
Videos of Evolution in Action - tim_sw
http://www.theatlantic.com/science/archive/2016/09/stunning-videos-of-evolution-in-action/499136/?single_page=true
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DanBC
> The experiments, described in the Sept. 9 issue of Science, are thought to
> provide the first large-scale glimpse of the maneuvers of bacteria as they
> encounter increasingly higher doses of antibiotics and adapt to survive —
> and thrive — in them.

The BBC TV programme Horizon showed the same giant petri dish 4 years ago.
This post contains a link to a slightly different clip with a smidgen more
background.

[https://news.ycombinator.com/item?id=5356309#5356479](https://news.ycombinator.com/item?id=5356309#5356479)

The other scary bit is that the 100x is toxic to humans, and that they cannot
add any more drug to the 1000x because they've reached the limits of
solubility.

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meowface
Video from the article:
[https://www.youtube.com/watch?v=plVk4NVIUh8](https://www.youtube.com/watch?v=plVk4NVIUh8)

Fairly frightening.

~~~
kyriakos
Extremely frightening. Took just 11 days to mutate to an antibiotic resistant
strain at 1000x concentration from zero resistance.

~~~
shiven
Haven't read the paper yet. But I expect to see a control where they plate the
same starter culture _directly_ on each log scale antibiotic concentration
(1,10,100,1000) to see if it contained resistant bacteria from the get go.
Thus testing if resistant mutants were always present in a population or they
arise _and_ are selected for by evolutionary process.

It is the _origin_ of mutants that is the more interesting question.

~~~
Retric
The video shows mutations in real time as bacteria grow or fail to grow in
various places.
[https://www.youtube.com/watch?v=plVk4NVIUh8](https://www.youtube.com/watch?v=plVk4NVIUh8)

It's more a demonstration than experiment, but visually it's just really
striking.

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rubicon33
I am curious - Are the bacteria really "evolving" at each subsequent boundary?
In the article/video, they specifically mention "mutations". That says to me,
that the bacteria are literally experiencing mutations within their nucleotide
pairs, that results in them becoming more resistant to the drug?

Couldn't it also be that among the initial population, there existed 1 (or
more) very very strong bacteria? At each boundary, the weak ones are dying off
(hence the pause in growth) while the strong ones continue to reproduce. Since
they're strong, but few, you witness a lag in overall growth of the population
which the article is saying is the "evolving" process, when really it's more
of a filter process. Filtering the strong, from the weak, by progressively
stronger antibiotic strands.

I guess ultimately I'm just wondering what they specifically mean by "evolve"
and "mutation".

~~~
zdean
Even if the mutation was part of the original soup of bacteria, the process in
the video still shows evolution. Either at time=0 or some point in the future,
a strain of bacteria was more fit to survive and produce viable offspring than
the others that died off in the presence of the antibiotic doses.

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jaunkst
Love it. One question, does the bacteria once it has conquered the known world
does it begin to traverse backwards into the previous sectors?

~~~
ceejayoz
I'd guess not. In many cases, these sorts of mutations are maladaptive outside
of that environment.

Put a polar bear in the tropics and it's not going to do so well - not just
because it's going to overheat, but because all the energy spent growing that
hair could've been better used on something else.

~~~
vibrio
This concept is key. Growth in the presence of antibiotic in pure culture on
agarose plates does not necessarily equal pathogenic potential. Every
adaptation probably has a cost to the bacteria, and if you throw in the immune
system and other competitive bacteria that may not be pathogenic, those 'super
bacteria' may be less super. All that said, as a microbiologist, antibiotic
resistance terrifies me, with the current economics of new drug development
being as daunting as the technical challenges.

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CommanderData
I would love to see this done with various bacteria against other chemicals.
For example, Bleach. Bleach denatures cells so in theory it would never happen
but it would be an interesting experiment.

~~~
vibrio
I'm not sure bleach would be that interesting. It's like asking deer to evolve
resistance to hunters' rifle bullets--it's too steep an evolutionary step.

~~~
GioM
Is it though? Imagine a world in which the only agent of selection was hunters
bullets. No sexual selection, no food shortage, nothing. In other words, an
absolutely perfect deer breeding ground.

Place a billion deer in this environment and shoot them all. A few survive.
Let numbers rise, and do it again.

Soon you start seeing deer with arteries and veins that are smaller, blood
that clots faster. Maybe the deer themselves are smaller, or their internal
organs are smaller but their muscles larger, fed by a larger number of smaller
veins. Perhaps muscle density is higher to offer better protection. Bone and
skull thickness increases.

Eventually you've got an animal with a small, very thick skull, with lots of
angles to increase the likelihood of ricochet, a heart protected by layers of
thick muscle and a reinforced, thickened ribcage. Veins and arteries are
reduced in size so much that it's practically impossible to bleed out, immune
system is in constant overdrive to fight infection, and the rest of the
internal organs are either shrunken, duplicated, or hardened against piercing
damage.

In any case, my point is, if we could set up an experiment with deer like we
can with bacteria, I think it's likely that we'd be surprised at what's
possible.

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vibrio
Well done on the deer analogy- I'm in over my head there. I appreciate and
agree with your point, and think my original response was glib and not clear.
Clearly, extremophilic archea have evolved to inhabit nearly every niche of
the earth (Deinococcus radiodurans is a great example). The point I took from
the video was not that bacteria are rapidly able to adapt to antibiotics,
that’s been known as long as antibiotics have existed, but the observation of
the instant in time when a bug figures out one of those discrete changes and
its offspring thrive. I believe the scale and breadth of adaptations required
to observe evolution of meaningful resistance to a universal denaturant such
as bleach would be prohibitive. Bleach destroys at the level of protein
chemistry, where as antibiotics are specifically toxic to bacterial
structures. The wholesale changes would be required of the organism, rather
than discrete mutations in the ribosome, cell wall, or other mechanisms known
to drive antibiotics resistance-probably what you can see changing in the
video. My awkward comment was intended to say I don’t think the scale and time
frame of the video assay would not be amenable to the scale of the study for
bleach resistance. You illustrate that same point in your comment. That said
this is all knowable first-hand, as generating or isolating bacterial strains
resistant to toxins is science one could do at home with probably less
investment that homebrewing beer, although without the fancy movies.

~~~
dredmorbius
Taking this discussion a step further: in the bullets/deer instance, you'd be
more likely to evolve a primary lifeform that looked more like a tree or grass
or slime-mold than a deer. That is, it either consists almost _entirely_ of
bullet-stopping material (wood), or is so lightweight that bullets don't
effectively transfer energy to it (grass), or the structure is entirely
decentralised such that a bullet, or even a hail of bullets, cannot disrubt
the systemic function of the organism -- it simply absorbs the projectiles and
functions around them.

A chlorine adaptation, if possible, would be along similar but chemical lines
-- you'd end up with a non-protein based chemistry, or something not affected
by chlorine, or which could buffer it to extreme levels.

Differential resistance to bleach at low concentrations might be possible to
breed for. That could be interesting. In a similarly horrifying sort of way.

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neom
[http://john.je/hQYZ](http://john.je/hQYZ) anyone know what this huge white
dot is?

Also, does that + this worry anyone else? [http://abcnews.go.com/Health/fda-
gmo-mosquito-test-fight-zik...](http://abcnews.go.com/Health/fda-gmo-mosquito-
test-fight-zika/story?id=41143198)

~~~
undersuit
Possibly a contamination. The article mentions they had to use lots of bleach
to prevent outside contaminants.

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WheelsAtLarge
This brings to mind how quantity will always beat one super power.

Example one bee will not kill a large predator but a swarm will.

One termite is joke but thousands will bring down a house.

I suspect one antibiotic will never beat bacteria in the long run. Looks to me
like it's a never ending battle. I hear about the post antibiotic era like we
had won the war at one time. What we won was a battle in a never ending war.

We hear about technology fixing all and jobs ending. Here's an area where
there will always be a need for research and solutions.

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fasteo
This reflects the importance of the dosage and duration when taking
antibiotics.

This video shows hormesis[1] at its best: How bacteria is able to develop
resistance over an increasing dose of antibiotic. I doubt that they would have
been able to survive when exposed from 0 to x1000.

[1]
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2248601/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2248601/)

~~~
DanBC
> I doubt that they would have been able to survive when exposed from 0 to
> x1000.

But neither would the patient.

~~~
fasteo
The clinical dosage is made just for this: Kill the bacteria; don't kill the
host

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lucio
I'm now worried about what they did to dispose of the central section.

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manmal
Those are likely easily killable by other antibiotics than the one used.

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yincrash
Or just use bleach.

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Animats
Wow. 11 days to develop antibiotic resistance.

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sliken
No, more like 2 days, 11 days was 1000x.

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kinkdr
Is it really that easy to create super bacteria? What stops one from using
something like this as a weapon?

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ss248
It is not that easy.

Mutation works both ways. You can also lose something very fast, if it's no
longer needed (basic rule of evolution - "Use it or lose it").

~~~
Ultimatt
Bacteria have a solution to that too though with the use of mobile genetic
elements called plasmids. So the genetics of something can float in the
population with locality to its relevance. Most antibiotic resistant bacteria
in hospitals get their resistance from ground dwelling bacteria people walk in
with their shoes.

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aaron695
@ISIS

