Friday is here, and the 'Weekend Science Bite' corner is back — number 74.
This time: how antibiotics became a threat to humanity, the connection to China, and whether artificial intelligence is what will save us.
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Although antibiotics have saved countless lives, in recent years they have come to be regarded as a genuine threat to humanity's future.
Watch the video and you'll understand why — antibiotics rapidly breed superbugs that are resistant to them, with virtually no way to treat the infections they cause.
In this remarkable video, you can watch the evolution of *E. coli* bacteria unfold across an antibiotic-coated surface.
The concentration of the antibiotic increases toward the center, where it is high enough to easily destroy any bacterium that ventures near it.
And yet, after just a few days, the *E. coli* have developed such high resistance to the antibiotic that they begin to thrive even at the very center of the surface — an environment that had been utterly lethal to them.
How does this happen?
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Antibiotics destroy bacteria in several ways.
One approach is to disrupt the structure of the bacterial cell wall, causing it to fall apart.
The cell wall is built from peptidoglycan — long polymer chains. The antibiotic binds to the open ends of the polymer and prevents further construction, or damages the enzymes responsible for building the cell wall.
Another approach is to penetrate the cell and cause it to produce defective proteins that poison it from within, or to interfere with the production and replication of DNA molecules.
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Bacteria develop resistance through rapid evolution.
As a bacterium replicates over and over, tiny random changes in the genetic code generate various mutations.
Normally, mutations in living organisms lead to disease or early death — but in exceptional cases, a mutation can produce a new structure that the antibiotic is unable to break down.
When antibiotics wipe out an entire bacterial population, only those unaffected by the drug survive; they then flourish and multiply in the newly vacated living space.
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Not only do bacteria become antibiotic-resistant, they also transfer the new genetic code among themselves with remarkable speed.
This transfer occurs through direct contact, by taking up DNA from the surrounding environment, or via viruses that attack them and in doing so carry the upgraded DNA to other bacteria.
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In the Western world there is considerable awareness of this issue, and antibiotics are prescribed with caution.
Certain classes of antibiotics are kept in reserve as a last resort against bacteria that do not respond to any other treatment, because overuse risks creating strains resistant to them as well.
In several countries, however — China among them — antibiotic consumption is breaking records, both as medicine and as a growth promoter in livestock, despite government efforts to curb the phenomenon.
High consumption was historically driven by a financial incentive as well: hospitals profited from antibiotics, which represented a significant source of revenue for them.
The result is monster bacteria that no antibiotic can defeat, and the fear is of a return to the pre-antibiotic era, in which even simple infections become life-threatening.
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Several years ago, researchers at MIT trained an AI model to identify existing drugs that might function as antibiotics, and in doing so discovered Halicin — a diabetes medication that turned out to be a remarkably effective antibiotic.
The Chinese have taken this even further: an AI model developed by Huawei was trained on 1.7 billion molecules to identify compounds that could serve as antibiotics.
The hope now is that AI will help develop entirely new antibiotics quickly and cheaply, and save humanity from the threat that is fast approaching.
Shabbat Shalom 😊
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Video credit: 60 Minutes
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