AlexSorokin

Finally, the discussion about risks of mirror life truly goes mainstream. https://www.science.org/doi/10.1126/science.ads9158 https://purl.stanford.edu/cv716pj4036

These JCVI-syn3.0 bacteria (that are able to replicate) are not truly synthetic. They are obtained by genome transplantation into already existing cell (top-down approach). Bottom-up approach (using phospholipid bags filled with synthetic compounds) is still in its infancy.

I think it is really hard to predict when it happens, but I am quite sure that all building blocks can be synthesized very soon (see also https://doi.org/10.1002/cbic.202200537), because it is a self-accelerating process which already started. The real problem is to assemble the minimal artificial cell, which is able to replicate (not nesessary designed as a replicator).

Meanwhile, mirror ribosome is on the way. https://www.science.org/doi/10.1126/science.abm0646 https://cen.acs.org/biological-chemistry/synthetic-biology/Mirror-image-polymerase-makes-key/100/web/2022/10

For cell-free systems yield is about 1g/L, scalable. https://doi.org/10.1016/j.coche.2017.10.003 So cell-free is somewhere between chemical and microbiological production. And it allows to synthesize many different proteins in one test tube. When an assembly of artificial cells (of normal chirality) will become possible, it's time to stockpile antibiotic enantiomers in your medical kit... Some antibiotics are produced as racemic mixture, so it it won't be a problem.

One molecule of thermostable DNA-polymerase can incorporate about 10^5 nucleotides into DNA during routine polymerase chain reaction. And the only limiting factor here is that 92-95°C is too high even for thermostable enzyme. Taq-polymerase is very cheap, so reaction is optimized for speed, not for the effectiveness per molecule. Anyway, mass production of nucleic acids enantiomers is possible even with chemical synthesis. Proteins (especially big ones, and those needed post-translational modification) are muck harder to be made. I think it is something like reiterated solving of an "chicken or the egg" problem: you need to decide what is cheaper to create first. Fully artificial cell-free protein synthesis systems will be a huge step forward. Presently such systems are made from cell extracts (so it's more like an omelette,not egg or chicken). By the way, take a look at https://doi.org/10.1093/nar/gkx079. PCR with a bacterial mirror polymerase. Twice bigger than that virus polymerase, much more effective. And Racemic crystallography is another motivation for producing mirror proteins.

Hi all. I think we don't even have to make a cyanobacteria to do the job. Even E.coli can grow on minimal media with only mineral salts and glycerol, which is symmetric, as a single source of organic carbon. So does mirrored E.coli. And there is plenty of potential food for the Mirror Life in our environment. Although triglicerides (fats) are technically not symmetric (if all three radicals are different) their (+) and (-) forms may be digested by enzyme of any chirality, leading to glycerol(symmetric) and fat acids (also symmetric). Glycine, citric acid, acetic acid and many other molecules are all symmetric and can be the source of carbon. A potential pathogen doesn't have to be able to digest its host completely (and none of them actually do). From the point of view of a mirrored microbe we are Petri dishes, with a relatively inert medium soaked with tasty solution of low-molecular food. Natural nucleosides and nucleotides contain D-sugars, but nucleotide bases are symmetric and could be used as a building block for RNA and DNA of Mirror life. Non-photosynthetic Mirror life can deplete oceans and atmosphere of CO2 as well. Their lipids can be digested, but D-proteins are much more prone to hydrolysis, and carbohydrates of the cell wall will be probably almost undigestible. Something like 100 kg/m^2 (quick calculation, could be wrong) of deposits on the seabed and it's over.