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Caltech scientists have created a strain of bacteria that can make small but energy-packed carbon rings that are useful starting materials for creating other chemicals and materials. These rings, which are otherwise particularly difficult to prepare, now can be "brewed" in much the same way as beer.
The bacteria were created by researchers in the lab of Frances Arnold, Caltech's Linus Pauling Professor of Chemical Engineering, Bioengineering and Biochemistry, using directed evolution, a technique Arnold developed in the 1990s. The technique allows scientists to quickly and easily breed bacteria with the traits that they desire. It has previously been used by Arnold's lab to evolve bacteria that create carbon-silicon and carbon-boron bonds, neither of which is found among organisms in the natural world. Using this same technique, they set out to build the tiny carbon rings rarely seen in nature.
"Bacteria can now churn out these versatile, energy-rich organic structures," Arnold says. "With new lab-evolved enzymes, the microbes make precisely configured strained rings that chemists struggle to make."
In a paper published this month in the journal Science, the researchers describe how they have now coaxed Escherichia coli bacteria into creating bicyclobutanes, a group of chemicals that contain four carbon atoms arranged so they form two triangles that share a side. To visualize its shape, imagine a square piece of paper that's lightly creased along a diagonal.
[...] Unlike other carbon rings, such as cyclohexanes and cyclopentanes, bicyclobutanes are rarely found in nature. This could be due to their [inherent] instability or the lack of suitable biological machineries for their assembly. But now, Arnold and her team have shown that bacteria can be genetically reprogrammed to produce bicyclobutanes from simple commercial starting materials. As the E. coli cells go about their bacterial business, they churn out bicyclobutanes. The setup is kind of like putting sugar and letting it ferment into alcohol.
[...] The precision with which the bacterial enzymes do their work also allows the researchers to efficiently make the exact strained rings they want, with a precise configuration and in a single chiral form. Chirality is a property of molecules in which they can be "right-handed" or "left-handed," with each form being the mirror image of the other. It matters because living things are selective about which "handedness" of a molecule they use or produce. For instance, all living things exclusively use the right-handed form of the sugar ribose (the backbone of DNA), and many chiral pharmaceutical chemicals are only effective in one handedness; in the other, they can be toxic.
(Score: 4, Interesting) by c0lo on Tuesday April 10 2018, @01:07PM (5 children)
I do hope the strain they engineered is incapable to live outside a strict set of conditions, because it it escapes in the wild we are very likely to literally see an epidemic of cancer.
Most methylating agents [wikipedia.org] (molecules that can't wait to get rid of a methyl group - i.e. the binding of that group is one of high energy) are carcinogens.
The ionizing radiation (photons with high enough energy - UV and over) are carcinogens.
If a microbe can produce high-energy molecules inside your body, I believe you cam guess what effect those molecules will have.
Now, high chances that the engineered strain can't compete with the others in the wild - the energy they bound in those molecules is an energy they won't use - not a great evolutionary trait to spend energy into something that's not contributing to your survival.
But... what if their organism manages to use those molecules in their energy cycle (e.g. the way ATP is used by almost all organisms alive) and suddenly what was a disadvantage becomes a survive-and-thrive trait - energy for you, poison for others?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by FatPhil on Tuesday April 10 2018, @02:10PM (2 children)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 3, Interesting) by c0lo on Tuesday April 10 2018, @10:09PM (1 child)
Well, yes/maybe, but the liver knows how to deal with it.
However, methylating agents are a different kind of beast from a simple methyl group.
See DNA methylation [wikipedia.org] and you'll get the explanation why those substances willing to get rid of their already existing methyl group will wreak havoc in your body.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by FatPhil on Wednesday April 11 2018, @04:38PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 4, Informative) by Taibhsear on Tuesday April 10 2018, @02:59PM
That's not what they mean by high-energy. It has nothing to do with UV damage to DNA. They mean in the carbon bonds. When molecules have bond angles that are more acute than their preferred state they are considered high energy. Think of taking a stick and bending it. It wants to be relatively straight but can take some bending. When you let go it'll pop back into being straight again. Carbon rings of less than 6 carbon atoms are higher energy. At 4 carbons the bonds are getting really stressed. At 3 carbons per ring the stick is about to snap. The higher energy bonds are WAY more reactive than other bonds and they'll tear up the other molecules in your cells to relieve that stressed state. I'm kind of curious how quickly the e.coli die from making these cyclobutanes.
(Score: 3, Informative) by HiThere on Tuesday April 10 2018, @06:25PM
It's not just a high chance, it's a near certainty. The engineered strain will not be able to compete in the wild. Making those rings is an energetically expensive process.
The only exception I could think of would be if the bacteria used the rings for energy storage, analogous to ATP. If so they might be able to compete in low phosphorus conditions. But they'd need a lot of other machinery to use the stored energy safely (just like ATP needs).
Even then, because those rings are expensive to make, the bacteria are going to want to hold onto them. They would only get released when the bacteria not just died, but decomposed. I really doubt they would make as good a weapon as hydrogen peroxide, which is already in use, and is a lot cheaper to make.
Seriously, I'd consider the bacteria making links to Silicon or Boron to be more threatening...and then not very.
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