pasadena, California.
One of the key advantages of the authors' new way of using capillary electrophoresis is that the process is relatively simple and easy to automate for liquid samples expected on ocean world missions: it involves combining a liquid sample with a liquid reagent, followed by chemical analysis under conditions determined by the team. By shining a laser across the mixture -- a process known as laser-induced fluorescence detection -- specific molecules can be observed moving at different speeds. They get separated based on how quickly they respond to electric fields. While capillary electrophoresis has been around since the early 1980s, this is the first time it has been tailored specifically to detect extraterrestrial life on an ocean world, said lead author Jessica Creamer, a postdoctoral scholar at JPL.
Now we just need a robotic craft capable of drilling a hole through kilometers of crust in order to reach one of the possible subsurface water oceans on Ceres, Ganymede, Callisto, Europa, Enceladus, Titan, Dione, Titania, Oberon, Triton, Pluto, Eris, etc.
(Score: 2) by butthurt on Monday January 30 2017, @09:21PM
[...] you seem to be skipping several steps in your own conjecture - chlorophyll, heme, etc. are extremely sophisticated molecules [...]
They're just the examples that came to mind of biological molecules that have symmetry.
[...] we're talking about pseudo-organisms that are likely still millions of years away from being able to synthesize their own chemistry [...]
I was talking about alien life of any sort, not necessarily very simple forms.
And just to be completely clear - I would freely concede that some protoorganism *might* find a use for using some amino acid in an opposing pair of chiralities [...]
That's all I was saying (although I wanted to include other chiral molecules besides amino acids). I was unaware that life on Earth, including mammals, does use D-amino acids.
https://en.wikipedia.org/wiki/D-amino_acid [wikipedia.org]
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC18334/ [nih.gov]
To avoid creating a chiral imbalance in the environment, it would have to use *EVERY* amino acid in its makeup in equal quantities. If even one amino acid were used in only one chirality, then the ecosystem would rapidly reflect that imbalance.
I'm not entirely following you. You seem to be supposing life-forms that can interconvert amino acids, but which are unable to change the handedness of those amino acids. However, we can instead suppose that such interconversions could proceed through glycine, which lacks chirality.
https://en.wikipedia.org/wiki/Glycine [wikipedia.org]
There have been a couple of occasions on Earth that come to mind when one organism produced molecules that other organisms were unable to metabolise. When plants began to produce oxygen, the atmosphere became oxidising; eventually life-forms arose that tolerated, and even depended upon, the oxygen. When plants began to produce lignin, at first deposits of the stuff formed (coal), then the deposition lessened because organisms developed the ability to break the lignin down. Similar events might happen on other worlds. Even if they didn't, organic molecules can be degraded into simpler molecules not only by living things, but by light or oxidation.
(Score: 2) by Immerman on Wednesday February 01 2017, @12:40AM
All I'm assuming is you've got a crude self-replicating amino-acd based molecular automata which almost certainly had no ability to synthesize anything, but only to assemble existing environmental components into copies of itself. I am decidedly NOT considering life, as by the time you have that the available chemical ecosystem will have already been completely reworked by a few (hundred?) million years of molecular automata spreading across the planet.
I will concede that after life is established and controlled bio-chemical synthesis has begun, then yes, perhaps it could evolve the ability to use and synthesize the now near-absent alternate chiralities of its component amino acids - it just seems exceedingly unlikely as either one would likely require dramatic mutation, and be useless if not fatal without the other.