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 of the evolutionary process. They were the first to develop new forms of life support, such as respiration, fermentation, photosynthesis, catalysis... and also found effective ways to coexist 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, like inside other mammals, there live an unimaginably 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; provide protection of the intestinal barrier from the penetration of microbes and toxins into the internal environment of the 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 dangerous only to humans. When infected, general intoxication of the body occurs, which leads to severe fever, rash throughout the body, and in severe cases, damage to the lymphatic system and, as a result, 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 developed countries of the world. 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. Mycobacteria cause more than 5 million deaths every year.

Many types of bacteria are useful and are successfully used by humans.

Firstly, beneficial bacteria are widely used in the food industry.

In the production of cheeses, kefir, and cream, it is necessary to coagulate milk, which occurs under the influence of lactic acid. Lactic acid is produced by lactic acid bacteria, which are part of starter cultures and feed on the sugar contained in milk. Lactic acid itself promotes the absorption of iron, calcium, and phosphorus. These beneficial elements help us fight infectious diseases.

When making cheese, it is pressed into pieces (heads). The cheese heads are sent to ripening chambers, where the activity of the various lactic acid and propionic acid bacteria that make up the cheese begins. As a result of their activity, the cheese “ripens” - acquires a characteristic taste, smell, pattern and color.

To produce kefir, a starter containing lactic acid bacilli and lactic acid streptococci is used.

Yogurt is a tasty and healthy fermented milk product. Milk for yogurt production must be of very high quality. It should contain a minimum amount of harmful bacteria that can interfere with the development of beneficial yogurt bacteria. Yogurt bacteria convert milk into yogurt and give it its distinctive flavor.

Rice. 14. Lactobacilli – lactic acid bacteria.

Lactic acid and yoghurt bacteria entering the human body with food help fight not only harmful bacteria in the intestines, but also viruses that cause colds and other infections. In the process of their life activity, these beneficial bacteria create such an acidic environment (due to the excreted metabolic products) that only a microbe very adapted to difficult conditions, such as E. coli, can survive next to them.

The activity of beneficial bacteria is used in the fermentation of cabbage and other vegetables.

Secondly, bacteria are used to leach ores in the extraction of copper, zinc, nickel, uranium and other metals from natural ores. Leaching is the extraction of minerals from ore that is not rich in them using bacteria, when other methods of extraction (for example, smelting ore) are ineffective and expensive. Leaching is carried out by aerobic bacteria.

Thirdly, beneficial aerobic bacteria are used to purify wastewater from cities and industrial enterprises from organic residues.

The main goal of such biological treatment is the neutralization of complex and insoluble organic substances in wastewater, which cannot be removed from it by mechanical treatment, and their decomposition into simple water-soluble elements.

Fourth, bacteria are used in the production of silk and leather processing, etc. The raw materials for the production of artificial silk are produced by special transgenic bacteria. Technical lactic acid bacteria are used in the tanning industry for swelling and deashing (processing of raw materials from solid compounds), in the textile industry, as an aid for dyeing and printing.

Fifth, bacteria are used to control agricultural pests. Agricultural plants are treated with special preparations that contain certain types of bacteria. Insect pests, consuming parts of plants treated with biological preparations, ingest bacterial spores with food. This leads to the death of pests.

Sixth, bacteria are used to produce various medications (for example, interferon) that kill viruses and support human immunity (defense).

And lastly, harmful bacteria also have beneficial properties.

Decay bacteria (coprophytic bacteria) destroy the corpses of dead animals, leaves of trees and shrubs that have fallen to the ground, and the trunks of dead trees themselves. These bacteria are a kind of orderlies for our planet. They feed on organic matter and turn it into humus - a fertile layer of soil.

Soil bacteria live in the soil and also provide many benefits in nature. Mineral salts produced by soil bacteria are then absorbed from the soil by plant roots. One cubic centimeter of the surface layer of forest soil contains hundreds of millions of soil bacteria.

Rice. 15. Clostridia are soil bacteria.

Bacteria also live in the soil and absorb nitrogen from the air, accumulating it in their bodies. This nitrogen is then converted into proteins. After the bacterial cells die, these proteins are converted into nitrogenous compounds (nitrates), which act as fertilizer and are well absorbed by plants.

Conclusion.

Bacteria are a large, well-studied group of microorganisms. Bacteria are found everywhere and people encounter them in their lives all the time. Bacteria can be beneficial to humans, or they can become a source of dangerous diseases.

Studying the properties of bacteria, combating their harmful manifestations and using the beneficial properties of the life activity of bacteria is one of the main tasks for humans.

Student of 6th grade B _________________________________ / Yaroslav Shchipanov /

Literature.

1. Berkinblit M.B., Glagolev S.M., Maleeva Yu.V., Biology: Textbook for grade 6. – M.: Binom. Knowledge Laboratory, 2008.

2. Ivchenko, T. V. Electronic textbook “Biology: 6th grade. Living organism." // Biology at school. - 2007.

3. Pasechnik V.V. Biology. 6th grade Bacteria, fungi, plants: Textbook. for general education textbook establishments, - 4th ed., stereotype. – M.: Bustard, 2000.

4. Smelova, V.G. Digital microscope in biology lessons // Publishing House “First of September” Biology. - 2012. - No. 1.

Bacteria appeared on Earth long before plants and animals - 4 billion years ago. Today these are the simplest single-celled organisms that live in the air, water, soil and even in the human intestines.

Did you know that the number of bacteria in the body is 1.3 times greater than the number of its own cells? In this article I will introduce you to the world of microscopic creatures and tell you how to consume foods without fear for your health.

Beneficial bacteria are friends of the immune system

Since bacteria are present in food, they inevitably enter the intestines. Several hundred species of microorganisms have settled inside humans. If there are no problems with the gastrointestinal tract, then 95% of the representatives of the intestinal microflora live peacefully and calmly, without causing harm to the carrier.

Interesting fact! The first time a person encounters microorganisms is during birth. When the baby passes through the birth canal, it receives lactobacilli from the mother.

The basis of the intestinal mucosa is made up of beneficial bacteria.

The most numerous of them are the following:

• lactobacilli;
• bifidobacteria;
• streptomycetes.

The former are also called lactic acid, because when they enter food they convert carbohydrates into lactic acid. People even use such bacteria to prepare food, in particular cheese.

Interesting fact! Many people with lactose intolerance can safely drink kefir or yogurt. The reason is lactobacilli, which break down milk sugar. Therefore, fermented milk products are usually well absorbed in the intestines.

Lactobacilli are in the form of rods or cocci (balls).

Perform the following functions in the body:

• produce enzymes that help better digest food, absorb vitamins, macro and microelements;
• prevent the proliferation of pathogenic microbes in the intestines;
• have the properties of “natural” antibiotics;
• prevent the growth of cancer cells, reduce inflammatory processes;
• accelerate metabolism, serve as a prevention of obesity;
• participate in the synthesis of important vitamins: B1, B2, K.

Bifidobacteria are considered no less useful for humans. You've probably heard about them from yogurt commercials. These microorganisms are rod-shaped, and they don’t even need oxygen to live. Contained in many fermented milk products.

Interesting fact! Bifidobacteria make up up to 90% of the healthy microflora of a baby under 1 year old. They enter the child's body from the mother along with breast milk.

Bifidobacteria have the same valuable properties as lactic acid bacteria.

In addition, they have additional “useful” features:

• reduce the risk of allergies;
• reduce the level of “bad” cholesterol;
• maintain healthy microflora of the vaginal mucosa, preventing thrush;
• restore liver and kidney function;
• stimulate intestinal motility and prevent constipation.

Many people know about the bacteria “lacto” and “bifido” in food. What kind of streptomycetes? These microorganisms live in soil and seawater. Externally they form long threads. They have pronounced antibiotic properties, therefore they are used for the production of well-known drugs, in particular, “Erythromycin”, “Tetracycline”. Since streptomycetes rarely enter the body from food, I will not dwell on them in detail.

TOP 5 products with beneficial bacteria

The best way to protect normal intestinal microflora and strengthen the immune system is to eat food obtained with the help of beneficial bacteria - bifido and lactic acid. And here’s what doctors and nutritionists suggest including in your diet:

Kefir

A true leader in the content of lacto and bifidobacteria. It has a pronounced antimycotic effect and is easily digestible. You can drink it to prevent thrush and other fungal diseases.

Contains calcium, magnesium, phosphorus, vitamins D, K2. Due to the low amount of calories, it is suitable for those losing weight.

Yogurt

Real “live” yogurt is rich in bifidobacteria and improves digestion. True, it is quite expensive and is not sold in every store.

Important! If yogurt contains sugar, fruit fillers or has a shelf life of more than 3 days, then it does not contain beneficial bacteria.

Soft cheese

I love feta cheese and mozzarella most of all; I often add them to leaf salads. Soft cheeses are rich not only in lactic acid bacteria, but also in calcium, fat-soluble vitamins, and amino acids. Not as high in calories as hard cheeses, they lower cholesterol levels and cleanse blood vessels.

Miso soup

Famous Japanese dish. The main ingredient of the soup is miso paste. It is one of the food products produced with the help of lactic acid bacteria. Legumes, rice or wheat are fermented to make paste. And also the soup usually includes other products with beneficial bacteria - feta cheese or tofu (soy cheese).

Sauerkraut

If you are against everything dairy, pay attention to pickled vegetables, which are also rich in lactic acid bacteria. Just choose products that have not been pasteurized. Heat treatment removes beneficial microorganisms.

Attention! 100 grams of sauerkraut contains 1/3 of the daily requirement of vitamin C, which is necessary to maintain a healthy immune system.

If you like pickled and pickled vegetables, try the Korean dish kimchi. It is not only tasty, but also helps you lose weight and is used in many diets.

Opportunistic microorganisms: keep the demographic situation under control

Opportunistic bacteria are microorganisms that are safe for humans if their number is small. Like migrants and refugees in an economically developed state.

If the intestines do not receive beneficial bifido and lactic acid bacteria, which are found in food, the population of opportunistic microorganisms grows.

And this is what it amounts to:

1. Vitamins and microelements are poorly absorbed. As a result, the immune system weakens.
2. Opportunistic bacteria release waste products that cause increased gas formation (flatulence), poison the body and provoke inflammatory processes.
3. Some microorganisms in large quantities cause serious bacterial infections.

The most common disease associated with the growth of opportunistic microbes in the intestines is dysbiosis. Its typical symptoms are stool disorder (alternating constipation and diarrhea), bloating, lethargy, and irritability. Often leads to the development of anemia and lack of vitamins.

Some types of opportunistic bacteria:

• E. coli (more than 100 varieties);
• Staphylococcus aureus;
• streptococci;
• helicobacter pylori;
• clostridia.

How to prevent the growth of the population of such microbes in the intestines? Consume foods rich in beneficial bacteria, as well as prebiotics. The latter serve as food for representatives of healthy microflora. Prebiotics are found in chicory, onions, garlic, wheat bran, oatmeal, and bananas.

Important! The bacterium helicobacter pylori is the main culprit of gastrointestinal diseases such as gastritis and ulcers.

Enemy bacteria: beware like fire

What bacteria spoil food and, when ingested, cause food poisoning or serious illness?

I will list the 4 most terrible “enemies” of health:

1. Salmonella. Lives in the intestinal tract of animals and birds, causing a serious disease - salmonellosis. A person can catch the bacteria by eating a raw egg or undercooked chicken. Salmonella enteritidis dies at temperatures above 70 degrees.
2. Proteus wand. Refers to bacteria that spoil food if sanitary standards are violated. Causes common food poisoning. “Tough” bacillus - can withstand temperatures up to 65 degrees, loss of moisture, and salty environments.
3. Listeria monocytogenes. It likes to breed in raw meat, soft cheeses and especially in unpasteurized cow's milk. May cause food poisoning 3 weeks after eating spoiled product. Dangerous for the nervous system of infants and pregnant women.
4. Clostridium botulinum. A very insidious bacterium that produces botulism toxin. The disease can be fatal, and the symptoms are similar to food poisoning. The risk of infection is especially high when eating canned food, unwashed vegetables and berries.

Important! If you experience food poisoning symptoms such as severe dry mouth and blurred vision, call an ambulance immediately. There is a risk of contracting botulism.

How to protect the body: prevention of food poisoning and diseases

Even as children, we were taught that we should wash our hands before eating. However, the most dangerous microorganisms hide inside spoiled food. Therefore, I want to tell you about how to protect food from bacteria.

Some important tips:

1. Wash food before eating or cooking. Many types of harmful bacteria (particularly Clostridium botulinum) live in soil. And if you don’t wash raw meat, the bacilli will accidentally get on your hands and then into your mouth. Don't forget about chicken eggs. They also need to be washed, although very few actually do this.
2. Do not cut raw meat and vegetables on the same board, use different knives. Many bacteria are killed during heat treatment. However, microbes from the cutting board can transfer to vegetables, and then migrate in a viable form to the salad.
3. Thaw meat or fish completely before cooking.. Otherwise, these products will not undergo complete heat treatment.
4. Throw away canned goods with cracks, leaks, or bulging lids.. Be aware of botulism toxin.
5. Wash your hands with soap before preparing food. Especially if you want to make something raw food.
6. N Do not consume products that have expired.

I will also focus on proper food storage. This is a whole science. Do not store prepared foods next to raw foods in the refrigerator. Colonies of bacteria quickly infect “clean” food if it is nearby.

Each type of product has its own terms and storage rules. For example, raw meat or fish should be placed at the top of the refrigerator and kept for no longer than 2 days. Cottage cheese, sour cream, kefir are stored in the middle compartment for a maximum of 5 days.

Important! Ready-made meat and fish dishes, cakes and pastries with cream, whole milk, boiled sausages and sausages spoil especially quickly. I advise you to use these products on the first day after purchase.

Bacteria are all around us. They cannot be hidden or abandoned. To protect the body from opportunistic and harmful microorganisms, you need to “make friends” with beneficial ones. To do this, consume fermented milk products, pickled vegetables, and follow the rules of hygiene and food storage. I hope the information in this article will help you avoid food poisoning and improve your health.

Bacteria have lived on planet Earth for more than 3.5 billion years. During this time they learned a lot and adapted to a lot. Now they help people. Bacteria and humans have become inseparable. The total mass of bacteria is enormous. It is about 500 billion tons.

Beneficial bacteria perform two of the most important environmental functions - they fix nitrogen and participate in the mineralization of organic residues. The role of bacteria in nature is global. They are involved in the movement, concentration and dispersion of chemical elements in the earth's biosphere.

The importance of bacteria beneficial to humans is great. They make up 99% of the entire population that inhabit his body. Thanks to them, a person lives, breathes and eats.

Important. They completely ensure his life.

Bacteria are quite simple. Scientists suggest that they were the first to appear on planet Earth.

Beneficial bacteria in the human body

The human body is inhabited by both useful and. The existing balance between the human body and bacteria has been refined over centuries.

Scientists have calculated that the human body contains from 500 to 1000 different types of bacteria or trillions of these amazing residents, which amounts to up to 4 kg of total weight. Up to 3 kilograms of microbial bodies are found only in the intestines. The rest of them are found in the genitourinary tract, on the skin and other cavities of the human body. Microbes fill the body of a newborn from the first minutes of his life and finally form the composition of the intestinal microflora by the age of 10-13 years.

The intestines are inhabited by streptococci, lactobacilli, bifidobacteria, enterobacteria, fungi, intestinal viruses, and non-pathogenic protozoa. Lactobacilli and bifidobacteria make up 60% of the intestinal flora. The composition of this group is always constant; they are the most numerous and perform the main functions.

Bifidobacteria

The importance of this type of bacteria is enormous.

• Thanks to them, acetate and lactic acid are produced. By acidifying the habitat, they suppress the growth of bacteria that cause rotting and fermentation.
• Thanks to bifidobacteria, the risk of developing food allergies in babies is reduced.
• They provide antioxidant and antitumor effects.
• Bifidobacteria take part in the synthesis of vitamin C.
• Bifidobacteria and lactobacilli take part in the absorption of vitamin D, calcium and iron.

Rice. 1. The photo shows bifidobacteria. Computer visualization.

Escherichia coli

The importance of bacteria of this species for humans is great.

• Particular attention is paid to the representative of this genus Escherichia coli M17. It is capable of producing the substance cocilin, which inhibits the growth of a number of pathogenic microbes.
• With the participation of vitamins K, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.

Rice. 2. The photo shows E. coli (three-dimensional computer image).

The positive role of bacteria in human life

• With the participation of bifido-, lacto-, and enterobacteria, vitamins K, C, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.
• Thanks to this, undigested food components from the upper intestines are broken down - starch, cellulose, protein and fat fractions.
• Intestinal microflora maintains water-salt metabolism and ion homeostasis.
• Thanks to the secretion of special substances, the intestinal microflora suppresses the growth of pathogenic bacteria that cause rotting and fermentation.
• Bifido-, lacto-, and enterobacteria take part in the detoxification of substances that enter from the outside and are formed inside the body itself.
• Intestinal microflora plays a big role in restoring local immunity. Thanks to it, the number of lymphocytes, the activity of phagocytes and the production of immunoglobulin A increase.
• Thanks to the intestinal microflora, the development of the lymphoid apparatus is stimulated.
• The resistance of the intestinal epithelium to carcinogens increases.
• Microflora protect the intestinal mucosa and provide energy to the intestinal epithelium.
• They regulate intestinal motility.
• The intestinal flora acquires the skills to capture and remove viruses from the host’s body, with which it has been in symbiosis for many years.
• The importance of bacteria in maintaining the body's thermal balance is great. The intestinal microflora feeds on substances undigested by the enzymatic system, which come from the upper gastrointestinal tract. As a result of complex biochemical reactions, a huge amount of thermal energy is produced. Heat is carried through the bloodstream throughout the body and enters all internal organs. This is why a person always freezes when fasting.
• Intestinal microflora regulates the reabsorption of bile acid components (cholesterol), hormones, etc.

Rice. 3. The photo shows beneficial bacteria - lactobacilli (three-dimensional computer image).

The role of bacteria in nitrogen production

Ammonifying microbes(causing decay) with the help of a number of enzymes they have are able to decompose the remains of dead animals and plants. When proteins decompose, nitrogen and ammonia are released.

Urobacteria decompose urea, which humans and all animals on the planet excrete every day. Its quantity is huge and reaches 50 million tons per year.

A certain type of bacteria is involved in the oxidation of ammonia. This process is called nitrophification.

Denitrifying microbes return molecular oxygen from the soil to the atmosphere.

Rice. 4. The photo shows beneficial bacteria - ammonifying microbes. They subject the remains of dead animals and plants to decomposition.

The role of bacteria in nature: nitrogen fixation

The importance of bacteria in the life of humans, animals, plants, fungi and bacteria is enormous. As you know, nitrogen is necessary for their normal existence. But bacteria cannot absorb nitrogen in the gaseous state. It turns out that blue-green algae can bind nitrogen and form ammonia ( Cyanobacteria), free-living nitrogen fixers and special . All these beneficial bacteria produce up to 90% of fixed nitrogen and involve up to 180 million tons of nitrogen in the soil nitrogen pool.

Nodule bacteria coexist well with legumes and sea buckthorn.

Plants such as alfalfa, peas, lupine and other legumes have so-called “apartments” for nodule bacteria on their roots. These plants are planted on depleted soils to enrich them with nitrogen.

Rice. 5. The photo shows nodule bacteria on the surface of a root hair of a legume plant.

Rice. 6. Photo of the root of a legume plant.

Rice. 7. The photo shows beneficial bacteria - cyanobacteria.

The role of bacteria in nature: the carbon cycle

Carbon is the most important cellular substance of the animal and plant world, as well as the plant world. It makes up 50% of the dry matter of the cell.

A lot of carbon is contained in the fiber that animals eat. In their stomach, fiber decomposes under the influence of microbes and then gets out in the form of manure.

Decompose fiber cellulose bacteria. As a result of their work, the soil is enriched with humus, which significantly increases its fertility, and carbon dioxide is returned to the atmosphere.

Rice. 8. Intracellular symbionts are colored green, and the mass of processed wood is yellow.

The role of bacteria in the conversion of phosphorus, iron and sulfur

Proteins and lipids contain large amounts of phosphorus, the mineralization of which is carried out You. megatherium(from a genus of putrefactive bacteria).

Iron bacteria participate in the processes of mineralization of organic compounds containing iron. As a result of their activity, large amounts of iron ore and ferromanganese deposits are formed in swamps and lakes.

Sulfur bacteria live in water and soil. There are a lot of them in manure. They participate in the process of mineralization of sulfur-containing substances of organic origin. During the decomposition of organic sulfur-containing substances, hydrogen sulfide gas is released, which is extremely toxic to the environment, including all living things. As a result of their vital activity, sulfur bacteria convert this gas into an inactive, harmless compound.

Rice. 9. Despite the apparent lifelessness, there is still life in the Rio Tinto River. These are various iron-oxidizing bacteria and many other types that can only be found in this place.

Rice. 10. Green sulfur bacteria in Winogradsky’s column.

The role of bacteria in nature: mineralization of organic residues

Bacteria that take an active part in the mineralization of organic compounds are considered the cleaners (sanitors) of the planet Earth. With their help, the organic substances of dead plants and animals are converted into humus, which soil microorganisms convert into mineral salts, so necessary for the construction of root, stem and leaf systems of plants.

Rice. 11. Mineralization of organic substances entering the reservoir occurs as a result of biochemical oxidation.

The role of bacteria in nature: fermentation of pectin substances

The cells of plant organisms are bonded to each other (cemented) by a special substance called pectin. Some types of butyric acid bacteria have the ability to ferment this substance, which, when heated, turns into a gelatinous mass (pectis). This feature is used when soaking plants containing a lot of fiber (flax, hemp).

Rice. 12. There are several ways to obtain trusts. The most common is the biological method, in which the connection between the fibrous part and surrounding tissues is destroyed under the influence of microorganisms. The process of fermentation of pectin substances in bast plants is called retting, and soaked straw is called trust.

The role of bacteria in water purification

Bacteria that purify water, stabilize its acidity level. With their help, bottom sediments are reduced and the health of fish and plants living in the water improves.

Recently, a group of scientists from different countries discovered bacteria that destroy detergents found in synthetic detergents and some medications.

Rice. 13. The activity of xenobacteria is widely used to clean up soils and water bodies contaminated with oil products.

Rice. 14. Plastic domes that purify water. They contain heterotrophic bacteria that feed on carbon-containing materials, and autotrophic bacteria that feed on ammonia- and nitrogen-containing materials. A system of tubes keeps them on life support.

Use of bacteria in ore dressing

Ability thionic sulfur-oxidizing bacteria used for enrichment of copper and uranium ores.

Rice. 15. The photo shows beneficial bacteria - Thiobacilli and Acidithiobacillus ferrooxidans (electron micrograph). They are capable of extracting copper ions to leach waste that is formed during the flotation concentration of sulfide ores.

The role of bacteria in butyric acid fermentation

Butyric acid microbes are everywhere. There are more than 25 types of these microbes. They take part in the process of decomposition of proteins, fats and carbohydrates.

Butyric acid fermentation is caused by anaerobic spore-forming bacteria belonging to the genus Clostridium. They are capable of fermenting various sugars, alcohols, organic acids, starch, and fiber.

Rice. 16. The photo shows butyric acid microorganisms (computer visualization).

The role of bacteria in animal life

Many species of the animal world feed on plants, the basis of which is fiber. Special microbes, located in certain parts of the gastrointestinal tract, help animals digest fiber (cellulose).

The importance of bacteria in animal husbandry

The vital activity of animals is accompanied by the release of huge amounts of manure. From it, some microorganisms can produce methane (“swamp gas”), which is used as fuel and raw material in organic synthesis.

Rice. 17. Methane gas as fuel for cars.

Use of bacteria in the food industry

The role of bacteria in human life is enormous. Lactic acid bacteria are widely used in the food industry:

• in the production of curdled milk, cheeses, sour cream and kefir;
• when fermenting cabbage and pickling cucumbers, they take part in soaking apples and pickling vegetables;
• they give a special aroma to wines;
• produce lactic acid, which ferments milk. This property is used for the production of curdled milk and sour cream;
• when preparing cheeses and yoghurts on an industrial scale;
• During the brining process, lactic acid serves as a preservative.

Lactic acid bacteria include milk streptococci, creamy streptococci, Bulgarian, acidophilus, grain thermophilic and cucumber bacilli. Bacteria of the genus streptococci and lactobacilli give products a thicker consistency. As a result of their vital activity, the quality of cheeses improves. They give the cheese a certain cheesy aroma.

Rice. 18. The photo shows beneficial bacteria - lactobacilli (pink), Bulgarian bacillus and thermophilic streptococcus.

Rice. 19. The photo shows beneficial bacteria - kefir (Tibetan or milk) fungus and lactic acid sticks before being directly added to milk.

Rice. 20. Fermented milk products.

Rice. 21. Thermophilic streptococci (Streptococcus thermophilus) are used in the preparation of mozzarella cheese.

Rice. 22. There are many varieties of mold penicillin. The velvety crust, greenish veins, unique taste and medicinal ammonia aroma of the cheeses are unique. The mushroom taste of cheeses depends on the place and duration of ripening.

Rice. 23. Bifiliz is a biological product for oral administration containing a mass of living bifidobacteria and lysozyme.

Use of yeast and fungi in the food industry

The yeast species mainly used in the food industry is Saccharomyces cerevisiae. They carry out alcoholic fermentation, which is why they are widely used in baking. The alcohol evaporates during baking, and carbon dioxide bubbles form a bread crumb.

Since 1910, yeast began to be added to sausages. Yeast of the species Saccharomyces cerevisiae is used for the production of wines, beer and kvass.

Rice. 24. Kombucha is a friendly symbiosis of a vinegar stick and yeast fungi. It appeared in our area back in the last century.

Rice. 25. Dry and wet yeast are widely used in the baking industry.

Rice. 26. View of yeast cells Saccharomyces cerevisiae under a microscope and Saccharomyces cerevisiae - “real” wine yeast.

The role of bacteria in human life: acetic acid oxidation

Pasteur also proved that special microorganisms take part in acetic acid oxidation - vinegar sticks, which are widely found in nature. They settle on plants and penetrate ripe vegetables and fruits. There are many of them in pickled vegetables and fruits, wine, beer and kvass.

The ability of vinegar sticks to oxidize ethyl alcohol to acetic acid is used today to produce vinegar, used for food purposes and in the preparation of animal feed - ensiling (canning).

Rice. 27. The process of ensiling feed. Silage is a succulent feed with high nutritional value.

The role of bacteria in human life: production of medicines

Studying the life activity of microbes has allowed scientists to use some bacteria to synthesize antibacterial drugs, vitamins, hormones and enzymes.

They help fight many infectious and viral diseases. Most often antibiotics are produced actinomycetes, less often – non-micellar bacteria. Penicillin, obtained from mold fungi, destroys the cell membrane of bacteria. Streptomycetes produce streptomycin, which inactivates the ribosomes of microbial cells. Hay sticks or Bacillus subtilis acidify the environment. They inhibit the growth of putrefactive and opportunistic microorganisms due to the formation of a number of antimicrobial substances. Bacillus subtilis produces enzymes that destroy substances that are formed as a result of putrefactive tissue decay. They are involved in the synthesis of amino acids, vitamins and immunoactive compounds.

Using genetic engineering technology, today scientists have learned to use for the production of insulin and interferon.

A number of bacteria are supposed to be used to produce a special protein that can be added to livestock feed and human food.

Rice. 28. In the photo, spores of Bacillus subtilis (colored blue).

Rice. 29. Biosporin-Biopharma is a domestic drug containing apathogenic bacteria of the genus Bacillus.

Using bacteria to produce safe herbicides

Today the application technique is widely used phytobacteria for the production of safe herbicides. Toxins Bacillus thuringiensis secrete Cry-toxins that are dangerous to insects, which makes it possible to use this feature of microorganisms in the fight against plant pests.

The use of bacteria in the production of detergents

Proteases or break down the peptide bonds between the amino acids that make up proteins. Amylase breaks down starch. Bacillus subtilis (B. subtilis) produces proteases and amylases. Bacterial amylases are used in the production of washing powder.

Rice. 30. Studying the life activity of microbes allows scientists to use some of their properties for the benefit of humans.

The importance of bacteria in human life is enormous. Beneficial bacteria have been constant companions of humans for many millennia. The task of humanity is not to disturb this delicate balance that has developed between microorganisms living inside us and in the environment. The role of bacteria in human life is enormous. Scientists are constantly discovering the beneficial properties of microorganisms, the use of which in everyday life and in production is limited only by their properties.

Articles in the section "What do we know about microbes"Most Popular Reading time: 4 min

The totality of bacteria inhabiting the human body has a common name - microbiota. In the normal, healthy human microflora there are several million bacteria. Each of them plays an 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 a child’s life, since they are responsible for the presence of an allergic reaction to any food product. 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 the development of bacterial vaginosis.

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 E. coli lies in the synthesis of cocilin, which actively resists the bulk of pathogenic microflora.

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

Enterococci

This type of microorganism colonizes the human intestine immediately after birth.

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

The beneficial properties of 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 of the nervous system, skin diseases, and 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 the absorption of fatty acids and 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, stimulating 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 develop for many years 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 dysbiosis of the oral cavity, vagina). The names that will prevail in the analyzes are: streptococcus, staphylococcus, micrococcus.

In normal conditions, 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 is a 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.