Beneficial and harmful human bacteria. Beneficial bacteria that inhabit the human body
People are trying to find new ways to protect themselves from their harmful influence. But there are also useful microorganisms: they promote the ripening of cream, the formation of nitrates for plants, decompose dead tissue, etc. Microorganisms live in water, soil, air, on the body of living organisms and inside them.
Shapes of bacteria
There are main 4 forms of bacteria, namely:
- Micrococci – located separately or in irregular clusters. They are usually motionless.
- Diplococci are arranged in pairs and can be surrounded by a capsule in the body.
- Streptococci occur in the form of chains.
- Sarcines form clusters of cells shaped like packets.
- Staphylococci. As a result of the division process, they do not diverge, but form clusters (clusters).
The bacterium has a complex structure:
- Wall cells protect a single-celled organism from external influences, give it a certain shape, provide nutrition and preserve its internal contents.
- Cytoplasmic membrane contains enzymes, participates in the process of reproduction and biosynthesis of components.
- Cytoplasm serves to perform vital functions. In many species, the cytoplasm contains DNA, ribosomes, various granules, and a colloidal phase.
- Nucleoid is the irregularly shaped nuclear region in which DNA is located.
- Capsule is a surface structure that makes the shell more durable and protects against damage and drying out. This mucous structure has a thickness of more than 0.2 microns. With a smaller thickness it is called microcapsule. Sometimes around the shell there is mucus, has no clear boundaries and is soluble in water.
- flagella are called surface structures that serve to move cells in a liquid environment or on a solid surface.
- Drank- thread-like formations, much thinner and fewer flagella. They come in various types, differ in purpose and structure. Pili are needed to attach the organism to the affected cell.
- Controversy. Sporulation occurs when unfavorable conditions arise and serves to adapt the species or preserve it.
We suggest considering the main types of bacteria:
Nutrients enter the cell through its entire surface. Microorganisms have become widespread due to the existence of different types of nutrition. To live, they need a variety of elements: carbon, phosphorus, nitrogen, etc. The supply of nutrients is regulated using a membrane.
The type of nutrition is determined by how carbon and nitrogen are absorbed and by the type of energy source. Some of them can obtain these elements from the air and use solar energy, while others require substances of organic origin to exist. They all need vitamins and amino acids that can act as catalysts for reactions occurring in their body. The removal of substances from the cell occurs through the process of diffusion.
In many types of microorganisms, oxygen plays an important role in metabolism and respiration. As a result of respiration, energy is released, which they use to form organic compounds. But there are bacteria for which oxygen is lethal.
Reproduction occurs by dividing the cell into two parts. After it reaches a certain size, the separation process begins. The cell elongates and a transverse septum is formed in it. The resulting parts disperse, but some species remain connected and form clusters. Each of the newly formed parts feeds and grows as an independent organism. When placed in a favorable environment, the reproduction process occurs at high speed.
Microorganisms are able to decompose complex substances into simple ones, which can then be used again by plants. Therefore, bacteria are indispensable in the cycle of substances; without them, many important processes on Earth would be impossible.
Do you know?
Conclusion: Don't forget to wash your hands every time you come home after going outside. When you go to the toilet, also wash your hands with soap. A simple rule, but so important! Keep it clean and bacteria won't bother you!
To reinforce the material, we invite you to complete our exciting assignments. We wish you good luck!
Task No. 1
Look carefully at the picture and tell me which of these cells is bacterial? Try to name the remaining cells without looking at the clues:
How will you react if you learn that the total weight of bacteria in your body is from 1 to 2.5 kilograms?
This will most likely cause surprise and shock. Most people believe that bacteria are dangerous and can cause serious harm to the body. Yes, this is true, but in addition to dangerous ones, there are also beneficial bacteria, which, moreover, are vital for human health.
They exist inside us, taking a huge part in various metabolic processes. Actively participate in the proper functioning of life processes, both in the internal and external environment of our body. These bacteria include bifidobacteria Rhizobium And E. coli, and many more.
Beneficial bacteria for humans
The human body has millions of all kinds of beneficial bacteria that take part in various functions of our body. As you know, the number of bacteria in the body ranges from 1 to two and a half kilograms; this volume contains a huge number of different bacteria. These bacteria can be present in all accessible parts of the body, but are mainly found in the intestines, where they help in digestion processes. They also play a very important role in helping to prevent bacterial infections of the genitals, and also yeast (fungal) infections.
Some beneficial bacteria for humans are regulators of the acid-base balance and are involved in maintaining pH. Some are even involved in protecting the skin (barrier function) from many infections. They are necessary and useful both as active workers in the processes of vitamin K production and in the normal functioning of the immune system.
Environment and beneficial bacteria
The name of one of the most beneficial bacteria in the external environment is Rhizobium. These bacteria are also called nitrogen-fixing bacteria. They are present in the root nodules of plants and release nitrogen into the atmosphere. Considered to be very beneficial for the environment.
Other equally important jobs performed by bacteria for the environment involve digesting organic waste, which helps maintain soil fertility. Azotobacters are a group of bacteria that are involved in the conversion of nitrogen gas into nitrates, which are used further down the chain by Rhizobium - nitrogen-fixing microbes.
Other functions of beneficial bacteria
Bacteria are beneficial by participating in fermentation processes. Therefore, in many industries that are associated with the production of beer, wine, yoghurt and cheese, they cannot do without the use of these microorganisms to carry out fermentation processes. Bacteria used in fermentation processes are called Lactobacillis.
Bacteria play an important role in wastewater treatment. They are used to convert organic matter into methane. Hence, they are used in many industries. Some bacteria are also useful in cleaning and eliminating oil spills on the surface of the Earth's water basins.
Other bacteria are used in the production of antibiotics such as tetracycline and streptomycin. Streptomyces are soil bacteria used in the industrial production of antibiotics in the pharmaceutical industry.
E.coli, are bacteria that are present in the stomach of animals such as cows, buffaloes, etc. help them digest plant foods.
Along with these beneficial bacteria, there are quite dangerous and harmful bacteria that can lead to infections, but they are few in number.
These microorganisms, or at least some of them, deserve to be treated well, because many bacteria are friendly to our bodies - in fact, they are beneficial bacteria and live in our bodies constantly, bringing only benefits. Over the past few years, scientists have discovered that of all the bacteria that live in our bodies, a minority are harmful to our health. In fact, most of the bacteria found in our bodies are beneficial to us.
Thanks to the Human Microbiome Project, a list of five beneficial bacteria that live in our bodies was compiled and made public. Although there are pathogenic strains of some of the bacteria, these types are quite rare. It should also be noted that even beneficial strains of these bacteria, if present in people with a severely weakened immune system and/or entering a part of the body where they should not be, can cause illness. However, this does not happen very often. Here is a list of five beneficial bacteria that live in our bodies:
1. Bifidobacterium longum
This microorganism is found in large quantities in the intestines of infants. They produce several acids that make the intestinal microflora toxic to many pathogenic bacteria. Thus, the beneficial bacteria Bifidobacterium longum serves to protect people from various diseases.
People cannot digest many molecules of plant food on their own. Present in the gastrointestinal tract, the bacteria Bacteroides thetaiotamicron break down such molecules. This allows people to digest the components present in plant foods. Without these beneficial bacteria, vegetarians would be in trouble.
3. Lactobacillus Johnsonii
This bacterium is vital for humans and especially for children. It is located in the intestines and greatly facilitates the process of milk absorption.
4. Escherichia coli
E. coli bacteria synthesize vital vitamin K in the human gastrointestinal tract. The abundance of this vitamin allows the human blood clotting mechanism to function normally. This vitamin is also necessary for the normal functioning of the liver, kidneys and gall bladder, metabolism and normal absorption of calcium.
5. Viridans Streptococci
These beneficial bacteria multiply rapidly in the throat. Although people are not born with them, over time, after a person is born, these bacteria find a way to enter the body. They reproduce there so well that they leave very little room for other, more harmful bacteria to colonize, thereby protecting the human body from disease.
How to protect beneficial bacteria from death
We need to use antibiotics only in extreme cases, since antibacterial drugs, in addition to pathogenic microorganisms, also destroy beneficial microflora, as a result of which an imbalance occurs in our bodies and diseases develop. In addition, you can also start regularly consuming fermented foods rich in beneficial strains of microorganisms (good bacteria), such as sauerkraut and other vegetables, fermented milk products (yogurt, kefir), kombucha, miso, tempeh, etc.
Washing your hands is necessary, but you should not go overboard with antibacterial soap, as this also contributes to the development of bacterial imbalance in the body.
Bacteria are very small, incredibly ancient and to some extent quite simple microorganisms. According to modern classification, they are classified as a separate domain of organisms, which indicates a significant difference between bacteria and other forms of life.
Bacteria are the most common and, accordingly, the most numerous living organisms; they are, without exaggeration, omnipresent and thrive in any environment: water, air, earth, as well as inside other organisms. So in one drop of water their number can reach several million, and in the human body there are about ten more of them than all our cells.
What are bacteria?
These are microscopic, predominantly single-celled organisms, the main difference of which is the absence of a cell nucleus. The basis of the cell, the cytoplasm contains ribosomes and a nucleoid, which serves as the genetic material of bacteria. All this is separated from the outside world by a cytoplasmic membrane or plasmalemma, which in turn is covered with a cell wall and a denser capsule. Some types of bacteria have external flagella; their number and size can vary greatly, but their purpose is always the same - they help bacteria move.
Structure and contents of a bacterial cell
What are bacteria?
Shapes and sizes
The shapes of different types of bacteria vary greatly: they can be round, rod-shaped, convoluted, stellate, tetrahedral, cubic, C- or O-shaped, or irregular.
Bacteria vary in size even more. Thus, Mycoplasma mycoides - the smallest species in the entire kingdom - has a length of 0.1 - 0.25 micrometers, and the largest bacterium Thiomargarita namibiensis reaches 0.75 mm - it can be seen even with the naked eye. On average, sizes range from 0.5 to 5 microns.
Metabolism or metabolism
When it comes to obtaining energy and nutrients, bacteria exhibit extreme diversity. But at the same time, it is quite easy to generalize them by dividing them into several groups.
According to the method of obtaining nutrients (carbons), bacteria are divided into:
- autotrophs- organisms that are capable of independently synthesizing all the organic substances they need for life;
- heterotrophs- organisms that are capable of transforming only ready-made organic compounds, and therefore require the help of other organisms to produce these substances for them.
By method of obtaining energy:
- phototrophs- organisms that produce the necessary energy as a result of photosynthesis
- chemotrophs- organisms that produce energy by carrying out various chemical reactions.
How do bacteria reproduce?
Growth and reproduction in bacteria are closely related. Having reached a certain size, they begin to reproduce. In most types of bacteria this process can occur extremely quickly. Cell division, for example, can occur in less than 10 minutes, and the number of new bacteria will grow exponentially as each new organism divides into two.
There are 3 different types of reproduction:
- division- one bacterium divides into two absolutely genetically identical ones.
- budding- one or more buds (up to 4) are formed at the poles of the mother bacterium, while the mother cell ages and dies.
- primitive sexual process- part of the DNA of the parent cells is transferred to the daughter, and a bacterium appears with a fundamentally new set of genes.
The first type is the most common and fastest, the latter is incredibly important, not only for bacteria, but for all life in general.
Rice. 1. The human body consists of 90% microbial cells. It 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.
Rice. 2. Bacteria inhabiting the oral cavity: Streptococcus mutants (green). Bakteroides gingivalis, causes periodontitis (lilac color). Candida albicus (yellow color). Causes candidiasis of the skin and internal organs.
Rice. 7. Mycobacterium tuberculosis. Bacteria have been causing diseases in humans and animals for many millennia. The tuberculosis bacillus is extremely stable in the external environment. In 95% of cases it is transmitted by airborne droplets. Most often affects the lungs.
Rice. 8. The causative agent of diphtheria is corynebacteria or Leffler's bacillus. It most often develops in the epithelium of the mucous layer of the tonsils, less often in the larynx. Swelling of the larynx and enlarged lymph nodes can lead to asphyxia. The pathogen's toxin is fixed on the membranes of the cells of the heart muscle, kidneys, adrenal glands and nerve ganglia and destroys them.
Rice. 9. Causative agents of staphylococcal infection. Pathogenic staphylococci cause extensive damage to the skin and its appendages, damage to many internal organs, foodborne toxic infection, enteritis and colitis, sepsis and toxic shock.
Rice. 10. Meningococci are the causative agents of meningococcal infection. Up to 80% of cases are children. The infection is transmitted by airborne droplets from sick and healthy carriers of bacteria.
Rice. 11. Bordetella pertussis.
Rice. 12. The causative agent of scarlet fever is streptococcus pyogenes.
Harmful water microflora bacteria
Water is the habitat for many microbes. In 1 cm3 of water you can count up to 1 million microbial bodies. Pathogenic microorganisms enter water from industrial enterprises, populated areas and livestock farms. Water containing pathogenic microbes can become a source dysentery, cholera, typhoid fever, tularemia, leptospirosis, etc. Vibrio cholerae and can remain in water for quite a long time.
Rice. 13. Shigella. Pathogens cause bacillary dysentery. Shigella destroys the epithelium of the colon mucosa, causing severe ulcerative colitis. Their toxins affect the myocardium, nervous and vascular systems.
Rice. 14. . Vibrios do not destroy the cells of the mucous layer of the small intestine, but are located on their surface. They secrete a toxin called choleragen, the action of which leads to disruption of water-salt metabolism, causing the body to lose up to 30 liters of fluid per day.
Rice. 15. Salmonella is the causative agent of typhoid fever and paratyphoid fever. The epithelium and lymphoid elements of the small intestine are affected. With the bloodstream they enter the bone marrow, spleen and gall bladder, from which the pathogens again enter the small intestine. As a result of immune inflammation, the wall of the small intestine ruptures and peritonitis occurs.
Rice. 16. Causative agents of tularemia (blue coccobacteria). They affect the respiratory tract and intestines. They have the ability to penetrate the human body through intact skin and mucous membranes of the eyes, nasopharynx, larynx and intestines. The peculiarity of the disease is damage to the lymph nodes (primary bubo).
Rice. 17. Leptospira. They affect the human capillary network, often the liver, kidneys and muscles. The disease is called infectious jaundice.
Harmful bacteria of soil microflora
Billions of “bad” bacteria live in the soil. In a 30-centimeter thickness of 1 hectare of land there are up to 30 tons of bacteria. Possessing a powerful set of enzymes, they are engaged in the breakdown of proteins into amino acids, thereby taking an active part in the processes of decay. However, these bacteria bring a lot of trouble to humans. Thanks to the activity of these microbes, food spoils very quickly. Man has learned to protect shelf-stable foods by sterilizing, salting, smoking and freezing. Some types of these bacteria can spoil even salted and frozen foods. enter the soil from sick animals and humans. Some types of bacteria and fungi stay in the soil for decades. This is facilitated by the ability of these microorganisms to form spores, which protect them from unfavorable environmental conditions for many years. They cause the most dangerous diseases - anthrax, botulism, and tetanus.
Rice. 18. The causative agent of anthrax. It remains in the soil in a spore-like state for decades. A particularly dangerous disease. Its second name is malignant carbuncle. The prognosis of the disease is unfavorable.
Rice. 19. The causative agent of botulism produces a powerful toxin. 1 microgram of this poison kills a person. Botulinum toxin affects the nervous system, oculomotor nerves, up to paralysis and cranial nerves. The mortality rate from botulism reaches 60%.
Rice. 20. The causative agents of gas gangrene multiply very quickly in the soft tissues of the body without air access, causing severe lesions. In a spore-like state, it persists in the external environment for a long time.
Rice. 21. Putrefactive bacteria.
Rice. 22. Damage to food products by putrefactive bacteria.
Harmful bacteria that damage wood
A number of bacteria and fungi intensively decompose fiber, playing an important sanitary role. However, among them there are bacteria that cause serious diseases in animals. Molds destroy wood. Wood staining mushrooms paint wood in different colors. House mushroom leads the wood to a rotten state. As a result of the vital activity of this fungus, wooden buildings are destroyed. The activity of these fungi causes great damage in the destruction of livestock buildings.
Rice. 23. The photo shows how the house fungus destroyed the wooden floor beams.
Rice. 24. Damaged appearance of logs (blueness) affected by wood-staining fungus.
Rice. 25. House mushroom Merulius Lacrimans. a – cotton wool mycelium; b – young fruiting body; c – old fruiting body; d – old mycelium, cords and wood rot.
Harmful bacteria in food
Products contaminated with dangerous bacteria become a source of intestinal diseases: typhoid fever, salmonellosis, cholera, dysentery etc. Toxins that are released staphylococci and botulism bacilli, cause toxic infections. Cheeses and all dairy products may be affected butyric acid bacteria, which cause butyric acid fermentation, resulting in products having an unpleasant odor and color. Vinegar sticks cause acetic fermentation, which leads to sour wine and beer. Bacteria and micrococci that cause rotting contain proteolytic enzymes that break down proteins, which gives products a foul-smelling odor and bitter taste. Products become covered in mold as a result of damage to mold fungi.
Rice. 26. Bread affected by mold.
Rice. 27. Cheese affected by mold and putrefactive bacteria.
Rice. 28. “Wild yeast” Pichia pastoris. The photo was taken with 600x magnification. The worst pest of beer. Found everywhere in nature.
Harmful bacteria that decompose dietary fats
Butyric acid microbes are everywhere. 25 of their species cause butyric acid fermentation. Life activity fat-digesting bacteria leads to rancidity of the oil. Under their influence, soybean and sunflower seeds become rancid. Butyric acid fermentation, which is caused by these microbes, spoils the silage, and it is poorly eaten by livestock. And wet grain and hay, infected with butyric acid microbes, self-heats. The moisture contained in butter is a good environment for reproduction. putrefactive bacteria and yeast fungi. Because of this, the oil deteriorates not only outside, but also inside. If the oil is stored for a long time, then it can settle on its surface. mold fungi.
Rice. 29. Caviar oil affected by fat-splitting bacteria.
Harmful bacteria affecting eggs and egg products
Bacteria and fungi penetrate into eggs through the pores of the outer shell and its damage. Most often, eggs are infected with salmonella bacteria and molds, egg powder - salmonella and .
Rice. 30. Spoiled eggs.
Harmful bacteria in canned food
for humans are toxins botulinum bacillus and perfringens bacillus. Their spores exhibit high heat resistance, which allows microbes to remain viable after pasteurization of canned food. Being inside the jar, without access to oxygen, they begin to multiply. This releases carbon dioxide and hydrogen, which causes the jar to swell. Eating such a product causes severe food toxicosis, which is characterized by an extremely severe course and often ends in the death of the patient. Canned meat and vegetables are amazing acetic acid bacteria, As a result, the contents of the canned food sour. Development does not cause bloating of canned food, since staphylococcus does not produce gases.
Rice. 31. Canned meat affected by acetic acid bacteria, as a result of which the contents of the cans turn sour.
Rice. 32. Swollen canned food may contain botulinum bacilli and perfringens bacilli. The jar is inflated by carbon dioxide, which is released by bacteria during reproduction.
Harmful bacteria in grain products and bread
Ergot and other molds that infect grains are the most dangerous for humans. The toxins of these mushrooms are heat stable and are not destroyed by baking. Toxicoses caused by the use of such products are severe. Torment, stricken lactic acid bacteria, has an unpleasant taste and specific smell, lumpy in appearance. Already baked bread is affected Bacillus subtilis(Bac. subtilis) or "gravitating disease." The bacilli secrete enzymes that break down bread starch, which is manifested, first, by an odor not characteristic of bread, and then by the stickiness and viscousness of the bread crumb. Green, white and capitate mold affects already baked bread. It spreads through the air.
Rice. 33. In the photo there is purple ergot. Low doses of ergot cause severe pain, mental disturbances and aggressive behavior. High doses of ergot cause painful death. Its action is associated with muscle contraction under the influence of fungal alkaloids.
Rice. 34. Mold mycelium.
Rice. 35. Spores of green, white and capitate molds can fall from the air onto already baked bread and infect it.
Harmful bacteria that affect fruits, vegetables and berries
Fruits, vegetables and berries are seeded soil bacteria, mold fungi and yeast, which cause intestinal infections. The mycotoxin patulin, which is secreted mushrooms of the genus Penicillium, can cause cancer in humans. Yersinia enterocolitica causes the disease yersiniosis or pseudotuberculosis, which affects the skin, gastrointestinal tract and other organs and systems.
Rice. 36. Damage to berries by mold fungi.
Rice. 37. Skin lesions due to yersiniosis.
Harmful bacteria enter the human body through food, air, wounds and mucous membranes. The severity of diseases caused by pathogenic microbes depends on the poisons they produce and the toxins that arise when they die en masse. Over the course of thousands of years, they have acquired many adaptations that allow them to penetrate and remain in the tissues of a living organism and resist immunity.
To study the harmful effects of microorganisms on the body and develop preventive measures is the task of man!
