Read on to learn what this fascinating superpower is and why magnetotactic bacteria work like a compass.

What are magnetotactic bacteria?

So-called magnetotactic bacteria are those bacteria that sense magnetic field lines and align with them. They then decide whether they swim toward the North or the South.

To actively swim through water, magnetotactic bacteria, like many other bacteria, have flagella. And they can have one flagellum on one side or one on each side or a bundle of flagella.

So far, researchers found magnetotactic bacteria on the whole planet and they mostly live in water sediments and oceans. Some magnetotactic bacteria even live in extreme spots like the hot springs in northern Nevada. Here, they grow happily at about 55 °C. 

Researchers gave these fascinating bacteria names that already let you guess their superpowers: Magnetospirillum magnetotacticum, Magnetospirillum magneticum, Magnetospirillum gryphiswaldense, Magnetococcus marinus or Desulfovibrio magneticus. And obviously, scientists keep discovering new species that can sense magnetic field lines.

Okay, now we know what magnetotactic bacteria are. Let’s look at what gives magnetotactic bacteria their superpowers to read magnetic field lines.

What are magnetosomes?

Magnetotactic bacteria can sense magnetic field lines because they have so-called magnetosomes.

Magnetosomes are tiny crystals of iron oxide or iron sulfide. And these crystals are surrounded by a lipid membrane within a so-called organelle. Magnetosome organelles lie within the bacterium and import and export iron from the bacterial cytosol.

These magnetosomes can have different shapes and sizes. Some crystals are cuboctahedral, prismal-shaped or even bullet-shaped. Like the super cool magnetosomes in the pictures below.

As you can see in the pictures, bacteria do not only have one magnetosome but several. And these magnetosomes can align in a perfectly straight line or cluster together on one side of the bacterium.

For a magnetosome chain or cluster to work, bacteria need to keep their shapes perfectly. For this, magnetotactic bacteria use so-called scaffold proteins. These scaffold proteins position the magnetosome within the bacterium and hold this chain in its place.

How do magnetotactic bacteria grow magnetosomes?

Because magnetosomes are made of iron, magnetotactic bacteria have very special iron uptake systems. These iron importers help the bacteria get as much iron into the cell as possible.

Then the bacterium needs to transport the iron toward the magnetosome. The problem is that free iron is actually toxic to the cell.

Hence, the bacterium needs to assure the iron does not come into contact with the cell content. Therefore, magnetotactic bacteria produce iron transporters that shield the iron from the surrounding. 

Now, the bacterium needs to carefully crystallise the iron to grow the magnetosome. This process is actually not well understood yet and researchers are on it to shed light on it.

Okay, now we know what magnetosomes are and how they are formed. Let’s look at how magnetosomes help bacteria sense the Earth’s magnetic field.

How do magnetotactic bacteria sense magnetic field lines?

Because magnetosomes are highly-concentrated iron crystals, they have a magnetic dipole. And since a bacterium has many magnetosomes aligned in a straight line, the magnetic dipole is increased.

So, the magnetosome chain works similarly to a compass needle and aligns along magnetic field lines. Just as a compass needle aligns with magnetic field lines and you align your position according to the compass needle.

And we have the scaffolding proteins that keep the magnetosome chains in place within the bacterium. Because of them, the whole bacterium aligns with the magnetosomes. So, when you think about it; the bacterium aligns with the magnetic field lines in a passive way.

Imagine you put a worm on a compass needle that it can’t move away from. The compass needle will always point North and thus the worm will always point North as well. So, no matter where the compass goes or how fast you turn yourself with that compass, the needle and the worm will always face north. But the worm is only aligning North passively. Same as the bacterium.

As we said at the beginning, magnetotactic bacteria always have a flagellum that helps them swim around. Similar to other motile bacteria, a bacterium swims because it rotates its flagellum. This moves the bacterium forward or backward.

But since the magnetotactic bacterium is aligned to the North or South, it will only swim toward the North or South.

And researchers found that magnetotactic bacteria can be either North-bound or South-seeking. Hence, depending on whether the bacterium lives in the northern or southern hemisphere, it will swim towards the North- or the South pole.

So, next time you want to hitchhike on a magnetotactic bacterium, ask it first where it is going!

Why do magnetotactic bacteria sense magnetic field lines?

Researchers do not have a clear answer to this one yet.

One hypothesis is that within the depth of the water, a bacterium has three dimensions to align to, swim to and explore. By aligning the bacterium to the Earth’s magnetic field, the bacterium only moves in one dimension. This makes the search for the perfect location easier. Otherwise, bacteria might swim aimlessly in all three dimensions and get lost.

Also, most magnetotactic bacteria are chemotactic and even aerotactic. This means they move towards oxygen – again to find the perfect spot to live and to find nutrients.

And some magnetotactic bacteria are even phototactic and swim away from blue light. Researchers think that because blue wavelengths are a sign of deep water, bacteria are trying to avoid going too deep. But this still needs some more research.

Do magnetotactic bacteria help other organisms?

Researchers found an amazing example of a symbiotic relationship in the microbial world.

They discovered magnetotactic bacteria that live on a eukaryotic protist. The two species exchange metabolic molecules, so they feed each other.

What I find really fascinating is that these two species together become a swimming magnetic superorganism. The researchers saw that the magnetotactic bacteria completely cover the surface of the protist. And because the magnetotactic bacteria have magnetosomes, they align with the magnetic field. Thus, the entirety of bacteria on the protist aligns the whole protist with the magnetic field. 

Interestingly, this species of magnetotactic bacteria lost their flagella during evolution. So they are unable to swim. But the protist still has a swimming rotor. Thus, because of the symbiosis, this multi-organism is able to sense and swim along the magnetic field lines. 

Magnetotaxis – a bacterial superpower

Okay, I hope I could convince you yet again how amazing bacteria are and that they do have superpowers.

Again, it is not a hundred percent clear yet, how sensing magnetic field lines help bacteria to survive. But as usual with evolution, if some species kept such an impressive superpower, it must have a big advantage. 

We just don’t understand it yet.

The post How bacteria read and follow the Earth’s magnetic field appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Gladly, we learned to use some of these bacterial superpowers to improve our own lives. This means that bacteria and their superpowers are pretty much everywhere you look. You can find their impact in the food you eat, the medicine you take or the bioplastics you use.

So, yes, you probably use microbes and their superpowers daily without even realising. In this article, we listed 20 of the most fascinating bacterial superpowers and how they help not only bacteria but also us.

Bacteria know exactly where they are going

Bacteria have a so-called flagellum with which they can swim in liquids. This flagellum works together with the super responsive chemotaxis system.

This fascinating mechanism helps bacteria understand where beneficial nutrients or harmful compounds are. The bacterium then decides to swim towards or away from that compound. Chemotaxis is thus essential for the survival of bacteria.

Read Chemotaxis helps bacteria move towards goodies

Bacteria are high-speed swimmers

With the above-mentioned flagella, bacteria can move in liquids. When they rotate their flagella, they can swim in one direction which helps them find nutrients or escape harmful situations.

Interestingly, the Olympic recordist for 50 metres freestyle swims 1.17 body lengths per second. However, the bacterium Escherichia coli swims 15 body lengths per second and the tiny Bdellovibrio bacteriovorus swims even 10x faster, moving 160 body lengths in one second.

Read Bacteria wrap themselves in their swimming flagella

Floating veils for large bacteria to attach to and fetch nutrients

Bacteria produce oxygen and give superpowers to everyone

This may sound a little trivial because we take oxygen for granted. But bacteria known as cyanobacteria first produced oxygen on this planet. A large part of the atmosphere’s oxygen today is produced in oceans by these bacteria and other single-celled organisms.

You can also find more on cyanobacteria in this article.

Bacteria can produce electricity

Some bacteria can align into long filaments – so-called cable bacteria. This alignment allows bacteria to produce electrons on one side by oxidizing metals. They can then transport the electrons along the filament. Bacteria on the other side of the filament use these electrons for oxygen reduction.

Thus, bacteria produce an electric current within certain water sediments, which researchers measured. Maybe one day they can use these filaments in some kind of seawater-based batteries.

Read Cable bacteria – unusual bacteria conduct electricity

Bacteria use superpowers to align to the magnetic fields

Some bacteria, like the Magnetospirillum, that live in water, have so-called magnetosomes. These are storage units for iron crystal-like structures. The iron inside can align with a magnetic field and even along the magnetic Earth field.

These aligned magnetosomes then give magnetic momentum to the bacterium. Based on that, the bacterium aligns itself with the magnetic field and can find an optimal location in its environment.

Read How bacteria read and follow the Earth’s magnetic field

Bacteria can reduce and produce gold – highly valuable bacterial superpowers

In gold mines in Australia, researchers found bacteria that form biofilms on gold particles. For example, the bacteria Delftia acidovorans and Cupriavidus metallidurans can reduce toxic gold-ions to elementary gold.

This means that these bacteria are directly involved in the biogeochemical cycling of this precious metal.

Bacteria kill their competitors

To survive and grow, bacteria have learned to outcompete other bacteria and microbes. For this, they developed fascinating nanoweapons that kill their competitors and leave them as the sole survivor.

Interestingly, there are several different of these bacterial nanoweapons, all working slightly differently. Read more about this bacterial superpower:

Bacterial killer weapons as biocontrol to protect plants

Nanoweapons make the killer differences in bacterial siblings

Understanding the type 6 secretion system spike of a bacterial killer machine

Bacteria and contact-dependent growth inhibition: Death on a stick

Bacteria have various superpowers to protect their hosts

Microbes and bacteria live in and around bigger organisms like the human body, plants or animals. They developed fascinating mechanisms to protect their hosts and support them in different ways.

Bacteria might help them digest food, help them grow or fight off harmful intruders. For example, our bodies would not work without the microbiome – all those microbes and bacteria in and on us. Read more about the human microbiome:

How bacteria in your gut microbiome defend pathogens

Bacteria on your hands strengthen your unique skin microbiome

“Follow your gut instinct” – how your gut microbiome influences your mental health

How a healthy gut microbiome protects you and how to keep its superpower

Bacteria and their superpowers light the way

Some bacteria have the superpower to produce light in a process called bioluminescence.

Interestingly, bioluminescent bacteria often live with other organisms in symbiosis. For example, some bioluminescent bacteria occupy the lure of the female anglerfish. This fish also uses them as a fishing rod for hunting.

Bacteria withstand heat and cold

Whether too cold or too hot. Some bacteria really don’t care.

Certain bacteria can survive at temperatures as low as -20°C, which is why they are called hypothermophiles. On the contrary, other bacteria live in hot water steams up to 122°C. Similarly, these bacteria are hyperthermophiles.

These extremophiles have special repair enzymes to keep their DNA and cell envelope intact even at such extreme temperatures. Consequently, some of these enzymes are being used in research and are daily tools in each research lab. Learn more about extremophiles:

Even at the dark and cold bottom of the sea, microbes flourish

Bacteria tolerate harmful radiation

Another extreme-loving bacterium: the radiotolerant Deinococcus radiodurans. This bacterium has very efficient proteins to protect its DNA. Plus, it produces special DNA repair machines. They super quickly recognize and repair any damage in the DNA after exposure to radiation.

With these mechanisms, these extremophiles can survive exposure to ionizing radiation. Some bacteria even survive in the cooling systems of nuclear reactors.

Bacteria go to sleep by forming spores

Some bacteria can form so-called spores which are bacteria “on hold”.

Bacteria go into this state in times of greatest starvation or drought. Their aim is to keep its genetic material safe while turning down all non-essential functions. In this state, bacteria do not have an active metabolism nor do they interact with the environment. They solely wait for better times to come until nutrients become available again.

Bacteria produce some of our favourite foods

Did you know that bacteria produce many of the foods you are consuming? By fermenting sugars to alcohols or acids, lactic bacteria and some yeasts give a delicious taste to common foods like cheese, yoghurt and kefir, kombucha, kimchi and sauerkraut, beer and wine, as well as chocolate.

Reason enough to be grateful for bacterial superpowers to produce amazing foods.

Bacteria can endure high pressure in the deep sea

Researchers found bacteria that can live up to 10 km deep inside the ocean. Yes!

This means these bacteria can endure pressures of up to 100 MPa. But, researchers don’t know yet how these bacterial cells function at such high pressure. However, they think that the proteins inside these bacteria form some kind of super glue-like complexes. This would then make the bacterial content more viscous to endure the pressure.

Read Even at the dark and cold bottom of the sea, microbes flourish

Bacteria produce oil

Many microorganisms, amongst them bacteria, produce natural oils which is why they are called oleaginous microorganisms. Mainly algae, bacteria and yeasts can produce biodiesel, while fungi, and some algae can produce healthy omega-3 fatty acids.

Now, researchers focus on engineering these organisms to enhance the accumulation of produced lipids, biodiesel and omega-3 fatty acids.

Bacteria repair their DNA super efficiently

Bacteria have to endure all sorts of environmental stresses, for example, temperature changes, antibiotics or challenges by competitors. To ensure that under all circumstances, their DNA remains undamaged after an attack, bacteria developed incredibly efficient DNA repair and fixing machines. These machines recognise any small damage in the DNA.

Read

How does Salmonella deal with stress – a journey through the human body

Bacteria destroy proteins to understand the environment

Bacteria nucleate ice and let it rain

Some bacteria can trigger water to form ice crystals at temperatures close to the melting point. One of these bacteria is Pseudomonas syringae.

This bacterium has special proteins on its outer surface that interact with water and triggers ice formation. These bacteria are even used to produce artificial snow in winter sports areas around the world.

Bacteria keep our environment clean

Some bacteria surely love their heavy metals! Many bacteria have special enzymes to reduce toxic metal ions. These bacteria are even used to clean waste in industrial waters or mines and are the basis for green chemistry.

Read Microbial bioremediation: microbes cleaning-up our toxic messes

Bacteria can change our blood types for a short amount of time

Some bacteria live in our blood and when they get hungry, they start cleaving off sugar molecules from our red blood cells. While this is not harmful to us at all, in clinical tests, this may look like a different blood type than our original one.

However, as soon as the body produces new blood cells, they will have our original sugars and therefore our normal blood type.

Read Bacteria changing blood types

Some bacteria are super small

Super small but super powerful!

While bacteria have all these superpowers, I am most amazed by the fact that they are so tiny and yet SO powerful. All these superpowers in such a small box!

To actually see bacteria, we need microscopes. And to have really good photographs of them, we then need EXTREMELY good microscopes. Look at the bacterial cells in the pictures here! They are just about 2 micrometres long…

Thank bacteria and their superpowers

After having read this list of bacterial superpowers, are you even more amazed by our bacterial friends now? Which of these bacterial superpowers is your favourite? Which of them would you like to learn more about? Let us know in the comment section below or send us an email with your question. We’re looking forward to hearing from you!

The post The incredible superpowers of bacteria: unveiling nature’s tiny heroes appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world