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A transgenic bacterium with synthetic DNA

For those who fear the fusion of synthetic beings with nature, it turns out that synthetic organisms that are based on the availability of specific substances for their development and which are not found in nature will not be able to compete or share their genetic material with the natural strains, and will die in their absence

A synthetic bacterium. Photo: Free University of Berlin
A synthetic bacterium. Photo: Free University of Berlin

The genetic information of all living things is stored in a DNA molecule consisting of four bases: adenine, cytosine, guanine and thymine. An international team of researchers has now succeeded in producing a bacterium containing DNA in which the base thymine has been replaced by a synthetic building block named 5-chlorouracil, a substance toxic to other organisms.

As described in the article detailing the results of the research and published in the scientific journal Angewandte Chemie International Edition, the experimental research was based on a unique technology developed by two of the researchers and which enables the directed evolution of organisms under particularly controlled conditions. Large populations of bacterial cells were grown in culture for long periods in the presence of a toxic substance - in this case, 5-chloro-uracil - in non-lethal concentrations, forcing the selection of genetic strains capable of dealing with and surviving high concentrations of the toxic substance.

In response to the appearance of such strains in the cell population, the concentration of the toxic substance in the growth medium increased, thus leaving the selection pressure constant. This automated method for long-term evolution was applied to the preparation of a genetically modified Escherichia coli bacterium unable to naturally synthesize the base thymine and which was forced to evolve instead using 5-chloro-uracil. After a breeding period of about a thousand generations, bacteria developed which are descendants of the original strain and which contained DNA in which the base thymine was completely replaced with 5-chloro-uracil. Genome analysis revealed many mutations in the DNA of the transgenic bacteria. The contribution of these mutations to the adaptation of the cells to a chlorine-containing base will be the subject of future studies.

Besides the obvious interest in this radical change in the chemistry of living systems for basic research, the scientists consider the result of their research to be of great importance for the field of "xenobiology", a subfield of synthetic biology. This young field in the life sciences focuses on the creation of new organisms that are not found in nature and that are engineered to contain optimal metabolic characteristics for the creation of alternative energy or the production of highly important synthetic chemicals.

Similar to genetically modified organisms (GMOs), these organisms are treated as a potential threat to natural ecosystems in the event that they are released from the laboratory, through direct competition with the organisms of the natural strain, or through the influence of their synthetic DNA.

 Scientists are aware of the fact that a physical barrier will not always succeed in preventing engineered life forms from reaching the natural environment, in the same way that radioactive isotopes are able to leak into the environment of a nuclear facility.

However, the researchers explain, synthetic organisms that are based on the availability of specific substances for their development and which are not found in nature, or those that contain non-natural building blocks in their genetic information, will not be able to compete or share their genetic material with the natural strains, and will die in their absence.

The news about the study

20 תגובות

  1. withering,

    I have a lot of sympathy for bacteria, especially those that help me grow the organic vegetables in the garden. And also for some of the bigger "parasites" (ants, mosses, diarrhea and cockroaches in the compost that do the job for me).

    It doesn't seem to me that we disagree, but I will emphasize again that a species that has been genetically modified by humans may be very violent towards a certain species (people or something else), although it is not certain that it will have an advantage for a long time compared to those living in its natural environment that will eventually overcome it, or - And this is the worst script - they will borrow certain features from it.

    This whole story can still cause enormous damage even in a short time, and nature will find a way to balance itself.

  2. the other me

    You wrote: "Nature always finds a way to reproduce and evolve the existing varieties, whether they were created naturally or not."

    Have you heard of extinct species? There are entire branches that included millions and trillions of individuals that did not survive evolution. It is true that in the meantime there have always been species that survived into the organisms that exist today but for many others nature did not find a solution.

    As soon as there is an unused niche, there is a selection pressure on the organisms to take advantage of it, i.e. - an organism that is in the same environment and will be able to utilize the resources in that niche (for example due to a mutation) will gain an advantage and will most likely prosper, usually at the expense of other organisms (because as a rule, resources are a limited thing) . From this point of view, you should understand that you and I constitute a very attractive niche for a huge variety of organisms, for which we are a warm and protected home as well as a rich source of food, therefore it is not surprising that we are constantly attacked by mosquitoes, bedbugs, lice, intestinal parasites, bacteria, viruses, etc. . The plagues that killed the most people were not engineered in the laboratories of scientists but in the "laboratory" of nature, therefore M.R. is right. who wrote to you that playing with fire is something that takes place on a regular basis naturally and I want to reinforce his words and say that as part of the process of evolution there is a constant selection in favor of creatures that will try to "bite" us. The next great plague will occur naturally simply because nature's laboratory is much, much larger and more thorough than anything humans are capable of doing today. In the meantime, any species of gods that the army can develop, nature can create as well and with much greater efficiency. It is true that theoretically in the future it will be possible to create artificial "viruses" (here I am using the term borrowed from the world of computers when originally the term was borrowed from the biological world of course) that are very different from what exists in nature and can cause tremendous damage, but for this we need an understanding and control at the molecular level that is much better than there is for us today. This is a scenario that is unlikely to happen in our lifetime. Worry about the flu, Worry about AIDS, Worry about salmonella and tetanus. A natural mutant in one of these viruses/bacteria will probably be the next serious predator of humans.

    The chance of lab-engineered strains surviving out there is much lower simply because they have to go through more adaptations than those strains that are already out there and thriving (ie highly adapted to their environment). A transgenic species has to somehow exist in this cruel world before it preys on humans so easily. Show some compassion for our bacterial brothers!

  3. R.H.

    As far as I understand you, in biological warfare you take any natural bacteria and make it much more deadly - a kind of super strain.

    I've read Jurassic Park and Creighton's statement rings true to me regardless of the Jurassic Park story, nature always finds a way to reproduce and evolve the existing species, whether created naturally or not.

  4. I am another
    Creighton said this about Jurassic Park. For the sake of the dramatic story, he talks (in the voice of the scientist in the story) about chaos theory and how it is impossible to predict and "nature will find its way". Now think what is the difference between a zoo of elephants, hippos, giraffes, lions and tigers and that of slightly larger animals, dinosaurs? The size of the animal? Big deal, so settings will be a little bigger. In fact I think what Creighton did was bring up the primal fear of the unknown. Just like people like you are afraid of the unknown bacteria described above, they are also afraid of a Jurassic park style park. How do you think it is possible to cause biological warfare with a bacterium to multiply without artificial substances? Why not simply use what is in nature?

  5. The other self:
    On the contrary! Every natural bacterial population contains many individuals that differ from each other in their genetics. These are actually varieties that have all come this far and there is no reason to doubt their durability.
    Every time the environment changes - certain strains are suppressed and other strains flourish.
    On the other hand, in genetic engineering, and especially in the one described here, genetics are created whose chances of being resistant outside the laboratory are zero.

  6. Even so... the formation of a super-resistant species in nature is quite rare as far as I understand.
    The creation of a strain by genetic engineering or through some human intervention, even unintentionally (hospital environment...) is much more common.

    And despite that... it's a rather pointless discussion, it's clear that researchers will continue to engineer bacteria with good intentions or not, there's nothing new here, and all the words that will be poured out here won't change that.

    And as I wrote in the first comment - Michael Creighton already said it before:

    Nature will always find its way.

  7. The other self:
    As mentioned, this game with fire takes place non-stop even without genetic engineering.
    Every day, billions upon billions of mutations are created in nature.
    That is why genetic engineering is not useless in sixty but in billions of billions.

  8. R.H., Michael,

    There is truth in your words, and of course medical research should continue.

    And even so, this is playing with fire - deliberately inducing bacteria can be used for research purposes that will benefit humanity as well as cause harm - biological warfare, etc.
    But even if we leave malicious intentions aside - even the bacteria that are engineered for research purposes may leak into the natural environment and since they were engineered in a deliberate way there is a possibility that they will become a super species in nature and cause a lot of damage.

    Of course these are rare cases (again, if women have malicious intentions aside) and still it is not an impossible scenario.

  9. I completely agree with the words of R.H. And I would like to add:
    Every mutation - even those that occur naturally (!) creates a "bacterium that nature does not know how to deal with" with exactly the same probability as a mutation created by genetic engineering.

  10. the other me
    Your argument is true for any research in bacteria. So in your opinion we should stop researching bacteria? So how do we stop the next epidemic like the one that happened in Germany? Do you think someone is "playing" with fire here? It is precisely through the research described above that it will perhaps lead to the development of safe laboratory strains for research, even if they escape they will not cause harm.

  11. Wasn't it E Coli that caused the fatal poisonings in Europe?
    Even its less harmful strains have destructive evolutionary potential - like most bacteria.

    What's more, they start with E today. Coli but will continue with others:
    "This young field in the life sciences focuses on the creation of new organisms that are not found in nature and that are engineered so that they contain optimal metabolic characteristics to create alternative energy or to produce highly important synthetic chemicals."

    As I wrote above - playing with fire.

  12. It seems to me that the hysteria of the commenters above is a bit exaggerated. In the end, it is about the E. coli bacterium that exists in nature everywhere and that is used as the number 1 tool in laboratories. They took this harmless bacterium and made it even less harmful in an amazing way by changing its DNA composition! (does mention the same bacteria that uses arsenic instead of phosphorus). So what is the danger here? Let's say it goes out into the wild and escapes, it is very likely that it will not compete with the normal bacteria for the breeding niches and it is assumed that it will become extinct because its nutrients do not exist. And even if it changes, at most, it will return to the E.coli that we all know. So what damage can he do? On the other hand, the research questions that can be tested with him are very interesting and important. So the benefit is infinitely greater than the risk in using this bacterium.
    Although much more dangerous is the research carried out on known pathogens, as usual the fear of the unknown is greatest.

  13. Why mix the categories? The bacterium described is not synthetic and not even so genetically engineered. All in all, this is a manipulation of evolutionary pressures. The same evolutionary pressures that caused the trait to be selected, will be reversed under normal natural conditions. So it is difficult to see a situation where they invade 'nature' and are at some relative advantage and then destroy or harm the acquired population.
    In contrast, in genetic engineering, you interfere with the mechanism of natural reproduction and then actually participate in 'reverse evolution'. Since the reality is that there is an almost infinite variety of variables in the natural environment and to this day super mechanisms of resource optimization and variety have functioned. And since one must suspect that the attention to the possible results of the human researcher is weaker than the evolutionary mechanism, there is a reasonable suspicion that the demon that came out of the test tube will find it difficult to return to it without damage.
    One can see the extent of human investment [worldwide - from all sides] in nuclear technology for the purposes of war, as a red light for the ability of the Umo Sapins to control the products of its research.
    And good luck to everyone involved in life-saving and life-enhancing research

  14. The reassuring sentence at the end:
    "However, the researchers explain, synthetic organisms that are based on the availability of specific substances for their development and which are not found in nature, or those that contain non-natural building blocks in their genetic information, will not be able to compete or share their genetic material with the natural strains, and will die in their absence."

    He has nothing to base himself on - just as the bacteria evolved to use the synthetic DNA bases, so they can evolve to return to using the natural DNA base - and thus compete with the natural strains. This is the whole idea behind evolution.

  15. It is quite clear that the most lethal weapon is the biological weapon.

    The end is near.

  16. They failed to calm me down. I'm still horrified by the thought of a synthetic germ.

  17. The damage that a genetically engineered bacteria can do is tens of times greater than a normal bacteria
    Because nature does not know how to deal with it, the entire ecosystem can collapse.
    Like the poisonous frogs in Australia.
    It is enough that one of them manages to find his way in the new world, and disaster is already on the way.

  18. playing with fire Laboratory conditions cannot perfectly mimic what happens in a natural environment. It is not possible to reliably predict beyond any doubt (100%) what might happen if genetically modified bacteria such as these reach a natural environment.

    Nature always finds its way (Jurassic Park...)

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