Keys, wallet, phone: the neuroscience behind working memory

Benjamin Thompson

Welcome back to the Nature Podcast, this week: an aurora on a cool brown dwarf…

Noah Baker

…and the workings of working memory. I’m Noah Baker.

Benjamin Thompson

And I’m Benjamin Thompson.

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Benjamin Thompson

First up on the show this week, we’ve got a bit of a space mystery for you. Over 40 light years from Earth there’s an object known as W1935. It’s a brown dwarf.

Jackie Faherty

So the definition of a brown dwarf is hazy.

Benjamin Thompson

This is Jackie Faherty from the American Museum of Natural History.

Jackie Faherty

They are objects that are in between stars and planets, so they just don't have enough mass to get hydrogen burning in their core. So the nuclear engine that drives our sun to shine, we don't have that in brown dwarfs. So a lot of times people like to call them ‘failed stars’ but I take offence at the word failure because who's to say they wanted to be a star in the first place. Like you could just as well call them overexcited planets and you have a really hard time distinguishing them from giant planets like Jupiter.

Benjamin Thompson

Despite their massive size, brown dwarfs like W1935 are difficult to spot.

Jackie Faherty

Oh, you've never seen one with your eye — I can I guarantee you that.

Benjamin Thompson

But you can see brown dwarfs with a telescope and that is what Jackie and her team have been doing, in part using the James Webb Space Telescope — the JWST. They wanted to learn more about what brown dwarves are made of and when they stumbled across W1935, well…

Jackie Faherty

Oh man, what can I tell you? It was discovered in part by a citizen scientist named Dan Castleton, who just happened to be volunteering and working with my team. And when we found it, it was just really, really cold looking. And we just wanted to know what kinds of things it was made of, we wanted to know how much ammonia it had, how much methane it had, and how much carbon chemistry did it have? We wanted to know how close to Jupiter it looked and that is what we tried to get out of the James Webb Space Telescope.

Benjamin Thompson

So you’ve used JWST then to look at W1935 to get a sense of what its atmosphere was like and what it was made of. And something really did pop out then when you looked at its spectrum using the telescope.

Jackie Faherty

Yeah, something popped out at us that confused us a lot at first. So we had a number of objects to compare it to. So that meant that we knew what normal could kind of look like. But in the case of 1935, it had a ‘bump’ is the best I can describe it to you. You can check out a figure from the paper and then see what I mean. And when I saw it, I turned to the modelers on my team and said, uh guys, what is the weird bump? And we searched and searched and searched for an answer when finally one of the modellers Caroline Morley said, maybe we should consider looking at Jupiter and comparing and we would be able to figure it out. And it could be emission, something glowing. And it turned out yada yada yada, that it does fit very well, with methane glowing, not absorbing light but emitting light. We're used to methane, it's all over these objects, but 99.9% of the time, it's absorbing. Why would it be emitting? You're not supposed to get emission in cold objects, because they're cold. My object radiates at about the temperature that you would cook something in the Great British Bake Off, like it's your oven temperature. So it's cold for a space-based object. It's very, very cold when you compare it to a star. So you don't expect features that emit which create these bumps in a spectrum.

Benjamin Thompson

And what's heating up then is kind of central to your work. Now, in many cases, you'd imagine that the heat would come from a star, right? But you suggest that this really isn't the case in this instance.

Jackie Faherty

Yeah, we have no star — this object is alone. We only know it as a single object. And without a host star, which was naturally that's what you start thinking we'll get — let's get that heat from somewhere, what kind of mechanism could do it? And we do see that within our own solar system, it's very clear that that's what happens. The sun has a solar wind that sends out some heat and it can heat the upper atmosphere of the other planets in our solar system Jupiter, Saturn, Uranus, Neptune, even Pluto can get a little bit of it. Our object has no host star, so we have to go to something else, as a helpful explanation.

Benjamin Thompson

And this mystery then of where this energy comes from is what you've been trying to figure out. And the conclusion you've come to is perhaps a rather unusual one, that maybe this energy is created by an aurora. I mean, let's talk about aurorae, I suppose, we're familiar with them here on Earth – I think of aurora borealis here in the Northern Hemisphere. How does that impart energy into the atmosphere?

Jackie Faherty

So what that is, is charged particles from the Sun interacting, both with our magnetic field, and then the atmosphere of the Earth. When those charged particles are glowing, when you see them glowing, there's energy coming from that and so that energy could then translate to a temperature change. Jupiter's got it too, there's beautiful imagery of the glowing that's coming out of its poles. That's why the conclusion that we drew for the extra phenomenon that we were seeing, that heat very likely could come from in auroral process. But you can already see we've got a problem because that auroral process has some ingredients that are necessary to make it happen.

Benjamin Thompson

And one of those is the charged particles, but the brown dwarf that you've been looking at you've said that there, well, there isn't a sun, there isn't a star to give those charged particles to make the aurora happen. So, the mystery then deepens here, if that's what's going on, where's it coming from?

Jackie Faherty

Well, that is the– that's the million dollar question out of our study, what is it that could be causing it? But right now, we just have ended in a speculative zone at the end of this paper to try and suggest that one fairly easy explanation, to get that plasma, would be from an unseen companion, that is spewing out a plasma that could get captured by the object if it had a strong magnetic field. And then the phenomenon would be very easy to see falling out from there.

Benjamin Thompson

And are there examples of that in the Universe that we can sort of draw parallels with?

Jackie Faherty

Yeah, so the aurora on Jupiter is also driven similar to how it's driven on Earth. But then Jupiter gets an extra bit and where does it get it from? Well, it gets it from one of its big moons, Io. And it happens to be the most volcanic place in the solar system. It is constantly erupting, spewing out material. And what we see is that material ends up contributing to the aurora on Jupiter, and you get these auroral spots that are linked to Io’s volcanic activity.

Benjamin Thompson

And so the working hypothesis then is that there potentially is something like that happening around W1935, around your brown dwarf.

Jackie Faherty

This is where I will emphasise the speculative part of where we're at. Could it be something else? I can't out rule anything, but this one feels the most likely to me. Another explanation could be an internal process. So, there's a gravity wave that suspected to happen maybe in the solar system too, where you get energy that pulses out from the interior of the planet all the way out towards the outer atmosphere. The problem with that process, though, is that it wouldn't just dump this heat into one portion of the atmosphere that would just heat the methane, we would have or should have seen more things in emission as that energy passed through other layers of the atmosphere. And the only part that we saw pop was the methane in this one portion of the upper atmosphere. So that seems to be more indicative that it's an external process.

Benjamin Thompson

And how might you go about answering the question as to what is causing this phenomenon this situation to happen? Like what are some of the key steps?

Jackie Faherty

Yeah, key step number one, we need more observations of the object. And we would like to get the radio observations down, so that we would be able to tell you how strong the magnetic field is on this object. The other thing that's a missing piece that I don't know is how fast it's spinning. So both of those would be critical to demonstrating that the auroral phenomenon hypothesis is the best one, because you can't get one if you don't have a strong magnetic field and you really can't get the ionosphere, which is the like, area where the plasma could be dumped into, unless the thing is spinning rapidly. So I also need the rotation rate of the object.

Benjamin Thompson

Now, your paper isn't the first evidence of an aurora in the atmosphere of a brown dwarf, but it is the coldest, and you'll be trying to figure out exactly what's going on. What will proving that this brown dwarf has an aurora — if that's what it turns out to be — why will this be important in kind of the cosmic scheme of things? I suppose.

Jackie Faherty

I mean, at the most basic level, it's a phenomenon that has gone under appreciated in exoplanets in worlds beyond our own. And extra heat in the upper atmosphere could definitely impact how we see life on worlds beyond our own. Aside from the fact that it could be showing us that a brown dwarf might have a world around it, and that's something we'd be very interested to understand how often it exists? How many more planets are unaccounted for? Because they're orbiting these ‘little engines that could’, brown dwarf objects.

Benjamin Thompson

That was Jackie Faherty from the American Museum of Natural History in the US. To read her paper about W1935 look out for a link in the show notes.

Noah Baker

Coming up, new research investigating how short-term memories are kept in mind. Right now, though, it’s time for the Research Highlights with Dan Fox.

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Dan Fox

The receptors needed to perceive the bitter taste of a hoppy beer or a black coffee have been found to have been present in some fish 450 million years ago. Bitter taste receptors help humans and other organisms to recognise potentially toxic compounds so that they can avoid consuming them. Now a team of researchers have scoured the DNA of 18 cartilaginous fishes, including sharks, rays and skates, for genes encoding these receptors. The researchers found that more than half of the species, including the great hammerhead, possess genes for bitter taste receptors that resemble those of humans. Like their human counterparts, the fish receptors are produced in the tastebuds allowing the animals to detect bitter substances. The authors say that this finding suggests that bitter taste receptors emerged earlier than previously thought and were already present in the common ancestor of jawed vertebrates. Hopefully that research won't leave a bitter taste in your mouth when you read it in full in Current Biology.

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If you've ever been on a flight and spotted a halo surrounding the aeroplane shadow, you've seen a phenomenon called a ‘glory’. Now for the first time, a team of astronomers have spotted one outside of our Solar System. The glory was observed occurring on an exoplanet called WASP-76b, a planet where one side continuously faces its star and temperatures exceed 2,400 degrees celsius. A team monitoring tiny changes in the light from the star saw a steep increase in the amount of light reflected back to Earth just before the planet’s orbit took it behind the star. The unusual sharpness of this spike suggests that a glory is beaming light in Earth’s direction. The researchers think it could be produced by light reflecting from clouds forming ahead of the frontier between the planet’s day and night sides, where the temperature drops radically. Bask in the glory of that research in Astronomy and Astrophysics.

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Noah Baker

If you cast your mind back a couple of weeks, you may remember Nick Petrić Howe talking about memory on the show. Back then he was investigating how DNA damage ultimately could lead to memories being stored — hopefully that did happened, and you remember what I am talking about!

But what about those fleeting memories that you keep in your head just as long as is necessary? Something like the name of a person you just met at a party, or the phone number that you’re about to dial, or even how I started this sentence.

These are known as working memories, they’re kept in your head for maybe a few seconds until you don’t need them anymore, then you probably forget them. If you're me, that inevitably includes you immediately forgetting the name of the person you just met.

But the fact is that working memory is tricky, and remembering those details, even for a few seconds, can be challenging.

Ueli Rutishauser

They are very susceptible to interference, as we all know. It’s certainly happened to me that I arrive somewhere and like ‘oh, why did I go here?’ So it’s that they require continuous focus to maintain them because if we even briefly get distracted they’re gone.

Noah Baker

This is Ueli Rutishauser, a neuroscientist who’s interested in how these fragile working memories are protected. It has been thought that there are certain persistently-active neurons that hold a memory as long as you focus on it, and then there are others that help maintain it, by helping you to not get distracted. But observing if this is actually what happens is tricky, as for a start it’s very difficult to look at the activity of individual neurons in humans.

However, there are certain procedures used to help people with conditions like epilepsy that allow researchers a window into neural activity. And this week in Nature, Ueli and his team have done just that and looked at brain activity whilst the working memory is being flexed. Nick called him up to find out more and Ueli started by laying out what researchers already know about working memory.

Ueli Rutishauser

So one of the classic findings in neuroscience, and there's literally hundreds of papers on this, is that you find brain oscillations of a particular kind. So there's theta brain oscillations, theta frequency oscillators, slow frequency oscillations, and superimposed on those theta oscillations are gamma oscillations. And these two are coordinated with each other – that's called phase-amplitude coupling. And phase-amplitude coupling is very prominent you see it over the frontal lobe very commonly during working memory maintenance and other activities that require attentional focus. So it has long been thought and theorised that phase-amplitude coupling its role or its function is to coordinate activity across the brain, and thereby control working memory and try to maintain it. So in this paper, we set out to test this theory directly for the first time at the single neuron level.

Nick Petrić Howe

And what did you find? Did you find that this theory is indeed what is going on during working memory? Or was it something else?

Ueli Rutishauser

Yes and no. So our initial hypothesis was that if phase-amplitude coupling is involved in controlling the maintenance of working memory, we theorised that phase-amplitude coupling should modulate the neurons that stored memories – meaning the maintenance neurons. So these neurons remained persistently active throughout the maintenance period. To our surprise, that was not the case. So we found a lot of neurons in the hippocampus, whose activity was coordinated by phase-amplitude coupling. But those were not the neurons that also maintained the memories, they were a separate group of neurons. So we observed that, indeed, when control was engaged, and when it was successful, those neurons were more modulated by phase-amplitude coupling but it was a separate subset of neurons. So ultimately, we ended up calling this group of neurons ‘PAC neurons’ for phase-amplitude coupling neurons. And sort of the second half of the paper is about what the properties of these neurons are, and how they ultimately control working memory content, despite being a different group of neurons.

Nick Petrić Howe

So the theory was that these maintenance neurons that maintain these memories, were the ones that were going to be more associated with these brain oscillations. But actually, it was a completely separate group of neurons that seemed to be more correlated, these PAC neurons are found in the hippocampus. So the idea is then that these two groups of neurons are kind of working together to make working memory work?

Ueli Rutishauser

Yes we think they are a reflection of these two different aspects of working memory with the PAC neurons being the control aspect and the maintenance neurons being the storage aspect. Now surprisingly, what we found is that these PAC neurons, they interact with the frontal lobe, so they coordinate their activity with oscillations in the frontal lobe. And this coordination was stronger when control was needed. So in our task, we showed the subject either three images to remember or one image. So the coordination of these PAC cells with the frontal lobe was stronger when the subjects were maintaining three images compared to when they only maintained one image. And this was only true for these PAC neurons. And it was not true for the maintenance neurons that maintained the memory, thus allowing us to claim that this is really the control aspect. But of course, this now leaves open the question how these two mechanisms interact and that's really the last part of the paper.

Nick Petrić Howe

So how is it then that you think they might be working together?

Ueli Rutishauser

Yeah so then ultimately, what we discovered what the PAC neurons do, they inject correlations into the population that make neural activity more correlated between the storage neurons. And these correlations are introduced, such that the information that the population carries is enhanced. Now, this was highly surprising because noise correlations, by and large are thought to be information limiting, meaning information destroying. So if things are more correlated, then there's less information. So this is one way the two systems could interact. And that's indeed, what we discovered.

Nick Petrić Howe

I mean, could it be working memory is very fragile, I guess, like it's easy to get distracted by something. Could these noise correlations be trying to almost I guess, remove the distractions or keep them out of your working memory?

Ueli Rutishauser

Yes, that's the idea.

Nick Petrić Howe

So what do you think this means then for our understanding of working memory?

Ueli Rutishauser

One of the really surprising aspects of this paper is that it has hippocampus in the title. So hippocampus is traditionally thought to be not involved in working memory, it's thought to be primarily involved in long-term memory encoding and storage. But in our paper, we also recorded from a number of other brain areas, including the nearby amygdala, several areas of the medial frontal cortex. And in all these other areas, did we find what we just discussed, this was very specifically a phenomena present in the hippocampus. And careful lesion studies have long indicated that this ought to be the case, because subjects with hippocampal damage, indeed, have problems with working memory, but only if there are distractors. So if there is no distraction, hippocampus is not required for working memory. But there is distraction or if the cognitive load is high, then this is very much the case. And in our paper, we would suggest that the reason why this is, is because the hippocampus plays a role in the control of working memory by interacting with the frontal lobe.

Nick Petrić Howe

And so what would you say are the sort of next steps for you? What do you want to find out next in this line of research?

Ueli Rutishauser

The fact that this mechanism is mediated by phase-amplitude coupling is very promising because phase-amplitude coupling this ultimately comes down to oscillations in the brain. And that's interesting, because such oscillations we can actually influence and modify using non-invasive stimulation. One of the things that we would really like to investigate is whether modulating phase-amplitude coupling through non-invasive brain stimulation would allow us to restore or improve working memory. And that will be a potential new treatment for working memory deficits, which, as I'm sure you know, are very prevalent in numerous diseases, including Alzheimer's, particularly at the early stages. That's like one of the early symptoms is working memory problems. So we want to explore whether one could use this for translational applications.

Noah Baker

That was Ueli Rutishauser, from Cedars-Sinai Medical Center, in the US. For more on that story, check out the show notes for a link.

Benjamin Thompson

Finally on the show, it’s time for the Briefing Chat where we discuss a couple of articles that have been featured in the Nature Briefing. Noah, why don’t you go first this week? What have you got for us?

Noah Baker

So yeah, I'm going to talk about some fairly bleak news this week. It's a story I read in the New York Times. Now, this is the announcement earlier this week that NOAA, the National Oceanic and Atmospheric Administration in the US, they've been working with a group of global partners, including the International Coral Reef Initiative to point out that we are now in the midst of the fourth global coral bleaching event.

Benjamin Thompson

I mean, the name kind of gives it away but that seems pretty awful, right?

Noah Baker

Yeah, indeed, it's certainly not good news. I think a little bit of a recap here on what we mean by coral bleaching. So when a coral is bleached, the symbiotic algae that lives inside coral is expelled – this happens in response to stress. In many cases, what we're talking about here is warming waters. And that leads the corals to have a white appearance. Now in the short term, this isn't great for corals but if that is left in that situation for too long it can lead to the deaths of the corals and that can take an awful lot of time to recover. Now, in this scenario, we're looking at a global coral bleaching event. And the way that this is determined is that researchers look at the extent of coral bleaching all over the world and in particular, they need to see that there have been bleaching events happening in all three ocean basins that contain corals all at once. And that is exactly what they've seen in this case.

Benjamin Thompson

I mean, we've talked on this podcast a fair bit about ocean heatwaves, I imagined that is probably related in this instance.

Noah Baker

Absolutely. So we'll get onto what this is related to in terms of global climate-patterns in a moment. But I guess, just a couple of numbers to indicate how problematic this is, in order for this to be a global bleaching event you need to see at least 12% of the reefs in each basin to be impacted. At the moment, we're looking at 54% of the world's corals that are experiencing bleaching and that is in large part due to heat stress over the past year. And there’s one of the researchers in this piece is quoted as saying, that that number is increasing by about 1% every week. So this bleaching that's being seen around the world is growing and spreading across all of these basins that contain corals, the Indian Ocean, the Pacific Ocean and the Atlantic Ocean.

Benjamin Thompson

Well, incredibly sobering numbers there. And what are the specific climate conditions then that you talked about?

Noah Baker

So obviously, all of this is happening in the context of a warming world as a result of climate change, but it is exacerbated in this case by the current El Niño cycle. So this is the only sort of slight silver lining, is that there is an expectation of this period of warming and this period of bleaching will be relatively short because of this enhanced El Niño effect coming to an end relatively soon. However, that isn’t to say that there might not be very long-term consequences of this kind of mass bleaching event. In particular, some of the corals that are being seen to have been bleached are corals that were previously thought to be relatively resistant to bleaching. Additionally, there are corals that are being bleached in zones of cooler water that were thought to be sort of refuges for corals. And so what we're seeing here is corals being affected more broadly than we've ever seen them affected before. In fact, people behind this research are saying that in a week or two, this event is likely to be the most spatially extensive global bleaching event on record.

Benjamin Thompson

I mean, goodness and of course, it's not just the coral themselves, they of course form habitats for fish and you know, other marine organisms as well.

Noah Baker

Absolutely. I mean, corals had been described by lots of people as like the ‘cradle of life’. There are lots of species that rely on coral, for nurseries, for example, when they're young. Corals also have a huge benefit to people as a resource, both in terms of people going in looking at them, of course, with tourism perspective, but also as a coastal defence, you know, corals absorb an awful lot of power from the ocean to protect inhabited areas. In fact, there have been some estimates that coral reefs are worth around $2.7 trillion annually, in terms of the services, the economic value that they provide to people.

Benjamin Thompson

To ask, what's to be done seems like a redundant question, right. Getting on top of climate change is, of course, the answer, but is there anything that immediately can be done in the short-term to ameliorate some of these pressing bleaching events?

Noah Baker

I mean, certainly, there are things that scientists are considering. So there are researchers in Japan, for example, that are looking to try to breed corals that are more resistant to bleaching, for example, to warming oceans. There's also been some evidence that corals have been migrating northward towards polar seas where things are cooler. But there's a lot of problems that have been raised about things like this migration, for example, because corals need access to sunlight. And as you go north, or as you go south towards polar regions, you decrease the consistency of the sunlight that reaches those corals, and that can cause problems and then being able to grow. Additionally, a lot of those seas get deeper, and you need to have shallow enough water for corals to be able to grow because they need to be able to access those wavelengths of light that get filtered out by water. And so in the short term, it's tricky to know exactly what you're going to do really, the overall message here is we need to slow down global warming. And to put that into some context, there was a 2018 report in the IPCC, the Intergovernmental Panel on Climate Change, that suggested that if the Earth is allowed to warm to 1.5 degrees above pre-industrial levels, that will lead to the vast majority of coral reefs being lost around the world. If it's allowed to get to 2 degrees, virtually all coral reefs will be lost. And we should point out that the current pledges by nations suggest that the earth is going to be on track for about two and a half degrees of warming. So this is a really significant problem that we need to be tackling right now.

Benjamin Thompson

We have covered a few times efforts to try and help the coral, I'm sure we'll continue to do so. Let's move on to my story today. And there is actually kind of a through line here, which we'll get to in a minute. But it's a story that that kind of had me going, ha, that's not normally how this works when I read the headline. And it's a story that read about in Nature and it's based on a paper in Science, and it's about nitrogen fixing, okay, now, this is a process that some microorganisms do to essentially turn molecular nitrogen N₂ gas into useful bioavailable compounds. Okay, now another organism has been found that can do this and it's rather unusual indeed.

Noah Baker

So when I think of nitrogen fixing, I think about nitrogen-fixing bacteria inside the roots of leguminous plants, peas, for example, allowing nitrogen to be fixed into ammonia or other equivalent things. What are we talking about here? Which organisms are able to fix nitrogen?

Benjamin Thompson

Yeah, well, I mean, you're absolutely right. So the textbook would say that nitrogen fixing happens in bacteria and archaea, right, so prokaryotes. Now researchers have shown that this new organism that can do it is a eukaryote, right? It's an algae, which is a completely different branch in the tree of life. So cells with a nucleus, right, eukaryotes, the sort of things that make up plants, that make up you and I. And the story here is in 2012, the team behind this work was studying this marine algae called Braarudosphaera bigelowii and apologies to anyone if I haven't quite got that right. And they saw that this algae kind of closely interacted with a bacterium called UCYN-A, okay, now this bacterium seemed to live either on or inside the algal cells, and the team hypothesised that it was converting nitrogen, as you say, into a useful compound, maybe ammonia or something and then the algae was giving something back. So that's the sort of symbiosis that you might see in the plant roots, for example, of course, coral are a symbiosis in a similar sort of way, right. So not an unusual thing to get a symbiosis like that either on or inside a eukaryote. But after studying it for a bit longer, they've suggested that this isn't two separate organisms. UCYN-A should be classified as an organelle, which is a fundamental sub-cellular structure that does a specific job like a mitochondria, okay. So they've called it a nitroplast. It's not two species anymore, it's one, with something else inside it.

Noah Baker

So this is exactly what scientists have hypothesised happened with the mitochondria, right? It was initially a symbiont, an endosymbiont that then became an organelle. And is this watching a similar process in action here, but for nitrogen fixing?

Benjamin Thompson

It seems like it might be and not just the mitochondrion, the chloroplast, as well is one of these potentially, it's thought it started life as a bacterium that got consumed and then off, we kind of go. And it seems that there are some key criteria to decide whether a bacterial cell has become an organelle. And even this is a bit hazy, to be honest with you. But it seems like in the first instance, the organelle, let's call it that must be passed down through generations of the host cell, right, they have to come together, because the root nodules that you talked about, they're picked up by the plant from the ground. And what the team here have done is they've imaged dozens of algal cells at various stages of cell division and found that this nitroplast splits in two just before the algal cell divides, there's one in the offspring cell and one in the parent cell. And the researchers also found that the nitroplast gets some of the proteins it needs to grow from the algal cell rather than making them itself. And one of the researchers quoted here says that this is quite a remarkable thing and they're quoted as saying, they really see all the hallmarks that we think is characteristic of organelles.

Noah Baker

I mean, it's really fascinating. And that is an awkward line to try to step along, you know, everything from an obligate symbiote, which we know exists, where you have symbiotic organisms that entirely rely on each other, but they are still two organisms all the way through to organelle, in which we can start to categorise this as part of one organism. I mean, from what you're telling me here, it feels like scientists are coming down on the side of you know what, maybe this isn't an obligate symbiont anymore, this is an actual organelle. What does this mean in terms of our understanding of the way that you carry it as work?

Benjamin Thompson

Yeah, well, I mean, it gives major insights into how this happens. Now, analysis from a previous study, they reckon the ancestors of the algae and the bacteria entered a symbiotic relationship around 100 million years ago. And then from that this has led to the nitroplast organelle. So the process of this happening, I suppose, in evolutionary terms is an interesting one to study. But could it actually be used as well? And that's something that researchers are interested in.

Noah Baker

I can absolutely believe they would be I mean, trying to create nitrogenous compounds is incredibly valuable from fertilisers and so on. And I can imagine that if there was some way to try to utilise this prokaryotic nitrogen-fixing entity, I can immediately see the eyes of biotechnologists lighting up thinking what could we do with this?

Benjamin Thompson

Yeah, I mean, one of the researchers themselves says that, you know, working out how the nitroplast interacts with its host cell could support efforts to engineer crops that fix their own nitrogen because say, getting atmospheric nitrogen and turning it into ammonia is really hard to do, right, bacteria and other microorganisms are brilliant at it. But for us to put sort of useful nitrogen into the soil we have to use like nitrogen-based fertiliser. So if we can engineer a plant that didn't need that, that would be quite something.

Noah Baker

A new organelle to create a self-fertilising crop. I mean, I can totally see why lots of people would be getting very excited about that. I'm imagining it's an awfully long way away from being able to actually be used.

Benjamin Thompson

Yeah, I mean, we're covering some ground here. I think we've compressed decades of research into a few sentences. And I think, you know, we kind of throw around that the textbooks will need to be rewritten, but it seems like they might. But let's leave it there for this week's Briefing Chat on that high note. And listeners, for more on those stories, and to get more like them delivered straight to your inbox look out for links in the show notes.

Noah Baker

And that's all for this week's show. But before we go, just time to let you know that we have a new video on our channel, all about the complicated workings of the biomechanical fly wing hinge. Now that's an awful lot of words, but it looks super cool. I'd encourage you to go and check it out. They've used AI, they've used robotics, they've used tiny little tethered fruit flies – there's a lot to see.

Benjamin Thompson

Yeah the fly wing turns out is one of the most intricate things that I've ever seen. I think you described it as like a clockwork mechanism that lets these little insects fly. So yeah, well worth a watch that one.

Noah Baker

And in the meantime, if you have anything that you would like to tell us do reach out to us on X, we're @NaturePodcast, or via email on podcast@nature.com. I'm Noah Baker.

Benjamin Thompson

And I'm Benjamin Thompson. Thanks for listening.