To grow and produce crops under almost any condition, plants need to make good use of all nutrients available to them. While they are masters at absorbing some nutrients from the air and soil, they are struggling with others.

One such problematic element is nitrogen. Even though nitrogen makes up about 80% of the atmosphere, it is mainly present as dinitrogen gas N₂.

This means two nitrogen atoms are tightly bound to one another via three strong and energy-rich bonds. In this form, plants can neither take up the nitrogen nor use any of the nitrogen atoms to make other molecules from them.

Yet, they need nitrogen since it is part of every DNA molecule, protein, the energy provider ATP and many vitamins. Hence, plants need a way to acquire that element in a simple way that does not cost them too much energy.

Enter bacteria.

Diazotrophic bacteria fix nitrogen

The so-called diazotrophs have developed a highly efficient enzyme complex to capture, or fix, dinitrogen from the atmosphere and break up its energy-rich bonds. This complex is the nitrogenase, and all diazotrophs use one of three types of nitrogenase.

The most efficient nitrogenase contains a molybdenum ion at its core, while other nitrogenases use vanadium or iron. These metals are extremely rare in the environment. Hence, depending on which one is available, bacteria regulate which of the three nitrogenases to produce.

After capturing a dinitrogen molecule, the nitrogenase enzyme transfers energy in the form of protons and electrons to it. This eventually breaks up the bond between the two nitrogen atoms and produces two ammonium ions NH₃⁺.

Bacteria then use the ammonium ions for their own growth and share the surplus with their friends and partners. In Nature, several symbiotic relationships exist between bacteria and other organisms which are based around the nitrogen-fixating superpower of bacteria.

Soil bacteria share fixed nitrogen with plants

The best known nitrogen-fixing organisms are soil bacteria from the families Bradyrhizobium, Frankia, Bacillus, Clostridium, Burkholderia and Pseudomonas. These either live freely in the soil or form symbiotic relationships with plants.

Especially important are symbiotic rhizobia like Bradyrhizobium and Frankia. Plants attract these soil bacteria to their roots by sending out special molecules, which the bacteria respond to via their quorum sensing receptors. Within the root network of legume plants, the bacteria then build little nodules in which they live protected from the surrounding.

Within the nodules, bacteria fix and convert nitrogen with their enzyme complexes, which requires a lot of energy. Gladly, the host plant provides this energy in the form of sugars and organic acids that it produces with photosynthesis. The plant then transports these molecules into the root nodules, where the bacteria break them up, extract their electrons and thus gain the necessary energy.

After breaking up the nitrogen using these very electrons, the bacteria transport the produced ammonium from the nodules into the plant. With the ammonium, the plant makes DNA, proteins and vitamins; everything that it needs to grow and produce crops and fruiting bodies. Hence, rhizobia bacteria are highly important for the health of plants as well as crop production and yield.

Marine bacteria can fix nitrogen

Soil bacteria are not the only nitrogen-fixing organisms; marine bacteria are also important for global nutrient cycles. For example, cyanobacteria form long filamentous multicellular organisms, with some cells specialised in nitrogen fixation.

Often, cyanobacteria are closely associated with other marine bacteria with which they share nitrogen. So far, scientists do not fully understand these types of interactions but are sure that nitrogen-fixing organisms are crucial for the marine food web and the survival of many species under water.

When temperatures are high enough and nitrogen concentrations are optimal, you can pretty much see the nitrogen-fixation process. A green blanket on the water surface is a sign for cyanobacteria that power both photosynthesis and nitrogen fixation with the carbon dioxide and nitrogen from the air. This so-called algae bloom is mainly due to cyanobacteria like Aphanizomenon, Dolichospermum, Anabaena and Synechococcus bacteria.

Soil bacteria as biofertilisers for sustainable food production

Since some soil bacteria are so efficient in fixing nitrogen and providing it to the plant, they have also become valuable in agriculture. Some so-called biofertilisers consist of bacteria that are added to soil or plants to build symbiotic relationships with them, helping them grow better and produce bigger crops.

Hence, biofertilisers containing bacteria are an efficient and sustainable way to produce more food and in higher quality. With this, farmers will rely less on synthetic fertilisers while maintaining high crop yields. Additionally, using nitrogen-fixing bacteria as biofertilisers helps protect the health of the soil and the environment.

The post How bacteria help feed the world by fixing nitrogen appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Whatever it was, chances are high that part of your food was fermented by microbes. As exceptionally healthy and tasty as fermented foods are, these would not exist if it weren’t for microbes and their fermentation superpowers.

Yet, microbial fermentation is a lot more than processing food and giving it a new taste or aroma. Indeed, depending on who you ask, microbial fermentation means slightly different concepts.

For once, fermentation is a metabolic pathway in some microbes and organisms. It is an energy-saving way to degrade and metabolise substrates and produce complex and energy-rich fermentation products.

Secondly, microbial fermentation describes the process of preserving food based on the fermentation pathway. For this, we let microbes break apart and ferment food in a controlled manner, eventually producing well-known fermented foods, like yoghurt, beer and chocolate.

Lastly, the industrial process of growing microbes in big cultures is often called microbial fermentation. The goal of this process is for microbes to produce a specific product – and often they do so through the fermentation pathway.

As you can see, the different definitions for microbial fermentation are grounded on the same principle: microbes degrading substrates and making fermentation products from them. Here, we will look closer at the biochemistry of microbial fermentation and explore some examples of where this microbial superpower naturally occurs and how we make use of it.

The biochemistry of microbial fermentation

From the view of a biochemist, fermentation is first of all a metabolic pathway to conserve energy. Most organisms gain energy from opening chemical bonds of molecules. This releases the energy-rich electrons that are bound within the bond. They then save these electrons in other molecules or fuel cellular machineries.

Most microbes have one preferred substrate for their metabolism. For many, this is glucose, the same sugar that our cells preferably burn and degrade. By degrading glucose, they (and us) produce several intermediary products, the most important one being pyruvate. This degradation process sets free several electrons, which microbes save in a molecule called ATP. ATP is the main fuel for microbial growth machines, swimming motors or transporters.

Sometimes microbes find themselves in environments with an excess of their preferred substrate. In this case, setting free all the energy would produce a lot of heat, damaging or even burning the cell. Hence, as an alternative, energy-conserving pathway, they switch to fermentation metabolism.

During this pathway, they degrade the substrate only partly, thus not extracting all available electrons from it. Instead, they use one of the intermediary products and bind it to another molecule in an energy-neutral reaction. This conserves the electrons and energy within the fermentation product.

What makes fermentation so fascinating: Many species have unique fermentation pathways. Depending on their genes, they branch off the fermentation pathway at any intermediate and produce different molecules.

For example, from pyruvate, some microbes produce ethanol, which we use for beer or wine production, and others produce lactic acid, like for yoghurt production. Other microbes ferment substrates like citrate or succinate and produce complex molecules like caffeine or colourful biopigments.

By conserving the high-energy electrons in the fermentation products, microbes produce fewer ATP molecules. Hence, they have less energy available at that moment. But if they need energy later, they can break down the fermentation product to extract the electrons. Often though, their energy levels are so high, that they even export the product to get rid of it.

Fermentation is thus a way for microbes to process molecules and conserve energy. Gladly, we learned to make use of this pathway as microbes help us convert energy-rich substrates into beneficial products.

Microbial fermentation for food preservation

One source of energy-rich substrates are carbohydrate and fibre-rich foods, which is why these are some preferred environments for microbes. By fermenting fruits, vegetables, milk and grains, microbes can grow and spread on seemingly any plant-based substrate.

Gladly, we learned to grow microbes and ferment food in controlled environments, making food fermentation one of the oldest human technologies. Throughout history, many cultures have optimised different fermentation processes and created all kinds of products.

Food fermentation can include adding so-called starter microbes to the food or using those microbes that naturally live in the foodstuff. These microbes break apart the carbohydrate component of the foodstuff to fuel their fermentation pathways.

The resulting fermentation products can be beneficial vitamins, antioxidants or molecules that change the aroma, taste, texture or stability of the foodstuff. The degradation and modification of the food itself and the accumulation of fermentation products, over time, make our well-loved cheeses, coffee, bread, chocolate, beer, wine, kombucha, yoghurt or kimchi.

For example, thanks to microbes, cheese and yoghurt taste and smell differently than the original milk. Coffee and chocolate get their complex and unique aromas only thanks to the microbial fermentation of coffee and cocoa beans.

During fermentation, many bacteria produce strong acids from the original substrate. Thus, the resulting food becomes acidic and sour, which prevents other microbes from growing and spoiling the food. That’s why food fermentation became an efficient way to conserve food. Many vegetables, like cabbages, pickles or olives, are thus preserved into sauerkraut or kimchi, sour pickles and olives, and the like. Also making kombucha, kefir or cheese are ways to preserve the original tea or milk.

When fermenting cereals, yeasts mainly produce carbon dioxide or ethanol. Carbon dioxide, for example, in sourdough bread makes the bread rise. In the beer-brewing and wine-making processes, yeast produces ethanol as well as several beneficial and aromatic molecules that give beers and wines their tasteful and diverse aromas.

About the microbes involved in food processing

Each fermented food has a unique community of microbes that changes with the fermentation process over time. With the rise of one microbial species, the pH of the food might change or a certain substrate becomes available, which might kill one species or feed and thus help another one grow.

In many vegetable-based fermentation products, lactic acid bacteria, such as Leuconostoc, Lactobacillus and Weissella, are the primary microbes. They produce acids which prevent food-spoiling microbes from growing. The acids also give the resulting kimchi and sauerkraut their sour and acidic tastes. On the contrary, in alkaline-fermented foods of Asia and Africa and in bean-fermented foods, such as tempeh, miso or natto, Bacillus bacteria are usually responsible for the fermentation process.

In milk fermentation, bacterial cultures are of two types: Lactococcus, Lactobacillus, Leuconostoc and Streptococcus bacteria that acidify the milk. This denatures the milk and produces yoghurt-type products, such as yoghurt, buttermilk and kefir.

As a second step during the cheese-making process, Brevibacterium, Propionibacterium, Debaryomyces, Geotrichum and Penicillium are added. These bacteria and fungi produce more complex molecules and give the ripening cheese its unique flavour, texture and aroma.

For cereal fermentation, yeasts are the most widely used microorganisms, producing beer, sourdough bread, sake and whiskey. For bread-making, the principal yeast is Saccharomyces cerevisiae. Other Saccharomyces species, as well as Torulaspora, Hanseniaspora and Pichia are responsible for fermenting most cereal-based drinks.

How the human body benefits from fermentation

As we’ve learned above, many fermented foods are full of microbes – as long as the food was not heated or pasteurized. Hence, when eating fermented foods, you also take in the microbes in and on the food. And these are ready to settle in your body, feed off your food and do some more fermentation.

After arriving in your gastrointestinal tract, the microbes start digesting part of your food too. They degrade the plant cell structures of vegetables, fruits, cereals, seeds and nuts as well as non-digestible fibres. This releases sugars which gut microbes ferment to short-chain fatty acids and gases, like methane. These fermentation products have beneficial effects on your digestion, mental and gut health as well as your immune system.

Hence, by eating fermented foods you gain beneficial microbes – some of them are the so-called probiotics. And by eating plant-based foods you give your gut microbes the appropriate food to ferment, which is what makes some of them prebiotics.

But this is not the only place where microbial fermentation takes place in your body. For example, Lactobacillus bacteria are the key players within the vaginal microbiome and their fermentation activities influence the health of women.

Within the vaginal tract, host cells provide Lactobacillus with glycogen. From this, the bacterium sets free glucose and ferments it to produce lactic acid and hydrogen peroxide. These molecules decrease the pH creating an acidic environment within the vagina. This acidity kills some pathogenic microorganisms directly and prevents others from growing. Hence, by feeding residential Lactobacillus bacteria, the body helps them grow and in return they protect it.

Microbial fermentation as a pillar of industrial production

The more we learn about microbes, bacteria and their fermentation pathways, the better we can use their metabolic superpowers for our own good. Especially the biotechnology and food industry are making great use of microbial fermentation.

We now grow microbes in big batches and harvest fermentation products, like bioethanol, lactic acid or vitamin B12. In many cases, microbes grow on plant-based products or even ferment waste into usable and, thus, green products. As you can guess, food fermentation based on appropriate starter cultures is taking place on large scales to produce many of our beloved foods.

As such, microbial fermentation is an essential part of our lives. Not only as a fundamental process in cellular metabolism and thus human health, microbial fermentation has become a key pillar in food production and preservation as well as industrial production.

As a sustainable tool to produce plant-based foodstuffs, pharmaceuticals and fuels, microbial fermentation may even play a crucial role in our journey towards a greener and more resilient future. Just another reason to be grateful to microbes and their fascinating superpowers.

The post Microbial fermentation impacts our food, industry and health appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

At the heart of this bacterium-plant relationship lies the soil bacterium Agrobacterium tumefaciens. Agrobacterium lives in the rhizosphere, the region in the soil close to plant roots. This area is full of secreted molecules from the plant as well as plenty of other soil microorganisms.

Agrobacterium tumefaciens is a versatile bacterium with two distinct lifestyles. In its free-living state, it happily lives and grows in the soil.

However, the bacterium also responds to some plant molecules, like sugars and acids, through its sensors on the surface. These molecules are often a sign of a wound within the plant root.

Once Agrobacterium tumefaciens detects such a molecule, it activates its virulence and makes it move toward the plant. The otherwise harmless bacterium is now a pathogen and can sneak into the plant where it goes on a big mission.

But just like animals, plants have defence mechanisms against bacterial pathogens as they recognise their bacterial surface. Depending on the plant’s immune system, the plant can be resistant or susceptible to the incoming intruder.

Luckily, Agrobacterium tumefaciens has the right weapons to counterattack, which is why it can infect many different plants.

Agrobacterium transfers its DNA into plants

Agrobacterium’s remarkable capability lies in its unique ability to transfer its own DNA into plant cells. For this, the bacterium has a special exporting machine sitting in its outer envelope.

Through this machinery, the bacterium sends some of its DNA. But not just any part. Agrobacterium tumefaciens has a special DNA portion in the form of a circle for this process. And on this so-called T-plasmid are only genes that help the bacterium during the plant-infection process.

When arriving in the plant cell, the T-plasmid is coated with specific bacterial proteins. These help the plasmid find its way to the nucleus of the plant cell.

Once landed in the nucleus, some of the plant’s systems are hijacked to destroy the proteins around the bacterial plasmid. This sets the plasmid free and it can now interact with the DNA of the plant cell.

Since the bacterial DNA-plasmid contains similar sequences as the plant DNA, these overlap so that the bacteria-DNA can integrate into the plant-DNA. Now, the bacteria-DNA is part of the plant-DNA and the plant activates the bacterial genes just as they were its own.

Transformed plants grow tumours as bacterial houses

Some of these activated bacterial genes cause the plant to produce certain plant hormones at very high levels. This hormonal imbalance triggers the cells to divide rapidly without control. The plant grows plant tumours, or so-called galls. You have probably seen them on the stems of plants or trees.

But Agrobacterium tumefaciens doesn’t merely cause tumours. Some of its genes – now present within the plant DNA – become factories to produce opines. Opines are an exclusive food source for the bacterium, allowing it to grow and thrive within its newly established plant-tumour home.

With Agrobacterium tumefaciens from microbiology to biotechnology

Once Agrobacterium tumefaciens’ superpower to transfer DNA into plant cells was discovered and understood, researchers used it extensively in the biotechnology field. They learned to introduce random pieces of DNA into plants, uncovering plant physiology and paving the way for genetically modified organisms.

By engineering specific DNA segments in the bacterium, researchers can transfer desirable traits and functions into plants. This technique, known as plant transformation, has enabled the development of genetically modified plants that resist pests, withstand harsh conditions or produce pharmaceutical proteins and vaccines.

A bacterium helps us unravel plant physiology

As we’ve seen so often in the microbial world, the smallest actors often have the grandest roles. Agrobacterium tumefaciens, a humble soil bacterium, is a true superhero when it comes to plant interactions.

Its ability to infect plants, exchange signals and transform its own genetic material has offered us valuable insights into the fascinating partnership between bacteria and plants. From the soil to the laboratory, Agrobacterium tumefaciens is at the forefront of illuminating the mysteries of nature and guiding us toward a deeper understanding of both the botanical and microbial worlds.

The post Learning with Agrobacterium tumefaciens: Understanding plants better appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

And some of these microbes learned to adapt to these special – or extreme – conditions. They can’t even cope in normal environments.

Extreme conditions or extreme environments can be anything that we consider uninhabitable for us. This can be extremely high or low temperatures, extremely high or low pressure, radiation or toxicity.

Some of these microbes actually love the extremes. And these so-called extremophiles have special superpowers that help them survive in hostile places – like the bottom of the sea.

What are extremophiles

For example, so-called thermophiles live and grow at temperatures above 50 °C and hyperthermophiles even at temperatures above 80 °C. On the other hand, psychrophiles love temperatures below 10 °C. Plus, researchers keep finding interesting new species in the permafrost soils of the Arctic and Antarctic.

Some extremophiles also have superpowers to survive in extremely salty or acidic places like saline lakes or acid mine drainages. And other extremophile microbes grow in places with high metallic or toxic concentrations or high pressure like at the deep sea of the ocean.

These extreme environments put a lot of pressure on microbes, which means they need to adapt to these conditions or they won’t survive. Hence, in these extreme environments, microbes are mutating more often or exchanging more DNA with other species to learn to cope with these challenging conditions.

Here, we will look at microbes and extremophiles that live and grow in the deep sea. In this dark place, microbial communities have developed fascinating mechanisms to adapt. And from here, they can also impact our global climate.

Extremophiles living in the deep sea

Imagine the bottom of the sea about 30 km underwater: It is dark since sunlight cannot shine this far. It is 2 – 3 °C cold while close to hydrothermal vents, it can be up to 400 °C all of a sudden. And the pressure at the sea bottom is extremely high since all that water is extremely heavy pushing everything down.

And yet, the bottom of the sea is full of happily-living, growing microbes that enjoy their times together, feeding each other and stabilising our ecology. These microbes can swim around in the open sea. Most of them attach to dirt or sediment particles on which they form biofilms.

As you can imagine, this environment doesn’t offer much food or energy. So, it is incredibly important that microbes interact with each other here to exchange meals and information. That’s why many microbes in the deep sea feed each other with one microbe producing a special substrate that another microbe likes to eat.

These microbial food webs are very important for our global nutrient cycles as deep-sea microbes sequester atmospheric gasses, like CO2, and degrade contaminants and pollutants. For example, thermophilic bacteria like Desulfovulcanus ferrireducens and Oceanithermus profundus live close to hydrothermal vents which is why they grow best at about 65 °C. These extremophiles get their energy from hydrogen gas and organic acids that swim in the ocean.

Also, during oil spillages in the ocean over recent years, researchers found many bacteria and fungi that can eat and degrade oil or petroleum. Hence, their need for food cleans our oceans of these harmful components.

How extremophiles adapt to the deep sea

The deeper you are in the ocean, the less oxygen is available for microbes to breathe. Hence, microbes had to become creative about where to get their energy from. For example, Desulfovulcanus ferrireducens mainly uses iron components for respiration and growth while Oceanithermus profundus prefers nitrogen gas. All over the oceans, there are SO MANY microbes eating these iron components and nitrogen gas. Hence, all their metabolic activities impact the iron and nitrogen cycles of the whole planet.

But microbes and bacteria in the deep sea did not only have to adapt their meals to these conditions. Deep-sea extremophiles also had to develop mechanisms to withstand the pressure and the cold of this hostile place.

At very low temperatures, proteins often get out of shape so that they lose their functions. This can mess up the whole bacterial cell, which is why psychrophilic bacteria have so-called chaperones that constantly check the bacterium for proteins that are out of shape. These chaperones then help the protein get back into normal shape and thus to its normal functioning state.

Extremophile bacteria have different membranes

Another way to adapt to hot and cold temperatures is for bacteria to change their membranes. As you might know from experience, fat gets solid when it’s cold and fluid when it’s hot. And since bacterial membranes are mainly made out of lipids and fats, thermophilic and psychrophilic bacteria need to make sure their membranes can cope with the extreme temperatures.

To prevent membranes from becoming too fluid and leaky at high temperatures, thermophilic microbes solidify their membranes. On the contrary, psychrophilic bacteria like Psychromonas and Marinomonas need to make sure that their membranes stay flexible at cold temperatures.

Luckily, this special cold-adapted membrane also helps bacteria withstand the high pressure in the deep sea. And to counteract the pressure inside the cell, piezophile bacteria produce a lot of stuff and basically crowd their cells with proteins. This aims to keep the cell pressure inside high against the high pressure from the outside.

However, investigating such high pressure is extremely difficult in the lab. That’s why researchers still don’t know much about the pressure adaption of extremophiles in the deep sea.

What we can learn from extremophiles in the deep sea

Even though we still don’t know much about the fascinating microbial life underwater, researchers are optimistic that they will find lots of helpful microbes. Whether adapted to the cold or to the heat, deep-sea microbes have incredible mechanisms to grow at extreme temperatures.

This means they contain proteins that function perfectly on either side of the temperature spectrum. So, researchers hope that we could use that knowledge to design tailor-made proteins for our daily lives. We could for example use them in households or in biotechnology applications, for example, to improve cleaning efficiency or reduce energy input.

Another important aspect is to explore how microbes in the deep sea affect our global climate. With climate change, our oceans are getting warmer and thus they contain less oxygen. This means that also microbes are likely adapting to these changes which in turn influences the global climate.

Hence, understanding how microbes cope with the conditions in the deep sea helps us comprehend the full impact of climate change. This might then give us an idea about how to prevent more damage to our beautiful planet. With the help of microbes.

The post Even at the dark and cold bottom of the sea, microbes flourish appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

And when it comes to the size of an organism, one thing is quite clear: The bigger, the more food they need.

This is also true for bacteria. Depending on the shape of a bacterium, bacterial cells are differently big or small. And the bigger a bacterium is, the more energy they need.

So, in a location where there is not much food, this might be a problem.

Not for superhero bacterium Thiovulum majus. This one is a huge bacterium with an incredibly amazing mechanism to find and get food for itself and its brothers and sisters.

Read on to find out what this bacterium does to not run out of food.

Large bacteria run out of food easily

Thiovulum majus is one of the bigger bacteria with about 10 – 15 μm cell length. Average-sized bacteria are usually around 1 μm in length and the smallest nanobacteria even only 0.2 μm.

This makes Thiovulum majus a giant under the bacteria. It is about 10 – 15 times bigger than other bacteria. And this means it also needs a lot more energy and nutrients.

Thiovulum majus also has an interesting lifestyle. It lives at the bottom of salt marshes, close to water sediments. Here, the water contains a lot of sulfur, which Thiovulum majus uses to gain energy.

However, Thiovulum majus also needs oxygen to live. Hence, within water, it needs to be in the perfect spot with the right oxygen and sulfur concentrations. Sounds easy, but is pretty complicated if you’re a bacterium drifting in water.

First, to find the optimal spot in water, Thiovulum majus uses chemotaxis to follow the right oxygen concentration. As soon as they are satisfied with a location, they need to make sure to stay in this position. And Thiovulum majus found an amazing mechanism to achieve that.

A floating veil keeps bacteria in place

Interestingly, Thiovulum majus produces a so-called tether or stalk. This is a strong but flexible string made of mucus. It is pretty sticky and works like the superglue of Caulobacter crescentus.

When Thiovulum majus swims in water, it carries this stalk at its end. Here, it can grow up to ten times as long as the bacterial cell itself. And the stalk can stick to stalks from other bacteria or particles in the water.

When many stalks stick to each other and to particles, they form a net-like layer in the water. This layer, or a white veil, floats above the sediment in the water and can become several centimetres in size.

Now, the bacteria are attached to this veil since their stalks are stuck within this mesh of stalks. Scientists found that on a veil with the surface area of your fingernail, around 100’000 Thiovulum majus bacteria are attached.

Every once in a while one such stalk breaks and thus releases the bacterium. However, Thiovulum majus uses its chemotaxis to swim in a U-shaped pattern which brings it back to the veil. Growing a new stalk, the bacterium attaches to the veil again to make sure it stays in the right location.

Hence, using chemotaxis and attaching to the veil keeps Thiovulum majus in a more or less fixed position in the water. And this location has the optimal concentration of both oxygen and sulfur.

High-speed rotating bacteria bring nutrients to the population

Now imagine, lots of Thiovulum majus bacteria live at this location of optimal oxygen concentration. At some point, the bacteria have used the available oxygen in that surrounding.

How to bring in new oxygen?

Looking at the Thiovulum majus bacteria, you can see that they have many flagella on their cell surfaces. And by rotating these flagella, the bacteria start to rotate as well. And by rotating the whole bacterial cells, the bacteria induce a water flow. This flow draws water from above towards the bacterial cells and the veil. And this freshwater brings a lot of oxygen to the bacterial population.

This rotation is incredibly fast and researchers studied this movement in the lab. They attached the bacteria to a glass surface and let them rotate. Through the rotation, it looked as if the bacteria formed little cells around them and they also pulled neighbouring cells close. This started to look like crystals of rotating bacterial cells.

This rotation of flagella lets Thiovulum majus swim with a speed of up to 600 μm/s. Don’t forget that Thiovulum majus is about 10 μm long. This means it can swim 60 times its own cell length in one second!

It’s as if you could swim about 100 m in one second. Yet, the World Record for swimming 100 m freestyle is currently at just below 45 seconds.

This high swimming speed makes Thiovulum majus the second-fastest bacterium that we know of. And this superpower explains why this bacterium is so powerful in inducing a water flow. With this constant mixing of water, the bacteria make sure they always have enough oxygen and nutrients to live.

Bacteria found ways to survive in different environments

I’m always impressed by the superpowers that bacteria have and their resilience. They learned to make the best out of each situation, found ways to use whatever they come across and adapted to live anywhere.

The question that remains now is: Why did Thiovulum majus become such a big bacterium? When they started using their rotating mechanism they brought in more nutrients. Did this help them become bigger because they had all the nutrients at hand?

Or did the bacterium grow big and then needed to find a mechanism to find and bring in more food? These are the kinds of questions scientists are probably looking into right now. And I can’t wait to learn the answer.

The post Floating veils for large bacteria to attach to and fetch nutrients appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

And while both viruses and bacteria can live within the same plant, animal or the human body – the so-called host – they can have completely different impacts on them.

A virus infection always has negative effects on the host.

In comparison, the interactions between bacteria and their hosts can be harmful or beneficial for both sides. While pathogenic bacteria harm their hosts, the host usually has a defence system to fight off these harmful bacteria.

However, often both bacteria and host gain from this interaction and form a type of symbiosis. For example, our gut bacteria are getting fed by what we eat. And as a thank you, they produce molecules or hormones that improve our health, immune system and even mood.

In special cases, these symbiotic bacteria even protect their hosts from other harmful microbes like viruses. For example, bacteria in and on our bodies fight off pathogenic microbes.

And the same happens in insects: The bacterium Wolbachia pipientis usually lives within insects and forms a symbiosis with its host. This protects the host from nasty virus infections.

Here we will look at how the bacterium does that and how we could use this symbiosis to fight off viruses ourselves.

Wolbachia pipientis protects insects from viruses

For a virus to grow and spread, it always needs a host and their cells to produce the virus. But when cells produce viruses, they lose energy, nutrients and get sick from the virus or even die. Hence, a virus infection is always harmful to the producing cell and thus the host.

And some viruses can only infect and grow in insects. Gladly, the bacterium Wolbachia can protect insects from some nasty viruses.

One way to do this is that the Wolbachia bacteria stop the virus from entering the insect cells. For this, the bacteria live on the inside of the cell close to the cell membrane. Here, they eat part of the lipids of the membrane and change what the membrane looks like on the outside.

From the outside, the virus cannot recognise the changed membrane and will not bind to it. Like this, the virus will not even enter the cell and the cell is protected from the virus.

Also, Wolbachia strengthens the immune system of insects. This helps the insects fight off the virus to keep them healthy and virus-free.

And some Wolbachia bacteria even eliminate viruses from host cells. However, it is not completely clear yet, how the bacteria achieve this.

Interestingly, different Wolbachia strains are differently effective against different viruses. This is really helpful for us since we could use these bacteria and their superpowers to keep us virus-free as well.

Using Wolbachia to protect us from Dengue fever

We all know how annoying mosquito bites are. But now imagine, when an infected mosquito bites us. The mosquito transfers those annoying toxins into our bodies that give us that terrible itch.

But when that mosquito is infected with a virus, it will also transfer that virus into our body. And unfortunately, many viruses from mosquitos cause dangerous diseases like Dengue fever, West Nile fever, Yellow Fever or Zika. Often, the infected person suffers very badly from this disease or even dies.

This is why researchers want to use the Wolbachia bacteria to protect us from these diseases. For this, they grow mosquitos in the lab and infect them with the Wolbachia bacteria. They then release these mosquitos into the environment – and here we’re talking around 30.000 mosquitos in one go. Can you feel the mosquito itches already on your skin?

These mosquitos then mix with the mosquitos in the environment so that the Wolbachia bacteria spread throughout the whole mosquito population. Now, Wolbachia protects the mosquitos from viruses like the Dengue virus.

And this also means keeping the Dengue virus away from us. And yes, researchers found that fewer people got infected with the Dengue virus after they release their lab-grown mosquitos. What an amazing way to protect us from these nasty viruses and their diseases!

Researchers also try to use these bacteria and their superpowers to protect us from other pathogenic microbes, for example, the Malaria-causing microorganism. I just hope that at the same time, they are looking for ways to make these annoying mosquito bites less itchy…

The post Wolbachia bacteria in mosquitos protect us from nasty viruses appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Glue produced by bacteria so that they stick themselves to (almost) any kind of surface?

Bacterial glue that if you covered a space the size of your index fingernail with it, it could hold a weight of up to 680 kg. This is almost ten people! With one fingernail full of bacterial glue! Are bacteria super strong or what?

Okay, you might ask yourself, why would bacteria need to produce such a strong glue? What are they trying to stick together?

Let’s have a look at this bacterial superhero and its superpower in more detail.

Meet Caulobacter crescentus and its superpower

The superhero that produces the strongest glue known in microbes is Caulobacter crescentus.

Caulobacter might even produce the strongest glue found in nature. Its glue is stronger than the ones that geckos produce on their toes to stick to surfaces. And yes, these animals can walk anywhere thanks to their sticky toes!

So, what does Caulobacter add to its glue to make it so sticky?

Sugar! Lots of different sugars create a glue that helps Caulobacter to stick to almost any surface. And because Caulobacter usually lives in water, its super glue is also water-resistant. This is also why the glue is so important for Caulobacter bacteria to grow.

Bacterial glue for almost any surface

To grow and reproduce, Caulobacter bacteria build biofilm houses. These biofilms protect the bacteria from the surroundings and help them become a community and support each other.

But to build a biofilm house, bacteria need a base. Just as you would start building a strong and stable base for your house, so do bacteria.

When Caulobacter decides to build a base for its biofilm house, it starts by growing a so-called stalk. This stalk is a long extension that grows out of the bacterium on one side.

Once this stalk attached to the surface, the Caulobacter produces its super glue. The glue drips out of the stalk and glues the bacterium to the surface. Now, the bacterium is strongly connected to the surface and can start growing.

Glued bacteria divide and grow biofilms

When bacteria grow, they divide their cells in the middle. Usually, when bacteria divide, they produce two identical cells. These are sibling cells that look the same and have the same abilities.

But the interesting thing about Caulobacter is that it produces two different sibling cells. They do not look the same and they have different abilities and goals.

Let’s look at what happens with our Caulobacter bacterium that is glued to a surface.

The bacterium gets longer until it divides in the middle. But when the cell divides, one end remains glued to the surface. The other end will lose the connection to its sibling and thus, to the surface.

This free sibling cell has a flagellum where the other one has the stalk. And thanks to the flagellum, this sibling cell is free to swim away.

So, the free sibling cell swims to a new place to find a new location where it can attach to. Once it found a new place to live, it loses the flagellum and instead grows a stalk. It now glues itself to the surface and the cycle starts from the beginning.

Like this, Caulobacter covers as much surface as possible until the base of the house is full of bacteria. After that, it starts growing on top of each other to finally build the top levels of the biofilm house.

And this is how the Caulobacter crescentus glue helps the bacterium to grow and survive.

Bacterial glue in the tube?

Researchers hope that one day we could use the Caulobacter crescentus glue for our daily lives. This bacterial glue would be biodegradable and thus better for the environment.

What is also remarkable about the Caulobacter crescentus glue is that it is stable in water. Since Caulobacter lives in water, it needs to make sure that it remains stuck to the chosen surface. Hence, it produces such a strong glue so its biofilm house won’t get washed away in the water.

Who would have thought that bacterial glue was a thing? That bacteria produce something so strong? But these are the things most organisms do to assure their own survival.

The post Bacterial glue to grow and survive appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

What is bacterial sporulation?

When a bacterium sporulates, it transforms from a rod-shaped bacterial cell (4-10 μm long) to a round, spherical spore (1-1.5 μm long).

Bacterial spores are surrounded by thick layers of cell wall material or peptidoglycan and many layers of proteins. These make the spore highly resilient and shield it from all kinds of environmental assaults, including UV radiation, desiccation and antibiotics. Within the spore, it protects the genetic material of the parent bacterium.

Now the spore is metabolically dormant. This means that the cell has stopped all activities which require energy, like growth and development.

Spores can remain stable for extremely long periods of time. In fact, researchers found Bacillus spores dating back almost 25 million years in the abdomen of extinct bees preserved in Dominican amber. Other samples date back 250 million years from salt crystals.

Why study sporulation?

To date, most studies aim to understand sporulation in the model bacterium Bacillus subtilis. Bacillus subtilis is a Gram-positive bacterium with a thick layer of peptidoglycan outside the cellular membrane.

One of the major reasons why is it relatively easy to study sporulation in Bacillus subtilis is its natural ability to take up foreign DNA and integrate it into its genome. This provides scientists with a wide range of tools for gene editing in Bacillus subtilis. And they can study the functions of different molecules in space and time during sporulation.

Some bacterial spore-formers can also be pathogenic in a human or animal host.

Examples include Bacillus anthracis (the causative agent of anthrax), Clostridium difficile (implicated in colon disease) and Clostridiumm botulinum (implicated in food poisoning). Spores of these pathogenic bacteria can secretly survive inside the host due to their ability to withstand harsh environments. But once they get access to nutrients, they germinate again and become viable bacteria. These bacteria can then release lethal toxins to cause diseases in their respective hosts.

There is some good news for the food lovers too though! Spores of a strain of Bacillus subtilis, Bacillus subtilis (natto) are used to ferment soybeans in a traditional Japanese dish called natto. The critical process in natto preparation is the germination of spores which then use nutrients from the soybeans to ferment them. The dish with its powerful smell and flavor is definitely for the bold!

How does sporulation work?

Normally, a bacterial cell divides in the middle to produce two identical daughter cells. Researchers call this process binary fission or vegetative growth.

But when a bacterium sporulates, the cell divides closer to one end of the cell, near a pole. This leads to the formation of two daughter cells of different sizes. The smaller cell is the forespore and the larger cell is the mother cell.

The two cells are separated by a wall made by the invagination of the cell membrane and the peptidoglycan. This wall is the septum.

Cell division leads to separation between spore and mother cell

Surprisingly, the wall separating the two daughter cells is almost four times thinner during sporulation than during vegetative growth (~22 nm vs ~80 nm).

Scientists have always wondered why the cell would need a thinner septum during sporulation. One reason can be that the forespore and the mother cell need to communicate with each other and exchange certain metabolites. A thinner septum can make this a lot easier because channels don’t have to go through a thick wall.

Another reason could be that the thinner septum is likely more flexible and easier to bend and stretch. Hence, the mother cell can move forward to engulf the forespore so that it is completely inside the mother cell.

Transporting DNA into the spore

When a bacterial cell divides vegetatively, it splits the bacterial DNA equally into two daughter cells.  But an interesting phenomenon occurs during sporulation.

The DNA is trapped at the septum such that the forespore has only 1/3^rd of the DNA and the remaining 2/3^rd stays in the mother cell. A transporter then pumps the rest of the DNA from the mother cell to the forespore.

Packing the whole DNA into the small volume of the forespore probably increases the turgor pressure in the forespore. Hence, the forespore inflates like air in a balloon to give it an ovoid shape.

Bringing the spore inside the mother cell

A critical process during endospore formation is when the mother cell engulfs the forespore. This means that instead of lying side by side, the forespore is now within the mother cell.

To engulf the forespore, the mother cell has to overcome two barriers:

(1) the peptidoglycan that surrounds the bacterial cell on the outside (shown by blue circles in the figure below), and

(2) the septum (also peptidoglycan) that separates the two cells (shown by green circles in the figure below).

But the septum and the bacterial cell envelope are also connected. At this so-called leading-edge the two peptidoglycan structures meet. Here, critical activity happens.

First, enzymes within the forespore (denoted by ‘1’ in the figure) make a new bond with the cell wall ahead of the leading edge. With a new bond between the two, the old bond is no longer needed. Thus, enzymes in the mother cell break this old bond (denoted by ‘2’ in the figure).

Like this, the mother cell can slowly move around the spore until it completed warps around it.

Wrapping the spore in a thick coat

Once the mother cell engulfed the forespore completely, the spore needs to mature. For this, the mother cell builds thick and protective layers around the spore to protect it from the environment.

Ultimately, the mother cell lyses and dies and releases the mature spore into the environment. Only when the environmental conditions become favourable again, spores germinate and normal vegetative growth cycle starts again. 

Bacterial sporulation – a tightly regulated process

Although the process of sporulation sounds pretty simple, it can be extremely challenging to comprehend from the point of view of the bacterial cellular machinery. More than 500 genes are active only during sporulation. And these are not active during vegetative growth.

Also, some genes are only active in the mother cell and others only active in the forespore. And each stage of spore formation needs to be tightly regulated!

The studies of spore formation in Bacillus subtilis have undoubtedly increased our appreciation of what else bacteria are capable of.

However, there are still many unanswered questions and unknown genes during sporulation that we need to study.

Also, we need to expand these studies to understand sporulation in pathogenic spore-formers like Clostridium difficile and Bacillus anthracis so that we can develop treatments for these disease-causing organisms!

Recent sequencing analysis of the human gut microbiota also indicate that around 50-60% of bacteria in a healthy host intestine are spore-formers. But we still don’t understand the functional and physiological relevance of the majority of them.

There is definitely lots to explore and understand about this one-of-a-kind process of sporulation in bacteria!

The post Sporulation in Bacillus subtilis: A strategy for bacterial hibernation appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

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

Geosmin is one of these bacterial products that easily vaporise into the air and often have distinct smells. They are called volatile compounds.

Some other volatile compounds make the taste of chocolate or the smell of Cheddar cheese. And others, like geosmin, the smell of rain.

Bacteria produce geosmin – a volatile organic compound

Geosmin has this specific earthy or musty odour. It is the natural smell after a refreshing summer rain; the earthy smell of beets or carrots but also the off-tastes in water or wine.

You probably know what I am talking about.

Geosmin itself is not toxic, however, toxic fungi and bacteria produce geosmin. To our brain, the smell of geosmin signals that toxic fungi or bacteria are growing. So, our brain protects us from those by telling us not to eat the food. Thanks, brain!

Animals can also “smell” geosmin. For example, when the vinegar fly senses geosmin, it understands that toxic fungi are growing. In this situation, geosmin also acts as a repellent and the fly chooses not to eat or live around that place.

On the contrary, some mosquito species are attracted to the smell of geosmin. For them, the geosmin smell means that they are close to a lake, so the mosquito chooses to lay its eggs in the vicinity. Later, the mosquito larvae grow in that lake where they already have a food source. They will eat the bacteria. So, to mosquitoes, the geosmin smell is a sign of food.

Streptomyces – a geosmin producer

There are a few families of bacteria that produce geosmin. One of them is bacteria from the Streptomyces family. And Streptomyces already has a pretty interesting lifestyle.

Streptomyces not only grows as a bacterial cell, but it also produces very long and thin arms that grow out of the bacterial cell; so-called mycelia. The mycelia from one bacterium form a connected network with mycelia from other bacteria. And this complex mycelia network can extend into the soil, spread around soil particles and even wrap around tiny organisms.

After forming an interconnected mycelial network, the Streptomyces bacteria produce spores. And interestingly, Streptomyces produces these spores at the end of the mycelia arms.

Bacterial spores are non-viable versions of bacterial cells, just like a plant seed is a non-viable version of a plant. Spores generally only contain the genomic DNA of the bacterium, proteins to stabilise the DNA and proteins to react to the environment.

Similar to plant seeds, spores are wrapped in a thick envelope to protect the spore from the surrounding. Then, when the environmental conditions are better, the spore – just like the plant seed – germinates and forms a viable bacterial (plant) cell. This cell can then grow and metabolise and form new mycelia.

Why do Streptomyces bacteria produce geosmin?

Interestingly, when Streptomyces starts forming spores, the bacteria also produce geosmin.

Research found that a little insect-like animal, the springtail, is actually attracted to geosmin-producing bacteria. These tiny invertebrates – also known as snow flies or Collembola – live in the soil. And here, they are especially attracted to Streptomyces spores.

Researchers saw that the springtail uses its tiny antennae to smell the geosmin. The insect then follows the geosmin smell and once it found the Streptomyces spores, it starts eating them.

What is the advantage of being eaten by springtails?

Yes, it seems that bacteria produce geosmin to attract animals and insects to be eaten by them. To understand the reason for that we have to know that the springtail is covered with a waxy outer layer. Spores, on the other hand, have a hydrophobic envelope that easily sticks to the waxy springtail. This makes the spores stick to the springtail.

And when the animal moves around in the environment, it carries the spores around. So, it seems that bacteria use the animal as transport vehicle.

Also, the researchers saw that the springtails absolutely love eating those Streptomyces spores. They even found that the spores are not digested by the springtails. Instead, the springtails had viable spores in their faeces from which the bacteria could grow again. This finding gave the researchers another clue that Streptomyces spores might use the animals for transport.

So, it seems that Streptomyces bacteria produce geosmin to attract insect-like animals to attach to them and use them to hitchhike to different places. In a new place, there might be more nutrients for the spores to germinate, form viable bacteria, grow and reproduce.

From this, the cycle starts over again, as the bacteria form mycelial networks again to produce spores. Then, the bacteria produce geosmin to attract insects to get carried somewhere else again.

Bacteria live with many more players in the environment

Yet, one thing to take into account at this point:

Both Streptomyces and springtails live in the soil and in this study, the researchers only looked at how these two species interact with each other.

In the soil, there are several other bacteria, fungi, viruses, insects or tiny animals. So far, we have no idea about how any of these other organisms could impact the interaction between Streptomyces and springtails. The researchers did this study in the controlled environment of the lab. But the whole game might completely change in the wild environment of the soil.

However, I still think this is a cool example of how bacteria trick animals for their own good.

Take away from this article:

• Bacteria produce volatile compounds like geosmin that animals can taste or smell and be attracted to or repelled from
• Bacteria specifically produce geosmin to attract springtails to eat the bacterial spores
• Springtails transport the bacterial spores to new places

The post Bacteria produce geosmin to trick bugs into hitchhiking appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world