And only thanks to pigments, life on Earth is possible. Pigments were the first molecules that microbes used to harvest sunlight. Microbes could then transform the light energy into chemical energy and produce oxygen.

Even the brown-reddish haemoglobin in your blood is an essential pigment as it transports oxygen within your body. Also for bacteria, pigments and their colours have life-saving functions. Here, we will look at how biopigments colour the bacterial world and what bacteria gain from producing them.

Bacterial pigments bring colour to the world of bacteria

Biopigments are molecules with complex chemical structures and at least one excited electron. Depending on the electron’s arrangement, a pigment absorbs light at a specific wavelength. It reflects the colour of the unabsorbed wavelength, which gives the pigment its colour.

As the function of pigments depends on the incoming light, sunlight plays a crucial role for bacteria with pigments. By adding certain pigments to their membrane, bacteria can adapt to environments that are directly affected by sunlight or the lack of it. This gives them an advantage over those bacteria that lack these pigments.

However, some bacteria also use pigments for other purposes, which we discuss further in this article.

Microbes harness photosynthetic power with colourful pigments

Sunlight is incredibly powerful since each light photon contains energy. Bacteria adapted to harvest energy from sunlight with special pigments.

Pigments can capture the incoming photon and transfer its energy to other molecules. This process transforms the incoming light energy into chemical energy. So-called phototrophic microbes are those that gain their energy from light.

The best-known example of a photosynthetic biopigment is chlorophyll in plants, algae and cyanobacteria. Cyanobacteria produce several complexes of bacteriochlorophylls to absorb blue and red light. As the green light is not absorbed, it is reflected, which is why chlorophyll – and thus cyanobacteria, algae and plants – are green.

Some bacteria harvest more light by producing several pigments of different types. They then arrange them in an optimal formation according to the incoming light.

For example, carotenoids capture energy in the green-blueish range and pass it on to the associated chlorophyll. Together, these photosynthetic complexes absorb light energy from almost the entire wavelength spectrum.

Halophilic bacteria and archaea are microbes that produce carotenoids to capture sunlight. You may have seen salt ponds with a reddish colour. This comes from the red and pink-coloured archaea Halobacteria, bacteria Salinibacter or algae Dunaliella. Thanks to their colourful carotenoids, these microbes adapt to salty waters that are exposed to direct sunlight.

Cyanobacteria in the deep sea, lagoons, lakes, ponds or rivers produce similar molecules to chlorophyll. These absorb the blue-green light in water, which allows these bacteria to survive in these dark environments. If you have ever seen a lagoon shining yellow or orange, this was probably due to the colourful cyanobacteria inside.

Bacterial biopigments protect from too much light

As light is full of energy, bacteria also need to protect themselves from getting burned. For this, they produce pigments that take up the excess light energy. Like this, the main photosynthetic complex does not get damaged.

Carotenoids and xanthomonadins are the colourful sun blockers of the microbial world. These molecules absorb high-energy light to protect chlorophyll from damage. Over 600 different carotenoids were described and they usually come in yellow-orange-reddish colours.

The yellow xanthomonadins absorb wavelengths within the energy-rich UV spectrum. Bacteria like Xanthomonas campestris live on plant leaves where they are exposed to direct sunlight. Hence, their yellow xanthomonadin coats are like self-made sunblocks protecting the bacteria.

Also, the pigment melanin shields the producing cell from energy-rich sunlight. Many bacteria living in the soil or bacterial spores produce these pigments. Here, melanin absorbs light from a wide range of the light spectrum to protect the inner of the cell. Hence, melanin-producing bacteria, like Vibrio cholerae and Streptomyces bacteria, are brown or black.

Bacterial pigments let electrons flow and save energy

Since bacterial pigments allow electrons to flow, they can also be energy conductors. Hence, some pigments are important components of energy complexes and synthesis machineries.

For example, yellow flavins are pigments involved in cellular metabolism. The main flavin is riboflavin, which you may know as vitamin B12. This essential molecule – produced only by bacteria – allows our bodies to work.

Phenazines are unique bacterial pigments with yellowish-green fluorescent colours. Pyocyanin, exclusively produced by Pseudomonas bacteria, shuttles electrons – and thus energy – during the respiration process. Hence, pyocyanin is essential for Pseudomonas as it keeps the bacteria healthy and alive.

Some biopigments have anti-oxidant effects

Bacterial pigments don’t just help adapt to external environmental conditions like the sunlight. They also guard the inner bacterial cell from stressful situations.

Excess or uncaptured energy or escaped light photons can react with oxygen. This process produces so-called oxygen radicals, which can damage molecules inside the bacterium. Known as oxidative stress, oxygen radicals can even become life-threatening for bacteria.

Carotenoids and xanthomonadins protect bacterial cells from oxidative stress. These pigments transform the free oxygen radicals into harmless molecules. Since carotenoids and their product vitamin A have similar functions in humans, it is only healthy for us to take up a lot of these with our diet.

In the bacterium Gemmatimonas aurantiaca, orange carotenoids also work like sunscreen and oxidative shield. These pigments both give the bacterium its bright orange colour and protect it from too much sunlight.

Bacteria combat microbial enemies with coloured pigments

As night falls, many bacterial pigments reveal their darker sides. They become important weapons for microbial warfare. Without sunlight, several pigments take on roles as virulence factors and antimicrobials as they mess up cells’ energy and oxygen household.

For example, prodigiosin is the red weapon of Serratia marcescens. As prodigiosin inhibits the growth of several bacterial, fungal and insecticidal pathogens, Serratia marcescens is an important biocontrol bacterium of plant disease.

You may have seen prodigiosin-producing Serratia bacteria on contaminated food. They develop these red, blood-like dots.

Violacein is a purple pigment with anti-viral, anti-bacterial and anti-cancer properties. For example, Chromobacterium violaceum sends membrane bubbles filled with violacein to kill bacterial enemies.

Similarly, Janthinobacterium lividum protects frogs and salamanders as it lives on their skins. Here, the bacterium throws violacein at pathogenic fungi that would otherwise infect and harm the animals.

Pyocyanin, the fluorescent electron-shuttling pigment in Pseudomonas, is also very sensitive to oxygen. It even turns Pseudomonas aeruginosa cultures in the lab blueish just by shaking and airing them.

Yet, not all bacteria have an appropriate coping mechanism for pyocyanin. Hence, these bacteria suffer oxidative stress when they come into contact with this pigment. This is why Pseudomonas uses pyocyanin also to fight bacterial and fungal enemies.

Vivid pigments colour the bacterial world

The Bacterial World is colourful – one of this blog’s taglines. You may have asked yourself what this is about and why bacteria have so many different colours.

From the dazzling pink of halophilic microorganisms to the sunny yellow of phytopathogens, bacterial pigments give their producers shiny and vibrant colours. But thanks to the colourful biopigments, bacteria also gain abilities to survive in new and challenging environments.

Some of these bacterial pigments are essential for us humans and even life on Earth. From some of these colourful biopigments, we produce vitamins that we need for our own metabolism. Also, every oxygen molecule that you just took up with your last breath, at some point, was transformed by a bacterial chlorophyll pigment.

So, I guess it is yet again time to be grateful to bacteria and their vibrant and life-enabling activities!

The post Creating the colours of the rainbow: Bacteria and the vibrant world of pigments appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

So, they talked of cocci and bacilli based on the spheres and rods that they saw under the microscope.

And they classified microbes and bacteria based on these shapes.

It came only with later, modern technologies that scientists learned that there was more to bacteria than their shapes. Even though bacteria looked similar, they had different superpowers.

Yet, some of these bacterial superpowers are indeed influenced by their cell shapes.

So, what is it about bacterial shapes? Why do bacteria look differently? And how do the different shapes of bacteria help them survive and thrive?

What gives bacteria their shapes?

To protect themselves from the environment, bacteria as well as all other organisms have cell envelopes. These keep the cellular machines and internal parts together so that a bacterium can function within this envelope.

And this envelope also gives bacteria their shape.

Both Gram-positive and Gram-negative bacteria have a layer of so-called peptidoglycan within their envelope. This peptidoglycan layer is made of sugars that are linked together by very strong bonds. This is why the peptidoglycan layer is pretty rigid and stiff and has a specific shape in each bacterium.

Either on the inside or on the outside, the peptidoglycan layer is linked to the cellular membranes. Together, these make up the bacterial envelope with a specific cell shape.

What different shapes do bacteria have?

Microbiologists have different ways to classify known bacterial shapes. Here, I will introduce you to the bacterial shapes according to what makes the most sense to me.

Rod-shaped bacteria

As the name suggests, these bacteria have a rod or cylindrical shape. Examples of rod-shaped bacteria are Escherichia coli and Bacillus subtilis.

Scientists are also convinced that rod-shaped bacteria are the evolutionary ancestors of all other bacterial shapes.

The shape comes from proteins that form long cables within the bacterial cell. These span out the whole bacterium from one end to the other.

Rod-shaped bacteria grow by two modes that we talk about in Why bacteria divide into two and grow with the help of a strong ring: First, they extend their cell size by growing the peptidoglycan, the cable proteins and the membrane.

Second, the cable proteins determine the middle of the cell, where the bacterium produces a special ring. Eventually, this ring narrows so that the bacterium divides and two bacterial cells form.

Spherical bacteria

The spherical bacteria – or so-called cocci – include many pathogenic bacteria like Staphylococcus aureus, Streptococcus pneumoniae and Neisseria gonorrhoeae.

Microbiologists think that spherical bacteria were once rod-shaped as well. However, spherical bacteria do not have these long cable proteins that extend their cell bodies. Thus, they stay spherical and grow by dividing their spherical cells right in the middle.

However, sometimes the two daughter cells do not completely divide and they stay attached to each other. This is why some spherical bacteria live as so-called diplococci.

Curved bacteria

Curved bacteria have the shape of a comma or banana and are sometimes also slightly twisted. Examples of curved or banana-shaped bacteria are Caulobacter crescentus and Vibrio cholerae.

These curved bacteria usually live in watery environments where there are flows. Here, the curved shape helps the bacteria to align with the flow while staying attached to a surface.

In the case of Caulobacter crescentus, one end of the bacterium is glued to a surface with a strong super glue. When this bacterium divides in the middle, one daughter cell remains attached to the surface, while the other one can swim away and find a new location to settle down.

Spiral bacteria

Spiral bacteria are a mix of rods and curves which give them a helical twist. Hence, these bacteria have a corkscrew shape.

Many pathogenic bacteria use their corkscrew shape to swim through gel-like solutions. This includes Helicobacter pylori and Campylobacter jejuni.

Since spiral – or helical – bacteria are also thinner, they can reach locations that are too narrow for other bacteria to reach. They also use their flagella to push themselves forward and “wriggle” through narrow pores.

Star-shaped bacteria

Some bacteria look even fancier than others: They are real stars – yes, bacteria with a star shape.

While we don’t know much yet about star-shaped bacteria, they belong to the so-called Stella species or are Methylomirabilis oxyfera. These usually grow in freshwater, soil and sewage.

The star shape comes from six little arms that extend out of the bacterial cell. These push and grow to the outside giving these bacteria a shiny star shape.

Why do bacteria have different shapes?

Now that we have seen the different shapes of bacteria, you might ask yourself, why do bacteria have these different shapes? How do they help them?

As always in biology, it comes down to how a property helps a bacterium survive in a certain location. Often, the cell shape gives a bacterium advantages over other bacteria and it is easier for them to settle down and face harsh environments.

For example, spherical cells have the lowest surface-to-volume ratio. This means they have a large envelope surface through which they can take up a lot of nutrients. All this while their cell volume is relatively small. So they don’t actually need that many nutrients. This helps cocci to grow in locations where there are little amounts of nutrients.

On the other hand, rod-shaped bacteria often have flagella. And thanks to their shapes, they are efficient swimmers. This allows them to swim to new places in cases of danger or the lack of nutrients.

Bacterial cell shapes help face harsh environments

Also, straight rod cells can pack into biofilms more efficiently and build organised structures. This helps them colonise different locations and resist dangerous environments.

Many rod-shaped bacteria also form longer filamentous organisms. These stronger and larger structures protect bacteria from being eaten by other organisms. Another advantage of these multicellular organisms is that they allow more cells to attach to surfaces and colonise hosts.

Lastly, both curved and helical bacteria use their shapes to get better around their environments. Curved bacteria grow in watery environments but also in our guts. Here, their shapes help them align with the flow of water or our gut content while they stay attached to a surface or the gut wall. This keeps them at their preferred location and protects them from being flushed away.

Spiral bacteria use a fascinating helical movement to screw through gel-like or viscous fluids. This for example helps pathogens swim through the mucus of our stomach and guts and colonise us and make us sick.

Bacteria and their shapes

Here, we looked at the different shapes that bacteria have and how these help them survive. Bacteria always face harsh and new environments and conditions and only survive if they have the right tools or means.

So, by adapting their shapes, bacteria often have advantages over other bacteria. Plus, they look cool and fabulous!

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

And looking at these bacterial siblings can help researchers understand the basic mechanisms of the bacterial world.

For example, some bacterial families contain both pathogenic and non-pathogenic bacteria. Pathogenic bacteria are those, that have weapons to infect us and make us sick.

On the contrary, non-pathogenic bacteria are harmless to us since they do not have these weapons.

But to fight off the dangerous bacteria, we still need to better understand what turns a harmless bacterium into a nasty one. Thus, researchers are trying to learn more about the differences between pathogenic and non-pathogenic bacteria.

So, what is better than looking at bacterial siblings that are both pathogenic and non-pathogenic. They often carry the same or similar genes. And yet, they have different weapons and some of these harm us while others don’t.

One interesting example of a bacterial family with diverse siblings is Vibrio cholerae.

Vibrio cholerae and its good and bad bacterial siblings

Bacteria from the Vibrio cholerae family live on zooplankton and shellfish in brackish waters. Every once in a while, we come into contact with such a bacterium when we eat seafood or drink contaminated water. And unfortunately, some siblings of the Vibrio cholerae family can cause very dangerous and even life-threatening diarrhoea. These are the pathogenic siblings.

But interestingly, not all bacterial siblings can infect our gastrointestinal tract. These non-pathogenic siblings do not have the right tools to infect and harm us.

Therefore, researchers have been curious about what distinguishes these pathogenic and non-pathogenic siblings.

All these siblings – pathogenic or non-pathogenic – have one killer machine in common. They use a bow to fire toxic arrows into prey cells. And these cells can be bacteria, amoebae or even human cells.

Yet, within the Vibrio cholera family, not every sibling has the same set of arrows and cannot fight the same target. Hence, researchers assumed that these different sets of arrows would give the siblings the skills to become a pathogen or not.

Vibrio cholerae siblings fight off amoebae with bow and arrow

Researchers looked at five siblings from the Vibrio cholerae family and their fighting behaviour. Let’s call these siblings Pan, Ariel, Bobby, Chris and Danny.

These five bacterial siblings all have the same bows. Yet, they have different arrows that give them different fighting powers.

So, the five siblings use these arrows to defend themselves against enemies in the environment, other bacteria or even their own siblings. Some of these enemies are even bigger microorganisms like amoebae.

These amoebae are like human immune cells. They hunt and eat bacteria in similar ways.

Hence, some Vibrio cholerae siblings use their bows and arrows to protect themselves from amoebae. For example, the siblings Chris and Danny have arrows that they fire into the amoebae. These arrows have toxic bullets attached to them so that they can kill the amoebae.

Ariel and Bobby have the same kind of arrows, but these do not carry the toxic bullets. Since Ariel and Bobby cannot kill amoebae, researchers suggested that only Chris and Danny use their toxic arrows to protect themselves from amoebae.

In comparison, Pan has the same arrow and the same toxic bullets. But Pan’s bow is not active. It only gets activated under certain circumstances. Hence, when Pan faces an amoeba, it gets eaten even though it has the weapon to defend itself. Poor Pan.

Vibrio cholerae siblings kill bacterial opponents with bow and arrow

Next, their different arrows also help our bacterial siblings when facing bacterial enemies. All siblings react and defend themselves in different ways.

Since Pan’s bow is inactive, it cannot fight off bacterial enemies. Even though it has many strong arrows. It just does not fire them.

The other siblings, however, know how to use their bows and arrows. And since their arrows deliver different toxic bullets, they kill with different efficiencies.

It becomes more interesting when these siblings fight each other. In these family fights, the toxic bullets make the difference.

For example, the four siblings Ariel, Bobby, Chris and Danny can all kill off Pan easily. This is because Pan does not have an active bow, so it would not fire any arrows. Pan does not stand a chance against its siblings.

Ariel has very toxic bullets. And it does not hesitate to fire them into its siblings to kill them.

Not Bobby. Bobby struggles with fighting off other bacteria as well as its siblings. Hence, researchers suggest that Bobby’s arrows and bullets are less toxic and thus less efficient to kill.

These types of experiments help researchers understand how bacterial siblings are immune to each other’s attacks. And it gives them some clues about what makes a toxic truly efficient.

Different powers give bacteria different advantages

Just as your special skills give you great opportunities or advantages in life, bacteria use their fighting powers to survive and thrive. They learned how to defend themselves against enemies of all kinds and families. And some of them seem to have more or less efficient ways to achieve this.

So, by learning about the defence mechanisms of bacteria, we might be able to find new and better ways to fight off the nasty bacteria ourselves. Let’s hope that one day we can fight them with their own weapons.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

How are they aware of their bacterial neighbours? 

They cannot see them or hear them. 

But do bacteria talk to other bacteria?

Yes, they do!

Like humans, bacteria talk to each other and socialize. But obviously, they cannot send messages or call each other. They have completely different communication channels that are not based on words.

So how do bacteria speak to other bacteria and even interact with them? 

They use special molecules. Researchers call these kinds of molecules extracellular signalling molecules. This means, bacteria produce these molecules and send them outside of the cell (extracellular). There, they can be a signal to other bacteria.

Microbiologists call this phenomenon quorum sensing. This means that a bacterium “senses” its “quorum”. A quorum means the number of other bacteria in the surrounding. Hence, with quorum sensing, a bacterium knows exactly how many other bacteria are nearby. 

The next step is then population-density dependent cell-to-cell communication. This fancy term means that only when enough bacteria are together (a high population), do they talk to each other (cell-to-cell communication).

But why is it important to bacteria to have all this bacterial chatting going on? Do they not like being lonely?

Why do bacteria need to talk to each other?

A community is always stronger than an individual. And the same is true for bacteria.

Many bacteria together can face the harshest environmental challenges. We also discuss the power of microbial communities when talking about multicellular organisms. 

But by using quorum sensing, bacterial cells are still individual cells. Yet, they act and react as a community; a real microbial community.

Bacteria have been using quorum sensing for millions of years. And it did shape evolution because bacteria learned to include others in their decision making. 

When bacteria face harsh conditions, they use quorum sensing to tell other bacteria in the surrounding that they are not alone. And as a community, they coordinate and tackle that challenging condition together. Therefore, bacteria developed mechanisms that respond to quorum sensing. 

For example, only when many bacteria live in the human body do they produce toxic virulence factors to make us sick. 

The same is true for biofilms. Bacteria only build their biofilm houses when they have other bacterial neighbours. 

On the contrary, a bacterium knows it is completely alone because no quorum sensing is happening. And when the bacterium also has no food, it might decide to sporulate. With this, the lonely bacterium assures to survive on its own until better times come.

Yes, quorum sensing controls a lot in the bacterial life, so how does this important mechanism actually work?

How does quorum sensing work? 

It all starts with one bacterium. 

One bacterium that produces these special quorum-sensing molecules. Researchers call these molecules autoinducers. And the bacterium sends these autoinducers out into the environment. We call this bacterium the sender.

Now, when another bacterium from the same family is nearby, it can recognize the autoinducer. This bacterium is the recipient. Both bacteria have specific receptors on its surface to which the autoinducer binds. 

Next, the recipient takes up the autoinducer. Inside the bacterial cell, the autoinducer can regulate genes. But only, when the amount of autoinducer inside the bacterium is high. 

Hence, when one bacterium sends out autoinducers, the recipient can only take up a few autoinducers. And these few molecules are not doing much on their own.

But now imagine, there are a hundred bacterial cells around. And each of them produces a few autoinducer molecules. Now, all recipient bacteria take up a lot of autoinducers. And a lot of autoinducers inside a bacterial cell start controlling genes. 

All these autoinducers can trigger the bacterium to produce nasty virulence factors or biofilm.

Therefore, with many bacteria around, they produce a lot of autoinducers and more bacteria take them up. Thus, more bacteria listen to each other. And then they produce more autoinducers and send them to the surrounding. Like this, they start chatting and making decisions together.

But what if the chatting bacteria are from different families? Do they still understand each other?

Is quorum sensing a microbial language? 

Researchers found that many bacteria use autoinducers to communicate with each other. And they also found that not all bacteria use the same autoinducer to communicate. 

It is like speaking different languages. 

And interestingly, some bacteria only produce one autoinducer. This is as if they only say one word. All the time.

And other bacteria produce several different autoinducers. So they speak several different words.

Imagine in a mixed microbial community. Different microbes produce hundreds of different autoinducers and send them to the environment. This means hundreds of different words spoken. Therefore, hundreds of different conversations and as such, a lot of chatting going on. 

But all these conversations are not always friendly. In some bacteria, quorum sensing also controls killer weapons. As soon as bacteria “hear” via the quorum sensing channel that other bacteria are around, they turn into fighters to kill the neighbour bacteria. 

As such, quorum sensing as a microbial language can lead to cooperation or competition between bacteria. And bacteria always try to adapt to new conditions. Therefore, by listening and responding to other bacteria, they developed new mechanisms. This is why quorum sensing played such an important role throughout evolution.

Where can we see bacteria talking in real life?

Scientists can see quorum sensing in the lab all the time. Often they grow bacteria in liquid in a glass flask. At the beginning, the bacteria are not many, so nothing happens.

After a while, bacteria grow in the flask and become a lot more cells and they do quorum sensing. And many bacteria start to produce colourful molecules as a response of quorum sensing.

For example, the bacterium Vibrio fischeri starts producing bioluminescence. Hence, the liquid with the bacteria starts to glow.

And these bacteria also use bioluminescence in nature. The Vibrio fischeri bacteria usually live inside the so-called light organ of the bobtail squid.

And at night, the bacteria grow and divide and do quorum sensing inside the squid. After a while, the bacteria start producing bioluminescence and the squid shines light towards the seafloor. Like this, it looks as if the squid is not present as it does not throw a shadow anymore.

With this mechanism, bacteria help the squid to survive at night. And all this through quorum sensing.

Quorum sensing – a fascinating language

Did we just convince you once again how amazing bacteria are?

Do you also think that quorum sensing is a fascinating language?

And is it not remarkable how bacteria can talk to each other and help each other?

So, yes, we think so. With this amazing mechanism, bacteria know they are not alone. And they can launch an appropriate response to an incoming signal. Just as you say “yes?” when someone calls your name. 

However, bacteria have their own language. And we are still learning to understand it.

The post Quorum sensing – or how bacteria talk to each other 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

Especially for the killing process, bacteria have a full arsenal of killer weapons at their disposal.

They can start a chemical war, burn their foes, roll over them or punch holes into them with a bow and arrow.

But each of these decisions comes with a price; they cost energy and resources.

Especially activating and shooting killer bows and arrows is incredibly costly for a bacterium.

So, before bacteria decide to kill, they need to take their whole environment into account.

Here, we will look at when bacteria activate and engage their nanoweapon, the type 6 secretion system.

A bacterial weapon to kill when needed

Bacteria have this incredibly efficient killer T6SS weapon that looks like a crossbow with arrows. They shoot these arrows together with toxins into their foes to kill them and get rid of them.

However, you can probably imagine that bacteria can’t just fire these arrows randomly all the time. Producing the machine as well as the arrows costs a lot of energy. Hence, bacteria need to make sure they only produce and fire this weapon when it is required. Or that they gain something out the kill – like when they protect their hosts from intruders. So, they need to decide well.

Two recent studies (here and here) looked at four different bacterial species from the Vibrio genus. They focused on these bacteria because they all have very similar bacterial nanoweapons but seem to use them differently.

Also, some bacteria from the Vibrio genus can cause diseases in us or marine animals. Hence, research focuses on these bacteria to better understand them.

Two proteins control the killer weapon

Generally, bacteria from the Vibrio genus use two proteins to control when to produce their T6SS weapons. We will call these two controllers protein X and protein Y.

Interestingly, in these species, protein Y also controls the motility of the bacterial cell. So, this protein regulates how active the bacterial rotor, the flagellum, is. If it’s rotating very fast, the bacterium can swim forward. If the rotor is quiet, the bacterium stands still.

On the other hand, protein X controls an activity called competence. Bacterial competence means that the bacterium produces a special machine on the cell surface. This machine picks up free DNA from the environment. Once a bacterium takes up external DNA, it can stitch the new DNA into its own DNA. Now, this bacterium has new “powers” depending on what the new DNA is for.

These two studies looked at the links between the two controller proteins and the killing machine. And what they found, helps us better understand the bacterial lifestyle and decision-making.

Bacteria decide to kill and steal DNA

One main focus of research is on the bacterium Vibrio cholerae. This pathogen lives on seafood and can cause extremely dangerous diarrhoea in us. This is why it is important for researchers to better understand how this bacterium lives and survives in water and in the environment.

In Vibrio cholerae, both proteins X and Y control the T6SS weapon. As soon as Vibrio cholerae killed a neighbouring bacterium, protein X activates the competence machine. Now, the bacterium can take up the DNA of the dead bacterium and integrate it into its own.

With this behaviour, Vibrio cholerae not only kills competitors but also evolves. After getting rid of a foe, it gets new DNA and thus new superpowers for challenging conditions.

However, sometimes Vibrio cholerae realises it does not have a chance against its competitor. In this case, protein Y activates motility and the bacterium can swim away and escape the predator.

Bacteria decide: should I kill or should I go?

Then, both studies looked at whether the control of the T6SS weapon works similarly in other Vibrio species. They looked at these bacterial species:

• Vibrio parahaemolyticus, which causes diarrhoea and lives in seafood
• Vibrio fischeri, a squid symbiont
• Vibrio alginolyticus, another seafood-poisoning cause

All of these bacteria live in marine environments and can live in fish or seafood. Since they all cause some form of diarrhoea, researchers try to understand these bacteria better to inhibit the diarrhoea-causing mechanisms.

Both Vibrio parahaemolyticus and Vibrio alginolyticus have two T6SS weapons while Vibrio fischeri only has one. Interestingly, they are all active at different temperatures, so bacteria already control their killing activity depending on how warm or cold it is.

Also, proteins X and Y control each T6SS weapon completely differently in each bacterium. There is no pattern. None.

So, why would very similar proteins have completely different impacts on the T6SS weapons in different bacteria?

And does this mean bacteria decide differently about whether to kill or not?

There is currently no clear answer to this. So, my guess would be that it depends on the killing power of the T6SS weapon. Some T6SS weapons can kill other bacteria. Then it makes sense to activate the competence machinery at the same time. Like this, the attacker bacterium can also take up the dead bacterium’s DNA. 

However, other T6SS weapons are supposed to kill higher species, like fungi or amoeba. But a bacterium could not use the DNA of such a species. In this situation, the competence machinery is not needed. Rather, motility would be more appropriate to escape this dangerous situation.

It remains mysterious around this T6SS killer machine and how bacteria decide to kill. Or not.

The post Should I kill or should I go? Bacteria making decisions appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

The soil of the forest is full of nutrients, metals, water, oxygen and everything else a bacterium wants and needs.

However, within this paradise, there is not only one bacterium. There are thousands of them. Even more.

And each one of them wants to survive, thrive, grow and reproduce.

So, every single bacterium is making sure it is the major inhabitant of this small place in the soil.

And sometimes, there is no other way than to kill the other bacteria.

To get rid of these annoying food-stealing neighbours, bacteria have developed some fancy killing machines. They poke, they shoot, they burn or they fight.

One of these machines is even more special than the other ones. The so-called type VI secretion system is an incredibly efficient nanoweapon. It works like a bow and arrow. And here, we will find out why.

A bacterial nanoweapon as a crossbow

You can imagine the type IV secretion system as a tiny crossbow with a sharp arrow. It looks similar to the bow and arrow in the picture below.

We call our bacterium with the crossbow an attacker (this is the one in grey). When our attacker meets another bacterium that could be a danger (like the one in purple) we call this one prey.

So, our attacker bacterium has this crossbow that sits on the inside of the bacterial membrane. And the crossbow has a strong stem (in black) that holds an arrow.

And the arrow of the type IV secretion system is the real deal. It consists of three different but important parts. Each one of them makes sure the prey bacterium suffers immensely.

In most cases, the arrow is incredibly powerful. As soon as the attacker shoots the arrow into the prey, the prey dies and the attacker wins. 

So, let’s look at this in more detail.

A bacterial nanoweapon with special arrows

The arrow is clamped within the crossbow and has a very sharp tip and a long spike. The tip of the arrow is needed to punch a hole into the prey bacterium.

After the attacker punched a hole in the membrane of the prey bacterium, it delivers the whole arrow into the prey. The interesting thing is that toxins are glued to the arrow. So, when the attacker shoots the arrow into the prey, the glued toxins reach the prey as well. 

And these toxins are the real problem. They are toxic and even lethal to the prey bacterium. So, yes, our attacker came here to kill.

Generally, bacterial toxins mean to destroy essential parts in the prey bacteria. And this is how the attacker kills and wins!

Bacteria have many toxins

There is another cool thing about these attacking bacteria. Some of them have more than just one crossbow. Some bacteria have even up to six different ones. So much killing potential!

And all of these crossbows can shoot different arrows. Sometimes, bacteria have around ten different arrows lying around in their cells.

To make it even more mind-blowing: Each of these arrows has its own specific toxin glued to it. And some arrows carry multiple different toxins. 

This means, that a bacterium has many different toxins. But don’t forget that within a bacterial cell, there are a bunch of other proteins and cellular stuff.

So, how does a bacterium make sure that it fires a specific arrow with a specific toxin?

Well, both the toxin and the arrow have fitting patches. And bacteria use these patches to glue a toxin to a specific arrow.

Once arrows are loaded to their designated crossbows, they sit in the membrane and wait to be fired. So, when a bacterium meets a prey that it wants to kill, it can choose between its crossbows, arrows and toxins. Each one of these combinations seems to have an advantage under a special circumstance and against a specific prey.

And our attacker can just choose what is right at that time.

The type VI secretion system – a truly special bacterial nanoweapon

Currently, scientists are working hard to understand exactly how this fascinating bacterial nanoweapon works. One goal is then to use this killer machine in other applications.

For example, one aim of researchers is to have a tool to kill bacteria that we cannot fight with commercial antibiotics anymore. Another idea is that we better understand how toxins glue to the arrow so that we can create bacteria that deliver therapeutics, vaccines or other drugs.

So, let’s see what future research into this amazing bacterial nanoweapon will bring us.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world