THE UNTOLD STORY OF BACTERIA

Science is lifting the lid on the secret lives of bacteria – and revealing how the smallest of organisms are the key to understanding ourselves and some of our biggest questions.

Bacteria survive, thrive, fight and die by the trillion every moment. They swim using nanoscopic motors, and battle with spears. They sense, communicate, remember. And as scientists discover more about these tiny organisms, it is becoming clear that bacteria wield huge influence over us, shaping Earth’s past, our present and the future for us all. We have only recently realised how much our lives are inextricably linked with the lives of bacteria. We really are living in a bacterial world.

WORLD-BUILDING BACTERIA

Earth has been a bacterial world for at least the last 3.5 billion years. In the oceans of our young planet, bacteria were among the first forms of life to emerge. Long before plants or animals had evolved, bacterial colonies flourished and grew.

And then, through two extraordinary events, bacteria changed the face of the Earth. 2.4 billion years ago, one type of bacteria started to release oxygen, creating the atmosphere as we know it. And shortly after that – on planetary timescales at least – bacteria created the complex cells required for all plant and animal life to evolve. Bacteria built the world we live in today.

DOMAINS OF LIFE

Tiny organisms once ruled the whole world. Up until two billion years ago, all life on Earth fell into two great domains – bacteria and archaea. Since that time, a third domain of life, eukaryotes, has thrived alongside the other two. It consists of plants, fungi, and animals, including us.

Bacteria are incredibly diverse, and can specialise to live nearly anywhere and eat almost anything. Together with the archaea, they represent the dominant form of life on Earth.

There are more species of bacteria than any other life form. The most recent estimate predicts that bacteria account for over three quarters of all species of life on Earth. This diversity is a mark of how bacteria have evolved to thrive in nearly all environments on this planet.

'Bacteria formed the Earth as we know it, and continue to shape it.'
Judith Armitage, biochemist
Graphic showing the evolutionary relationships of the three domains of life: Archaea, eukaryotes, and bacteria

Scientists once thought of archaea and bacteria as a single group of organisms. Then in 1977, genetic analysis revealed that archaea had a separate evolutionary history to bacteria and therefore represent an independent branch of life altogether.

Scientists once thought of archaea and bacteria as a single group of organisms. Then in 1977, genetic analysis revealed that archaea had a separate evolutionary history to bacteria and therefore represent an independent branch of life altogether.

WHAT ARE BACTERIA?

Bacteria are the simplest creatures we think of as being alive.

Fewer than 100 species of bacteria can do you any damage by causing infectious disease. The vast majority of species either live in you harmlessly, or actively keep bad at bay, like microscopic superheroes.

Bacterial cells are filled with a substance called cytoplasm, a concentrated mixture of proteins and nutrients needed for life. A single twisted and compacted loop of DNA carries their genetic code, but they may also have supplementary useful genes in tiny rings called plasmids.

Some bacteria have hair-like flagella that they rotate, or tiny retractable pili which they use like grappling hooks.

Bacteria come in many shapes and sizes. You could fit 2,000 of the smallest into a millimetre, while the largest are more than half a millimetre long and visible to the naked eye.

Graphic illustrating the five basic shapes of bacteria: Bacillus - rod; Spiral (Spirochaete); Coccus - ball; Comma; and Branched

Bacteria come in five basic shapes

Bacteria come in five basic shapes

EARTH’S FIRST LIFE-FORMS

The Earth was a sizzling-hot, barren lump of rock when it formed, 4.54 billion years ago. Gases hissed from the planet’s interior as it cooled, eventually allowing liquid water to accumulate and form oceans – in turn providing conditions for life to emerge. In the fertile warmth of hydrothermal vents on the ocean floor, microorganisms began to grow. The earliest evidence of this – still under debate – may be in rock samples from an ancient seafloor vent in Canada. The rocks contain strands and tubes made of iron oxide - similar to structures built today by bacteria that live around deep-sea vents.

Hydrothermal vents were the habitat that hosted the last universal common ancestor shared by all life forms, according to recent research. A vent called Loki’s Castle, up to 2,300 metres deep in the Atlantic off Greenland, yielded sediment samples that caused great excitement in 2015. It contained microbes whose DNA was like a missing link in understanding how complex cells – and thus all animals – evolved.
Image © Loki’s Castle - R.B. Pedersen, Centre for Geobiology, University of Bergen, Norway

POWER FROM THE DEEP
Hydrothermal vents on the ocean floor host incredible communities of species. But without any sunlight, it is bacteria that power the habitat by harnessing a cocktail of chemicals. Hot, mineral-rich water wells up from fissures where new ocean crust is formed at mid-ocean ridges. Bacteria harvest chemicals to release energy, forming thick mats that other species feed on, setting up a food web.

Some bacteria thrive in extreme environments such as hydrothermal vents and hot springs like Octopus Springs, in Yellowstone National Park. We call these bacteria extremophiles because they can live in temperatures up to 80 degrees Celsius and can survive in high concentrations of chemicals usually harmful to life.
Image © Octopus Springs, Yellowstone National Park, US, by Scott Chimileski and Roberto Kolter, Harvard Medical School

EARTH: 3.7 BILLION YEARS AGO
The Earth was very different 3.7 billion years ago. Acidic vapours swirled over the planet’s surface, under an orange sky. The land was black and lava-encrusted, and the seas were green with dissolved iron. Yet life was evolving in shallow waters.

In 2016, scientists discovered evidence of bacterial life that could date back to this very early period in Earth’s history. They identified fossilised remains of possible stromatolites, structures built by bacteria, in a rocky outcrop in western Greenland. These were accompanied by distinctive chemical signatures that suggest the processes of life. It is rare to discover rock from this early period of time that has not been altered beyond recognition.

THE GREAT OXYGENATION EVENT

If you look closely at these stromatolites in Shark Bay, Australia today, you will occasionally spot bubbles emerging from them as bacteria break the water down and release oxygen. This is the process that began when the atmosphere contained only 1 per cent oxygen, and resulted, two billion years later, in an atmosphere with 20 per cent oxygen.

Around 2.5 billion years ago, something incredible happened on Earth. Cyanobacteria living in the oceans evolved the ability to split water using energy from the Sun. Through this process, called photosynthesis, they began producing oxygen as a by-product. This was the start of the Great Oxygenation Event. The bacteria’s waste product, oxygen, permanently changed the make-up of the seas and atmosphere. This set the scene for complex life to develop. We owe our evolution, and our existence, to bacteria.

EVIDENCE OF OXYGEN
The Great Oxygenation Event left a colourful mark in rocks laid down 2.5 billion years ago. Traces of iron rusted on contact with the oxygen being pumped out by cyanobacteria. The rusty sediments fell to the bottom of shallow oceans, taking with them their red hue. Today, scientists can compare sedimentary rocks from before and after the rise in oxygen levels, and see the telltale sign of red rust.

Red layers of iron in this rock have been rusted by oxygen. They provide evidence of the timescale on which bacteria began producing oxygen in the oceans – although there is a chance the reddening happened after the rock formed.

'The air that we breathe is composed of 21% oxygen, but oxygen wasn't always present in Earth's atmosphere.'
Nicholas Tosca, geologist

THE GREAT ENGULFING

Bacteria took the lead in not one, but two crucial events in the story of life on Earth. As well as oxygenating the atmosphere, single-celled bacteria and archaea enabled multicellular life to evolve in an event called the Great Engulfing.

In a momentous event with planet-wide consequences, a single-celled organism engulfed a bacterium. It created a new type of cell – the eukaryotic cell – inside which the bacterium eventually became an energy powerhouse called the mitochondrion. These new cells also found ways to work together, building multicellular animal and plant life on a scale never seen before.

Then in a second event, some newly energised cells engulfed more bacteria, similar to the cyanobacteria that photosynthesise in modern oceans. These bacteria formed the chloroplasts that give plants the ability to make energy from sunlight.

Graphic showing once cell engulfing a smaller bacterium cell

Animal cells evolved when one single cell, possibly an archaeon, engulfed an aerobic bacterium – one that used oxygen to release energy. The bacterium evolved into the mitochondrion, the powerhouse of the cells of humans and other animals.

Animal cells evolved when one single cell, possibly an archaeon, engulfed an aerobic bacterium – one that used oxygen to release energy. The bacterium evolved into the mitochondrion, the powerhouse of the cells of humans and other animals.

WORLD-SHAPING BACTERIA

Today, bacteria shape our world in countless invisible ways. From species that rust iron and filter water, to those that live inside other creatures and influence both biology and behaviour, bacteria are constantly at work.

We rely on bacteria in innumerable ways. After a storm, the smell in the air comes from a chemical called geosmin that dead soil bacteria release. Humans can detect it at incredibly low concentrations, leading to the theory that in our past it helped us seek out sources of water.

Our bodies contain as many bacteria as they do human cells. Among the species that live in us are those that help repair our skin, tune our immune system and control how our fat is stored. This kind of coexistence is called symbiosis – and bacteria have evolved an incredible range of intimate relationships with us and with other species in this way.

LIVING WITH BACTERIA

The beewolf (Philanthus triangulum) is a type of wasp that preys on bees and has an ongoing relationship with helpful bacteria. When the female lays eggs, she wipes them with a bacteria-rich fluid that fights off dangerous pathogens during their long development period. When the adult finally emerges, it takes a sample of the bacteria to use when it lays its own eggs.

You and I, and much of the animal kingdom, live symbiotically with bacteria. We have a long-standing coexistence with a range of microorganisms that live in and on us. But the nature of the relationship we share with bacteria can be, as they say, complicated.

The kind of symbiosis called mutualism benefits both partners. In another kind called commensalism, one species derives benefit from another without either hurting or helping it. If a relationship is parasitic, it benefits only one of the partners. If the relationship sours, it may turn pathogenic, and one of the parties may not survive at all.

Partners in evolution
Could bacteria help to drive evolution in animal species? In the case of chitons, it does appear that symbiotic bacteria played a part in enabling different populations to take advantage of particular biological settings. Over time these populations evolved to form new species, resulting in a great diversity of closely related chitons with the ability to survive in a wide range of environments.

Many squid, including this Hawaiian Bobtail Squid, camouflage themselves in moonlight with two underside chambers filled with glowing bacteria - Aliivibrio fischeri. Through an effect called counterillumination, the light produced on their bodies prevents them from appearing as a dark silhouette from below.

A light in the dark
Bioluminescent bacteria live symbiotically with marine animals such as anglerfish, ponyfish and Hawaiian Bobtail Squid. The bacteria make parts of the body glow, acting as camouflage to help hide the animals from predators and prey. Bright light also allows host animals to communicate in the darkness and lure their prey to within striking distance. In some cases the animal’s bodies would not reach maturity without the bacteria. Bioluminescence has evolved at least 27 times in fish, according to recent research.

Scleractinian corals in their juvenile stage seek out particular communities of bacteria living on reefs and rocks. Once they find the right bacterial neighbours they settle and metamorphosis is triggered.

Settling down
Some marine invertebrates such as corals, and their relatives hydroids, live symbiotically with bacteria. Microorganisms play a role at each stage of these animals’ life cycles - from the process of deciding when and where the free-swimming juveniles settle in their environment, to their metamorphosis and division as settled adults. Without these bacterial markers the ocean’s coral reefs, the most biodiverse environment on earth, would look very different.

Leeches live on blood they suck from other animals, usingbacteria in their gut to extract nutrients.

Dietary requirements
In the sea, on the land and in the air, animals and bacteria live in mutually beneficial relationships based on access to food and nutrition. Animals with high fibre diets rely on a diverse gut microbiome to digest cellulose, a tough component of plant cell walls.

Aeromonas is a bacterium often found in the gut of blood-sucking creatures, enabling them to digest their high-protein, low carbohydrate meals. One way for animals to ensure that they always have the right bacteria to help them digest their food is to share bacteria with their community by eating each other’s faeces or consuming special fluids that contain concentrations of the bacteria.

Eurema hecabe is a yellow butterfly in which Wolbachia bacteria skew the sex ratio by feminizing males and lowering reproductive rates.

Favouring females
Wolbachia bacteria are parasites in many species of insect. Because Wolbachia is passed down via the female’s eggs, it is advantageous to have more female than male offspring, and so it has evolved the ability to skew the population in favour of females. It does this through a variety of methods, from killing embryos of males to making a species parthenogenic, in which all offspring are female clones of their mother.

Toxic team
Tetrodotoxin is one of the deadliest toxins, widely found in marine animals. It works by paralysing prey, or poisoning unsuspecting creatures that eat it, by interfering with nerve signals. However, animals do not produce the substance themselves – a variety of species of bacteria is responsible. In UK shellfish species, higher sea surface temperatures are allowing Vibrio bacteria to flourish, increasing the risk of a dose of food poisoning.

This tiny species of octopus has a highly venomous bite that it uses to disable its prey. The venom is produced by Vibrio bacteria in its saliva glands. There is no known antivenom.

THE GUT & BEYOND

The range of bacteria in our gut – collectively called our microbiome – is set by what we receive at birth from our mothers, and what happens to us in early life. To some extent, it is also influenced by where we have travelled, our diet and medicine, and who we live with – right down to our pets.

While antibiotics treat our bacterial infections, they can also wipe out useful bacteria species in your gut. On the other hand, owning a pet dog may help increase the diversity of your microbiome and keep you healthier.

'The densest bacterial population on the planet is found in mammal guts.'
Christoph Tang, cellular pathologist

THE MICROBIOME-GUT- BRAIN AXIS

New research suggests that our gut bacteria may have a surprising influence on our brains and behaviour, from our mood, to our susceptibility to disease. Scientists have already found clear signs of this microbiome-gut- brain link in animals, and are uncovering more evidence that it also exists in humans – but the mechanism is not yet clear.

Mice bred to have no gut microbiome can’t respond normally to stress. They explore an unfamiliar place with less anxiety than normal mice – but when stressed, they overreact in a potentially harmful way. If their gut microbiome is restored, however, their behaviour becomes more confident.

'There is now convincing evidence to suggest that nurturing your good bacteria can benefit brain function'
Philip Burnet, neuroscientist
Inflatable white and transparent sculpture of an E. coli cell suspended from the roof of Oxford University Museum of Natural History

This 28-metre long inflatable E. coli sculpture was created by artist Luke Jerram in collaboration with researchers from the University of Sheffield, who loaned it to the Museum for the Bacterial World exhibition. Although it has a bad reputation for making people ill, there are millions of E. coli living harmlessly in your gut right now, keeping more dangerous bacteria at bay. E. coli are also vital in medical research. Described as the ‘workhorse’ of biomedicine, these bacteria are used by scientists as tiny bio-factories, making useful products for research, medicine and industry.

This 28-metre long inflatable E. coli sculpture was created by artist Luke Jerram in collaboration with researchers from the University of Sheffield, who loaned it to the Museum for the Bacterial World exhibition. Although it has a bad reputation for making people ill, there are millions of E. coli living harmlessly in your gut right now, keeping more dangerous bacteria at bay. E. coli are also vital in medical research. Described as the ‘workhorse’ of biomedicine, these bacteria are used by scientists as tiny bio-factories, making useful products for research, medicine and industry.

BACTERIA FEED THE WORLD

Bacteria are agents of change. If food is fermenting, bacteria are often at work. If a crop is growing, bacteria have helped supply nitrogen to make it happen. And if waste is decaying, once again, bacteria are busy.

In fact, bacteria are champions of recycling, driving the circulation of carbon, nitrogen, sulphur and phosphorus around the planet. Bacteria turn these elements into substances plants and animals can use in life – and then after death, bacteria break them down again.

All life needs nitrogen to grow, but neither plants nor animals can access it without assistance from bacteria. Nitrogen-fixing bacteria convert nitrogen gas from the air into ammonia, in the soil, in water, and in nodules on the roots of bean and pea plants.

Nitrifying bacteria then turn the ammonia into nitrates which the plants can use to make proteins. These enable the plants to grow larger, with more roots and leaves, and to produce more abundant crops which animals and people eat. Bacteria act as decomposers, breaking down dead organisms and sending nitrogen back into the soil as ammonia. They also release nitrogen back into the atmosphere through the denitrification process.

Kimchi in a glass jar

To make kimchi, vegetables including baechu cabbage are fermented with Leuconostoc, Lactobacillus and a range of other bacterial species. By making the environment more acidic, the bacteria that promote rotting are suppressed, and the food is preserved.

A piece of Swiss cheese with holes in

The holes in some Dutch cheeses appear because bacteria convert lactic acid into carbon dioxide gas. To control the size of the holes, cheese-makers vary the temperature and length of time over which they age the cheese.

Sourdough bread sliced on a bread board

Sourdough bread begins with a starter culture containing Lactobacillus bacteria. The baker feeds the culture with flour and water, and the bacteria convert sugars to the acids that will give the bread its flavour. Natural yeasts then start to make carbon dioxide and ethanol and after six days, the starter is ready for actual bread-making.

Kimchi in a glass jar

To make kimchi, vegetables including baechu cabbage are fermented with Leuconostoc, Lactobacillus and a range of other bacterial species. By making the environment more acidic, the bacteria that promote rotting are suppressed, and the food is preserved.

A piece of Swiss cheese with holes in

The holes in some Dutch cheeses appear because bacteria convert lactic acid into carbon dioxide gas. To control the size of the holes, cheese-makers vary the temperature and length of time over which they age the cheese.

Sourdough bread sliced on a bread board

Sourdough bread begins with a starter culture containing Lactobacillus bacteria. The baker feeds the culture with flour and water, and the bacteria convert sugars to the acids that will give the bread its flavour. Natural yeasts then start to make carbon dioxide and ethanol and after six days, the starter is ready for actual bread-making.

WORLD-CHANGING BACTERIA

Today, studies of bacteria are radically changing the way we think about the future. As scientists examine bacteria more closely than ever before, surprising abilities and activities of different species have come into sharp focus.

Far from being a passive microbial mass, bacteria can survive, sense, communicate and remember. Some swim by rotating a tail, using intricate motors. They survive attack with a range of strategies, some of which involve spearing an opponent to make them explode.

Discoveries like these are fascinating in their own right. But by harnessing bacterial behaviours, we may be able to tackle some of the biggest challenges our planet faces.

‘Bacteria live in very complex communities, and within that they behave like any other community’
Judith Armitage, microbiologist

SURPRISING SKILLS

Memory
Bacteria can detect a one per cent change in the level of a background chemical – and retain that information. They swim along, testing whether they sense a higher or lower level of the substance in their new location – a trick that shows they must have a memory function. Then, depending on what they find, they continue the same way or change direction.

A Bdellovibrio bacteriovorus bacterium uses memory to choose direction of movement.
Image: © Bdellovibrio bacteriovorus, Liz Sockett, University of Nottingham

A Bdellovibrio bacteriovorus bacterium uses memory to choose direction of movement.
Image: © Bdellovibrio bacteriovorus, Liz Sockett, University of Nottingham

Movement
Tiny protein motors allow some bacteria to move by whirling a tail called a flagellum. Research has recently shown that different species gear their motors for success in the places they live. Campylobacter, for example, has its motor geared to give enough torque to bore through thick mucus in the gut.

Other species of bacteria can direct their own movement with incredible precision by extending hair-like proteins called pili that grasp the surface like a grappling hook. They then retract these, dragging themselves over the surface. This allows individual cells of a bacterium to locate the best spots on a surface according to where the most nutrients are.

Cryo-electron tomography reveals the motor that drives movement of Helicobacter pylori flagella.
Image: © Helicobacter pylori motor, Liu Lab, Yale School of Medicine

Cryo-electron tomography reveals the motor that drives movement of Helicobacter pylori flagella.
Image: © Helicobacter pylori motor, Liu Lab, Yale School of Medicine

Warfare
Chemical weapons are part of the armoury of some species of bacteria. Some produce toxins that can damage their opponent’s DNA, or in other cases the cell wall, causing the cell to explode. At the same time, they themselves are immune to the toxin’s action.

When Vibrio cholera bacteria meet an opponent, they can fire a speargun to penetrate their enemy with a deadly poison. Recent findings show that a sheath of over 200 interconnected cogwheel rings surrounds an inner spear. When it fires, the sheath contracts and pushes the toxic spear outwards. This drills a hole into the target cell in only two milliseconds.

Cryo-electron microscopy showing the spear and sheath of Vibrio cholera.
Image © Bacterial nano-sized speargun, Marek Basler, Biozentrum, University of Basel

Cryo-electron microscopy showing the spear and sheath of Vibrio cholera.
Image © Bacterial nano-sized speargun, Marek Basler, Biozentrum, University of Basel

Survival
In hostile circumstances, some bacteria can form protective layers and become spores. In this dormant state, they resist heat, UV radiation and disinfectants and can emerge in a perfectly viable state, centuries later. Spores recovered from the abdomens of Egyptian mummies can germinate after hundreds of years. Other spores have been sent into space and survived the UV radiation.

One thing that bacteria cannot survive is infection by some kinds of bacteriophage. These viruses infect a bacterial cell, reproduce and then cause the cell to burst and die. Other phages, however, integrate their DNA into the bacteria’s own genome, piggybacking on the bacteria’s reproduction cycle.

Scanning electron microscope image of bacteriophages, coloured green, attacking E. coli, coloured blue.
Image © Miika Leppänen, Nanoscience Center, University of Jyvaskyla

Scanning electron microscope image of bacteriophages, coloured green, attacking E. coli, coloured blue.
Image © Miika Leppänen, Nanoscience Center, University of Jyvaskyla

Evolution
Many bacteria reproduce quickly through the process of binary fission and therefore adapt rapidly to their environment. However, some also take an evolutionary shortcut by picking up or dropping whole sections of DNA at once. Rather than transferring genetic material only parent cell to daughter cell, bacteria can also swap genes directly with each other. This is known as horizontal gene transfer and allows bacteria to gain new properties such as the ability to degrade artificial pesticides, or gain antibiotic resistance.

Transmission electron microscope image of Caulobacter
at various stages of reproduction through binary fission.
Image © Dividing Caulobacter, Yves Brun, Department of Biology, Indiana University Bloomington

Transmission electron microscope image of Caulobacter
at various stages of reproduction through binary fission.
Image © Dividing Caulobacter, Yves Brun, Department of Biology, Indiana University Bloomington

Communication
Groups of bacteria keep in touch with one another by emitting signal molecules, a bit like pheromones, that enable the community to sense how big it is. This trick, called quorum sensing, allows the bacteria to be sure of safety in numbers before beginning to take action.

Vibrio fisheri are bacteria that live symbiotically with marine animals like Hawaiian Bobtail Squid. They begin to bioluminesce only when the colony reaches a large enough size to be effective, saving energy until then.

Bioluminescent Vibrio bacteria growing on an agar plate.
Image © Scott Chimileski and Roberto Kolter, Harvard Medical School

Bioluminescent Vibrio bacteria growing on an agar plate.
Image © Scott Chimileski and Roberto Kolter, Harvard Medical School

Bacterial warfare – two colonies of E. coli fight using toxins. Each colony can detect the incoming toxin from the other and ramps up its own toxin production in response, leading to a large no-man’s land where all cells are killed. Individual bacteria have evolved resistance to the opposite colony’s toxin and reproduced to form new colonies visible as islands within the bacterial no man’s land.
Image © E. coli colonies fighting, Despoina Mavridou, Foster Lab, University of Oxford

Bacterial warfare – two colonies of E. coli fight using toxins. Each colony can detect the incoming toxin from the other and ramps up its own toxin production in response, leading to a large no-man’s land where all cells are killed. Individual bacteria have evolved resistance to the opposite colony’s toxin and reproduced to form new colonies visible as islands within the bacterial no man’s land.
Image © E. coli colonies fighting, Despoina Mavridou, Foster Lab, University of Oxford

HARNESSING THE POWER OF BACTERIA

What are the most significant issues you feel the world faces? Tackling diseases of body and mind? Dealing with waste and pollution? Providing food and clean water for everyone? Making other planets habitable for humans? The tiniest of organisms – bacteria – may offer creative ways to approach the biggest problems.

From clearing oil spills to eating plastic, halting infection to purifying water, even delivering targeted medicines using nanobots, bacteria have positive potential to help us. Their abilities continue to surprise the scientists who know them the best, and who seek to harness their properties for good.

Halting dengue fever
Up to half a billion people catch dengue fever each year. Scientists recently discovered that Wolbachia bacteria may help stop the virus from reproducing inside the mosquitoes that carry it – preventing them from passing it to humans. Wolbachia live in up to 60 per cent of other insect species already, and are very efficient at spreading through populations, which scientists hope may lead to the halt of dengue and other viruses.

Clearing oil spills
In 2010 the Deepwater Horizon oil spill released a disastrous 4.2 million barrels of oil into the Gulf of Mexico. However, the oil cleared faster than anticipated because bacteria such as Colwellia, Neptuniibacter and Alcanivorax helped break up the dangerous hydrocarbon rings. Now scientists are working out how to harness the ability among sea-dwelling bacteria to break oil down.
Image: © Deepwater Horizon oil spill, Kris Krüg

Disrupting pathogens
The fact that bacteria can communicate means they act as a team – waiting for a colony to grow large enough to make you ill for example. If scientists can learn to disrupt this communication process, they may be able to combat virulently infectious bacteria. Pseudomonas aeruginosa and Staphylococcus aureus, which cause wound infections, are two bacteria under investigation.
Image: © Pseudomonas aeruginosa colony, Scott Chimileski

Might bacteria help tackle plastic pollution - Emily Flashman, biochemist

Can we evolve bacteria to protect us from disease? - Kayla King, evolutionary biologist

Might we create synthetic biological motors modelled on bacteria? - Richard Berry, physicist

Listen to the full set of Bacterial World audio recordings.

‘By studying a single human and the dynamics of the bacterial species within them, we can gather an enormous data set - as complex if we were studying a rain forest. The findings could be revolutionary for microbiology and ecology.’
Kevin Foster, zoologist

BASH THE BUG

Tuberculosis (TB) still kills more people each year than any other infectious disease. What is worse, recent TB cases are resistant to the standard antibiotic treatment. In response, researchers have set up Bash the Bug, a project in which citizen scientists across the world can help identify which antibiotics, at which doses, are effective against different TB strains.

The scientific team are collecting up to 100,000 samples of TB-causing bacteria – Mycobacterium tuberculosis – over the next few years. Volunteers then visually gauge the effectiveness of doses of 14 different antibiotics at stopping the bacteria growing. Over 10,000 people have already joined in and helped fight antibiotic resistance – join them at bashthebug.net.

Bacterial World was generously supported by: