Horizon Magazine – More Than A Dodo

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

In the summer of 2014 a strange building began to take shape just outside MoMA PS1, a contemporary art centre in New York City. It looked like someone had started building an igloo and then got carried away, so that the ice-white bricks rose into huge towers. It was a captivating sight, but the truly impressive thing about this building was not so much its looks but the fact that it had been grown.

The installation, called Hy-Fi, was designed and created by The Living, an architectural design studio in New York. Each of the 10,000 bricks had been made by packing agricultural waste and mycelium, the fungus that makes mushrooms, into a mould and letting them grow into a solid mass.

This mushroom monument gave architectural researcher Phil Ayres an idea. ‘It was impressive,’ said Ayres, who is based at the Centre for Information Technology and Architecture in Copenhagen, Denmark. But this project and others like it were using fungus as a component in buildings such as bricks without necessarily thinking about what new types of building we could make from fungi.

That’s why he and three colleagues have begun the FUNGAR project – to explore what kinds of new buildings we might construct out of mushrooms.

Mushrooms might sound like an outlandish building material. But there is certainly good reason to drastically rethink construction. Buildings and construction are responsible for 39% of anthropogenic carbon dioxide emissions – and a whopping 21% of those emissions come just from the making of steel and concrete. Construction also uses vast amounts of natural resources. Take sand, one of the principal ingredients in concrete. It takes a special sort, with just the right roughness, to make concrete. These days it is a lucrative commodity and controlled in some parts of the world by sand mafias and stolen by the boatload from islands.

Such troubles are set to worsen over the next decades as the world’s population grows faster and gets wealthier. We need a lot more homes and if you do the maths, the amount we need to build is staggering. ‘It’s like building a Manhattan every month for the next 40 years,’ said Ayres, borrowing a line from Bill Gates.

Fungi bricks

Can fungi really help? Absolutely, says mycologist Professor Han Wosten at Utrecht University in the Netherlands. Fungi are not consumers of CO2 like plants are. They need to digest food and so produce carbon dioxide, like animals do. However, the organic waste streams (such as straw or other low value agricultural waste) that the fungi digest would be degraded to CO2 anyway, either by composting or burning. Plus, fungi bricks permanently fix some of that waste inside them and so act as a store of carbon. All this makes fungi buildings a climate win – and certainly miles better than using concrete, steel and bricks.

The mycelium composite can be grown over a woven scaffold for a period of 7-10 days, eventually encasing the structure. Image credit - FUNGAR/CITA, 2019-2020 — The mycelium composite can be grown over a woven scaffold for a period of 7-10 days, eventually encasing the structure. Image credit – FUNGAR/CITA, 2019-2020

The FUNGAR project began in late 2019 and so far Prof. Wosten has been experimenting with how to make building materials. At Prof. Wosten’s lab in Utrecht, the team have been combining mycelium, the ‘roots’ of fungi, with agricultural waste such as straw. Then they allow the fungi to grow for about two weeks, until the fungus has colonised the straw. This binds the straw together, producing a white-ish foam-like material. Then they heat-treat it to kill the organism. They can also process it, for example by applying coatings or by squashing it. ‘If we press it we can get a material like hardboard,’ said Prof. Wosten. By varying the type of fungi and agricultural waste, the growth conditions and the post-processing, Prof. Wosten says they are getting all sorts of candidate building materials with different mechanical properties.

‘It’s very early days to start saying your house will be made entirely of fungus,’ said Ayres. But parts of it already can be. Mogu, a company based near Milan in Italy, already produces and sells sound-dampening velvet-textured wall tiles and floor tiles based on mycelium foam. The company’s chief technology officer Antoni Gandia is another FUNGAR project partner. He said that Mogu is also developing mycelium-based insulation material for buildings.

Ayres is hoping that the FUNGAR project will go way beyond just using fungi-based products as components in existing building designs. He wants to think about what entirely new kinds of building might be made from fungi. Foremost in his mind is building with living fungus.

‘It’s very early days to start saying your house will be made entirely of fungus.’

Phil Ayres, Centre for Information Technology and Architecture, Copenhagen, Denmark

Living fungus

There are two principal advantages to this. First, living fungus might behave as a self-healing material, simply re-growing if it becomes damaged. Second, mycelium networks are capable of information processing. Electrical signals run through them and change over time in a manner almost akin to a brain. ‘We’ve discovered that fungal materials respond to tactile stimulation and illumination by changing their patterns of electrical activity,’ said Prof. Andrew Adamatzky at the University of the West of England in Bristol, UK, who is coordinating the project with Ayres.

The idea is that perhaps the very structure of a mushroom building might sense and respond to its environment independently. It might for instance sense when CO2 levels from the mycelium are building up and open the windows to release the gas, according to Gandia.

Building with living mycelium will be a big challenge. This is because the longer it grows, the more of the substrate material – the straw, or whatever waste – it decomposes. Since the straw gives the materials their structural integrity, allowing the fungi to grow for too long isn’t desirable. There may be ways around this though. Depriving the fungi of water puts it into a dormant state: alive but not growing. And so one of Ayres’ ideas is to construct walls with two layers of dead fungus enclosing a layer of living fungus inside. This set up would shut out water from the inner layer, keeping the fungus there dormant.

A creamy-coloured, slightly bumpy and curved panel created from a mould — Mycolite panels are made by pouring the composite into a mould. Image credit – FUNGAR/CITA, 2019-2020

One of the few other people who have explored working with fungi in construction is Jonathan Dessi Olive at Kansas State University in the US. He says that working with living mycelium is a very interesting new idea because it offers the possibility of the building being able to heal itself. But for him the real attraction of what he calls ‘myco-materials’ is that they ‘give us a way of reshaping how we think about the permanence of architecture.

‘What if some – not all – of our buildings were meant to only last a couple of years and could thereafter be recycled into shelter, food, or energy?’ he said.

The next major goal for the FUNGAR project is to build a small, freestanding building. They plan to pull that off within a year and then spend time monitoring it as it ages. It is crucial, says Ayres, to be able to monitor the living structure and see how it changes. It isn’t yet clear exactly what sorts of structures might end up being made from fungi, but they will probably start small. ‘I wouldn’t be crossing a bridge made of fungi, would you?’ joked Prof. Wosten.

You might be wondering what happened to Hy-Fi, that igloo-like structure in New York. The answer points to one of the most beautiful things about mycelium buildings. No wrecking ball or slow decay for them. It was taken down and composted.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

This post Why future homes could be made of living fungus was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

21 August 20201 October 2020

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Bees use shark ‘supersense’ to help find food

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Armed with sensitive antennae and wide-angled compound eyes, bees have a sophisticated set of senses to help them search out pollen and nectar as they buzz from flower to flower.

But new research is revealing that bumblebees may employ another hidden sense that lets them detect when a flower was last visited by another insect.

Professor Daniel Robert, an expert in animal behaviour and senses at the University of Bristol, UK, has discovered that bumblebees have the ability to sense weak electrostatic fields that form as they fly close to a flower.

‘A bee has a capacity, even without landing, to know whether a flower has been visited in the past minutes or seconds, by measuring the electric field surrounding the flower,’ Prof. Robert explained.

The discovery is one of the first examples of electroreception in air. This sense has long been known in fish such as sharks and rays, which can detect the weak electrical fields produced by other fish in the water. Water-dwelling mammals such as platypus and dolphins have also been found to use electric fields to help them hunt for prey.

But rather than hunting for fish, bees appear to use their ability to sense electrical fields to help them find flowers that are likely to be rich in pollen and nectar.

Charge
Bees develop an electrostatic charge because as they fly they lose electrons due to the air rubbing against their bodies, leading to a small positive electric charge. The effect is a bit like rubbing a party balloon against your hair or jumper, except the charge the bees accumulate is around 10,000 times weaker.

Flowers, by comparison, are connected to the ground, a rich source of electrons, and they tend to be negatively charged.

These electrostatic charges are thought to help bees collect pollen more easily. Negatively charged pollen sticks to the positively charged bee because opposite charges attract. Once the pollen sticks to the bee, it too becomes more positively charged during flight, making it more likely to stick to the negatively charged female part of a flower, known as a stigma.

Bees develop a positive electric charge as they fly, which helps them to collect pollen from negatively charged flowers. Image credit – Pxfuel.com/DMCA

But Prof. Robert and his colleagues wondered whether there could be more to this interaction. When they put an electrode in a flower, they detected a current flowing through the plant whenever a bumblebee approached in the air. Their study revealed that the oppositely charged flower and bee generate an electrostatic field between them that exerts a tiny attractive force.

To study whether the bees are aware of this electrostatic field, they then offered bumblebees discs with or without sugar rewards. Those with sugar also had 30 volts of electricity flowing through them to create an electrical field. They showed that the bees could sense electrical field and learn that it was associated with a reward. Without the charge, bees were no longer able to correctly identify the sugary disc.

Research by another group published shortly after Prof. Robert’s own work also showed that honey bees are also able to detect an electrical field. But exactly how the insects were able to do this remained a mystery, leading Prof. Robert to set up the ElectroBee project.

Very few animals have the capacity to read the stars and use it to find, north, south, east or west.
Professor Eric Warrant, Lund University, Sweden

Hairs
He has discovered that fine hairs on the bees’ bodies move in the presence of weak electrical fields. Each of these hairs has nerves at its base that are so sensitive they can detect tiny movements – as little as seven nanometres – caused by the electrical field.

Prof. Robert believes that when a bee visits a flower, it may cancel out some of the negative charge and so reduce the electrostatic field that forms when bees approach. This change in the strength of the electrostatic field could allow other bees flying past to work out whether a flower is worth visiting before they land, helping to save time and energy.

Other signals, such as changes in the colour and smell of flowers, happen in minutes or hours, while switches in electric potential occurs within seconds.

Prof. Robert and his team are now testing their theory that the electric field helps bees know which flowers to visit by counting visits by bumblebees to flowers in a meadow this summer and measuring electric fields around the flowers.

Their findings could help scientists better understand the relationship between plants and pollinating insects, which may prove crucial for improving the production of many vital fruit crops that rely upon bees for pollination.

Prof. Robert is also investigating whether bumblebees use their electrostatic charge to communicate to their nest sisters about the best places to fly for pollen.

But while bumblebees use their extraordinary sensory power to find food just a few kilometres from their nests, another insect is using another hidden sense to make far longer journeys.

The Bogong moth can travel more than 1,000km to hibernate in caves during the Australian summer. Image credit – Lucinda Gibson & Ken Walker, Museum Victoria/Wikimedia, licenced under CC BY-SA 3.0

In Australia, Bogong moths (Agrotis infusa) flitter steadily from various parts of the country and make their way towards the Snowy Mountains in the southeast. They fly for many days or even weeks to reach the high alpine valleys of the highest mountain range in the country, sometimes travelling over 1,000km. Once there, the insects hibernate in caves typically above 1,800m for the Australian summer, before making the return journey.

The only other insect known to migrate so far is the monarch butterfly in North America. But while the monarch butterfly relies in part on the sun’s position for navigation, the moths fly by night. Professor Eric Warrant, a zoologist at Lund University in Sweden, has been fascinated with how these insects, just a couple of centimetres in length, managed such a feat ever since he was a student in Canberra, Australia.

Moth mystery
He suspected that the moths might use the Earth’s magnetic field to find their way, so his team tethered moths to a stalk that allowed them to fly and turn in any direction before surrounding them with magnetic coils to manipulate Earth’s magnetic field.

For two years, experiments failed. While the moths did appear to be influenced by the magnetic field, they were using something else to navigate too – their vision.

‘It is a little like how we would go hiking,’ said Prof. Warrant, who is trying to unravel how the moths sense the Earth’s magnetic fields in his project MagneticMoth. ‘We’d take a reading from a compass, then look for something to walk towards in that direction, a tree or mountain peak.’

His research has already shown that the moths check their internal compass every two or three minutes and continue to make for a visual cue ahead. But what are the insects able to see at night?

Further research revealed something remarkable. When Prof. Warrant downloaded an open source planetarium programme called Stellarium and projected the Australian night sky above the moths, he discovered they were using the stars.

‘Very few animals have the capacity to read the stars and use it to find, north, south, east or west,’ said Prof. Warrant. ‘We (humans) learnt how to do it. Some birds do it.’

But insect eyes of bogongs mean they don’t simply follow one guiding star. Rather they are sensitive to panoramic scenes.

‘In the southern hemisphere, the Milky Way is much more distinct than it is here in the northern hemisphere,’ said Prof. Warrant. ‘It really is a stripe of pale light in which there are interspersed very bright stars.’ He believes that the moths are at least in part guided to their cool alpine caves by the light of the Milky Way.

Prof. Warrant believes that Bogong moths naviagte in part by using the Milky Way as a guide. Image credit – Dave Young/Flickr, licenced under CC BY 2.0

The discovery could also lead to the development of new types of navigation for our own species too. GPS, for example, relies upon a constellation of satellites that are vulnerable to disruption. Prof. Warrant believes studying an insect capable of flying 1,000km to a cave using a brain the size of a rice grain, could help us find alternatives too.

‘Animals seem to solve complex problems with little material and low amounts of energy,’ Prof Warrant said.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

This post Bees use shark ‘supersense’ to help find food was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

Top image: Fine hairs on bees’ bodies can sense tiny changes in electrostatic fields, enabling them to sense whether another bee has visited a flower before them. Image credit – Unsplash/George Hiles, licenced under Unsplash licence

15 November 201910 January 2020

More than a Dodo2 Comments

Changing climate is narrowing options for migrating birds

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Across an entire desert or ocean, migratory birds make some of the most extreme journeys found in nature, but there are still huge gaps in our understanding of how they manage to travel these vast distances and what a changing climate means for their migration patterns.

‘Some species of migrants might be affected by a changing climate,’ said Professor Stuart Bearhop, an animal ecology expert from the University of Exeter. ‘There is evidence from a number of populations that climate change probably is going to have some impact on the demography (population levels).’

Bearhop ran the STATEMIG project, which studied the migration of Brent Geese along their journey from Ireland to the Arctic where they breed. He found that the volatility of today’s seasons was affecting the geese’s population levels because the weather was playing havoc with their breeding patterns.

‘Wet years are predicted to increase with climate change as temperature rises, but, of course, because they travel so far north, it doesn’t mean rain, it means snow,’ he said. Brent Geese are more likely to breed when the weather is cold and clear, but when there is more snow there are fewer places to safely raise their young and feed.

The team observed that in the colder years the birds were breeding later in the year, causing ripple effects for their populations. The geese did not have enough time to raise their offspring to independence before winter, or there was not enough food for them to survive.

Bearhop says the snowy years saw more offspring die or be abandoned by adults. That means if snowy years persist then it could pose a long-term risk to the population of these birds.

Brent Geese

Bearhop chose Brent Geese because they follow a routine migration and their young stay with their parents for at least a year. These reliable patterns reveal useful insights into population levels and what could be affecting their migration.

To gather their data, STATEMIG researchers observed the geese in Ireland and Iceland before the birds flew to the Arctic to breed around July. In Ireland and Iceland they attached identity tags to the birds and took some physical measurements to use as reference points over several years.

When the geese returned to Ireland and Iceland around late August, with their chicks, the researchers could compare the population levels and get an idea of how environmental factors had shaped their journeys.

‘There are multiple factors that have likely driven the evolution of migration, these likely differ among species and the debate is about which ones are most important,’ said Bearhop.

Debate

Bearhop says the two key reasons birds migrate is because of a competition of territory and to take advantage of seasonal ‘pulses’ of vegetation growth or gluts of insects to ensure they have enough food to raise their young.

STATEMIG’s research emphasises the importance of the latter and Bearhop hopes it could lead to further research that explores how changes to feeding grounds will affect populations of migratory birds.

According to Dr Sissel Sjöberg, a bird migration researcher from the University of Copenhagen, Denmark, scientists understand some parts of why birds migrate, like knowing where they eat and breed, but they do not have the tools to accurately understand them during the entire migration.

For instance, there are high resolution tags that can be put on some big birds to track their location, but these do not fit on smaller birds which make up most of the ones migrating.

Tiny backpacks worn by noctural small birds contain a pressure sensor which provides an update every five minutes of the birds’ behaviour during migration. Image credit - Dr Sissel Sjöberg — Tiny backpacks worn by noctural small birds contain a pressure sensor which provides an update every five minutes of the birds’ behaviour during migration. Image credit – Dr Sissel Sjöberg

These tags also do not provide insights into other aspects, like altitude or how they traverse over huge, inhospitable areas where they may not be able to land, like the Sahara desert or the Pacific Ocean.

Dr Sjöberg is the principal researcher of the BIRDBARRIER project which is putting tiny backpacks on nocturnal small birds migrating long distances, such as red-backed shrikes and great reed warblers. These backpacks contain an activity log with a pressure sensor to determine heights and provide updates every five minutes of their behaviour during the journey, which can be correlated with weather forecasts or detailed landscape maps.

‘It is clear they go higher in their flights then we thought before,’ said Dr Sjöberg, adding that experts previously thought their size limited them to flying at 2,000-3,000 metres above sea-level, but she has observed them fly at almost 6,000 metres.

Dr Sjöberg says they could be doing this to find stronger winds that carry them longer distances, which require less energy to fly in and increase their chances of survival.

She says the biggest risk for these birds is to stop in the hostile terrains they cross because it could be difficult to take off again or find the same heights. Safe places to land are crucial to these birds on their intercontinental journeys because they have favourable conditions, including sources of food, but in some places they are getting smaller, for instance, in the Sahara where the desert is expanding.

‘Those (safe) areas are getting smaller and smaller so there is more competition,’ said Dr Sjöberg, who will continue to collect data from the backpacks for several more months before analysing it for some new insights.

She hopes that her research will help identify the most important areas for birds, which could help inform authorities on how to better protect these safe havens.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

This post Changing climate is narrowing options for migrating birds was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

9 September 201915 November 2019

More than a Dodo2 Comments

What colour were the dinosaurs?

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

What colour were the dinosaurs? If you have a picture in your head, fresh studies suggest you may need to revise it. New fossil research also suggests that pigment-producing structures go beyond how the dinosaurs looked and may have played a fundamental role inside their bodies too.

The latest findings have also paved the way for a more accurate reconstruction of the internal anatomy of extinct animals, and insight into the origins of features such as feathers and flight.

Much of this stems from investigations into melanin, a pigment found in structures called melanosomes inside cells that gives external features including hair, feather, skin and eyes their colour – and which, it now turns out, is abundant inside animals’ bodies too.

‘We’ve found it in places where we didn’t think it existed,’ said Dr Maria McNamara, a palaeobiologist at University College Cork in Ireland. ‘We’ve found melanosomes in lungs, the heart, liver, spleen, connective tissues, kidneys… They’re pretty much everywhere.’

The discoveries in her team’s newest research, published in mid-August, were made using advanced microscopy and synchrotron X-ray techniques, which harness the energy of fast-moving electrons to help examine fossils in minute detail.

Using these, the researchers found that melanin was widespread in the internal organs of both modern and fossil amphibians, reptiles, birds and mammals – following up a finding they made last year that melanosomes in the body of existing and fossil frogs in fact vastly outnumbered those found externally.

What’s more, they were surprised to discover that the chemical make-up and shape of the melanosomes varied between organ types – thus opening up exciting opportunities to use them to map the soft tissues of ancient animals.

Secondary

These studies also have further implications. For one, the finding that melanosomes are so common inside animals’ bodies may overhaul our very understanding of melanin’s function, says Dr McNamara. ‘There’s the potential that melanin didn’t evolve for colour at all,’ she said. ‘That role may actually be secondary to much more important physiological functions.’

Her research indicates that it may have an important role in homeostasis, or regulation of the internal chemical and physical state of the body, and the balance of its metallic elements.

‘A big question now is does this apply to the first, most primitive vertebrates?’ said Dr McNamara. ‘Can we find fossil evidence of this? Which function of melanin is evolutionarily primitive – production of colour or homeostasis?’

Choosing colours for dinosaur reconstructions is a combination of evidence, modern references, and artistic guesswork. Image copyright: Julius Csotonyi

At the same time, the findings imply that we may need to review our understanding of the colours of ancient animals. That’s because fossil melanosomes previously assumed to represent external hues may in fact be from internal tissues, especially if the fossil has been disturbed over time.

Dr McNamara says her research has also shown that melanosomes can change shape and shrink over the course of millions of years, potentially affecting colour reconstructions.

Further complicating the picture is that animals contain additional non-melanin pigments such as carotenoids and what is known as structural colour, which was only recently identified in fossils. In 2016, a study by Dr McNamara’s team on the skin of a 10-million-year-old snake found that these could be preserved in certain mineralised remains.

‘These have the potential to preserve all aspects of the colour-producing gamut that vertebrates have,’ said Dr McNamara.

She hopes over time that these findings and techniques will together help us to much more accurately interpret the colours of ancient organisms – though in these early days, she doesn’t have examples of animals for which this has already changed.

We’re just at the tip of the iceberg when it comes to fossil colour research.

Dr Maria McNamara, University College Cork, Ireland

Deep time

Many of the significant strides in this area have come out of a project that Dr McNamara leads called ANICOLEVO, which set out to look into the evolution of colour in animals over deep time – or hundreds of millions of years.

The project’s starting point was that previous animal colour studies largely omitted in-depth fossil analysis, leaving a significant gap by basing what we know about colour mainly on modern organisms.

But it has since led to even wider investigation. Dr McNamara says it is providing fresh hints on the kinds of biological structures and processes that are essential for survival in terrestrial and aquatic environments. ‘It looks like we’ll be able to look into much broader, exciting questions about what it means to be an animal,’ she said.

Part of her research on two fossils found in China even showed that flying reptiles known as pterosaurs had feathers, potentially taking the evolution of these structures back a further 80 million years to 250 million years ago. The fossils contained preserved melanosomes with diverse shapes and sizes, one of the tell-tale signs of feathers.

Two fossils found in China showed that flying reptiles known as pterosaurs had feathers, indicating the structures evolved earlier than previously thought. Image credit – Zixiao Yang

‘We were able to show for the first time that not only were dinosaurs feathered, but an entirely different group of animals, the pterosaurs, also had feathers,’ said Dr McNamara.

Another project she worked on, called FOSSIL COLOUR, compared the chemistry of colour patterns between fossil and modern insects. Again, says Dr McNamara, these don’t entirely map onto each other.

‘It’s already clear that the fossilisation process has altered the chemistry somewhat, so we’re doing experiments to try to understand these changes.’

What’s evident is that there’s lots still to find out about colour. ‘We’re just at the tip of the iceberg when it comes to fossil colour research,’ said Dr McNamara.

Thermoregulation

Other researchers agree that there’s more to animal colour than meets the eye. Dr Matthew Shawkey, an evolutionary biologist at Ghent University in Belgium, said that looking into properties and functions beyond colour’s use for visual means like signalling and camouflage will be critical to understanding its true significance.

‘For example, how do colours affect thermoregulation? Flight? Such functions may be complementary to, or even more significant, than purely visual functions,’ he said.

Dr Shawkey is looking into such questions, with one of his recent studies indicating that the wing colour of birds may play an important role in flight efficiency by leading to different rates of heating.

‘What started as a novelty of deciphering dinosaur colours has turned into a very serious field which is studying the origins of key pigment systems, how the evolution of colourful structures may have helped drive major evolutionary transitions like the origin of flight, and how colour is related to ecology and sexual selection,’ said Dr Steve Brusatte, a vertebrate palaeontologist and evolutionary biologist at the University of Edinburgh, UK.

Ultimately, we may be able to find out more about colour than once thought possible. ‘When I was growing up, so many of the dinosaur books I read in school said that we would never know what colour they were,’ said Dr Brusatte. ‘But as is so often the case in science, it was silly to treat this as impossible.’

He said he is excited to see what comes next, with the field just in its infancy: ‘Palaeontologists now have a whole new window into understanding the biology and evolution of long-extinct organisms.’

Top image: Aline Dassel/Pixabay, licensed under Pixabay licence

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

The article Fossil colour studies are changing our idea of how dinosaurs looked was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

19 March 201921 March 2019

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Bacteria keep us healthy – but could they keep us young?

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo. Our Bacterial World exhibition is open until 28 May.

A study in mice has indicated that the make-up of bacteria in the gut is linked with learning abilities and memory, providing a potential avenue of research into how to maintain cognitive functioning as we age.

It’s part of a field of research looking at the link between gut bacteria and ageing to help people live healthier lives in old age. The proportion of the EU population aged 80 or over is predicted to more than double between 2017 and 2080, with those aged 65-plus rising from 20 to almost 30%.

However, the connection between the make-up of microbiota in the gut, brain functions and ageing has been unclear – with cause and effect difficult to establish. Dr Damien Rei, a postdoctoral researcher into neurodegenerative and psychiatric diseases at the Pasteur Institute in France, decided to examine the different types of microbiome that appear in younger and older mice to understand better what might happen in people too.

Coloured scanning electron micrograph (SEM) of *Escherichia coli* bacteria (red) taken from the small intestine of a child. *E. coli* are part of the normal flora of the human gut, though some strains cause illness.

He found that when he transferred gut bacteria in older mice to young adult mice, there was a strong effect on reducing learning and memory. And when the opposite was done, with older mice receiving microbiota from younger mice, their cognitive abilities returned to normal. The older mice were aged about a year and a half – equivalent to about 60-plus human years.

‘Despite being aged animals, their learning abilities were almost indistinguishable from those of young adult mice after the microbiota transfer,’ said Dr Rei – adding that this indicated strong communication between the gut and brain. ‘When I saw the data, I couldn’t believe it. I had to redo the experiment at least a couple of times.’

Furthermore, by seeing what was happening to the neuronal pathways of communication between the gut and brain when the aged microbiota was transferred to the younger mice, they were then able to manipulate these pathways. By doing this, he says they could block or mimic the effects of the aged microbiota.

Dr Rei’s study, which was carried out as part of a project called Microbiota and Aging, has not yet been published, but he hopes this could happen by the end of the summer. He is also looking into human gut microbiota in older people and those with Alzheimer’s disease, but said it is too early to reveal further details about this research.

Translating

However, Dr Rei pointed out that there is a big challenge in translating results in mice to people, not only because of the significant ethical barriers, but also the differences in physiology. ‘The immune system of a mouse is very different to one of a human. The gut microbiota is also very different because mice eat very different things to what we do,’ he said.

Research is still a long way off from making real inroads into using this type of research to combat neurodegenerative diseases such as Alzheimer’s, says Dr Rei. Indeed, he says, there is no convincing evidence yet that looking at the gut microbiota is the way to go. But he believes the mouse study opens doors to further investigation into mechanisms behind age-related changes.

‘The data on the mice was really the first stepping stone, and it was a way for us to understand the potential of manipulating the gut microbiota,’ said Dr Rei.

Pinning down the link between gut bacteria and ageing is not straightforward, according to Dr Thorsten Brach, a postdoctoral researcher at the University of Copenhagen in Denmark. ‘It’s known that ageing is a multifactorial process and it’s hard, especially when it comes to the microbiome, to separate the effects of ageing specifically from all other aspects,’ he said.

He worked on a project called Gut-InflammAge, which looked at the link between gut microbes, inflammation and ageing, led by associate professor Manimozhiyan Arumugam.

As part of their work, the team investigated the effects of mild periodic calorie restriction in mice to explore the potential impact of healthy-ageing diets involving fasting. Unexpectedly, calorie-restricted mice accumulated more body fat – which the researchers speculate may have been down to overeating between these periods – but also saw a mild ‘rejuvenation’ of their blood profile so it more closely resembled that of younger mice.

Despite being aged animals, their learning abilities were almost indistinguishable from those of young adult mice after the microbiota transfer.
Damien Rei, Pasteur Institute, France

The researchers did observe a difference between the microbiota composition in the different groups, but overall in the study the differences found were not big enough to suggest more than healthy variability between individuals. The study therefore supported the view that diet and lifestyle are more critical than age and gender in shaping the microbiota, said the researchers – though Prof. Arumugam said it would be more revealing to follow changes in individual people’s microbiomes over time.

The studies carried out so far indicate there is still a long way to go in painting an accurate picture of the link between microbiota and the ageing process. Prof. Arumugam also pointed out that microbiome analysis is lagging behind technologically compared with genetics research, with disease cause and effect harder to establish than with genes.

But research is gradually improving our understanding. Prof. Arumugam said that though his team’s study did not achieve a ‘breakthrough’, it helped give more insight into this area and raised questions over previous assumptions.

And research in this area could ultimately change how we view ageing, says Dr Rei, seeing it as more fluid than just ‘a totally one-way road with no turning back, except in the movies like Benjamin Button.’

The research in this article was funded by the EU.

Top image: Flickr/Pedro Simoes CC BY 2.0

This post Bacteria keep us healthy – but could they keep us young? was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

25 February 20191 March 2019

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Bird immune systems reveal harshness of city life

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Researchers have found that many internal defence mechanisms that are quiet in rural birds are much more active in those in cities. These biological pathways are pumping out extra antioxidants, immune system cells and detoxifiers – a sign that urban life is challenging their health.

Globally, bird numbers are dropping. According to figures published by conservation organisation BirdLife International last year, 40% of bird species have declining populations while 7% are increasing in number. BirdLife cites urbanisation as a force destructive to many bird species, but a few do well in cities, such as the adaptable great tit, whose population is on the rise.

City wildlife have a different experience of predators, food availability and diseases than those in the country. This may be helpful to them – for example, humans leave food out for birds in their gardens. But they also have to cope with a fragmented habitat and with noise, air and light pollution. Scientists want to understand these forces in order to get a better grasp of the dramatic drop in some bird populations.

A research group in Sweden has been studying great tits living in 500 nestboxes in the city of Malmö, and a similar number in the forest. Great tits were chosen partly because they are well-studied and also because their use of nestboxes makes it easy for researchers to locate and examine them. The researchers check the boxes weekly during spring, weighing chicks with tiny balances, measuring them with adapted rulers, and tapping them for blood, according to Dr Hannah Watson, an ecologist at Lund University in Sweden.

An early study revealed that the urban birds had higher levels of antioxidants circulating in their blood than rural birds – a defence mechanism against attack from free radicals – toxic versions of oxygen atoms.

‘Exposure to air pollution would generate more free radicals (in the body) which can then increase what’s called oxidative stress – a kind of cellular level stress,’ said Dr Watson. ‘The free radicals cause damage to DNA, lipids, proteins – all the macromolecules in the cell.’

Switched on
To explore the consequences in more detail, she compared RNA (a counterpart to DNA) samples between the two populations, in a project called URBAN EPIGENETICS.

While genes code for the structure and maintenance of a living thing, they only function if they are switched on – or expressed. This happens via a bit of chemistry, methylation, which can be triggered by environmental factors.

Dr Watson found that genes responsible for the city birds’ immune responses had been upregulated, implying that they were fighting off more infections than rural birds. Similarly, other genes, such as those for neutralising poisons, for inflammation and for antioxidant production to combat free radicals, were also switched on.

‘It’s only the birds of really good quality that are able to actually survive the nestling period in the city.’
Dr Hannah Watson, Lund University, Sweden

‘We showed big differences in terms of the genes that are expressed and the levels they are expressed at,’ she said. ‘We interpret this as being consistent with our prediction that birds living in the city are exposed to more of these environmental stressors.’

But this doesn’t necessarily mean that urban birds are suffering, says Dr Watson. ‘It could just indicate that they’re able to respond and cope.’

To understand whether the birds were taking urban stress in their stride, Dr Watson joined a study led by one of her colleagues in which they measured the caps – telomeres – at the ends of the birds’ chromosomes.

Over the last decade, scientists have shown that telomeres gradually shorten each time a cell divides, and also in response to other stressors, eventually reaching a stage of senescence, or deterioration, which corresponds to an organism’s old age and death. In fact, the length of a creature’s telomeres, it turns out, seems to foretell its lifespan. The team conjectured that, if the urban stresses were actually affecting the great tits’ ability to survive, this would be revealed in the lengths of their telomeres.

They found that city chicks that were ready to fledge had on average shorter telomeres than those of fledgling forest chicks.

Great tits living in urban areas fight off more infections than their rural cousins. Image Credit - CC BY-SA 4.0 — Great tits living in urban areas fight off more infections than their rural cousins. Image Credit – CC BY-SA 4.0

Weeded out
Those with the shortest telomeres were less able to cope with urban stresses and died before reaching adulthood. Paradoxically, that meant that adult great tits in the city were likely to be stronger than the average forest adult because the weaker ones had been weeded out.

‘It’s only the birds of really good quality that are able to actually survive the nestling period in the city,’ said Dr Watson.’ In fact, the researchers think that while multiple stressors in the city are wiping out younger, weaker birds, they may not be of much consequence during adult life for those tough enough to make it that far.

Urban living may also mean that the social structures that served a species well in the natural habitat have become no longer necessary or even harmful.

House sparrows in the wild, for example, compete with each other for food according to a dominance hierarchy that is determined largely by size. But in cities, there are two key differences – food is more abundant and house sparrows are smaller, possibly because they don’t need to store body fat since winters are milder. Either factor could undermine the way they normally compete for food.

Likewise, house sparrows are known for the way they cooperate to mob potential predators. But when the danger shifts from a bird of prey to a cat or dog, this behaviour could become redundant.

With their numbers in decline, but still strong at as many as 1.3 billion globally, their toughness, aggression and ability to survive around humans suggests they seem to do well in urban areas.

Dr Lyanne Brouwer, an animal ecologist at Radboud University Nijmegen in the Netherlands, is studying house sparrows in a variety of urban habitats as they engage in their cooperative and competitive behaviours in a project called UrbanBird, which runs until 2020. She is using observations gathered by ordinary people, as well as her own field work to understand the causes and longterm effects of any behavioural change in the way house sparrows interact with each other. Ultimately this could help predict how urbanisation could affect other species and biodiversity.

‘It’s really interesting to see that all the factors that could affect social behaviour, like for example food availability or the predators that are around, are all very different in cities – so how would that affect these social behaviours? It turns out there is basically nothing known about how such behaviours change in cities,’ she said.

The research in this article was funded by the EU.

This post Bird immune systems reveal harshness of city life was originally published on Horizon: the EU Research & Innovation magazine | European Commission.