All types of bacteria and their names. Bacteria are useful and harmful

At this very moment, man, when you read these lines, you are benefiting from the work of bacteria. From the oxygen we breathe in to the nutrients our stomachs extract from our food, we have bacteria to thank for thriving on this planet. In our body there are about ten times more microorganisms, including bacteria, than our own cells. Essentially, we are more microbes than people.

It's only recently that we've begun to understand a little about microscopic organisms and their impact on our planet and health, but history shows that centuries ago our ancestors were already harnessing the power of bacteria to ferment foods and drinks (whoever heard of bread and beer?).

In the 17th century, we began to study bacteria directly in our bodies in close connection with us - in the mouth. Antoni van Leeuwenhoek's curiosity led to the discovery of bacteria when he examined a plaque between his own teeth. Van Leeuwenhoek waxed poetic about the bacteria, describing the bacterial colony on his teeth as “a little white substance, like hardened dough.” Placing the sample under a microscope, van Leeuwenhoek saw that the microorganisms were moving. So they are alive!

You should know that bacteria have played a critical role on Earth, being key to the creation of breathable air and the biological richness of the planet we call home.

In this article, we will provide you with an overview of these tiny but very influential microorganisms. We'll look at the good, the bad, and the downright bizarre ways that bacteria shape human and environmental history. First, let's look at how bacteria differ from other types of life.

Bacteria Basics

Well, if bacteria are invisible to the naked eye, how can we know so much about them?

Scientists have developed powerful microscopes to look at bacteria - which range in size from one to a few microns (millionths of a meter) - and figure out how they relate to other life forms, plants, animals, viruses and fungi.

As you may know, cells are the building blocks of life, from the tissues of our body to the tree that grows outside our window. Humans, animals and plants have cells with genetic information contained in a membrane called the nucleus. These types of cells, called eukaryotic cells, have specialized organelles, each of which has a unique job to help the cell function.

Bacteria, however, do not have a nucleus, and their genetic material (DNA) floats freely inside the cell. These microscopic cells have no organelles and have other methods of reproduction and transfer of genetic material. Bacteria are considered prokaryotic cells.

Do bacteria survive in an environment with or without oxygen?

Their shape: rods (bacillus), circles (cocci) or spirals (spirillum)

Are the bacteria gram-negative or gram-positive, that is, do they have an outer protective membrane that prevents staining of the cell interior?

How bacteria move and explore their environment (many bacteria have flagella, tiny whip-like structures that allow them to move around in their environment)

Microbiology - the study of all types of microbes, including bacteria, archaea, fungi, viruses and protozoa - distinguishes bacteria from their microbial cousins.

Bacteria-like prokaryotes, now classified as archaea, were once together with bacteria, but as scientists learned more about them, they gave bacteria and archaea their own categories.

Microbial nutrition (and miasma)

Like people, animals and plants, bacteria need food to survive.

Some bacteria—autotrophs—use basic resources like sunlight, water, and environmental chemicals to create food (think of cyanobacteria, which have been converting sunlight into oxygen for 2.5 million years). Other bacteria are called heterotrophs by scientists because they get their energy from existing organic matter as food (for example, dead leaves on forest floors).

The truth is that what may be tasty to bacteria will be disgusting to us. They have evolved to absorb all types of products, from oil spills and nuclear byproducts to human waste and decomposition products.

But a bacteria's affinity for a particular food source could benefit society. For example, art experts in Italy turned to bacteria that can eat excess layers of salt and glue, reducing the durability of priceless works of art. The ability of bacteria to process organic matter is also very beneficial for the Earth, both in soil and in water.

From daily experience, you're well aware of the odor caused by bacteria as they consume the contents of your trash can, digesting leftover food and emitting their own gaseous byproducts. However, this is not all. You can also blame bacteria for causing those awkward moments when you pass gas yourself.

One big family

Bacteria grow and form colonies when given the chance. If food and environmental conditions are favorable, they reproduce and form sticky clumps called biofilms to survive on surfaces ranging from rocks to the teeth of your mouth.

Biofilms have their pros and cons. On the one hand, they are mutually beneficial to natural objects (mutualism). On the other hand, they can be a serious threat. For example, doctors who treat patients with medical implants and devices have serious concerns about biofilms because they provide real estate for bacteria. Once colonized, biofilms can produce byproducts that are toxic—and sometimes fatal—to humans.

Like people in cities, cells in a biofilm communicate with each other, exchanging information about food and potential dangers. But instead of calling neighbors on the phone, bacteria send notes using chemicals.

Also, bacteria are not afraid to live on their own. Some species have developed interesting ways to survive in harsh environments. When there is no more food and conditions become unbearable, bacteria preserve themselves by creating a hard shell, an endospore, which puts the cell into a state of dormancy and preserves the genetic material of the bacterium.

Scientists find bacteria in such time capsules that were stored for 100 and even 250 million years. This suggests that the bacteria can self-storage for a long time.

Now that we know what opportunities colonies provide to bacteria, let's figure out how they get there - through division and reproduction.

Bacteria reproduction

How do bacteria create colonies? Like other life forms on Earth, bacteria need to replicate themselves in order to survive. Other organisms do this through sexual reproduction, but not bacteria. But first, let's discuss why diversity is good.

Life undergoes natural selection, or the selective forces of a certain environment allow one type to flourish and reproduce more than another. You may remember that genes are the machinery that instructs a cell what to do and determines what color your hair and eyes will be. You get genes from your parents. Sexual reproduction results in mutations, or random changes in DNA, which creates diversity. The more genetic diversity there is, the greater the chance that an organism will be able to adapt to environmental constraints.

For bacteria, reproduction does not depend on meeting the right microbe; they simply copy their own DNA and divide into two identical cells. This process, called binary fission, occurs when one bacterium splits into two, copying DNA and passing it on to both parts of the divided cell.

Since the resulting cell will ultimately be identical to the one from which it was born, this method of propagation is not the best for creating a diverse gene pool. How do bacteria acquire new genes?

It turns out that bacteria use a clever trick: horizontal gene transfer, or the exchange of genetic material without reproducing. There are several ways that bacteria use to do this. One method involves collecting genetic material from the environment outside the cell - from other microbes and bacteria (through molecules called plasmids). Another way is viruses, which use bacteria as a home. When viruses infect a new bacterium, they leave the genetic material of the previous bacterium in the new one.

The exchange of genetic material gives bacteria the flexibility to adapt, and they adapt if they sense stressful changes in the environment, such as food shortages or chemical changes.

Understanding how bacteria adapt is extremely important for fighting them and creating antibiotics for medicine. Bacteria can exchange genetic material so frequently that sometimes treatments that worked before no longer work.

No high mountains, no great depths

If you ask the question “where are the bacteria?”, it is easier to ask “where are there no bacteria?”

Bacteria are found almost everywhere on Earth. It is impossible to imagine the number of bacteria on the planet at any one time, but some estimates put their number (bacteria and archaea together) at 5 octillion - a number with 27 zeros.

Classifying bacterial species is extremely difficult for obvious reasons. There are now approximately 30,000 officially identified species, but the knowledge base is constantly growing, and there are opinions that we are just the tip of the iceberg of all types of bacteria.

The truth is that bacteria have been around for a very long time. They produced some of the oldest fossils, dating back 3.5 billion years. Scientific research suggests that cyanobacteria began creating oxygen approximately 2.3-2.5 billion years ago in the world's oceans, saturating the Earth's atmosphere with the oxygen we breathe to this day.

Bacteria can survive in the air, water, soil, ice, heat, on plants, in the intestines, on the skin - everywhere.

Some bacteria are extremophiles, meaning they can withstand extreme conditions that are either very hot or cold, or lack the nutrients and chemicals we typically associate with life. Researchers found such bacteria in the Mariana Trench, the deepest point on Earth at the bottom of the Pacific Ocean, near hydrothermal vents in water and ice. There are also bacteria that like high temperatures, such as those that color the opalescent pool in Yellowstone National Park.

Bad (for us)

While bacteria make important contributions to human and planetary health, they also have a dark side. Some bacteria can be pathogenic, meaning they cause illness and disease.

Throughout human history, certain bacteria have (understandably) gotten a bad rap, causing panic and hysteria. Take the plague, for example. The bacterium that causes the plague, Yersinia pestis, not only killed more than 100 million people, but may have contributed to the collapse of the Roman Empire. Before the advent of antibiotics, drugs that help fight bacterial infections, they were very difficult to stop.

Even today, these pathogenic bacteria seriously scare us. Thanks to the development of resistance to antibiotics, bacteria that cause anthrax, pneumonia, meningitis, cholera, salmonellosis, tonsillitis and other diseases that still remain close to us always pose a danger to us.

This is especially true for Staphylococcus aureus, the bacterium responsible for staph infections. This “superbug” causes numerous problems in clinics, since patients very often contract this infection when implanting medical implants and catheters.

We've already talked about natural selection and how some bacteria produce a variety of genes that help them cope with environmental conditions. If you have an infection and some of the bacteria in your body are different from others, antibiotics may affect most of the bacterial population. But those bacteria that survive will develop resistance to the drug and remain, waiting for the next chance. Therefore, doctors recommend completing the course of antibiotics to the end, and in general using them as rarely as possible, only as a last resort.

Biological weapons are another frightening aspect of this conversation. Bacteria can be used as a weapon in some cases, in particular anthrax was used at one time. In addition, not only people suffer from bacteria. A separate species, Halomonas titanicae, has shown an appetite for the sunken ocean liner Titanic, eating away at the metal of the historic ship.

Of course, bacteria can cause more than just harm.

Heroic bacteria

Let's explore the good side of bacteria. After all, these microbes gave us delicious foods like cheese, beer, sourdough and other fermented elements. They also improve human health and are used in medicine.

Individual bacteria can be thanked for shaping human evolution. Science is collecting more and more data about microflora - microorganisms that live in our bodies, especially in the digestive system and intestines. Research shows that bacteria, new genetic materials, and the diversity they bring to our bodies allow humans to adapt to new food sources that have not been exploited before.

Let's look at it this way: by lining the surface of your stomach and intestines, bacteria “work” for you. When you eat, bacteria and other microbes help you break down and extract nutrients from your food, especially carbohydrates. The more diverse the bacteria we consume, the more diversity our bodies gain.

Although our knowledge of our own microbes is very limited, there is reason to believe that the absence of certain microbes and bacteria in the body may be associated with human health, metabolism and susceptibility to allergens. Preliminary studies in mice have shown that metabolic diseases like obesity are associated with a diverse and healthy microbiota, rather than our prevailing “calories in, calories out” mentality.

The possibility of introducing certain microbes and bacteria into the human body that may provide certain benefits is currently being actively explored, but at the time of writing, general recommendations for their use have not yet been established.

In addition, bacteria played an important role in the development of scientific thought and human medicine. Bacteria played a leading role in the development of Koch's 1884 postulates, which led to the general understanding that disease is caused by a specific type of microbe.

Researchers studying bacteria accidentally discovered penicillin, an antibiotic that saved many lives. Also, quite recently, in connection with this, an easy way to edit the genome of organisms was discovered, which could revolutionize medicine.

In fact, we are just beginning to understand how to benefit from our cohabitation with these little friends. In addition, it is not clear who is the true owner of the Earth: people or microbes.

The bacterial organism is represented by one single cell. The forms of bacteria are varied. The structure of bacteria differs from the structure of animal and plant cells.

The cell lacks a nucleus, mitochondria and plastids. The carrier of hereditary information DNA is located in the center of the cell in a folded form. Microorganisms that do not have a true nucleus are classified as prokaryotes. All bacteria are prokaryotes.

It is estimated that there are over a million species of these amazing organisms on earth. To date, about 10 thousand species have been described.

A bacterial cell has a wall, a cytoplasmic membrane, cytoplasm with inclusions and a nucleotide. Of the additional structures, some cells have flagella, pili (a mechanism for adhesion and retention on the surface) and a capsule. Under unfavorable conditions, some bacterial cells are capable of forming spores. The average size of bacteria is 0.5-5 microns.

External structure of bacteria

Rice. 1. The structure of a bacterial cell.

Cell wall

The cell wall of a bacterial cell is its protection and support. It gives the microorganism its own specific shape.
The cell wall is permeable. Nutrients pass inward and metabolic products pass through it.
Some types of bacteria produce special mucus that resembles a capsule that protects them from drying out.
Some cells have flagella (one or more) or villi that help them move.
Bacterial cells that appear pink when Gram stained ( gram-negative), the cell wall is thinner and multilayered. Enzymes that help break down nutrients are released.
Bacteria that appear violet on Gram staining ( gram-positive), the cell wall is thick. Nutrients that enter the cell are broken down in the periplasmic space (the space between the cell wall and the cytoplasmic membrane) by hydrolytic enzymes.
There are numerous receptors on the surface of the cell wall. Cell killers - phages, colicins and chemical compounds - are attached to them.
Wall lipoproteins in some types of bacteria are antigens called toxins.
With long-term treatment with antibiotics and for a number of other reasons, some cells lose their membranes, but retain the ability to reproduce. They acquire a rounded shape - L-shape and can persist in the human body for a long time (cocci or tuberculosis bacilli). Unstable L-forms have the ability to return to their original form (reversion).

Rice. 2. The photo shows the structure of the bacterial wall of gram-negative bacteria (left) and gram-positive bacteria (right).

Capsule

Under unfavorable environmental conditions, bacteria form a capsule. The microcapsule adheres tightly to the wall. It can only be seen in an electron microscope. The macrocapsule is often formed by pathogenic microbes (pneumococci). In Klebsiella pneumoniae, the macrocapsule is always found.

Rice. 3. In the photo is pneumococcus. Arrows indicate the capsule (electronogram of an ultrathin section).

Capsule-like shell

The capsule-like shell is a formation loosely associated with the cell wall. Thanks to bacterial enzymes, the capsule-like shell is covered with carbohydrates (exopolysaccharides) from the external environment, which ensures the adhesion of bacteria to different surfaces, even completely smooth ones.

For example, streptococci, when entering the human body, are able to stick to teeth and heart valves.

The functions of the capsule are varied:

protection from aggressive environmental conditions,
ensuring adhesion (sticking) to human cells,
Possessing antigenic properties, the capsule has a toxic effect when introduced into a living organism.

Rice. 4. Streptococci are capable of sticking to tooth enamel and, together with other microbes, cause caries.

Rice. 5. The photo shows damage to the mitral valve due to rheumatism. The cause is streptococci.

Flagella

Some bacterial cells have flagella (one or more) or villi that help them move. The flagella contain the contractile protein flagellin.
The number of flagella can be different - one, a bundle of flagella, flagella at different ends of the cell or over the entire surface.
Movement (random or rotational) is carried out as a result of the rotational movement of the flagella.
The antigenic properties of flagella have a toxic effect in disease.
Bacteria that do not have flagella, when covered with mucus, are able to glide. Aquatic bacteria contain 40-60 vacuoles filled with nitrogen.

They provide diving and ascent. In the soil, the bacterial cell moves through soil channels.

Rice. 6. Scheme of attachment and operation of the flagellum.

Rice. 7. The photo shows different types of flagellated microbes.

Rice. 8. The photo shows different types of flagellated microbes.

Drank

Pili (villi, fimbriae) cover the surface of bacterial cells. The villus is a helically twisted thin hollow thread of protein nature.
General type drank provide adhesion (sticking) to host cells. Their number is huge and ranges from several hundred to several thousand. From the moment of attachment, any .
Sex drank facilitate the transfer of genetic material from the donor to the recipient. Their number is from 1 to 4 per cell.

Rice. 9. The photo shows E. coli. Flagella and pili are visible. The photo was taken using a tunneling microscope (STM).

Rice. 10. The photo shows numerous pili (fimbriae) of cocci.

Rice. 11. The photo shows a bacterial cell with fimbriae.

Cytoplasmic membrane

The cytoplasmic membrane is located under the cell wall and is a lipoprotein (up to 30% lipids and up to 70% proteins).
Different bacterial cells have different membrane lipid compositions.
Membrane proteins perform many functions. Functional proteins are enzymes due to which the synthesis of its various components, etc. occurs on the cytoplasmic membrane.
The cytoplasmic membrane consists of 3 layers. The phospholipid double layer is permeated with globulins, which ensure the transport of substances into the bacterial cell. If its function is disrupted, the cell dies.
The cytoplasmic membrane takes part in sporulation.

Rice. 12. The photo clearly shows a thin cell wall (CW), a cytoplasmic membrane (CPM) and a nucleotide in the center (the bacterium Neisseria catarrhalis).

Internal structure of bacteria

Rice. 13. The photo shows the structure of a bacterial cell. The structure of a bacterial cell differs from the structure of animal and plant cells - the cell lacks a nucleus, mitochondria and plastids.

Cytoplasm

The cytoplasm is 75% water, the remaining 25% is mineral compounds, proteins, RNA and DNA. The cytoplasm is always dense and motionless. It contains enzymes, some pigments, sugars, amino acids, a supply of nutrients, ribosomes, mesosomes, granules and all sorts of other inclusions. In the center of the cell, a substance is concentrated that carries hereditary information - the nucleoid.

Granules

The granules are made up of compounds that are a source of energy and carbon.

Mesosomes

Mesosomes are cell derivatives. They have different shapes - concentric membranes, vesicles, tubes, loops, etc. Mesosomes have a connection with the nucleoid. Participation in cell division and sporulation is their main purpose.

Nucleoid

A nucleoid is an analogue of a nucleus. It is located in the center of the cell. It contains DNA, the carrier of hereditary information in a folded form. Unwound DNA reaches a length of 1 mm. The nuclear substance of a bacterial cell does not have a membrane, a nucleolus or a set of chromosomes, and does not divide by mitosis. Before dividing, the nucleotide is doubled. During division, the number of nucleotides increases to 4.

Rice. 14. The photo shows a section of a bacterial cell. A nucleotide is visible in the central part.

Plasmids

Plasmids are autonomous molecules coiled into a ring of double-stranded DNA. Their mass is significantly less than the mass of a nucleotide. Despite the fact that hereditary information is encoded in the DNA of plasmids, they are not vital and necessary for the bacterial cell.

Rice. 15. The photo shows a bacterial plasmid. The photo was taken using an electron microscope.

Ribosomes

Ribosomes of a bacterial cell are involved in the synthesis of protein from amino acids. The ribosomes of bacterial cells are not united into the endoplasmic reticulum, like those of cells with a nucleus. It is ribosomes that often become the “target” for many antibacterial drugs.

Inclusions

Inclusions are metabolic products of nuclear and non-nuclear cells. They represent a supply of nutrients: glycogen, starch, sulfur, polyphosphate (valutin), etc. Inclusions often, when painted, take on a different appearance than the color of the dye. You can diagnose by currency.

Shapes of bacteria

The shape of a bacterial cell and its size are of great importance in their identification (recognition). The most common shapes are spherical, rod-shaped and convoluted.

Table 1. Main forms of bacteria.

Globular bacteria

The spherical bacteria are called cocci (from the Greek coccus - grain). They are arranged one by one, two by two (diplococci), in packets, in chains, and like bunches of grapes. This location depends on the method of cell division. The most harmful microbes are staphylococci and streptococci.

Rice. 16. In the photo there are micrococci. The bacteria are round, smooth, and white, yellow and red in color. In nature, micrococci are ubiquitous. They live in different cavities of the human body.

Rice. 17. The photo shows diplococcus bacteria - Streptococcus pneumoniae.

Rice. 18. The photo shows Sarcina bacteria. Coccoid bacteria cluster together in packets.

Rice. 19. The photo shows streptococcus bacteria (from the Greek “streptos” - chain).

Arranged in chains. They are causative agents of a number of diseases.

Rice. 20. In the photo, the bacteria are “golden” staphylococci. Arranged like “bunches of grapes”. The clusters are golden in color. They are causative agents of a number of diseases.

Rod-shaped bacteria

Rod-shaped bacteria that form spores are called bacilli. They have a cylindrical shape. The most prominent representative of this group is the bacillus. The bacilli include plague and hemophilus influenzae. The ends of rod-shaped bacteria may be pointed, rounded, chopped off, flared, or split. The shape of the sticks themselves can be regular or irregular. They can be arranged one at a time, two at a time, or form chains. Some bacilli are called coccobacilli because they have a round shape. But, nevertheless, their length exceeds their width.

Diplobacillus are double rods. Anthrax bacilli form long threads (chains).

The formation of spores changes the shape of the bacilli. In the center of the bacilli, spores form in butyric acid bacteria, giving them the appearance of a spindle. In tetanus bacilli - at the ends of the bacilli, giving them the appearance of drumsticks.

Rice. 21. The photo shows a rod-shaped bacterial cell. Multiple flagella are visible. The photo was taken using an electron microscope. Negative.

Rice. 22. The photo shows rod-shaped bacteria forming chains (anthrax bacilli).

Both the school curriculum and specialized university education necessarily consider examples from the kingdom of bacteria. This ancient form of life on our planet appeared earlier than any others known to man. For the first time, scientists estimate that bacteria formed about three and a half billion years ago, and for about a billion years there were no other forms of life on the planet. Examples of bacteria, our enemies and friends, are necessarily considered as part of any educational program, because it is these microscopic life forms that make possible the processes characteristic of our world.

Features of prevalence

Where in the living world can you find examples of bacteria? Yes, almost everywhere! They are found in spring water, desert dunes, and elements of soil, air and rocks. In Antarctic ice, for example, bacteria live at a frost of -83 degrees, but high temperatures do not interfere with them - life forms have been found in sources where the liquid is heated to +90. The population density of the microscopic world is evidenced by the fact that, for example, bacteria in a gram of soil are uncountable hundreds of millions.

Bacteria can live on any other form of life - on a plant, an animal. Many people know the phrase “intestinal microflora,” and on TV they constantly advertise products that improve it. In fact, it was, for example, formed by bacteria, that is, normally, innumerable microscopic life forms also live in the human body. They are also on our skin, in our mouth - in a word, anywhere. Some of them are truly harmful and even life-threatening, which is why antibacterial agents are so widespread, but without others it would simply be impossible to survive - our species coexist in symbiosis.

Living conditions

Whatever example of bacteria you give, these organisms are extremely resilient, can survive in unfavorable conditions, and easily adapt to negative factors. Some forms require oxygen to survive, while others can survive just fine even without it. There are many examples of bacteria that survive excellently in an oxygen-free environment.

Research has shown that microscopic life forms can survive extreme cold and are not affected by extreme dryness or elevated temperatures. The spores by which bacteria reproduce can easily cope even with prolonged boiling or treatment at low temperatures.

What are they?

When analyzing examples of bacteria (enemies and friends of humans), we must remember that modern biology introduces a classification system that somewhat simplifies the understanding of this diverse kingdom. It is customary to talk about several different forms, each of which has a specialized name. So, cocci are called bacteria in the shape of a ball, streptococci are balls collected in a chain, and if the formation looks like a bunch, then it is classified as a group of staphylococci. Such microscopic forms of life are known when two bacteria live in one capsule covered with a mucous membrane. These are called diplococci. Bacilli are shaped like rods, spirilla are shaped like spirals, and vibrios are an example of a bacterium (any student who is taking the program responsibly should be able to give it) that is similar in shape to a comma.

This name was adopted to refer to microscopic life forms that, when analyzed by Gram, do not change color when exposed to crystal violet. For example, pathogenic and harmless bacteria from the gram-positive class retain a purple tint even if washed with alcohol, but gram-negative bacteria are completely discolored.

When examining a microscopic life form, after a Gram wash, it is necessary to use a contract dye (safranin), under the influence of which the bacterium will turn pink or red. This reaction is due to the structure of the outer membrane, which prevents the dye from penetrating inside.

Why is this necessary?

If, as part of a school course, a student is given the task of giving examples of bacteria, he can usually remember those forms that are discussed in the textbook, and for them their key features have already been indicated. The staining test was invented precisely to identify these specific parameters. Initially, the study aimed to classify representatives of microscopic life forms.

The results of the Gram test allow us to draw conclusions regarding the structure of cell walls. Based on the information obtained, it is possible to divide all identified forms into two groups, which are further taken into account in the work. For example, pathogenic bacteria from the gram-negative class are much more resistant to the influence of antibodies, since the cell wall is impenetrable, protected, and powerful. But for gram-positive ones, the resistance is noticeably lower.

Pathogenicity and interaction features

A classic example of a disease caused by bacteria is an inflammatory process that can develop in a wide variety of tissues and organs. Most often, this reaction is provoked by gram-negative life forms, since their cell walls trigger a reaction from the human immune system. The walls contain LPS (lipopolysaccharide layer), in response to which the body generates cytokines. This provokes inflammation, the host’s body is forced to cope with increased production of toxic components, which is due to the struggle between the microscopic life form and the immune system.

Which ones are known?

In medicine, special attention is currently paid to three forms that provoke serious diseases. The bacterium Neisseria gonorrhoeae is transmitted sexually, symptoms of respiratory pathologies are observed when the body is infected with Moraxella catarrhalis, and one of the very dangerous diseases for humans - meningitis - is provoked by the bacterium Neisseria meningitidis.

Bacilli and diseases

Considering, for example, bacteria and the diseases they provoke, it is simply impossible to ignore bacilli. This word is now known to any layman, even if he has little idea of the characteristics of microscopic life forms, but it is this type of gram-negative bacteria that is extremely important for modern doctors and researchers, as it provokes serious problems in the human respiratory system. There are also known examples of diseases of the urinary system provoked by such infection. Some bacilli negatively affect the functioning of the gastrointestinal tract. The degree of damage depends both on the person’s immunity and on the specific form that infected the body.

A certain group of gram-negative bacteria is associated with an increased likelihood of hospital-acquired infection. The most dangerous of the relatively widespread ones cause secondary meningitis and pneumonia. The most careful should be the workers of medical institutions in the intensive care unit.

Lithotrophs

When considering examples of bacterial nutrition, special attention should be paid to the unique group of lithotrophs. This is a microscopic form of life that receives energy from an inorganic compound for its activities. Metals, hydrogen sulfide, ammonium, and many other compounds from which the bacterium receives electrons are consumed. The oxidizing agent in the reaction is an oxygen molecule or another compound that has already undergone the oxidation stage. Electron transfer is accompanied by the production of energy stored by the body and used in metabolism.

For modern scientists, lithotrophs are interesting primarily because they are living organisms that are quite atypical for our planet, and the study allows us to significantly expand our understanding of the capabilities that some groups of living beings have. Knowing the examples, the names of bacteria from the class of lithotrophs, and examining the peculiarities of their life activity, it is possible to some extent restore the primary ecological system of our planet, that is, the period when there was no photosynthesis, oxygen did not exist, and even organic matter had not yet appeared. The study of lithotrophs gives a chance to understand life on other planets, where it can be realized through the oxidation of inorganics, in the complete absence of oxygen.

Who and what?

What are lithotrophs in nature? Example - nodule bacteria, chemotrophic, carboxytrophic, methanogens. At present, scientists cannot say for sure that they have discovered all the species belonging to this group of microscopic life forms. It is assumed that further research in this direction is one of the most promising areas of microbiology.

Lithotrophs take an active part in cyclic processes that are important for the conditions of life on our planet. Often the chemical reactions provoked by these bacteria have a rather strong effect on the space. Thus, sulfur bacteria can oxidize hydrogen sulfide in sediments at the bottom of a reservoir, and without such a reaction the component would react with the oxygen contained in the water layers, which would make life in it impossible.

Symbiosis and confrontation

Who doesn’t know examples of viruses and bacteria? As part of the school course, everyone is told about Treponema pallidum, which can cause syphilis and flambesia. There are also bacterial viruses, which are known to science as bacteriophages. Studies have shown that in just one second they can infect 10 to the 24th degree of bacteria! This is both a powerful tool for evolution and a method applicable to genetic engineering, which is currently being actively studied by scientists.

The importance of life

There is a misconception among the common people that bacteria are only the cause of human disease, and there is no other benefit or harm from them. This stereotype is due to the anthropocentric picture of the surrounding world, that is, the idea that everything is somehow correlated with a person, revolves around him and exists only for him. In fact, we are talking about constant interaction without any specific center of rotation. Bacteria and eukaryotes have interacted for as long as both kingdoms have existed.

The first method of fighting bacteria invented by mankind was associated with the discovery of penicillin, a fungus capable of destroying microscopic life forms. Fungi belong to the kingdom of eukaryotes and, from the point of view of the biological hierarchy, are more closely related to humans than plants. But research has shown that fungi are far from the only and not even the first that became the enemy of bacteria, because eukaryotes appeared much later than microscopic life. Initially, the struggle between bacteria (and other forms simply did not exist) took place using the components that these organisms produced in order to win a place for existence. Currently, a person, trying to discover new ways to fight bacteria, can only discover those methods that have been known to nature for a long time and were used by organisms in the struggle for life. But drug resistance, which scares so many people, is a normal resistance reaction inherent in microscopic life for many millions of years. It was this that determined the ability of bacteria to survive all this time and continue to develop and multiply.

Attack or die

Our world is a place where only those adapted to life, capable of defending themselves, attacking, and surviving can survive. At the same time, the ability to attack is closely related to options for protecting oneself, one’s life, and interests. If a certain bacterium could not escape antibiotics, that species would die out. Currently existing microorganisms have fairly developed and complex defense mechanisms that are effective against a wide variety of substances and compounds. The most applicable method in nature is to redirect the danger to another target.

The appearance of an antibiotic is accompanied by an effect on the molecule of a microscopic organism - on RNA, protein. If you change the target, then the site where the antibiotic can bind will change. A point mutation, which makes one organism resistant to the effects of an aggressive component, becomes the reason for the improvement of the entire species, since it is this bacterium that continues to actively reproduce.

Viruses and bacteria

This topic is currently causing a lot of conversation among both professionals and ordinary people. Almost every second person considers himself an expert on viruses, which is connected with the work of mass media systems: as soon as the flu epidemic approaches, people talk and write about viruses everywhere. A person, having become acquainted with this data, begins to believe that he knows everything that is possible. Of course, it is useful to get acquainted with the data, but do not be mistaken: not only ordinary people, but also professionals currently have yet to discover most of the information about the peculiarities of the life of viruses and bacteria.

By the way, in recent years the number of people convinced that cancer is a viral disease has increased significantly. Many hundreds of laboratories around the world have conducted studies from which this conclusion can be drawn regarding leukemia and sarcoma. However, for now these are just assumptions, and the official evidence base is not enough to make a definitive conclusion.

Virology

This is a fairly young field of science, born eight decades ago when they discovered what causes tobacco mosaic disease. Much later, the first image was received, although it was very inaccurate, and more or less correct research has been carried out only in the last fifteen years, when the technologies available to mankind have made it possible to study such small forms of life.

Currently, there is no exact information about how and when viruses appeared, but one of the main theories is that this form of life originated from bacteria. Instead of evolution, degradation took place here, development turned back, and new single-celled organisms were formed. A group of scientists claims that viruses were previously much more complex, but lost a number of features over time. A condition that is accessible to modern man for study, the diversity of genetic data are only echoes of different degrees, stages of degradation characteristic of a particular species. How correct this theory is is still unknown, but the presence of a close connection between bacteria and viruses cannot be denied.

Bacteria: so different

Even if modern man understands that bacteria surround him everywhere, it is still difficult to realize how much the processes of the surrounding world depend on microscopic life forms. Only recently have scientists discovered that living bacteria even fill the clouds where they rise with steam. The abilities given to such organisms are surprising and inspiring. Some cause water to change into ice, causing precipitation. When the granule begins to fall, it melts again, and a stream of water - or snow, depending on the climate and season - falls on the ground. Not long ago, scientists suggested that bacteria could be used to increase rainfall.

The described abilities have so far been discovered during the study of a species that has received the scientific name Pseudomonas Syringae. Scientists have previously assumed that clouds that are clear to the human eye are filled with life, and modern means, technologies and instruments have made it possible to prove this point of view. According to rough estimates, a cubic meter of cloud is filled with microbes in a concentration of 300-30,000 copies. Among others, there is the mentioned form of Pseudomonas Syringae, which provokes the formation of ice from water at a fairly high temperature. It was first discovered several decades ago while studying plants and grown in an artificial environment - it turned out to be quite simple. Currently, Pseudomonas Syringae is actively working for the benefit of humanity in ski resorts.

How does this happen?

The existence of Pseudomonas Syringae is associated with the production of proteins that cover the surface of the microscopic organism in a network. When a water molecule approaches, a chemical reaction begins, the lattice is leveled, a network appears, which causes the formation of ice. The core attracts water and increases in size and mass. If all this happened in the cloud, then the increase in weight makes it impossible to soar further and the granule falls down. The shape of precipitation is determined by the air temperature near the earth's surface.

Presumably, Pseudomonas Syringae can be used during drought periods by introducing a colony of bacteria into a cloud. Currently, scientists do not know exactly what concentration of microorganisms can provoke rain, so experiments are being carried out and samples are taken. At the same time, it is necessary to find out why Pseudomonas Syringae moves in clouds, if the microorganism normally lives on the plant.

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.

Third, 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 auxiliary 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.

What bacteria are there: types of bacteria, their classification

Bacteria are tiny microorganisms that appeared many thousands of years ago. It is impossible to see microbes with the naked eye, but we should not forget about their existence. There are a huge number of bacilli. The science of microbiology deals with their classification, study, varieties, structural features and physiology.

Microorganisms are called differently, depending on their type of action and function. Under a microscope, you can observe how these small creatures interact with each other. The first microorganisms were quite primitive in form, but their importance should in no case be underestimated. From the very beginning, bacilli developed, created colonies, and tried to survive in changing climatic conditions. Different vibrios are able to exchange amino acids in order to grow and develop normally.

Today it is difficult to say how many species of these microorganisms there are on earth (this number exceeds a million), but the most famous ones and their names are familiar to almost every person. It doesn’t matter what kind of microbes there are or what they are called, they all have one advantage - they live in colonies, which makes it much easier for them to adapt and survive.

First, let's figure out what microorganisms exist. The simplest classification is good and bad. In other words, those that are harmful to the human body cause many diseases, and those that are beneficial. Next we will talk in detail about what the main beneficial bacteria are and give their description.

You can also classify microorganisms according to their shape and characteristics. Many people probably remember that in school textbooks there was a special table depicting various microorganisms, and next to them was the meaning and their role in nature. There are several types of bacteria:

cocci - small balls that resemble a chain, as they are located one after another;
rod-shaped;
spirilla, spirochetes (have a convoluted shape);
vibrios.

Bacteria of different shapes

We have already mentioned that one of the classifications divides microbes into types depending on their forms.

Bacillus bacteria also have some characteristics. For example, there are rod-shaped types with pointed poles, thickened, rounded or straight ends. As a rule, rod-shaped microbes are very different and are always in chaos, they do not line up in a chain (with the exception of streptobacilli), and do not attach to each other (except for diplobacilli).

Microbiologists include streptococci, staphylococci, diplococci, and gonococci among spherical microorganisms. These can be pairs or long chains of balls.

Curved bacilli are spirilla, spirochetes. They are always active, but do not produce spores. Spirilla is safe for people and animals. You can distinguish spirilla from spirochetes if you pay attention to the number of whorls; they are less convoluted and have special flagella on their limbs.

Types of pathogenic bacteria

For example, a group of microorganisms called cocci, and more specifically streptococci and staphylococci, become the cause of real purulent diseases (furunculosis, streptococcal tonsillitis).

Anaerobes live and develop well without oxygen; for some types of these microorganisms, oxygen becomes fatal. Aerobic microbes require oxygen to thrive.

Archaea are practically colorless single-celled organisms.

You need to beware of pathogenic bacteria, because they cause infections; gram-negative microorganisms are considered resistant to antibodies. There is a lot of information about soil, putrefactive microorganisms, which can be harmful or beneficial.

In general, spirilla are not dangerous, but some species can cause sodoku.

Types of beneficial bacteria

Even schoolchildren know that bacilli can be useful and harmful. People know some names by ear (staphylococcus, streptococcus, plague bacillus). These are harmful creatures that interfere not only with the external environment, but also with humans. There are microscopic bacilli that cause food poisoning.

You definitely need to know useful information about lactic acid, food, and probiotic microorganisms. For example, probiotics, in other words good organisms, are often used for medical purposes. You may ask: for what? They do not allow harmful bacteria to multiply inside a person, strengthen the protective functions of the intestines, and have a good effect on the human immune system.

Bifidobacteria are also very beneficial for the intestines. Lactic acid vibrios include about 25 species. They are found in huge quantities in the human body, but are not dangerous. On the contrary, they protect the gastrointestinal tract from putrefactive and other microbes.

Speaking of good ones, one cannot fail to mention the huge species of streptomycetes. They are known to those who have taken chloramphenicol, erythromycin and similar drugs.

There are microorganisms such as azotobacter. They live in the soil for many years, have a beneficial effect on the soil, stimulate plant growth, and cleanse the soil of heavy metals. They are indispensable in medicine, agriculture, medicine, and the food industry.

Types of bacterial variability

By their nature, microbes are very fickle, they die quickly, they can be spontaneous or induced. We will not go into detail about the variability of bacteria, since this information is more interesting to those who are interested in microbiology and all its branches.

Types of bacteria for septic tanks

Residents of private houses understand the urgent need to purify wastewater, as well as cesspools. Today, you can quickly and efficiently clean drains using special bacteria for septic tanks. This is a huge relief for a person, since cleaning sewers is not a pleasant task.

We have already clarified where biological wastewater treatment is used, and now let’s talk about the system itself. Bacteria for septic tanks are grown in laboratories; they kill the unpleasant odor of wastewater, disinfect drainage wells, cesspools, and reduce the volume of wastewater. There are three types of bacteria that are used for septic tanks:

aerobic;
anaerobic;
live (bioactivators).

Very often people use combined cleaning methods. Strictly follow the instructions on the product, ensuring that the water level is conducive to the normal survival of bacteria. Also remember to use the drain at least once every two weeks to give the bacteria something to eat, otherwise they will die. Don't forget that chlorine from cleaning powders and liquids kills bacteria.

The most popular bacteria are Doctor Robic, Septifos, Waste Treat.

Types of bacteria in urine

In theory, there should be no bacteria in urine, but after various actions and situations, tiny microorganisms settle wherever they want: in the vagina, in the nose, in water, and so on. If bacteria are detected during tests, this means that the person suffers from diseases of the kidneys, bladder or ureters. There are several ways that microorganisms enter the urine. Before treatment, it is very important to examine and accurately determine the type of bacteria and the route of entry. This can be determined by biological culture of urine, when bacteria are placed in a favorable habitat. Next, the reaction of bacteria to various antibiotics is checked.

We wish you to always remain healthy. Take care of yourself, wash your hands regularly, protect your body from harmful bacteria!