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.

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

And with an increasing global population, it will be important to find ways to increase the world’s food supply in sustainable ways.

Adding microbial communities, called biofertilizers, to soil can increase crop yield and plant health all without adding any toxic chemicals.

Lucky for us that microbes once again can help save our planet by addressing our global food crisis.

A global challenge

While the global population grows to almost 8 billion people, the land for agriculture remains limited. One way to meet this growing challenge is to increase the quantity of food produced on the same amount of land.

In the past, farmers added expensive chemical fertilizers to their crops. These meant to increase important soil nutrients – specifically nitrogen and phosphorus – and help the plants produce more food.

Unfortunately, these chemicals enter and pollute nearby water systems, harming our health as well as the health of our planet. Plus, producing these chemical fertilizers releases greenhouse gases that add to climate change.

One sustainable method to increase crop production is to add microbial communities to agricultural plants; so-called microbial biofertilizers.

Microbes as biofertilizers

These biofertilizers are soil microorganisms that provide nutrients, stimulate growth, and improve plant health. Also, biofertilizers are more sustainable, less toxic, and cheaper than traditional fertilizers.

Here, we will look at what biofertilizers actually do and how these microbes work for the plants.

Helping plants get nutrients

All living organisms need nitrogen, but not all nitrogen found in the soil is in a useable form. In fact, nitrogen is a major limiting nutrient for plants because most nitrogen in the soil is in a form that plants cannot use.

Hence, microorganisms first need to “fix” the nitrogen and then convert it into a usable form. For this, bacteria make an enzyme called nitrogenase that converts nitrogen from atmospheric nitrogen (N₂) to ammonia (NH₃). Now, plants can absorb this nitrogen form and use it for energy and growth.

Some plants have evolved to work with bacteria to make it easier for them to absorb the fixed nitrogen. For example, the roots of certain legume plants include special root nodules. In these live nitrogen-fixing bacteria called Rhizobia. When chickpea seeds were grown together with these bacteria, their yield increased 250%. Also, adding Bradyrhizobium species to mung bean plants promoted plant growth and yield and plants had a higher tolerance to insecticides.

Cyanobacteria also help plants fix nitrogen. When wheat plants grew together with cyanobacteria species Calothrix ghosei, Hapalosiphon intricatus, and Nostoc species, they grew higher and had more grain. Additionally, co-cultivation with Nostoc or Anabaena species resulted in increased root length and wheat plant nitrogen levels. Cyanobacteria are important nitrogen-fixing bacteria in aquatic environments too, especially for rice production.

Helping plants grow

Besides nitrogen, soil bacteria can provide plants with many nutrients, vitamins, and plant hormones. These are called phytohormones. Phytohormones promote plant growth by acting as signaling molecules to regulate plant metabolism and stress response.

When Rhizobia bacteria grew together with the mustard plant Brassica juncea and produced phytohormones, the plants grew better. Also, in corn (maize), inoculation with Azospirillum brasilense resulted in increased plant growth correlated with elevated phytohormone levels.

Over 80% of Rhizobia bacteria produce the major phytohormone indole-3-acetic acid (IAA). This phytohormone regulates plant growth, cell differentiation, and stress response. Thus, when bacteria secrete indole-3-acetic acid, it promotes root growth. This helps plants take up nutrients better.

In addition to a single bacterial species, communities of microbes help plants stay healthy and grow. Archaea, bacteria and fungi all associate with the roots of plants and synergistically provide nutrients to the plant. Researchers are studying these communities to understand important microbial interactions. The aim is to design microbial communities specific to each crop that promote higher crop production in the future. Just think, one day you could order a biofertilizer optimized for your unique climate, soil, and plant!

Fighting plant enemies

Not only do microbes provide their hosts with nutrients to promote growth, they also protect their hosts from deadly pathogens. Especially fungal pathogens are known enemies that threaten plants.

For example, Pseudomonas and Bacillus strains release toxic chemicals such as hydrogen cyanide to inhibit fungi that infect coffee plants. Other Bacillus strains produce antifungal molecules and simultaneously increase corn (maize) seedling growth. The bacterium Ochrobactrum anthropi TRS‐2 can fight fungi, and application of this bacterium on tea plants decreased brown root rot caused by the fungi Phellinus noxius.

Some bacteria even produce biofilms on the roots of plants as a barrier against invading fungal pathogens!

Agricultural crops are also prone to infection by nematodes, commonly called roundworms. Nematophagous bacteria can deter nematode growth by sending out toxins, and competing for nutrients. For example, Pasteuria penetransbacteria infects nematodes, while Pseudomonas strains can produce antibiotics against nematodes that infect potato plants. No matter the pathogen, soil bacteria have evolved ways to promote and protect their host plant.

Microbial biofertilizers assist our global challenge

As the world’s population increases, we will need sustainable and inexpensive ways to increase agricultural production. Just as microbes add nutrients and flavors to our meals, bacteria can nourish our crops as well. Plus, biofertilizers are a greener, healthier, and less expensive alternative to traditional chemical fertilizers.

So, next time you go out into your garden, think about adding some biofertilizers like compost or manure instead of chemicals to help your fruits and vegetables grow.

Along with bacteria, we can help save the planet!

Take away messages from this week’s article:

• The increasing human population is creating a global food crisis 
• Microbes can act as biofertilizers by providing important nutrients and helping promote plant growth
• Microbial biofertilizers are a sustainable and inexpensive way to increase global food production

The post Microbes as biofertilizers appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Do bacteria always only live in one form; either they are single cells or multicellular?

How do we distinguish between unicellular and multicellular bacteria?

Which advantage do bacteria gain from sticking together and forming multicellular organisms?

What are some examples of multicellular bacteria?

In this article, we will answer exactly these questions!

Let’s dig in!

What makes multicellular bacteria?

Scientists define multicellularity as a form of “biological organisation in which a permanent cell aggregate exhibits an activity more complex than that of the individual cells“.

This means that multicellular bacteria are only present in their multicellular forms. True multicellular organisms cannot go back being single-celled.

Hence, bacterial biofilms are no true multicellular organisms. Bacteria can decide between these two lifestyles; they actively produce the biofilm when needed and they break it off and become single cells again.

Also, a bacterial colony in a petri dish is not a multicellular organism. In a colony, a bunch of bacterial cells grow on top of each other. But the cells in the colony are not organised and they do not function in an organised manner.

Multicellular bacteria are organised

The difference here lies in the term biological organisation. Multicellular bacteria are organised due to two different concepts:

They work in an organised manner; bacteria within the multicellular organism need to communicate with each other. Thanks to communication, every bacterium within the organism knows what is going on, so it can react in an organised manner.

Just as when your stomach is empty, it tells your brain that you’re hungry and you react accordingly by eating. Your stomach and your brain are communicating with each other.

The second way to organise multicellular bacteria is by using different functions to advance the whole organism. Within a multicellular organism, some bacteria undergo a process called cell differentiation. Cell differentiation is what makes a human stem cell develop into a skin cell or a blood cell. And this skin or blood cell has more specialised functions than the stem cell that it was before.

The same can happen in multicellular bacteria. Some bacteria develop into specialised cells. These specialised bacterial cells have functions that other cells (or the single version of the bacteria) do not have.

Now, some of the bacteria have additional functions or abilities. And thus, the whole multicellular organism gains new bacterial superpowers that can advance the organism.

Why do bacteria form multicellular organisms?

Here, evolution plays a massive role since multicellularity has so many advantages.

In multicellular organisms, the labour is divided. Just as it is easier for you and your co-workers to work in a team with everyone doing what they are best at. With bacterial cells taking on new functions through cell differentiation, the whole organism profits.

Another advantage is that when bacteria cluster together, they can protect their core. And some multicellular bacteria keep their spores within the core for protection. Like this, their most vulnerable members are protected.

Also, multicellular bacteria are generally bigger than single bacterial cells. This makes it more difficult for attackers to prey on this organism. And we know how much bacterial warfare is going on in the microbial world.

What are some cool examples of multicellular bacteria?

Researchers have not found that many yet. But those multicellular bacteria, that they started to investigate, are pretty cool.

Well, that’s what I think, but see for yourselves.

Multicellularity in chains: filamentous cyanobacteria

Filamentous cyanobacteria are Earth’s oldest multicellular organisms. And thanks to them, we have all this precious oxygen on our planet.

Some cyanobacteria form long chains, so-called filaments. In such an organisation, the whole chain of cyanobacteria is surrounded by one common outer membrane. This means, that all cyanobacteria cells within the filament share one periplasm. And they use this periplasm to communicate with each other and exchange nutrients.

Also, filamentous cyanobacteria like the Anabaena species can undergo cell differentiation. In the picture above, you can see a chain of Anabaena cells. Some cells are smaller, which are the undifferentiated cells, and some are bigger blobs.

The normal-sized cells have photosystems and they perform photosynthesis to produce oxygen.

But when cyanobacteria do not have enough nitrogen, they start to differentiate into those bigger cells, so-called heterocysts. And these heterocysts are now able to fix nitrogen. This helps the organism with its nitrogen limitation.

The reason why Anabaena needs these two cell types is because the chemical processes of oxygen production and nitrogen fixation interfere with each other. They can not happen within one cell, which is why cyanobacteria need to have a different cell type for each process.

In the end, the cells share the produced oxygen and the fixed nitrogen with the whole filament. So everyone is happy with this arrangement.

Multicellular bacteria as electricity producers: cable bacteria

Cable bacteria form – similarly to cyanobacteria – long filaments that are surrounded by one common outer membrane. And they use this arrangement to transport electrons and conduct electricity.

We talked about multicellular cable bacteria in detail in the article Cable bacteria – unusual microbes conducting electricity. Head there to read about this special kind of multicellular bacteria.

Multicellular organisms in cell aggregates: Myxobacteria

Some bacteria, like the well-characterised Myxobacteria, can form huge cell aggregates of up to 100’000 cells. These cell aggregates are called fruiting bodies and their main function is to feed and transport their spores.

The spores have a special place within the Myxococcus fruiting body: They are kept at the core of the fruiting body. Here, they are safe and protected from the surrounding.

Interestingly, myxobacteria are also known as wolf-pack predators, because of the way they attack their preys. They kill their preys by launching a massive attack and secreting lethal bacterial toxins. This kills the prey instantly and the whole fruiting body can feed on the prey.

Multicellular organisms forming hyphae networks: Streptomyces bacteria

Streptomyces bacteria develop a complex network of hyphae within the soil. With this network, Streptomyces bacteria can branch into different directions and elongate the branch tips.

Within the branches, some hyphae within the soil have secluded compartments with walls to separate them from the rest of the network. Yet, Streptomyces uses the hyphae to transport nutrients and chemicals and to communicate.

But when nutrients are missing, the branches grow out of the soil and into the air. Here, they form spores and produce geosmin and antibiotics. This geosmin attracts insects that distribute the spores in the environment.

Plus, by producing antibiotics, Streptomyces tries to kill those microbes that want to eat the spores.

The superhero of multicellularity: Magnetotactic multicellular prokaryotes

Ever since I heard about these bacteria, they became my favourites. And not only because these multicellular bacteria cannot even survive as single cells.

All cells within the magnetic berry are connected to a common core. On the outside of the berry, bacteria have flagella.

And because many of these bacteria assemble together and each one has several flagella, the whole berry is basically covered in bacterial flagella. When all of these flagella start rotating together, the whole berry becomes incredibly fast.

The second feature is, that these magnetotactic bacteria sense the Earth’s magnetic field lines thanks to their magnetosomes. Hence, this magnetotactic superorganism is even more sensitive to the Earth’s magnetic field, which gives it probably even more superpowers.

Lastly, the multicellular magnetotactic bacteria respond to blue light and swim away from it. This is a completely new bacterial ability and researchers are still not sure why these bacteria do that.

Unfortunately, we do not know much about these fascinating organisms, because they are incredibly difficult to grow in the lab. Until now, researchers could only image these bacteria from environmental samples as they still do not know what these bacteria need to survive in the lab.

Multicellular bacteria – an advanced lifestyle

As we have seen in this article, bacteria can grow either as single cells or as multicellular organisms.

By teaming up with their sibling cells, multicellular bacteria gain new superpowers, they can spread out and protect their weakest team members.

From an evolutionary point of view, forming multicellular organisms was a super important step. Only thanks to this, highly-developed animals with all their different cells and organs could develop.

The post Together we are strong – bacteria form multicellular organisms appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

We are completely surrounded by them and we surely would not be the same if it was not for our microbial friends.

Unfortunately, every once in a while, we read and hear negative news articles about certain players of the microbial world. And then we forget that many other microbes and bacteria are actually very helpful to us, our health, the environment and food production.

But the goal of the BacterialWorld blog is to remind you how colorful and interesting the microbial world is.

20 interesting microbes everyone should have heard about

The microbial world consists of many interesting players: bacteria, viruses, phages, fungi, protozoa, unicellular eukaryotes and microscopic animals. And together, they all make the microbial world such a diverse and fascinating environment.

So, here, we assembled a list of common and interesting microbes. Some of them you might find delightful, others you rather want to avoid and that is okay.

We want you to be aware that there are many more cool microbes and bacteria out there than what you hear in the news.

And that thanks so research, we know a lot about how to use these microbes or how to avoid them if they are dangerous.

For this list, I got help from microbe lover Rachel and her GIANTmicrobes which she introduced during the #MicrobesinMay challenge on Twitter.

Ready to learn about the microbial world and interesting bacteria and microbes?

1. The bacterium Escherichia coli

Escherichia coli is rod-shaped and can have flagella all around its cell. 

Most people have heard of Escherichia coli because of contaminated food or lakes. However, most strains are harmless and this bacterium is actually super important for your digestive health.

This is also why Escherichia coli is by far the most intensively studied and best-understood organism on the planet.

Escherichia coli serves as a model organism for microbiology and biotechnology. It is helping scientists to learn about everything DNA-related, as well as protein production and cell growth. In most research labs of biological or life sciences, scientists use this organism every day to produce proteins, produce gene fragments or use it as a vehicle for plasmids and vectors.

2. The Influenza virus

The influenza virus is an RNA orthomyxovirus that causes respiratory infections, which you may know as the ‘seasonal flu’. Luckily, there is a vaccine against the flu that you should get every year if you are able to.

Influenza is an RNA virus that contains 8 genetic segments. Generally, RNA viruses are prone to mutate a lot; this happens during so-called antigenic drift and antigenic shift events. These “shifts and drifts” can change the structure of the virus’s surface proteins. Unfortunately, this change makes it harder for our immune system to recognize and respond to the virus.

Because the flu virus is ever-changing, you should help your immune system to recognize the new antigens. You can do this best by getting the new FluShot every season. But be aware that each virus is different and a FluShot will not protect you against other viruses.

3. The fungus Saccharomyces cerevisiae

You may encounter this fungus – almost on a daily basis. Saccharomyces cerevisiae is also known as the common yeast.

We use this yeast to make beer and bread. Like many other microorganisms, Saccharomyces cerevisiae performs microbial fermentation. This means it eats sugar and turns it into alcohol in beer and CO2 for bubbles in beer and bread.

We cannot state enough that the yeast Saccharomyces cerevisiae is a fungus and not a bacterium. It produces rounded cells and researchers use it as a model organism for eukaryotes. This means its DNA is enclosed in a membrane and not swimming around freely as in bacteria. Humans are also eukaryotes, so lots of knowledge of human cellular and molecular biology comes from yeast research.

Saccharomyces cerevisiae also plays a role in biotechnology. Some strains produce biofuels while others produce recombinant proteins that we use as therapeutics.

4. The bacterium Lactobacillus acidophilus

Lactobacillus acidophilus gets its name because it produces lactic acids from sugars, which usually makes its surrounding very acidic.

Lactobacillus acidophilus cells are rod-shaped and usually grow in pairs or chains. This bacterium lives in our mouths and guts where it prevents the growth of other bacteria by maintaining a healthy microbiota.

This bacterium also helps make yogurt, since it breaks apart milk sugars to make acids and other healthy molecules. This is why Lactobacillus acidophilus is also a probiotic, meaning a microbe that promotes health. There are many claims out there promoting its use to increase health, but more research is needed.

5. The Rhinovirus

The Rhinovirus may look cute but it is one of those nasty viruses that you may not like. It causes the common cold and we all know how we feel not cute with a cold. There are more than 100 different varieties of rhinoviruses and together they cause almost half of all colds.

Rhinovirus is an RNA virus in a 20-sided capsid. They are some of the smallest viruses and can spread by aerosol or direct contact. The virus replicates best in temperatures slightly cooler than body temperature, like in the nose. In fact, “rhino” means nose in Greek.

Currently, there is no vaccine against Rhinovirus. And since it’s a virus, antibiotics won’t work against it.

The best way to protect yourself is good hand hygiene and physical distance from people with a cold.

6. The microscopic water bear

One of the most interesting and cutest microbes is definitely the water bear.

But what exactly are water bears?

Hypsibius dujardini are microscopic creatures, classified as the Tardigrada phylum.

As the name suggests water bears resemble bears and walk on eight tiny legs. Tardigrade means “slow walker”. So if you imagine a slow-walking bear through water, this is kind of what water bears are!

Besides being adorable, water bears can survive extreme conditions and they are found worldwide in diverse environments. Many species live in water or around moss. To survive in any habitat, water bears enter a state of cryptobiosis where it dries out and stops its metabolism. In this state, they can last several decades.

Water bears can live in hot springs, polar ice, mountains and deep in the ocean. In fact, researchers found that water bears can even survive the vacuum of space! That’s good since a capsule containing some crashed on the moon in 2019.

Learn more about what tardigrades look like under the microscope.

7. The microscopic rotifers

To us, Rotifers are certainly one of the most interesting and cutest microbes. These microscopic animals are almost all female and can reproduce without the involvement of males.

Rotifers are tiny free-living creatures found mostly in freshwater. Rotifers have a cylindrical body and a ring of cilia around their heads. When the cilia move, it appears as a wheel (rotifer means “wheel bearer”). This movement pushes food into the animal and helps them move through the water.

Rotifers are sexually dimorphic and the males are much smaller and usually do not live long.

Reproduction of this microbe is rather interesting: Unfertilized eggs grow as clones within their mother. But studies have found genetic differences without sexual reproduction. It is now just a question of how?

8. The bacterium Porphyromonas gingivalis

The bacterium Porphyromonas gingivalis causes bad breath and gum disease, so make sure to brush and floss regularly to keep it in check.

Porphyromonas gingivalis cells are rod-shaped and live in our mouths. They are anaerobic, so they don’t need oxygen to grow. This may seem odd since we should have oxygen in our mouths all the time. However, many different microbes grow in our mouths where they form biofilms. These are layers of almost no oxygen, in which the bacteria settle.

In the oral biofilm, the dental plaque, Porphyromonas gingivalis lives close to the gum line where oxygen is depleted. Here, the bacteria can infect the gum and cause erosion called periodontitis.

9. The Rubellavirus

The “little red” Rubellavirus is known to produce red rashes on children’s arms and faces. Luckily, there is a vaccine to prevent infection.

Rubella is an RNA virus in a 20-sided capsid wrapped by a lipid membrane. Also called German measles because it was first identified in Germany, rubella was once a common childhood disease causing rash, fever and sore throat. While it posed minor risks to children, rubella could be deadly for the unborn in the womb.

Today rubella is very rare because of the MMR vaccine, which protects against mumps, measles, and rubella. Thanks to scientific research and vaccination, many countries could be declared “free of endemic transmission of rubella”.

10. The morbillivirus

Separately, the virus that causes the measles. This virus leads to red spots all over the body and can be deadly. Fortunately, the MMR vaccine prevents infection.

Morbillivirus is a spherical RNA virus. Measles is very contagious and spreads by personal contact and contaminated surfaces. It infects the respiratory system and causes rash, fever, cough, running nose and red eyes. Measles can cause serious complications and be deadly for kids.

Today, morbillivirus is still responsible for more than 100 000 deaths yearly, down from more than 2 million deaths annually. This is due to the introduction and widespread use of the MMR vaccine.

11. The bacterium Shigella dysenteriae

If you’ve ever experienced Shigella dysenteriae, you would remember! This bacterium infects the intestines and causes shigellosis, which is incredibly painful and uncomfortable. Antibiotics treat this disease, but hygiene is the best prevention.

Shigella dysenteriae are rod-shaped bacteria. They have a biological needle with which they fire the so-called ‘Shiga toxin’ into our gut cells. This leads to stomach pain and watery diarrhea.

This bacterium travels through the fecal-oral route, from contaminated food or hands. It is very contagious because it needs only a few cells to make someone sick.

What’s the best way to protect yourself? Always cook food thoroughly to kill all bacteria. And wash your hands to prevent spread!

12. The human papillomavirus

This virus may look cute, but human papillomavirus has been linked to certain cancers! The human papillomavirus is a common virus that infects many. Thankfully, there is a new vaccine to prevent high-risk infections.

The human papillomavirus is a DNA virus surrounded by a circular capsid. This virus is very common and in most cases, one may not have any symptoms while the body clears the virus.

Sometimes, the virus causes small tumors called papillomas that appear as warts. If left untreated, those tumors can become cancerous.

The human papillomavirus spreads by direct contact and is one of the most common sexually transmitted diseases worldwide. A vaccine is available to prevent infection from the major cancer-associated human papillomavirus types.

13. The bacterium Anabaena

Anabaena, known as cyanobacteria, are photosynthetic bacteria, even though they resemble eukaryotic algae. These helpful bacteria contain pigments that give Anabaena the blue-green colour.

Commonly found in aquatic environments, cyanobacteria use their pigments to convert light into energy. Using that light along with CO2 and water, they convert it to sugar and oxygen. In fact, cyanobacteria are a major source of oxygen in our atmosphere today!

The bacteria are even more interesting since some of their cells have special superpowers. These so-called heterocysts can “fix” nitrogen.

Heterocysts have extra thick- cell walls to exclude oxygen that otherwise harms nitrogen-fixing enzymes. The heterocysts then share the fixed nitrogen with surrounding cells.

14. The bacterium Clostridium botulinum

Clostridium botulinum produces a neurotoxin known for causing botulism. But that same toxin is also a component of Botox. Just another way we use microbes for good.

Clostridium botulinum is a rod-shaped, spore-forming, anaerobic bacterium. Found in soils, it can enter the food supply as spores. Under correct conditions, like in canning, spores germinate and produce the toxin. Thus, food should be processed with high heat and pressure to kill spores.

The botulinum toxin is the most toxic substance known and causes paralysis. While botulism is serious and can be deadly, scientists found ways to use the muscle-paralyzing function of this toxin. In small doses, the toxin treats muscle disorders such as spasms. Also found in Botox, the toxin paralyzes muscles that lead to wrinkles.

15. The varicella-zoster virus

Remember those itchy spots caused by chickenpox? I do! But now many children don’t have to experience the results of the varicella-zoster virus because of the chickenpox vaccine (lucky them!).

The varicella-zoster virus is a highly contagious DNA herpesvirus. As a primary infection, the virus causes so-called varicella. You might remember this as body rash and itchy blisters that last a few days.

Yet, the varicella-zoster virus actually can remain dormant in our nervous system (called latency) and reactivate later in life. This secondary infection can then lead to herpes zoster, also called shingles.

While chickenpox is usually a non-serious childhood disease, shingles affect adults and can have serious complications and pain. That’s why there is a separate shingles vaccine, too. No one wants to be itchy or in pain, so make sure to get the vaccine!

16. The bacterium Borrelia burgdorferi

Borrelia burgdorferi is a spirochete bacterium shaped like a corkscrew with flagella at both ends. These bacteria live in ticks and can infect humans when bitten by an infected tick.

These bacteria cause Lyme disease, a zoonotic disease where the pathogen jumps from an animal to a human.

Lyme disease is best known for causing a bull’s eye rash. But it also causes fever, headaches and fatigue. Some cases of Lyme disease are asymptomatic and if left untreated can lead to serious neurological or heart issues. Make sure to protect yourself when going hiking and camping.

17. The bacterium Listeria monocytogenes

This bacterium has made headlines, but not for anything fun. Listeria monocytogenes has led to many food recalls because of contamination concerns. It can grow at 0°C, so even refrigerated food can be infected.

Listeria monocytogenes cells are rod-shaped and covered with flagella. This food-borne pathogen causes listeriosis that may result in sepsis, meningitis, or death. It’s especially dangerous for immunocompromised and unborn, which is why pregnant women shouldn’t eat soft cheese or uncooked meat.

Listeria monocytogenes is found in environments where food grows. Contamination can occur during food harvesting and processing. Once inside a human cell, they manipulate it so that the cell propels the bacteria into the next cell.

18. The Epstein-Barr virus

Did you know that the Epstein-Barr virus is one of the most common human viruses? It causes the commonly called kissing disease because we transfer the virus by saliva and bodily fluids.

The Epstein-Barr virus is a DNA herpesvirus with a lipid envelope. Most infections occur in childhood and are asymptomatic or with only mild symptoms. Roughly 90% of adults have antibodies against Epstein-Barr, which means they were once infected with this virus.

When infecting adults for the first time, the Epstein-Barr virus can cause mononucleosis. Symptoms include fever, sore throat and extreme fatigue, lasting weeks to months. You can prevent the spread by not sharing utensils or drinking cups.

19. The bacterium Staphylococcus aureus

One of the best-known bacterial warriors is Staphylococcus aureus and its methicillin-resistant super brother MRSA. These two can infect almost all parts of the human body with their arsenal of virulence factors.

Staphylococcus aureus cells are round-shaped and form grape-like clusters. Most people have this Gram-positive bacterium in their nose or on their skin.

Unfortunately, with certain triggers, this harmless bacterium can become a pathogen. Then, Staphylococcus aureus produces virulence factors, such as toxins, enzymes, and antibody-inactivating proteins. These bacteria can also form biofilms on medical implants.

What about MRSA? Those are strains of Staphylococcus aureus that are resistant to the antibiotic methicillin (Methicillin-resistant Staphylococcus aureus). Antibiotic resistance occurs when bacteria acquire ways to inactive antibiotics and has become a worldwide health crisis.

20. The protozoan Toxoplasma gondii

Love cats? Well, those cats might have a ‘friend’: Toxoplasma gondii. This parasite can be carried by cats and is one of the most common parasites in the world. The infection causes toxoplasmosis which is an important zoonosis.

Toxoplasma gondii is an obligate intracellular parasite. It can reproduce sexually only in cats (called the definitive host) or asexually in any warm-blooded host (such as mice or humans). A cat can become infected by eating an infected mouse, then pass the infection to humans via litter.

Toxoplasmosis infections can occur from eating contaminated food or from infected cat droppings. In most cases, the infection is asymptomatic. However, immunocompromised and pregnant people are at risk for complications.

Which one is your favorite among the interesting microbes?

We hope we could give you a broad overview of interesting microbes and bacteria common in the environment and on the human body. This list of common microbes is meant to raise awareness of how multifaceted the microbial world is.

Yes, some of these microbes cause diseases. But thanks to research, we now have ways to boost our immune systems to clear diseases caused by pathogens or to prevent microbial diseases in the first place with vaccines.

And don’t forget that so many microbes are actually super helpful and fun to look at! Just look at this cute water bear dancing around!

If you have questions about any of these microbes or want to learn more about any player in the microbial world, comment below or send us an email.

And if you want to know more about Rachel and interesting bacteria, follow her on Twitter, or connect with her on LinkedIn.

The post 20 interesting microbes everyone should have heard about 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