Bacteria brief information. Microbes A story about bacteria 5

Bacteria are present everywhere, absolutely everywhere, in every human body there are literally countless numbers of them. But don’t let this scare you - not all bacteria are pathogenic; most of them, on the contrary, are necessary for the normal functioning of not only humans, but also other living organisms.

1. Scientists believe that there are more than a million species of bacteria in the world, although to date only about 10 thousand of them have been described and studied.
2. Although bacteria were first seen under a microscope in the second half of the 17th century, the term “bacterium” itself did not appear until 150 years later.
3. The man who discovered the connection between bacteria and disease was Louis Pasteur in 1850. His research in the field of medicine was continued by Robert Koch, who at the beginning of the 20th century became a Nobel laureate for studying the causative agents of tuberculosis.
4. All the information necessary for the life of bacteria is stored in one DNA - when unfolded, its length exceeds 1 mm.
5. Bacteria can have from zero to thousands of flagella, with the help of which they move through space.
6. Bacteria are on average 0.5 to 5 micrometers in size.
7. Bacteria are able to sink into a liquid and float to its surface, changing their density.
8. They also know how to obtain energy through respiration, fermentation and photosynthesis.
9. Bacteria appeared on the planet about 4 billion years ago and were the first living creatures to inhabit the Earth.
10. It was thanks to bacteria that oxygen began to accumulate in the Earth’s atmosphere, reaching a concentration suitable for breathing over several billion years. The accumulation of oxygen was a boon for the planet, but a real disaster for bacterial species not adapted to such an environment. These organisms either died out en masse or moved to places with an oxygen-free environment.
11. Bacteria not only cause diseases, but also participate in the formation of fertile soils, minerals, and the destruction of the bodies of dead animals and plants. Thanks to bacteria, oxygen and carbon dioxide are retained in the atmosphere.
12. It is some bacteria that cause such severe and fatal diseases as leprosy, plague, cholera, syphilis, anthrax, tuberculosis and many others.
13. Research has shown that bacteria are crucial in the formation of living organisms of any level of complexity.
14. Bacteria are the most important participants in digestion, especially in herbivores.
15. Several thousand years ago, people began to use lactic acid bacteria to make yogurt, cheese, cottage cheese and other products.
16. Bacteria that cause dangerous diseases can be used as weapons - although this is prohibited by international conventions.
17. Using bacteria, you can clean soil and water contaminated with petroleum products.
18. Every person's body is inhabited by thousands of species of bacteria. At the initial stage of human life, they help in the formation of his immunity.
19. The human intestine contains up to 2.5 kg of bacteria, the number of cells of which significantly exceeds the number of cells in the human body.
20. South Korean scientists have found that the most bacterial colonies are found on the handles of shopping carts in supermarkets (1,100 colonies per ten square centimeters). They are followed by computer mice in Internet cafes - there are half as many bacteria on door handles in public toilets.

Heat. There is a bottle of bread kvass on the table. The liquid foams. And suddenly the gas ejects the plug with a deafening noise. It is possible to understand why this gas was formed only by knowing the properties of invisible creatures - microbes

There is an abrasion on the boy's hand. He was too lazy to lubricate the wound with iodine. After a few days, a purulent tumor forms on the arm. And only a surgeon’s knife can prevent dangerous consequences. The fact is that along with the speck, microbes entered the living tissue.

A spirochete with numerous flagella was photographed using an electron microscope at a magnification of 8 thousand times.

What are microbes? These are the smallest living creatures, each of which for the most part is just one cell. Many of them can be seen in a microscope only with a magnification of at least 300-500 times. Microbes are very diverse. The most famous of them are bacteria, actinomycetes, molds, and yeasts. Microbial Science - microbiology studies mainly various bacteria, actinomycetes, as well as molds and yeasts related to fungi.

Microscopic plants - mold, or molds, are classified as microbes, despite their relatively large size and complex development. Mold consists of numerous thin branching and intertwining threads - gif. A plexus of hyphae forms mycelium; This is the body of mold, capable of growing strongly. During the development process, in certain places, special, vertically growing hyphae appear - conidiophores, on which spores are formed - conidia. Conidia are carried, like dandelion seeds, over considerable distances. When they settle on the soil or on plants, they germinate under favorable conditions: this is how new mold begins to live.

The bacterium was photographed using an electron microscope at a magnification of 17 thousand times. The compacted contents of the bacterium are surrounded by a membrane and numerous flagella - organelles of movement.

Tutu yeast, which is bought in a store is a huge accumulation of living cells. Each individual cell is so small that it can only be seen with a microscope. Most often, these cells are round or oval, their diameter is 8-10 microns, i.e. 0.008 - 0.01 mm. In many yeast species, reproduction occurs by spores. In this case, 2 or 4, and in others up to 12 dense bodies - spores are formed inside each cell. Each spore subsequently produces a new young yeast cell. Yeast also reproduces in a simpler way - by budding: a small protrusion appears in the cell, it quickly grows and forms a bud. After 20-30 minutes, the bud separates from the mother cell, and the young yeast fungus begins to live independently.

Bacteria They also belong to the plant world, although, with very rare exceptions, they do not have chlorophyll, which is characteristic of most plants. The bacteria are very small. A pinhead can accommodate hundreds or thousands of bacteria. The cell length of most rod-shaped bacteria is from 1 to 3 µm; the length of some bacteria is only 0.4 µm. Their shape is varied: balls, commas, sticks, some have flagella. Bacteria reproduce by division.

Each type of bacteria has its own specific shape. In the first three circles of the top row are cocci and streptococci; in the next four of the upper and lower rows - rod-shaped bacteria; in the next two bottom rows - vibrios; in the latter - spirilla.

Ball-shaped bacteria are called cocci. If cocci are located scatteredly, singly, they are called micrococci; if they are connected in pairs - diplococci. Cocci collected in chains are called streptococci; they resemble beads strung on a thread. Streptococci include lactic acid bacteria and bacteria that cause suppuration.

Rod-shaped bacteria are also diverse. Some cells have rounded ends, while others have blunt or pointed ends. Sticks connected in a chain are called streptobacteria. Slightly curved sticks belong to the group vibrios, more strongly curved - to spirilla

If you scrape off plaque from a tooth, place it on a piece of glass and examine it under a microscope, you can see how quickly they fly by, like snakes. spirochetes - thin threads with many curls. This spirochete is quite harmless, but among the spirochetes there are also very harmful ones, for example, the causative agent of relapsing fever.

A peculiar group of microbes are actinomycetes, or radiata fungi, usually found in the soil. Actinomycetes form long, sometimes over 600 microns, branched, very thin mycelium, its width does not exceed 0.8 microns. Actinomycetes on nutrient media form colonies, which consist of mycelium growing on the surface of the medium. In addition, they form aerial mycelium, on which conidiospores appear. With their help, actinomycetes reproduce. They can also reproduce in separate pieces of mycelium.

Most microbes cannot tolerate unfavorable environmental conditions. They die from high temperatures, ultraviolet rays, and strong chemicals. But some types of bacteria can tolerate difficult living conditions. In some bacteria, for example the tuberculosis bacillus, the body membrane is impregnated with an insulating substance resembling wax, while in others the membrane is covered with mucus. In some bacteria, under unfavorable conditions, part of the cell contents becomes compacted, dehydrated and turns into a spore with a dense shell, which is impregnated with resin-like substances, resistant to external influences and almost impenetrable to water and acids. Finding itself in favorable conditions, the spore swells, germinates and turns into a regular active bacterium. Bacteria that form spores are called bacilli.

Spore-forming microbes are common in soil. During one experiment, 94 species of different soil bacilli were examined. Of the total number of isolated bacilli, 43% did not die after five hours of boiling, 15% remained alive after spending 12 hours in boiling water, and 11% remained alive even after thirty hours of boiling. Of course, it was not the bacilli themselves that withstood such a test, but only their spores.

A microbiologist must know the needs and properties of a wide variety of bacteria, yeasts, and molds. Depending on their properties, various nutrient mixtures are prepared in laboratories on which individual types of microbes can be grown. This mixture is called nutrient medium.

Scientists have found methods for growing, or, as they say, cultivating, microbes in laboratory conditions, including the most harmful ones - the causative agents of plague, tetanus, cholera, diphtheria. Microbes are grown in a special nutrient medium - meat and fish broths and decoctions. Add gelatin or agar-agar to the broth; in this case, the nutrient medium takes on the appearance of jelly. On the surface of the jelly, spread a thin layer of a drop with soil diluted in it or another substance in which microbes live. This stage of experience is called sowing.

The microbial population of the droplet under study is more or less evenly distributed over a relatively large area. Each microbe multiplies in the place where it settles. Within a day, his numerous offspring appear around this place. You cannot see one bacterium without a microscope, but billions of them, closely adjacent to each other, occupy an area of ​​several millimeters. Such an accumulation of homogeneous microbes on the surface of a dense nutrient medium is called colony. The method of sowing on a liquid or solid nutrient medium determines the degree of microbial contamination of soil, water or food products.

A particle of an individual colony can easily be transferred into a test tube with a nutrient medium. This will already be a breeding of homogeneous microbes, which is called pure culture. The pure culture method is widely used in industry, medicine and agriculture.

It allows you not only to detect and highlight an invisible enemy, but also to prepare protective equipment against him. Active pure yeast cultures are used in bakeries, lactic acid bacteria - for the production of cheeses, lactic acid, acidophilus and many other valuable products.

Bacteria are microorganisms consisting of just one cell. A characteristic feature of bacteria is the absence of a clearly defined nucleus. That is why they are called “prokaryotes,” which means nuclear-free.

Currently, science knows about ten thousand species of bacteria, but there is an assumption that there are more than a million species of bacteria on earth. Bacteria are believed to be the most ancient organisms on Earth. They live almost everywhere - in water, soil, atmosphere and inside other organisms.

Appearance

Bacteria are very small and can only be seen with a microscope. The shape of bacteria is quite diverse. The most common forms are in the form of sticks, balls and spirals.

Rod-shaped bacteria are called "bacilli".

Bacteria in the form of balls are cocci.

Bacteria in the form of spirals are spirilla.

The shape of the bacterium determines its mobility and ability to attach to a particular surface.

Structure of bacteria

Bacteria have a fairly simple structure. These organisms have several main structures - nucleoid, cytoplasm, membrane and cell wall, in addition, many bacteria have flagella on the surface.

Nucleoid- This is something like a nucleus; it contains the genetic material of the bacterium. It consists of only one chromosome, which looks like a ring.

Cytoplasm surrounds the nucleoid. The cytoplasm contains important structures - ribosomes, necessary for bacteria to synthesize protein.

Membrane, covering the cytoplasm from the outside, plays an important role in the life of the bacterium. It delimits the internal contents of the bacterium from the external environment and ensures the processes of exchange between the cell and the environment.

The outside of the membrane is surrounded cell wall.

The number of flagella may vary. Depending on the species, one bacterium has from one to a thousand flagella, but there are bacteria without them. Bacteria need flagella to move through space.

Nutrition of bacteria

Bacteria have two types of nutrition. One part of bacteria is autotrophs, and the other is heterotrophs.

Autotrophs create their own nutrients through chemical reactions, while heterotrophs feed on organic substances that other organisms have created.

Bacteria reproduction

Bacteria reproduce by division. Before the division process, the chromosome located inside the bacterium doubles. Then the cell divides in two. The result is two identical daughter cells, each of which receives a copy of the mother's chromosome.

The importance of bacteria

Bacteria play a vital role in the cycle of substances in nature - they convert organic residues into inorganic substances. If there were no bacteria, then the entire earth would be covered with fallen trees, fallen leaves and dead animals.

Bacteria play a dual role in human life. Some bacteria are of great benefit, while others cause significant harm.

Many bacteria are pathogenic and cause various diseases, such as diphtheria, typhoid, plague, tuberculosis, cholera and others.

However, there are bacteria that benefit people. This is how bacteria live in the human digestive system, which contribute to normal digestion. And lactic acid bacteria have long been used by people to produce lactic acid products - cheeses, yogurt, kefir, etc. Bacteria also play an important role in the fermentation of vegetables and the production of vinegar.

Bacteria brief information.

Microbes are widespread in nature; huge quantities of them are found in soil, water, and air. They are truly omnipresent, found everywhere where there is life, and are human companions.

Due to their high adaptability, microbes can exist in the most incredible conditions: in strong poisons, in nuclear reactors, in hot springs and at the lowest temperatures.

The main source of the spread of microbes is the soil, where there are all conditions for their life activity - organic and mineral nutrients, moisture, protection from sunlight. Soil microbes decompose all plant residues, food waste and other simpler compounds, thereby improving soil fertility. In soil, microorganisms can remain viable for a long time, especially when dried or at low temperatures. Among them, pathogenic microbes are often found - causative agents of infectious diseases in humans and animals. From the soil, microbes are spread with dust, rain streams, and enter the air, water, and food products.

The natural habitat of microbes is water. The pathogens of many intestinal and other diseases can not only persist in it, but also develop.

Air is an unfavorable environment for the development of microorganisms due to the lack of nutrients and moisture. In addition, the sun's rays have a detrimental effect on microbes.

Microbes enter the air with dust. The cleaner the air, the fewer microbes it contains. The greatest number of microbes is contained in the air of large industrial cities, as well as in the air of closed, poorly ventilated rooms and in areas where people are very crowded. With dry cleaning, infrequent floor washing, and the presence of dirty brushes and rags in the room, the content of microbes in the air increases. Air is a source of microbial contamination of food products, equipment, etc. Microorganisms that cause influenza, tuberculosis and other diseases can be transmitted through the air. Many microbes are found on the surface of the human body, on his clothes, hands, mouth, and intestines.

Due to their small size, microbes can be carried with dust by air currents, insects and animals. Finally, a person himself, when talking, coughing or sneezing, spreads millions of microbes around him in the surrounding air, among which may be pathogens of infectious diseases of humans, plants and animals.

Microorganisms are divided into bacteria, molds, yeasts and viruses. The first three types of microorganisms are of greatest importance in the food industry. The most common and numerous group is bacteria.

Bacteria Depending on the shape, they are divided into spherical, rod-shaped and convoluted.

Globular bacteria, or cocci, most often found in nature. They differ in the nature of division and the arrangement of cells. Cocci can be single cells (micrococci), connected in pairs (diplococci), in chains (streptococci) and clusters in the form of grapes (staphylococci). Many staphylococci and streptococci cause pustular skin diseases, boils, sepsis, sore throat and a number of other diseases in humans. In addition, staphylococci, when they get on food, often cause food poisoning.

Rod-shaped bacteria have the shape of short or long shelves. They can be single, connected in pairs or in a chain. Rod-shaped bacteria include intestinal, tuberculosis, diphtheria bacilli, etc.

Twisted bacteria have a variety of shapes - from slightly curved in the shape of a comma (the causative agent of cholera) to spirals with numerous curls (the causative agent of syphilis).

Bacteria reproduce in conditions favorable for their development by dividing the cell into two parts every 20-30 minutes. Their ability to reproduce is enormous. Thus, one bacterium can produce about 70 generations per day, and after five days the resulting mass of cells can fill the basins of all seas and oceans.

Molds or fungi They are widespread in nature and are unicellular and multicellular microorganisms. Because molds require air to grow, they grow primarily on the surface of foods, forming a fluffy coating of varying colors called mycelium. The mycelium consists of thin, intertwined threads - hyphae.

Molds reproduce by spores that form at the ends of hyphae. Once on food, the spores grow into new mold. Molds develop well at low temperatures and often grow on the walls of damp warehouses; they can affect food stored in refrigerators and ice boxes.

The fight against mold is based mainly on eliminating conditions favorable to its development.

Viruses- the smallest microscopic creatures that can only be observed using an electron microscope. Viruses include the causative agents of smallpox, influenza, measles, polio, rabies, foot-and-mouth disease and other infectious diseases. Viruses can also infect animals and plants.

Today, every adult and most children know that we are surrounded by billions of microscopically small creatures called microbes.


They live literally everywhere: in the air we breathe, in the water we drink, on an apple plucked from a branch, and on the fur of a domestic cat. But does everyone have a good idea of ​​what microbes are and how dangerous they are, and most importantly, is it worth waging an uncompromising, widespread war against them?

What are microbes?

Before answering the question of what microbes are, we should remember the Dutch optician Anton Leeuwenhoek, who made his living by grinding magnifying glasses. One day Leeuwenhoek decided to create a special device that would magnify small objects by more than a hundred times.

When the device (later called a microscope) was ready, the experimenter began to examine various objects with its help. Imagine his surprise when, in a drop of ordinary water, he discovered many small creatures that were actively swimming, colliding and even eating each other. Leeuwenhoek called these creatures microbes, which means "tiniest creature".

In a word "germs" It is customary to call all living beings that are indistinguishable without a microscope, except for viruses. Their sizes range from fractions of a micron to several microns. Some are multicellular organisms, but most are made up of just one cell.

Today scientists know that microbes are the most ancient living beings. They have existed for more than three and a half billion years, of which for about a billion years they were the only inhabitants of the Earth.

Diversity of microbes

The world of microscopic creatures living on our planet is extremely diverse. Microbes include:

- bacteria;

- protozoa - amoebas, etc.;

- microscopic fungi.

It is believed that bacteria belong to the class of plants, protozoa and fungi - to "protozoa", relatively speaking, are of animal origin.

Microbes are distinguished by their shape. For example, the ending -cocci is added to the names of round bacteria: staphylococci, streptococci, etc. Spiral-shaped microbes are called spirochetes, rod-shaped ones are called bacilli. The outlines of bifidobacteria are similar to a two-pronged fork.


Some microbes have bizarre shapes, resembling multi-rayed stars, triangles and other geometric shapes. Some of them are motionless and cannot move, while others have special flagella, with the help of which they swim quite quickly in liquid.

How dangerous are microbes?

Once in an environment favorable to themselves, microbes begin to actively multiply, trying to fill all the space suitable for their existence. Since they reproduce, as is known, by division, their number increases many times over in a very short period of time. If reproduction occurs in the physiological fluids of the human body, then the increased number of microbes can have an extremely negative impact on a person’s well-being.

The fact is that for their vital functions they use nutrients intended for the cells of the body, and thereby disrupt the normal functioning of organs. Moreover, in the process of life they release toxic substances that have an extremely adverse effect on the body. And the more of them appear, the worse a person feels.

To fight microbes in the human body, there is a whole set of protective means: an increase in temperature, an increase in the number of leukocytes in the blood that remove toxins, as well as special bacteriophage cells that are able to attack bacteria and destroy them, preventing them from multiplying. But if the body is weakened, it cannot produce protective substances quickly and in sufficient quantities - and then the person gets sick.

It could be a common cold or an upset stomach that goes away quickly, causing only mild discomfort. But many diseases caused by bacteria are very dangerous and can lead to death: scarlet fever, malaria, cholera, tuberculosis, etc. Severe diseases are caused by staphylococci - spherical bacteria that cause serious inflammatory processes in tissues.


To avoid many diseases, you should follow simple rules: wash your hands often, do not eat unwashed vegetables and fruits, do not drink untreated or unboiled water, keep your home clean and keep things in order. Well, if you happen to get sick and the doctor prescribes antibiotics - special medicines that destroy bacteria, then you need to take the entire course of medicine, without quitting treatment in the middle.