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Mirror bacteria research poses significant risks, scientists warn

the-scientist.com

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Re: Mirror bacteria research poses significant risks, scientists warn

#161

Post by danwills »

throw310822 wrote: post #155
throwup238 wrote: post #153

Earlier quoted context omitted.

How would we test that the mirror antibiotics actually work without developing mirror organisms and exposing ourselves to the associated risks? They aren’t going to be mirror copies of terrestrial organisms, there’s no guarantee that mirror copies of our antibiotics will work (AFAIK it’s actually very unlikely). Protein binding sites change when mirrored because it’s not just mirror image but a change in how the prot…

> Protein binding sites change when mirrored because it’s not just mirror image but a change in how the proteins twist when folding, which is why most of them are sensitive to chirality Wouldn't this pretty much rule out the synthetic creation of mirror bacteria? We should not just be able to rewrite a simple existing lifeform in mirrored version; we should recode all its proteins from scratch so that they keep their…

I think the folding/etc would all be mirrored as well if all the components were on mirror-chirality and the overall molecular-kinetic behavior of the result would in-theory be the same when zoomed-out too (assuming it doesn't encounter too many normal-chirality molecules I guess - would be just as dangerous to them as mirror-chirality is to us).

This should mean that if the DNA is mirror (no need to alter the sequence), and the RNA/proteins/etc are as well (like 100% made of the mirror-chiral molecules), then in isolation it might work just the same as regular-life, just twisting the other way?

Kinda does seem like it might be a bit arbitrary what direction things should curl in, however there are maybe aspects of how quantum-spin might interact with things that might rule out stability with mirror-chirality? I am not a QM scientist but I do find it very fascinating!

Re: Mirror bacteria research poses significant risks, scientists warn

#162

Post by f1shy »

michaelmrose wrote: post #77
mr_toad wrote: post #14

I don’t understand why the innate immune response wouldn’t default to attacking an organism made of chiral molecules, since it attacks anything it doesn’t recognise. And while the adaptive immune response might not immediately recognise a novel organism, is there something that would prevent it ever adapting?

Stuff binds to other stuff because the magnetic domains and shape match up well enough. There is no way to effect something that attacks everything it doesn't recognize because a) there is no ooeration that represents not matching and b) if there was such a cell would be a short lived bomb that would blow up your body. You adaptive immune system learns to and antigen when a short lived immune cell is semi randomly ge…

In biology is much much muuuuch more about physics as chemistry. Is all about the shapes of very big molecules.

Re: Mirror bacteria research poses significant risks, scientists warn

#163

Post by serial_dev »

efitz wrote: post #131

Maybe we should manufacture and stockpile mirror antibiotics, in case of accidental or intentional release of such organisms. This appeals to me both as a defensive/protective measure and as a deterrent to others who might look to weaponize such organisms.

This is how every arms race starts.

"The baddies will use this as a weapon, so we need to get ahead of this, and manufacture the nastiest variants we can come up, so that we know how to DEFEND against them. It's defense, I say!"... Then eventually there is a lab leak, and there is a pandemic on your hand.

Re: Mirror bacteria research poses significant risks, scientists warn

#164

Post by Aerroon »

shaky-carrousel wrote: post #156

That's sensationalism. Mirror bacteria would be at a severe disadvantage as there are no natural mirror aminoacids. Normal bacteria will quickly evolve to consume mirror aminoacids. And there are much much more normal bacteria than any possible mirror bacteria. They would be wiped out pretty quickly.

I thought the same thing initially, but I'm not as convinced after looking a bit more into it. Ie I think it's a possible risk.

>as there are no natural mirror aminoacids. Normal bacteria will quickly evolve to consume mirror aminoacids.

There are and they already have:

>D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free.

https://pubmed.ncbi.nlm.nih.gov/24647559/

On the one hand, this does indicate that the "mirror bacteria" might not starve immediately, but on the other hand it shows that "non-mirror bacteria" would already be there in large numbers.

Re: Mirror bacteria research poses significant risks, scientists warn

#166

Post by d--b »

Also: in all risk analysis you'd have to consider the upside. The upside here is none. We are 99.9% sure that there's nothing special about our side of the mirror. So with 0 upside besides "writing a paper" or "because no one has done it, so who knows?", it doesn't really matter that the risk may be small. It just doesn't make sense to do it.

Re: Mirror bacteria research poses significant risks, scientists warn

#167

Post by geysersam »

nmstoker wrote: post #148
geysersam wrote: post #147

If this is such a powerful niche for an organism to be in, why haven't they already emerged naturally over the 3 billion year history of life on earth?

Life forms are effectively locked into the current set of chiral molecules. For a cell to flip, it would need all the corresponding mirror changes to happen as well, since the behaviours are interlinked - this makes it something that would be highly unlikely to occur due to evolution and why it's only realistic if carried out by people all at once.

That argument would be a good one if the time scale was shorter.

But over the course of the entire evolution of life on earth...

It's hard to argue that the step from chirality A to B is larger than all the other insanely unlikely steps evolution has taken. From earliest proto-life to complex multicellularity and beyond.

Re: Mirror bacteria research poses significant risks, scientists warn

#168

Post by Aerroon »

notfed wrote: post #120
roenxi wrote: post #109

Doesn't sound very scary on the face of it. Apparently [0] the problem with Thalidomide was that the chirality could spontaneously reverse, so that sort of thing must happen frequently in nature. If bacteria haven't figured out how to use mirroring under evolutionary pressure it probably doesn't actually have any advantages over following the herd. [0] https://en.wikipedia.org/wiki/Homochirality#In_biology

I think the ostensibly scary subject here is mirror DNA or RNA , not anything-that-doesn't-self-replicate. > If bacteria haven't figured out how to use mirroring It's unclear bacteria have ever "attempted" it. The synthesis of DNA is incredibly intricate and complex, and the set of proteins that do it are believed only to have ever evolved once. In order for a bacteria to have "attempted" this, it would have to evolv…

>It's unclear bacteria have ever "attempted" it.

They have: https://pubmed.ncbi.nlm.nih.gov/24647559/

Re: Mirror bacteria research poses significant risks, scientists warn

#169

Post by roenxi »

jefftk wrote: post #121
roenxi wrote: post #109

Doesn't sound very scary on the face of it. Apparently [0] the problem with Thalidomide was that the chirality could spontaneously reverse, so that sort of thing must happen frequently in nature. If bacteria haven't figured out how to use mirroring under evolutionary pressure it probably doesn't actually have any advantages over following the herd. [0] https://en.wikipedia.org/wiki/Homochirality#In_biology

> that sort of thing must happen frequently in nature Individual chiral molecules can happen naturally, sure, but not entire organisms. From the report: In a mirror bacterium, all of the chiral molecules of existing bacteria—proteins, nucleic acids, and metabolites—are replaced by their mirror images. In the fitness landscape there is an absolutely enormous gulf between standard and mirror bacteria, large enough that…

Nature has built a lot of bacteria over the millennia. It probably has experimented with just building the whole thing backwards.

That sounds simpler to do than, say, evolving a cogwheel (which does happen occasionally) or actually developing some of these molecules in the first place. It'd be weird for evolution to struggle so much on trying such a simple concept somewhere. This is a process that naturally figured out solar power, a bunch of mechanical engineering properties, various chemical techniques, all sort of fluid dynamics and statics, radiation resistance, sensing and control systems, etc, etc. If it doesn't build things backwards, more likely than not it is because it doesn't work well. The process knows how to do quite complex engineering tasks.

Re: Mirror bacteria research poses significant risks, scientists warn

#170

Post by nmstoker »

geysersam wrote: post #167
nmstoker wrote: post #148

Earlier quoted context omitted.

Life forms are effectively locked into the current set of chiral molecules. For a cell to flip, it would need all the corresponding mirror changes to happen as well, since the behaviours are interlinked - this makes it something that would be highly unlikely to occur due to evolution and why it's only realistic if carried out by people all at once.

That argument would be a good one if the time scale was shorter. But over the course of the entire evolution of life on earth... It's hard to argue that the step from chirality A to B is larger than all the other insanely unlikely steps evolution has taken. From earliest proto-life to complex multicellularity and beyond.

The issue is not that one chirality has to flip and you can accumulate change over long time periods, it's that every occurrence of chirality had to flip at once or the things won't work together: so the DNA has to mysteriously all get reversed (v difficult when all the DNA/RNA machinery is handed in the other direction), plus all the supporting items need to flip at that same point for all sorts of other cell functions that interlink (energy supply, waste handling etc etc).

But if your argument is given the extraordinary timeframes then why didn't life evolve again separately in the other chirality, so it wasn't descended from the earlier cells but was just a new unrelated line, then that is harder to generalise about but I recall hearing that there are sometimes slight advantages to one chirality over the opposite in certain cases as the reaction rates can differ (this is the same concept behind kinetic resolution). Perhaps life based on the less effective form would get crowded out by the more effective form, but I would defer to experts here as it's not my area.

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