7. Invincible Moss Piglets

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I'm Hannah Fry.

And I'm Dara O'Brien.

And this is Curious Cases.

The show where we take your quirkiest questions, your crunchiest conundrums, and then we solve them.

With the power of science.

I mean, do we always solve them?

I mean, the hit rate's pretty low.

But it is with science.

It is with science.

I have issues with this week's show title.

Tell me.

Well it just says Invincible Moss Piglets.

Yeah?

Okay.

Go through it word by word for me.

Well

Invincible.

Yeah agree.

Okay moss?

Yeah.

Piglets.

Yeah.

Are they all these are all terms we're...

Yeah, what's your problem?

I feel we have to communicate this both to me and to the people at home.

Okay, we're talking tardigrades.

Okay, yeah, I faintly know about tardigrades.

What What do you know about tardigrades?

Well, I didn't know they were invincible moss piglets for a start.

I've heard them refer to water bears.

I've heard various nicknames.

They get a lot of them.

They're very difficult to kill.

Okay.

Are they piglets?

Yeah.

Yes.

Are they made of moss?

They live in moss.

I think by the end of the half hour, you will be convinced that there is no other title greater.

Okay.

Because the thing is, you've actually had a lot of questions come in to curiouscases at bbc.co.uk about tardigrades.

Have a listen to this one.

My name's Vivian Parrish, and I live on the Isle of Lewis in the Outer Hebrides.

In Star Trek Discovery, they had this massive tardigrade that was shooting the ship around the galaxy on a mycelial network.

So I know that's science fiction, but there are things that we can learn from tardigrades.

They seem to be able to withstand radiation and they live through droughts.

And how can they actually help us if we do go to space?

So can they give us any information to protect ourselves?

Okay, so we're hinting at the Invincible there, not so much the Moss Piglet.

No, no, that's coming later.

Okay, Vivian Mossa wasn't the only one.

A chap called Andrew Love also wrote, and he noted, I often hear the joke that come the apocalypse, the only thing left alive will be cockroaches and Keith Richards.

But are there any other organisms that could live after the end times?

In particular, what about tardigrades?

Just cut to the chase, Andrew.

Just ask, what about tardigrades?

Don't have to give the big bill.

I think it made it much more colourful that it included Keith Richards.

And I think, you know, any opportunity to include Keith Richards should be taken.

I'm just saying, if it was like a Telegram situation, I had to pay by the word, just what about Tardigrades?

Would have achieved the same thing.

Here's the thing, though.

Today, Tardigrades, next week, we're going to do Keith Richards an entire

episode.

It's half an hour enough to really,

at a molecular level, probe what's going on with Keith Richards.

He survived the apocalypse.

So this is it.

This is what we're doing today.

We are seeing whether these little superbugs can genuinely survive an apocalypse.

And to do that, we are going to talk to a couple of experts to see what they make of it.

Yes, trapped in the studio with us, we have Dr.

James Fleming from Oslo University.

And after searching through the scrublands and remote grassy plains, we have also captured from the University of Copenhagen Dr.

Nadia Muberg.

Yeah, why is this so Scandinavian this particular episode?

Is there a particular Scandinavian tardigrade obsession?

Well, well, I think Scandinavians actually love love tardigrades, I guess.

You're the go-to people for this.

It used to be pillaging.

I know when it was

upgraded.

Yeah.

Okay, we're going to get to the the magical powers that these things have in a moment, but I think it's it's it's better that we start off with the basics.

So so can we describe what tard grades look like?

So they're tiny creatures, less than a millimeter,

has eight legs with a mouth opening and a anus or cloaca in the other end.

So they have most of the organ systems that you would normally see in larger animals.

So they have a gut system, they have a brain, they have a ventral nerve cord, they have a lot of muscles and they have gonads.

They are built of around one thousand cells.

They're quite cute in a lot of ways.

Well well at least some of them are.

Some of them look like genuine bears.

That's why they have the popular name water bears.

But they are also of species that are more alien-like, with

long sensory organs coming out of the head and different places on their body.

So a tardigrade is not just a tardigrade, there is 1,500 species described of them and we probably have, well, we know we have many more that we haven't described or found yet.

And as well as water bears, I mean people do actually call them moss piglets, don't they?

They do call them moss piglets and that's because they live in mosses.

So there are a lot of species living within the marine environment, within the ocean.

We have species living in freshwater ponds and then we have a lot of species um which live in in mosses and and and and lichens also they're a little they are a little bit piglety i mean they've got like quite round tummies on the front of their noses there's i mean i'm using i'm using body parts that they don't have here but on sort of the front of what you might call their face is almost what looks like a little snout so they have um something that is called stylets that come out of the mouth regions with the which they use to to penetrate cells of other animals and plants.

And then they have a large suction pharynx which they use to suck out whatever fluids they can get out of the cells that they penetrated and then they have a gut system like other animals have so there is actually quite a lot of complexity.

They are very small so they are less than a millimeter but you have quite a lot of complexity within this maybe 500 microns of an animal.

Is that too small to see with the naked eye?

Some of them have very strong colors and if they do have that you will be you could see them just barely.

But otherwise,

you would need 20 to 30 times of magnification, right, to be able to see them.

Would you just find them in your garden?

I mean,

are they constrained to certain parts of the world,

or do you find them in people's gardens?

So, you would find them, for example, on your roof,

in the goddess, the roof goddess, you will find them.

The thing about tardigrays is that they are actually aquatic animals.

And this means that although they have invaded land, they require a film of water surrounding them in order to be active.

And that means that if they don't have, even though they are living maybe on in your garden, in the moss, on your roof, they will only be active and, so to speak, alive if they have this water film around them.

James, the thing that always distracts me about tardigrades is, well, their appearance, obviously, because they look like little mammals.

They do look like they have the shape of a little bear with a face.

They have a body, limbs, and a face.

Yeah, I mean, that really quite like distinctive kind of lumbering gait that you see whenever you see them under the microscope is part of why they're called water bears, because they do have this very bear-like movement under the microscope.

And they've been around for a long time?

A very long time, yeah.

So

the

first tardigrade fossils date back to the Cambrian, which is 530 million years ago, roughly.

That's like pre-dinosaurs.

Yeah, yeah, yeah, yeah.

That's about 400 million years pre-dinosaurs.

Whoa.

But

are they everywhere?

Yeah, pretty much.

Yeah.

Indeed, one of the most studied tardigrades on the planet was first found in a rain gutter in England.

Do you find them in very cold places?

You do, yeah.

So there are a few species that live in Antarctica.

Achitoncus antarcticus.

That's got a good name.

Arctic and us on the end.

It's a scam.

It's a whole thing.

Latin's just a.

It's a thing to get fun.

Did you go looking for Linux?

Yeah, so that's what I've been doing this afternoon.

I was very graciously provided by your producer with some moss from his roof.

I believe he took his life into his own hands.

Yeah, he clambered onto it.

I was told stories of a rickety stepladder.

Very adventurous.

So I've been steadily sieving through that.

So really all you need is a bunch of kitchen equipment.

If you have a box of the moss that you've collected, you hydrate the moss overnight, so you keep it in some water overnight.

And then you get a sieve, you squeeze the moss through the sieve and into a petri dish, and then look through the petri dish with your microscope.

Oh, that's really easy.

It's very, very straightforward, yeah?

Yeah.

Did you find any?

I did find one.

Can we see it?

You can see a picture of it.

Unfortunately, and this is another chink in the invincibility claim, while trying to transfer it from the Petri dish that was full of moss fluid into something nice so that I could actually show you,

it got stuck in the pipette and died.

What the what?

As Nadia, well, yes.

Apocalypse, no problem.

Pipettes,

more difficult.

Way more fragile than they've been led to believe.

So shearing forces can sometimes be a problem for tardigrades.

Show us the photo of.

Yes.

Okay, I am looking at a photo taken down a microscope.

Yes.

And it looks,

well, it looks like there's a little sort of really tiny worm at the bottom.

Yes, that's an ematode.

Yeah, at the bottom.

Yep.

Disgusting.

And I'll be honest with you.

Oh, hang on.

Is that it there?

Yeah.

That little guy.

Oh, yeah, that little guy.

Okay, so you can sort of see this.

Well, you can see a couple of the legs.

Oh, no, you can see all three legs.

You can see all the legs, and you can also just about make out the little claws as well on the bottom.

Oh, look at that.

There he is, little water piggy.

Since past.

Yeah, no longer with us, actually.

He's not as joined together as he was during the photograph.

Is that his little face there?

That is actually the back pair of legs.

The little faces right to the front.

Yeah, all the way around.

Yeah, yeah.

Oh, my God.

Yeah, no, no, no.

I get the shape of him all right.

Yeah.

Wow.

Congratulations.

And then you killed him.

And I killed him.

I'm sorry.

Casually murdered the one, the one we found.

I mean, we've talked up their ubiquity and their invincibility.

Found one, killed it.

That's the running total at the moment.

Tell you what they, what doesn't kill them, though.

drought

because they they do they are pretty famous now dear for this one incredible ability that they can just survive total drought how on earth do they do that bottom line is that that we don't actually really know.

One thing that we do know is that when the water leaves, it's very important for them that they chuck in their cells and they chuck in their organ systems and they contract into what is called a ton state.

And when the water is then gone, then there will be like this very small ton,

maybe a volume decrease of 80 or 90% or something like that.

When water then comes back, then they will be able to revive.

And come back to life.

And come back to life.

So they basically stop their metabolism.

And this is the way they have adapted to life on land, is that when the water, they come from water, or life comes from the ocean originally, so did we,

but they have adapted to land by simply allowing water to leave their bodies.

So they close down all their life's processes and then they wait.

Wait until water comes back into the musk cushion or the rain garter, and then they start living again.

I mean, this sounds like a sort of extreme form of hibernation.

It is.

But how long can they survive like this?

So there are good empirical data, data made in the lab,

that say 20 years

at least.

We have some Japanese colleagues that have revived tardigrades from Antarctica after they have been frozen for 30 years.

I think there is an anecdotal report from the 40s with an Italian guy that rehydrated some muscles from a museum that were 120 years old.

And

then he saw a little bit of movement from the tardigrades, but they never came really back to life.

So 30 years, we have good empirical data on that.

And seeing in the perspective of the normal tardigrade life, which is maybe a month or two months, then I mean, putting 30 years on top is quite a lot, actually.

But look, if we just curled into a ball,

there's a lot more chemically happening here.

Yeah, that's, yeah, unfortunately, that's not going to work.

Chemically, there are quite a lot of theories on what's going on.

They actually have a suite of genes that are unique to tardigrades, tardigrade-specific heat-soluble genes, that help reinforce the cells against dehydration.

Some species of tardigrade have up to 33 unique genes just to deal with drying out that no other animal on earth seems to have, which is kind of quite a serious investment into this kind of singular strategy.

We aren't exactly sure how all of this is working on a protein level, but we're starting to come to some understanding of what's happening.

There is one protein that last year we were able to visualize its expression within the cell as the tardigrade was entering the ton state.

So we could see where it was appearing as the animal dehydrated.

And it looks like

they

form fibrous struts inside of the cell that seem to prevent the cells from shriveling.

to a state that would damage the nucleus and all of the important internal cell things.

Whereas others proteins form these gels that stick around the scaffold.

Almost, you can think of it a bit like a kind of intracellular cork.

So they're built to reorder themselves to a certain extent so that the important bits will remain protected.

One of the things that we have been working with in my group in Copenhagen is actually the muscle systems, and they are built of actin and myosin filaments, which are also what we have.

And we see that when the tardigrades they tuck in their cells and the organs, they use their muscles, and it's very important that they have ATP while doing this.

ATP is the energy reserve of the cells.

And once the water sort of disappears from or totally evaporates from the turn state, then our hypothesis is that these filaments and the tardigrades are filled with muscles.

This is one of the organ systems that are really large compared to their small size.

Then the filaments will actually lock in a redo state.

So the myosin filaments and the actin filaments, they cannot detach when ATP is gone.

And this is much like what we see when actually when we die, the rigamortis state is what happens when myosin is still attached to actin.

And this is how they keep their 3D structure while in the cryptobiotic state.

How quickly does this whole process occur?

Not just the drying air, but how quickly do they resurrect?

Minutes, many, many minutes.

I mean, if it's just a sediment from the rain gutter, it will take a few minutes

that you can rewipe them, maybe

20 minutes, 30 minutes.

The longer time they have been in the desiccated state, the longer time it will take them to revive.

Sucks!

The new musical has made Tony award-winning history on Broadway.

We demand to be heard!

Winner, best score!

We demand to be seen!

Winner, best book!

We demand to be quality!

It's a theatrical masterpiece that's thrilling, inspiring, dazzlingly entertaining, and unquestionably the most emotionally stirring musical this season.

Suffs playing the Orpheum Theater, October 22nd through November 9th.

Tickets at BroadwaySF.com.

Okay, all right, in terms of apocalypses, then.

So, drought, check.

Floods, check.

Well, the water makes.

Yes, yeah, floods are fine.

Their ground is floods.

Floods are absolutely fine.

But our listener, Vivian, she was asking about space travel and and whether we could learn anything from tardigrades by sending them to space.

And you know what?

She was on to something.

Hi, I'm Thomas Boothby and in 2021, I sent tardigrades into space.

Our animals were sent in a frozen sort of state of stasis up to the International Space Station.

And once they were in space, they were thawed out and they were cultured on the space station for up to four generations.

And what we really wanted to do was to look at how tardigrade gene expression was changing under those conditions over time.

As we leave Earth's atmosphere, which is very protective, you get exposed to much more of this cosmic and solar radiation.

You know, one thing that radiation does is it damages our DNA.

And so, you know, we expected and we saw, are seeing that the tardigrides upregulate genes involved in repairing broken DNA.

They also upregulate genes involved in making sort of prophylactic strategies for this.

So they produce things called reactive oxygen species scavengers, which can help sort of ameliorate the effects of radiation before they have time to really do a lot of damage.

The idea is that if we can learn about the tricks that tartarids use to do this, we might be able to develop countermeasures or therapies that would allow humans to have a more productive and long-term presence in space.

I say.

By the way, that was Thomas Boothby from the University of Wyoming.

So, all right, they're resistant to radiation.

Tell us a little bit more.

How resistant are we talking?

So, one of the ones we found in the rain gutter today, Ramazzotius varianatus, can comfortably survive while active up to 5,000 grays,

which is, this is a measurement of radiation per unit weight.

Humans can take about five.

How on earth are they doing this, though?

There seems to be a tendency for tardigrades to up-regulate these damage-suppressing proteins that repair the DNA rather than actually

really attempting to resist high amounts of radiation.

It's perhaps better to think of it more as healing than it is actually resisting.

Because obviously when it comes to humans being in space, the dangers in cosmic radiation and the damage it would cause in terms of mutating DNA or cancer risk for long-term space exploration is something that's very, very people are very aware of.

So can we learn from them?

So very, very recently, there was a Japanese research group that showed that they were able to express tardigrade genes inside cultured human cells.

Oh.

Like a fusion.

However

there's something very very different between doing that in a Petri dish and doing that in a person.

I mean give me the caveats in a minute.

I want to know the results first.

Was it was were these human cells when they were like had been infused with tardigrade DNA suddenly superhuman?

They were able to survive a higher amount of radiation than regular human cells could.

Not quite to tardigrade levels, but yeah,

better than the baseline, better than me.

I mean, there's a lot of upside from five to five thousand.

There's a lot of space to wiggle there.

Because tardigrades also have, there are at least two other missions in which tardigrades have done exciting work in space.

They were put on the outside of a probe once and left floating around for 10 days, like unprotectedly in the freezing code.

Oh, yeah, pointedly.

They

put out there for 10 days to float around, yeah.

And then they tried resurrecting them and I think it was more than 50% of them or 60% of them returned.

Yes, yeah.

So they had just over a 50% survival rate after being exposed directly to the vacuum of space.

Which is higher than your pipette.

Yeah, higher than my pipette.

100% death.

Much higher than me when exposed to the vacuum of space.

The tantalizing space trip they made, however, was in 2019.

They're in the Beresheet probe, an Israeli probe, that crashed onto the moon.

And it is thought it had on board a number of tardigrades in the crash, which may have ended up on the surface of the moon.

Yeah, so they sent a mission to the moon.

It crashed and it contained a few thousand tardigrades on that mission.

Uh-oh.

As tardigrades can, in theory, survive the vacuum of space, do we now have tardigrades on the moon?

Moon Moon moss piglets.

Moon moss piglets living on the moon moss, like clangers.

Unfortunately,

or fortunately, I mean unfortunately for all the pure tardigrades in the crash, but fortunate for any concerns about ecological disaster.

Or,

you know, indigenous moon piglets.

Indigenous moon piglets, yeah.

It

seems that the tardigrades wouldn't have survived the crash.

We found this out because a group at Queen Mary's University in London shot tardigrades in the ton state out of a gun.

Jesus.

This is what scientists are doing with your public money, people.

At close to 900 miles per hour, which is quite close to the crash velocity, and found out that even within their super protective ton state,

that does not save them, unfortunately.

Not even one.

Wow.

I mean, it'd be more poignant if there's one.

Just one.

One victim.

One just staring at the earth in in a curved in a curled up state mummy yeah wondering why why am i the only one who survived i mean how many do you need to launch out the gun at what speed before you get a probability version below 0.05 yeah i agree i want to see the footage of this experiment i want to see how this is done but the methodology of it all seems to say yeah if you are concerned about the well-being of these tardigrades um just don't write to us

I mean, so the question is, as originally asked, was could they survive an apocalypse?

I think that it depends what the cause of that apocalypse is.

So, as we mentioned before, these potential, at least proto-tardigrades that we found in the Cambrian period, 500 million years ago, there have been at least five really major mass extinctions since then.

Not just the asteroid that destroyed all the dinosaurs, but also grand eruptions of undersea vents that choked almost all of the life out of the ocean.

There have been huge turnovers in what life on Earth looks like.

And for some reason, tardigrades seem to have done quite well with that.

So there's been five mass extinctions.

They can probably survive a sixth.

There are other types of apocalypse though, Nadia.

What about a nuclear apocalypse?

So they are definitely vulnerable to mechanical stress, as James showed you guys, but they are also vulnerable to high temperatures, right?

As regards a nuclear fallout, yeah,

that would probably be okay.

But as long as the temperature

doesn't,

they're absolutely fine.

Just as long as the apocalypse doesn't involve pipettes from space, yeah.

I mean, that's their one weakness, that's their only weakness.

They're kryptonite, yeah.

It's just me, it's just me.

He's the only person who's managed to kill

a tardigrade in all this time.

I mean, they're 500 million years old.

I know.

I mean, it feels like each of them individually is 500 million years old.

And they've just been sitting here waiting, and then you pick one of them up and then crushed it with a piece of, you know, chemistry equipment from like a school lab.

Yeah.

You know?

What an end.

It's an astonishing end.

We did answer the question, though.

We very much did.

I mean, we don't know if we can learn from them, but tantalizingly, that prospect was put before us.

But they themselves remain,

I'll give you invincible

on the ground that we've only had pipettes for the last 200.

A blink of the eye.

Honestly, geologic to a 2000 degrade, no time at all since the pipettes arrived.

They're a natural predator arrived.

So actually, yeah, up until that point, up until the making of fine glass tubing,

they ruled supreme.

It certainly did.

Well, thank you so much to our guests, Nadia Moebeck and James Fleming.

I think they've got a shout at being the superheroes of the microscopic world.

Oh, yeah.

I mean, I now feel they're like the eternal, some sort of you know, creature that predates us, has been there the entire time.

That's slow, like, you know,

yeah.

And when time ends, it'll be a tardigrade who's there to just hand over the

scrolls.

You know,

this too shall pass.

I have seen every scroll.

Scrolls.

These predate trees, mate.

Oh, yeah, true, yeah.

Well, Well, they've got some form of writing it all down.

Like, otherwise, how would they remember it all?

Or they just very quickly went, oh, I can't be bothered.

I'm just currently to evolve.

I mean, who hasn't wanted to go, I'm just going to currently pause and expel all the fluid in my body and just call me a tenuous scrad.

I'm going to sit this one out.

But look, can we dedicate it to the one tardigrade in the moon?

I think we should dedicate it to the one tardigrade that lost his life for our episode.

Oh, my God.

Absolutely.

Oh, my.

The only tardigrade that's ever died.

died, apart from the one they put into a gun and fired at a wall.

I wonder if they survived.

I know who we tested.

Let's fire them from a gun at a wall and see what we pick up.

But are we sure that they definitely died though, or were they just pretending to be dead?

Because it sounds like they're pretty good at that.

Yeah, absolutely.

How would you know?

How would you know?

You'd be prodding them for ages.

There's nothing coming off.

The uh, got some mortar for you.

I've got some motor, go to your favourite water.

Turn this into an ocean.

And there's nothing, nothing coming back off.

Nothing.

That's what we're doing.

I do really like the idea, though.

If you have been sick, if If you are 600 million years old, just everything feels very small to you, doesn't it?

You know,

they did start saying, you know, they're not using, they're not calling things Riz

and using slang, and Bay went right past them.

You know, all these things, like, whatever.

They don't care about trends.

You think the Taylor Swift versus the Beatles matters to a Target?

Absolutely not.

All the length of your socks for a millennial or Gen Z, no one cares.

No targets.

In many ways, they are an example to us.

These things have come and gone.

They'd be there going, none of these trends mean anything to me, for I am target gray and I will endure.

Whoa, hey, come with that pipette.

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