Where do beneficial bacteria live? What bacteria are beneficial to humans?

Bacteria are the smallest ancient microorganisms invisible to the naked eye. Only under a microscope can one examine their structure, appearance and interaction with each other. The first microorganisms had a primitive structure; they developed, mutated, created colonies, and adapted to a changing environment. exchange amino acids with each other, which are necessary for growth and development.

Types of bacteria

School biology textbooks contain images different types bacteria that differ in shape:

1. Cocci are spherical organisms that differ in relative position. Under a microscope, it is noticeable that streptococci form a chain of balls, diplococci live in pairs, and staphylococci live in randomly shaped clusters. A number of cocci cause various inflammatory processes when they enter the human body (gonococcus, staphylococcus, streptococcus). Not all cocci living in the human body are pathogenic. Conditionally pathogenic species take part in the formation of the body’s defenses against external influences and are safe if the balance of the flora is maintained.
2. Rod-shaped ones differ in shape, size and ability to form spores. Spore-forming species are called bacilli. The bacilli include: tetanus bacillus, anthrax bacillus. Spores are formations inside a microorganism. Spores are insensitive to chemical treatment, their resistance to external influences is the key to preserving the species. It is known that spores are destroyed when high temperature(above 120ºС).

Shapes of rod-shaped microbes:

• with pointed poles, like fusobacterium, which is part of the normal microflora of the upper respiratory tract;
• with thickened poles resembling a club, like corynebacterium - the causative agent of diphtheria;
• with rounded ends, such as those of E. coli, which are necessary for the digestion process;
• with straight ends, like the anthrax bacillus.

Gram(+) and gram(-)

Danish microbiologist Hans Gram conducted an experiment more than 100 years ago, after which all bacteria began to be classified as gram-positive and gram-negative. Gram-positive organisms create a long-term stable bond with the coloring substance, which is enhanced by exposure to iodine. Gram-negative, on the contrary, are not susceptible to the dye, their shell is firmly protected.

Gram-negative microbes include chlamydia, rickettsia, and gram-positive microbes include staphylococci, streptococci, and corynebacteria.

Today in medicine the test for gram(+) and gram(-) bacteria is widely used. is one of the methods for studying mucous membranes to determine the composition of the microflora.

Aerobic and anaerobic

How do bacteria live

Biologists define bacteria as a separate kingdom; they are different from other living things. This single cell organism without a core inside. Their shape can be in the form of a ball, cone, stick, or spiral. Prokaryotes use flagella to move.

Biofilm is a city for microorganisms and goes through several stages of formation:

• Adhesion or sorption is the attachment of a microorganism to a surface. As a rule, films are formed at the interface of two media: liquid and air, liquid and liquid. The initial stage is reversible and film formation can be prevented.
• Fixation - bacteria release polymers, ensuring their strong fixation, forming a matrix for strength and protection.
• Maturation - microbes merge and exchange nutrients, microcolonies develop.
• Growth stage - bacteria accumulate, merge, and are displaced. The number of microorganisms ranges from 5 to 35%, the rest of the space is occupied by the intercellular matrix.
• Dispersion - microorganisms periodically detach from the film, attach to other surfaces and form a biofilm.

The processes that occur in a biofilm are different from what happens to a microbe that is not integral part colonies. Colonies are stable, microbes organize a unified system of behavioral reactions, determining the interaction of members inside the matrix and outside the film. Human mucous membranes are inhabited by a large number of microorganisms that produce a gel for protection and ensure the stability of the functioning of organs. An example is the gastric mucosa. It is known that Helicobacter pylori, which is considered the cause of gastric ulcers, is present in more than 80% of examined people, but not everyone develops peptic ulcers. It is assumed that Helicobacter pylori, being members of the colony, is involved in digestion. Their ability to cause harm manifests itself only after certain conditions are created.

The interaction of bacteria in biofilms is still poorly understood. But today, some microbes have become human assistants when carrying out restoration work and increasing the strength of coatings. In Europe, manufacturers of disinfectants offer to treat surfaces with bacterial solutions containing safe microorganisms that prevent the development of pathogenic flora. Bacteria are used to create polymer compounds and will also eventually generate electricity.

The totality of bacteria inhabiting the human body has common name– microbiota. In a normal, healthy human microflora there are several million bacteria. Each of them plays important role for the normal functioning of the human body.

In the absence of any type of beneficial bacteria, a person begins to get sick, the functioning of the gastrointestinal tract and respiratory tract is disrupted. Beneficial bacteria for humans are concentrated on the skin, in the intestines, and on the mucous membranes of the body. The number of microorganisms is regulated by the immune system.

Normally, the human body contains both beneficial and pathogenic microflora. Bacteria can be beneficial or pathogenic.

There are many more beneficial bacteria. They make up 99% of the total number of microorganisms.

In this situation, the necessary balance is maintained.

Among the different types of bacteria that live on the human body are:

• bifidobacteria;
• lactobacilli;
• enterococci;
• coli.

Bifidobacteria

This type of microorganism is the most common and is involved in the production of lactic acid and acetate. It creates an acidic environment, thereby neutralizing most pathogenic microbes. Pathogenic flora ceases to develop and cause processes of rotting and fermentation.

Bifidobacteria play an important role in the life of a child, since they are responsible for the presence of an allergic reaction to any food products. In addition, they have an antioxidant effect and prevent the development of tumors.

The synthesis of vitamin C is not complete without the participation of bifidobacteria. In addition, there is information that bifidobacteria help to absorb vitamins D and B, which are necessary for a person to function normally. If there is a deficiency of bifidobacteria, even taking synthetic vitamins of this group will not bring any results.

Lactobacilli

This group of microorganisms is also important for human health. Thanks to their interaction with other inhabitants of the intestine, the growth and development of pathogenic microorganisms is blocked and pathogens of intestinal infections are suppressed.

Lactobacilli are involved in the formation of lactic acid, lysocine, and bacteriocins. This is a great help for the immune system. If there is a deficiency of these bacteria in the intestines, then dysbiosis develops very quickly.

Lactobacilli populate not only the intestines, but also the mucous membranes. So these microorganisms are important for women's health. They maintain the acidity of the vaginal environment and prevent development.

Escherichia coli

Not all types of E. coli are pathogenic. Most of them, on the contrary, perform a protective function. The usefulness of the genus lies in the synthesis of cocilin, which actively resists the bulk of pathogenic microflora.

These bacteria are useful for the synthesis different groups vitamins, folic and nicotinic acid. Their role in health should not be underestimated. For example, folic acid is necessary for the production of red blood cells and maintenance normal level hemoglobin.

Enterococci

They help absorb sucrose. Living mainly in the small intestine, they, like other beneficial non-pathogenic bacteria, provide protection against excessive proliferation of harmful elements. At the same time, enterococci are considered to be relatively safe bacteria.

If they begin to exceed permissible limits, various bacterial diseases develop. The list of diseases is very long. Starting from intestinal infections, ending with meningococcal.

Positive effects of bacteria on the body

Beneficial features non-pathogenic bacteria are very diverse. As long as there is a balance between the inhabitants of the intestines and mucous membranes, the human body functions normally.

Most bacteria are involved in the synthesis and breakdown of vitamins. Without their presence, B vitamins are not absorbed by the intestines, which leads to disorders nervous system, skin diseases, decreased hemoglobin.

The bulk of undigested food components that reach the large intestine are broken down precisely by bacteria. In addition, microorganisms ensure the constancy of water-salt metabolism. More than half of all microflora is involved in the regulation of absorption fatty acids, hormones.

The intestinal microflora forms local immunity. It is here that the bulk of pathogenic organisms are destroyed and the harmful microbe is blocked.

Accordingly, people do not feel bloating and flatulence. An increase in lymphocytes provokes active phagocytes to fight the enemy and stimulate the production of immunoglobulin A.

Beneficial non-pathogenic microorganisms have a positive effect on the walls of the small and large intestines. They maintain a constant level of acidity there, stimulate the lymphoid apparatus, the epithelium becomes resistant to various carcinogens.

Intestinal peristalsis also largely depends on what microorganisms are in it. Suppressing the processes of decay and fermentation is one of the main tasks of bifidobacteria. Many microorganisms long years develop in symbiosis with pathogenic bacteria, thereby controlling them.

Biochemical reactions that constantly occur with bacteria release a lot of thermal energy, maintaining the overall thermal balance of the body. Microorganisms feed on undigested residues.

Dysbacteriosis

Dysbacteriosis is a change in the quantitative and qualitative composition of bacteria in the human body . In this case, beneficial organisms die, and harmful ones actively reproduce.

Dysbacteriosis affects not only the intestines, but also the mucous membranes (there may be dysbacteriosis oral cavity, vagina). The names that will prevail in the analyzes are: streptococcus, staphylococcus, micrococcus.

IN in good condition beneficial bacteria regulate the development of pathogenic microflora. The skin and respiratory organs are usually under reliable protection. When the balance is disturbed, a person experiences the following symptoms: intestinal flatulence, bloating, abdominal pain, frustration.

Later, weight loss, anemia, and vitamin deficiency may begin. From the reproductive system there is abundant discharge, often accompanied by an unpleasant odor. Irritation, roughness, and cracks appear on the skin. Dysbacteriosis side effect after taking antibiotics.

If you notice such symptoms, you should definitely consult a doctor, who will prescribe a set of measures to restore normal microflora. This often requires taking probiotics.

Bacteria are the most ancient organism on earth, and also the simplest in their structure. It consists of just one cell, which can only be seen and studied under a microscope. A characteristic feature bacteria is the absence of a nucleus, which is why bacteria are classified as prokaryotes.

Some species form small groups of cells; such clusters may be surrounded by a capsule (case). The size, shape and color of the bacterium are highly dependent on the environment.

Bacteria are distinguished by their shape into rod-shaped (bacillus), spherical (cocci) and convoluted (spirilla). There are also modified ones - cubic, C-shaped, star-shaped. Their sizes range from 1 to 10 microns. Certain types of bacteria can actively move using flagella. The latter are sometimes twice the size of the bacterium itself.

Types of forms of bacteria

To move, bacteria use flagella, the number of which varies—one, a pair, or a bundle of flagella. The location of the flagella can also be different - on one side of the cell, on the sides, or evenly distributed throughout the entire plane. Also, one of the methods of movement is considered to be sliding thanks to the mucus with which the prokaryote is covered. Most have vacuoles inside the cytoplasm. Adjusting the gas capacity of the vacuoles helps them move up or down in the liquid, as well as move through the air channels of the soil.

Scientists have discovered more than 10 thousand varieties of bacteria, but according to scientific researchers, there are more than a million species in the world. general characteristics bacteria makes it possible to determine their role in the biosphere, as well as to study the structure, types and classification of the kingdom of bacteria.

Habitats

Simplicity of structure and speed of adaptation to environmental conditions helped bacteria spread over a wide range of our planet. They exist everywhere: water, soil, air, living organisms - all this is the most acceptable habitat for prokaryotes.

Bacteria were found both on south pole, and in geysers. They are found on the ocean floor, as well as in upper layers air envelope of the Earth. Bacteria live everywhere, but their number depends on favorable conditions. For example, a large number of bacterial species live in open water bodies, as well as soil.

Structural features

A bacterial cell is distinguished not only by the fact that it does not have a nucleus, but also by the absence of mitochondria and plastids. The DNA of this prokaryote is located in a special nuclear zone and has the appearance of a nucleoid closed in a ring. In bacteria, the cell structure consists of a cell wall, capsule, capsule-like membrane, flagella, pili and cytoplasmic membrane. Internal structure formed by cytoplasm, granules, mesosomes, ribosomes, plasmids, inclusions and nucleoid.

The cell wall of a bacterium performs the function of defense and support. Substances can flow freely through it due to permeability. This shell contains pectin and hemicellulose. Some bacteria secrete a special mucus that can help protect against drying out. Mucus forms a capsule - a polysaccharide chemical composition. In this form, the bacterium can tolerate even very high temperatures. It also performs other functions, such as adhesion to any surfaces.

On the surface of the bacterial cell there are thin protein fibers called pili. There may be a large number of them. Pili help the cell pass on genetic material and also ensure adhesion to other cells.

Under the plane of the wall there is a three-layer cytoplasmic membrane. It guarantees the transport of substances and also plays a significant role in the formation of spores.

The cytoplasm of bacteria is 75 percent made from water. Composition of the cytoplasm:

• Fishsomes;
• mesosomes;
• amino acids;
• enzymes;
• pigments;
• sugar;
• granules and inclusions;
• nucleoid.

Metabolism in prokaryotes is possible both with and without the participation of oxygen. Most of them feed on ready-made nutrients of organic origin. Very few species are capable of synthesizing organic substances from inorganic ones. These are blue-green bacteria and cyanobacteria, which played a significant role in the formation of the atmosphere and its saturation with oxygen.

Reproduction

In conditions favorable for reproduction, it is carried out by budding or vegetatively. Asexual reproduction occurs in the following sequence:

1. The bacterial cell reaches its maximum volume and contains the necessary supply of nutrients.
2. The cell lengthens and a septum appears in the middle.
3. Nucleotide division occurs inside the cell.
4. The main and separated DNA diverge.
5. The cell divides in half.
6. Residual formation of daughter cells.

With this method of reproduction there is no exchange genetic information, so all daughter cells will be an exact copy of the mother cell.

The process of bacterial reproduction in unfavorable conditions more interesting. Scientists learned about the ability of sexual reproduction of bacteria relatively recently - in 1946. Bacteria do not have division into female and reproductive cells. But their DNA is heterogeneous. When two such cells approach each other, they form a channel for the transfer of DNA, and an exchange of sites occurs - recombination. The process is quite long, the result of which is two completely new individuals.

Most bacteria are very difficult to see under a microscope because they do not have their own color. Few varieties are purple or green in color due to their bacteriochlorophyll and bacteriopurpurin content. Although if we consider some colonies of bacteria, it becomes clear that they release colored substances into their environment and acquire bright color. In order to study prokaryotes in more detail, they are stained.

Classification

Classification of bacteria can be based on indicators such as:

• Form
• way to travel;
• method of obtaining energy;
• waste products;
• degree of danger.

Bacteria symbionts live in community with other organisms.

Bacteria saprophytes live on already dead organisms, products and organic waste. They promote the processes of rotting and fermentation.

Rotting cleanses nature of corpses and other organic waste. Without the process of decay there would be no cycle of substances in nature. So what is the role of bacteria in the cycle of substances?

Rotting bacteria are an assistant in the process of breaking down protein compounds, as well as fats and other compounds containing nitrogen. Having carried out a difficult chemical reaction, they break the bonds between molecules organic organisms and capture protein molecules and amino acids. When the molecules break down, they release ammonia, hydrogen sulfide and other harmful substances. They are poisonous and can cause poisoning in people and animals.

Rotting bacteria multiply quickly in conditions favorable to them. Since these are not only beneficial bacteria, but also harmful ones, in order to prevent premature rotting of products, people have learned to process them: drying, pickling, salting, smoking. All these treatment methods kill bacteria and prevent them from multiplying.

Fermentation bacteria with the help of enzymes are able to break down carbohydrates. People noticed this ability back in ancient times and still use such bacteria to make lactic acid products, vinegars, and other food products.

Bacteria, working together with other organisms, do very important chemical work. It is very important to know what types of bacteria there are and what benefits or harm they bring to nature.

Meaning in nature and for humans

It was already noted above great importance many types of bacteria (during the processes of decay and various types fermentation), i.e. fulfilling a sanitary role on Earth.

Bacteria also play a huge role in the cycle of carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, calcium and other elements. Many types of bacteria contribute to the active fixation of atmospheric nitrogen and convert it into organic form, helping to increase soil fertility. Of particular importance are those bacteria that decompose cellulose, which is the main source of carbon for the life of soil microorganisms.

Sulfate-reducing bacteria are involved in the formation of oil and hydrogen sulfide in medicinal mud, soils and seas. Thus, the layer of water saturated with hydrogen sulfide in the Black Sea is the result of the vital activity of sulfate-reducing bacteria. The activity of these bacteria in soils leads to the formation of soda and soda salinization of the soil. Sulfate-reducing bacteria convert nutrients in rice plantation soils into a form that becomes available to the roots of the crop. These bacteria can cause corrosion of metal underground and underwater structures.

Thanks to the vital activity of bacteria, the soil is freed from many products and pests and is filled with valuable nutrients. Bactericidal preparations are successfully used to combat many types of insect pests (corn borer, etc.).

Many types of bacteria are used in various industries to produce acetone, ethyl and butyl alcohols, acetic acid, enzymes, hormones, vitamins, antibiotics, protein-vitamin preparations, etc.

Without bacteria, the processes of tanning leather, drying tobacco leaves, producing silk, rubber, processing cocoa, coffee, soaking hemp, flax and other bast-fiber plants, sauerkraut, wastewater treatment, leaching of metals, etc. are impossible.

Bacteria appeared approximately 3.5-3.9 billion years ago, they were the first living organisms on our planet. Over time, life developed and became more complex - new, each time more complex forms of organisms appeared. Bacteria did not stand aside all this time; on the contrary, they were the most important component evolutionary process. They were the first to develop new forms of life support, such as respiration, fermentation, photosynthesis, catalysis... and also found effective ways coexistence with almost every living creature. Man was no exception.

But bacteria are an entire domain of organisms, numbering more than 10,000 species. Each species is unique and has followed its own evolutionary path, and as a result has developed its own unique forms of coexistence with other organisms. Some bacteria have entered into close mutually beneficial cooperation with humans, animals and other creatures - they can be called useful. Other species have learned to exist at the expense of others, using the energy and resources of donor organisms - they are generally considered harmful or pathogenic. Still others have gone even further and become practically self-sufficient; they receive everything they need for life from the environment.

Inside humans, as well as inside other mammals, lives an unimaginable a large number of bacteria. There are 10 times more of them in our bodies than all the cells of the body combined. Among them, the absolute majority are useful, but the paradox is that their vital activity, their presence within us is a normal state of affairs, they depend on us, we, in turn, on them, and at the same time we do not feel any signs of this cooperation. Another thing is harmful, for example, pathogenic bacteria, once inside us their presence immediately becomes noticeable, and the consequences of their activity can become very serious.

Beneficial bacteria

The vast majority of them are creatures that live in symbiotic or mutualistic relationships with donor organisms (within which they live). Typically, such bacteria take on some of the functions that the host body is not capable of. An example is bacteria that live in the human digestive tract and process part of the food that the stomach itself is not able to cope with.

Some types of beneficial bacteria:

Escherichia coli (lat. Escherichia coli)

It is an integral part of the intestinal flora of humans and most animals. Its benefits are difficult to overestimate: it breaks down indigestible monosaccharides, promoting digestion; synthesizes vitamins K; prevents the development of pathogenic and pathogenic microorganisms in the intestines.

Macro photo: colony of Escherichia coli bacteria

Lactic acid bacteria (Lactococcus lactis, Lactobacillus acidophilus, etc.)

Representatives of this order are present in milk, dairy and fermented products, and at the same time are part of the intestinal and oral microflora. They are capable of fermenting carbohydrates and in particular lactose and producing lactic acid, which is the main source of carbohydrates for humans. By maintaining a constantly acidic environment, the growth of unfavorable bacteria is inhibited.

Bifidobacteria

Bifidobacteria have the most significant effect on infants and mammals, constituting up to 90% of their intestinal microflora. By producing lactic and acetic acids, they completely prevent the development of putrefactive and pathogenic microbes in the child’s body. In addition, bifidobacteria: promote the digestion of carbohydrates; protect the intestinal barrier from the penetration of microbes and toxins into internal environment body; synthesize various amino acids and proteins, vitamins K and B, useful acids; promote intestinal absorption of calcium, iron and vitamin D.

Harmful (pathogenic) bacteria

Some types of pathogenic bacteria:

Salmonella typhi

This bacterium is the causative agent of a very acute intestinal infection, typhoid fever. Salmonella typhi produces toxins that are harmful exclusively to humans. When infected, general intoxication of the body occurs, which leads to severe fever, rash throughout the body, severe cases- to damage to the lymphatic system and, as a consequence, to death. Every year, 20 million cases of typhoid fever are recorded worldwide, 1% of cases lead to death.

Colony of Salmonella typhi bacteria

Tetanus bacillus (Clostridium tetani)

This bacterium is one of the most persistent and at the same time the most dangerous in the world. Clostridium tetani produces an extremely toxic poison, tetanus exotoxin, which leads to almost complete damage to the nervous system. People with tetanus experience terrible pain: all the muscles of the body spontaneously tense to the limit, and powerful convulsions occur. The mortality rate is extremely high - on average, about 50% of those infected die. Fortunately, a tetanus vaccine was invented back in 1890; it is given to newborns in all countries. developed countries peace. In underdeveloped countries, tetanus kills 60,000 people every year.

Mycobacteria (Mycobacterium tuberculosis, Mycobacterium leprae, etc.)

Mycobacteria are a family of bacteria, some of which are pathogenic. Various representatives of this family cause such dangerous diseases as tuberculosis, mycobacteriosis, leprosy (leprosy) - all of them are transmitted by airborne droplets. Every year, mycobacteria cause more than 5 million deaths.

Bacteria are the most numerous inhabitants of planet Earth. They inhabited it in ancient times and continue to exist today. Some species have even changed little since then. Bacteria, beneficial and harmful, literally surround us everywhere (and even penetrate into other organisms). With a rather primitive unicellular structure, they are probably one of the most effective forms of living nature and are classified as a special kingdom.

Margin of safety

These microorganisms, as they say, do not drown in water and do not burn in fire. Literally: they can withstand temperatures up to plus 90 degrees, freezing, lack of oxygen, pressure - high and low. We can say that nature has invested a huge margin of safety in them.

Bacteria beneficial and harmful to the human body

As a rule, the bacteria that inhabit our bodies in abundance do not receive due attention. After all, they are so small that they seem to have no significant significance. Those who think so are largely mistaken. Beneficial and harmful bacteria have long and reliably “colonized” other organisms and successfully coexist with them. Yes, they cannot be seen without the help of optics, but they can cause harm to our body.

Who lives in the intestines?

Doctors say that if you add together just the bacteria that live in the intestines and weigh them, you get something like three kilograms! Such a huge army cannot be ignored. Many of the microorganisms continuously enter the environment, but only some species find favorable conditions for living and life there. And in the process of evolution, they even formed a permanent microflora, which is designed to perform important physiological functions.

"Wise" neighbors

Bacteria have long played an important role, although until very recently people had no idea about it. They help their owner with digestion and perform a number of other functions. What are these invisible neighbors?

Permanent microflora

99% of the population resides permanently in the intestines. They are ardent supporters and helpers of man.

• Essential beneficial bacteria. Names: bifidobacteria and bacteroides. They are the vast majority.
• Associated beneficial bacteria. Names: Escherichia coli, enterococci, lactobacilli. Their number should be 1-9% of the total.

You also need to know that under appropriate negative conditions, all these representatives of the intestinal flora (with the exception of bifidobacteria) can cause diseases.

What are they doing?

The main functions of these bacteria are to help us in the digestion process. It has been noted that dysbiosis can occur in a person with poor nutrition. As a result - stagnation and constipation and other inconveniences. When a balanced diet is normalized, the disease usually recedes.

Another function of these bacteria is guard. They monitor which bacteria are beneficial. To ensure that “strangers” do not penetrate their community. If, for example, the causative agent of dysentery, Shigella Sonne, tries to penetrate the intestines, they kill it. However, it is worth noting that this only occurs in the body relatively healthy person, with good immunity. Otherwise, the risk of getting sick increases significantly.

Fickle microflora

Approximately 1% of the body of a healthy individual consists of so-called opportunistic microbes. They belong to the unstable microflora. At normal conditions they perform certain functions that do not harm a person, they work for the benefit. But in certain situations they can manifest themselves as pests. These are mainly staphylococci and various types of fungi.

Dislocation in the gastrointestinal tract

In fact, the entire digestive tract has a heterogeneous and unstable microflora - beneficial and harmful bacteria. The esophagus contains the same inhabitants as in the oral cavity. In the stomach there are only a few that are acid-resistant: lactobacilli, Helicobacter, streptococci, fungi. The microflora in the small intestine is also sparse. Most bacteria are found in the colon. Thus, when defecating, a person is capable of excreting over 15 trillion microorganisms per day!

The role of bacteria in nature

It is also, of course, great. There are several global functions, without which all life on the planet would probably have ceased to exist long ago. The most important is sanitary. Bacteria eat dead organisms found in nature. They, in essence, work as a kind of wipers, preventing deposits from accumulating dead cells. Scientifically they are called saprotrophs.

Another important role of bacteria is participation in the world on land and sea. On planet Earth, all substances in the biosphere pass from one organism to another. Without some bacteria, this transition would simply be impossible. The role of bacteria is invaluable, for example, in the circulation and reproduction of such an important element as nitrogen. There are certain bacteria in the soil that make nitrogenous fertilizers for plants from nitrogen in the air (microorganisms live right in their roots). This symbiosis between plants and bacteria is being studied by science.

Participation in food chains

As already mentioned, bacteria are the most numerous inhabitants of the biosphere. And accordingly, they can and should participate in the inherent nature of animals and plants. Of course, for humans, for example, bacteria are not a main part of the diet (unless they can be used as a food additive). However, there are organisms that feed on bacteria. These organisms, in turn, feed on other animals.

Cyanobacteria

These (an outdated name for these bacteria, fundamentally incorrect with scientific point vision) are capable of producing huge amounts of oxygen as a result of photosynthesis. Once upon a time, it was they who began to saturate our atmosphere with oxygen. Cyanobacteria continue to do this successfully to this day, producing a certain portion of the oxygen in the modern atmosphere!