The emergence of various types of bacteria. Bacteria - what diseases cause bacteria, names and species

A combination of bacteria inhabiting the human body has a general name - microbiota. In a normal, healthy microflora, there are several million bacteria. Each of them plays an important role for the normal functioning of the human body.

In the absence of any kind of useful bacteria, a person begins to get sick, the work of the gastrointestinal tract, respiratory tract is disturbed. Useful bacteria for humans are concentrated on the skin, in the intestine, on the mucous membranes of the body. The number of microorganisms is adjusted using the immune system.

Normally, the human body contains both useful and pathogenic microflora. Bacteria is useful and pathogenic.

Useful bacteria is much more. They constitute 99% of the total number of microorganisms.

With this position, the required balance is observed.

Among the various types of bacteria living on the human body can be allocated:

• bifidobacteria;
• lactobacillia;
• enterococci;
• intestinal wand.

Biofidobacteria

This type of microorganisms are the most common, involved in the process of producing lactic acid and acetate. It creates a sour Wednesday, most of the most pathogenic microbes are neutralized. Pathogenic flora ceases to develop and cause rotting and fermentation processes.

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

The synthesis of vitamin C is not without bifidobacteria. In addition, there is information that bifidobacteria helps to be absorbed by the Vitamins D and B, which are necessary for a person for normal life. If there is a deficiency of bifidobacteria, even the reception of synthetic vitamins of this group will not bring any result.

Lactobacterial

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

Lactobacteria is involved in the formation of lactic acid, lysocin, bacteriocinnes. This is an excellent help of the immune system. If there is a deficit of these bacteria in the intestines, the dysbacteriosis develops very quickly.

Lactobaccuses are populated not only the intestines, but also mucous. So these microorganisms are important for women's health. They maintain the acidity of the vagina environment, do not allow development.

Intestinal wand

Not all kinds of intestinal sticks are pathogenic. Most of them on the contrary perform a protective function. The usefulness of the genus consists in the synthesis of a quocilina, which actively opposes the bulk of the pathogenic microflora.

These bacteria are useful for the synthesis of different groups of vitamins, folic and nicotinic acid. It is impossible to underestimate their role for health. For example, folic acid is necessary for the production of red blood cells and maintaining a normal hemoglobin level.

Enterococci

They help to absorb sucrose. Upgraded mainly in the small intestine, they, like other useful non-pathogenic bacteria provide protection against excessive reproduction of malicious elements. At the same time, enterococci belong to conditionally safe bacteria.

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

Positive effect of bacteria on the body

The beneficial properties of non-pathogenic bacteria are very diverse. As long as there is a balance between the inhabitants of the intestine and mucous membranes, the human body is functioning normally.

Most bacteria participate in the synthesis and splitting processes. Without their presence, the vitamins of the group are not absorbed by the intestine, which leads to violations from the nervous system, skin diseases, lowering hemoglobin.

The bulk of non-digested components of food reached a large intestine is split precisely thanks to bacteria. In addition, microorganisms ensure the constancy of water-salt metabolism. More than half of the entire microflora participates in the regulation of suction of fatty acids, hormones.

The intestinal microflora forms local immunity. It is here that the main mass of pathogenic organisms is destroyed, a malicious microbe is blocked.

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

Useful non-pathogenic microorganisms have a positive effect on the walls of a thin and large intestine. They maintain a constant level of acidity, stimulate lymphoid apparatus, epithelium becomes resistant to different carcinogens.

Intestinal peristalsis also depends largely on what microorganisms are in it. Suppression of rotation and fermentation processes is one of the main tasks of bifidobacteria. Many microorganisms are developing in symbiosis with pathogenic bacteria, thereby controlling them.

Biochemical reactions that constantly occur with bacteria, isolated a lot of thermal energy, maintaining a common thermal balance of the body. Food microorganisms are not digested residues.

Dysbacteriosis

Dysbacteriosis - This is a change in the quantitative and high-quality composition of bacteria in the human body . At the same time, the useful organisms dying, and maliciously multiply multiplied.

Dysbacteriosis affects not only the intestines, but also mucous membranes (may be the dysbacteriosis of the oral cavity, vagina). In the analyzes will be prevailing the names: Streptococcus, Staphylococcus, micrococcus.

In normal condition, useful bacteria regulate the development of pathogenic microflora. Skin coverings, respiratory organs are usually under reliable protection. When the balance of man is disturbed, the following symptoms are disturbed: intestinal flatulence, bloating, abdominal pain, disorder.

Later, weight loss, anemia, avitaminosis can begin. From the side of the sexual system, abundant allocations are observed, often accompanied by an unpleasant odor. Irritation, roughness, cracks appear on the skin. Dysbacteriosis Side effect after receiving antibiotics.

If such symptoms are found, it is necessary to consult a doctor who will appoint a set of measures to restore normal microflora. Often this requires reception of probiotics.

Microbiology studies the structure, life activity, living conditions and the development of the smallest organisms, called microbes, or microorganisms.

"Invisible, they constantly accompany the person, invading his life as friends, as enemies," said Academician V. L. Omeliansky. Indeed, microbes are everywhere: in the air, in water and in the soil, in the human body and animals. They can be useful, and they are used in the production of many food products. They can be harmful to cause diseases of people, damage to products, etc.

Microbes were discovered by Dutch A. Levenguk (1632-1723) at the end of the XVII century, when he made the first lenses that gave an increase in 200 or more times. The microworld seen him, Levenguk described and sketched microorganisms found to them on various objects. He marked the beginning of the descriptive nature of the new science. The discovery of Louis Pasteur (1822-1895) proved that microorganisms differ not only by the form and structure, but also the peculiarities of life. Paster found that yeast cause alcohol fermentation, and some microbes are able to cause contagious diseases of people and animals. Pasteur entered the story as the inventor of the method of vaccination against rabies and Siberian ulcers. R. Koch's microbiology (1843-1910) is worldwide (1843-1910) - opened the pathogens of tuberculosis and cholera, I. I. Mechnikov (1845-1916) - developed phagocytic theory of immunity, founder of virology D. I. Ivanovsky (1864-1920), F. Gamaley (1859-1940) and many other scientists.

Classification and morphology of microorganisms

Microbes - This is the smallest, mostly unicellular living organisms visible only in the microscope. The size of microorganisms is measured in micrometers - MKM (1/1000 mm) and nanometers - nm (1/1000 microns).

Microbes are characterized by a huge variety of species, characterized by the structure, properties, the ability to exist in different conditions of the medium. They can be Unicellular, multicellular and Non-thechkival.

Microbes are divided into bacteria, viruses and phages, mushrooms, yeast. Separately distinguish the varieties of bacteria - rickettsia, mycoplasm, the simplest (protozoons) is a special group.

Bacteria

Bacteria - Preferably unicellular microorganisms in size from the tenths of the micrometer, such as mycoplasma, up to several micrometers, and the spirochete is up to 500 microns.

There are three main forms of bacteria - spherical (cocci), chopsticks (bacilli, etc.), convolutions (vibrines, spirochetes, spirillas) (Fig. 1).

Character Bacteria (Cockki) They are usually the shape of the ball, but there may be a little oval or bean-shaped. Cockki can be located apart (micrococci); pairwise (diplococci); In the form of chains (streptococci) or grape clouds (staphylococci), package (Sarcin). Streptococci can cause angina and grinding inflammation, staphylococci - various inflammatory and purulent processes.

Fig. 1. Forms of bacteria: 1 - micrococci; 2 - streptococci; 3 - sardines; 4 - wands without a dispute; 5 - chopsticks with disputes (bacillos); 6 - Vibrins; 7- spirochetes; 8 - spirillas (with flagella); Staphilococci

Chopper bacteria the most common. The sticks can be solid, to combine pairs (diplobacteria) or in chains (streptobacteria). The backed rods include intestinal wand, salmonellase pathogens, dysentery, abdominal typhoid, tuberculosis, etc.. Some rod-shaped bacteria have the ability to form under adverse conditions. disputes. Spore-forming sticks are called Bacillus. Bacills resembling the form of spindle, called Clostridia.

Sponework is a complex process. Spores differ significantly from the usual bacterial cell. They have a dense shell and a very small amount of water, they do not require nutrients, and the reproduction is completely stopped. Spores are capable of long-term drying, high and low temperatures and can be in viable state dozens and hundreds of years (disputes of Siberian ulcers, botulism, tetanus, etc.). Once upon a favorable environment, disputes germinate, i.e., turn into a conventional vegetative breeding form.

Cross bacteria May be in the form of a semicolon - vibrions, with several curls - spirillas, in the form of a thin convoluted sticks - spirochetes. The vibrios include the causative agent cholera, and the causative agent of syphilis - spirochet.

Bacterial cell It has a cell wall (shell), often covered with mucus. Often the mucus forms a capsule. The contents of the cell (cytoplasm) separates the cell membrane from the shell. The cytoplasm is a transparent protein mass in colloid state. In the cytoplasm there are ribosomes, a nuclear apparatus with DNA molecules, various inclusions of spare nutrients (glycogen, fat, etc.).

Mycoplasma - Bacteria, devoid of cell walls, need for their development in the growth factors contained in yeast.

Some bacteria can move. Movement is carried out with the help of flagellas - thin threads of different lengths performing rotational movements. The flagellas can be in the form of a single long thread or in the form of a beam, can be located along the entire surface of the bacteria. Flames have many row-shaped bacteria and almost all curved bacteria. Character bacteria, as a rule, do not have flavors, they are fixed.

Bacteria are multiplied by division into two parts. The fission rate can be very high (every 15-20 minutes), while the number of bacteria is rapidly increasing. Such rapid division is observed on food products and other substrates rich in nutrients.

Viruses

Viruses - A special group of microorganisms that do not have a cellular structure. The dimensions of the viruses are measured by nanometers (8-150 nm), so they can only be seen using an electron microscope. Some viruses consist only of protein and one of nucleic acids (DNA or RNA).

Viruses cause such common human diseases such as influenza, viral hepatitis, cortex, as well as animal diseases - lush, animal plague and many others.

Bacteria viruses are called Bacteriophages, viruses mushrooms - Mikophagami etc. Bacteriophages are found everywhere where there are microorganisms. Phages cause microbial cell death and can be used to treat and prevent certain infectious diseases.

Mushrooms are special vegetable organisms that do not have chlorophyll and do not synthesize organic matter, but need ready-made organic substances. Therefore, mushrooms are developing on various substrates containing nutrients. Some mushrooms are capable of causing plant diseases (potato cancer and phytoofer, etc.), insects, animals and humans.

Mushroom cells differ from the bacterial presence of nuclei and vacuoles and look like vegetable cells. Most often they have the form of long and branching or intertwining threads - Gifs. From gifs formed mycelium, or mushroom. Mycelium may consist of cells with one or more nuclei or be non-calm, representing one gigantic multi-cage. Fruit bodies develop on mycelium. The body of some mushrooms can consist of single cells, without the form of mycelium (yeast, etc.).

Mushrooms can multiply in different ways, including vegetative way as a result of GIF division. Most fungi multiply with sexual and sexual ways with the formation of special breeding cells - dispute. Disputes are usually able to continue to remain in the external environment. Ripe disputes can be transferred to considerable distances. Finding into the nutrient medium, disputes quickly develop in gifs.

The extensive group of mushrooms represent mold mushrooms (Fig. 2). Widely common in nature, they can grow on food products, forming well-prominent raids of different color. The reason for the spoofing of products is often the mukorovy mushrooms that form a fluffy white or gray mass. The Mukorovy Mushroom Reezopus causes a "soft rot" of vegetables and berries, and the Mushroom Botritis covers the raid and softens apples, pears and berries. Mushrooms from the kind of sheniumillium may be causative agents of products.

Separate types of mushrooms are capable not only to lead to spurry products, but also produce toxic substances for a person - mycotoxins. These include some types of mushrooms of Aspergillus, the genus Fusarium, etc.

The beneficial properties of individual species of mushrooms are used in the food and pharmaceutical industry and other industries. For example, mushrooms kind of sheniumillium are used to obtain antibiotics of penicillin and in the production of cheeses (rocochebert and kamambhem), mushrooms of Aspergillus genus - in the production of citric acid and many enzyme preparations.

Aktinomycets. - Microorganisms having signs and bacteria, and mushrooms. According to the structure and biochemical properties of actinomycetes are similar to bacteria, and by the nature of breeding, the ability to form gifs and myceliums is similar to mushrooms.

Fig. 2. Types of mold mushrooms: 1 - Singleillium; 2- Aspergillus; 3 - MORKO.

Yeast

Yeast - Unicellular fixed microorganisms with a size of no more than 10-15 microns. The shape of the yeast cage is more often round or oval, less rarely, crucible or similar to lemon. Cells of yeast with their structure are like mushrooms, they also have a kernel and vacuole. The reproduction of yeast takes place, dividing or disputes.

The yeast is widespread in nature, they can be found in the soil and on plants, in food products and various waste of production containing sugar. The development of yeast in food can lead to their spoilement, causing fermentation or zaking. Some types of yeast have the ability to turn sugar into ethyl alcohol and carbon dioxide. This process is called alcohol fermentation and is widely used in the food industry and winemaking.

Some kinds of yeast Claims cause human disease - candidiasis.

Bacteria

Bacteria, simple unicellular microscopic organisms belonging to the kingdom of Prokaryotae (prokaryo-you). They do not have a clearly selected nucleus, in most of them there is no chlorophyll. Many of them possess mobility, swim with the help of sticky flags. We multiply mainly division. In adverse conditions, many of them are able to preserve inside the dispute with high resistance due to the dense protective shells. Are divided into aerobic and anaerobic. Although pathogenic bacteria cause most human diseases, many of them are harmless or even useful for a person, since they constitute an important link of food chains; For example, they contribute to the processing of plant and animal fabrics, the transformation of nitrogen and sulfur in amino acids and other compounds that can use plants and animals. Some bacteria contains chlorophyll, and they are involved in photosynthesis. see alsoArchaebatic Eubacteria, Procarniot.

Bacteria exist in three basic forms and species: spherical (a), bearing the name of the Cockkops, Pa-Loch (Bacillus, B) and Spiral (Spirilla, C). Cockki is found in the form of lumps (staphylococci, 1), couples in two (diplococci. 2) or chains (streptococci, 3). In from the dishes from the Cockkops, which are unable to move, the bacillos are moving freely; Some of them, referred to as per randomy, are equipped with a plurality of flagella (4) and can float, and monotrile forms (5, see in Figure below) have only one Bacillus flagery can also be called disputes (6) to survive the period of adverse conditions of spirillas can Having a corkscrew shape, such as Leproquet Leplospira (7), and can be weakly curved, with flagella, such as Spirillum (8). Images are given with increasing x 5000

Bacteria do not have the kernel; Instead, they have a nucleoid (1), the only DNA loop. It contains genes, chemically encoded programs that determine the structure of the bacteria. On average bacteria have 3000 genes (for comparison: human is 100,000). The cytoplasm (2) also contains glycogen granules (food) (3) and ribosomes (4), which give the cytoplasm grainy appearance and serve to produce protein in many bacteria, it also contains the smallest genetic elements called plasmids. Most bacteria, but not all, there are hard protective walls of cages (B). They are two main types The first type has one thick (10-50 nm) layers. Bacteria with such a type of cells are called gram-positive, because they are painted in bright purple color with a gram dye. Gram-negative bacteria, as shown, have thinner walls (1) with an additional layer of proteins and lee-peids outside (2). This type of cells is not colored by purple. Such a difference in the properties finds the application of the body's protective cells in medicine recognize bacteria precisely on their walls. The cell membrane (3) surrounds the cytoplasm. It has a thickness of just a few molecules of proteins and lipids and is a barrier, thanks to which a live cell controls the receipt inside and removes various substances from it. Some bacteria move (C), using flavors (1), which are spinning at the expense of the hook (2). Energy for movement provides the flow of protons through the membrane of the cell (3), which drives a disc from protein molecules (4), located in the membrane. The rod (5) connects this protein "rotor" with a crochet with a different disk (6), which seals the cell wall.

Prior to the creation of effective systems of sanitation and the discovery of antibiotics of the epidemic of serious diseases caused by bacteria, again and again rushed in Europe, the symptoms of many bacterial diseases are caused by the effect of toxic proteins (called toxins), which are produced by bacteria. The botulin toxin produced by the Clostridium Botulinum bacterium (it causes food poisoning) is one of the strongest poisons known in our time. The tetanus isxin produced by the relative Clostridium Tetani (1) infects deep and contaminated wounds. When the nerve impulse (2) causes a voltage in the cell of the muscular tissue, the toxin blocks the relaxing part of the signal, and the muscles remain strained (which is why this disease is called a tetanus). In developed countries, the majority of killer bacteria are currently under control, tuberculosis and diphteria does not represent a serious problem. However, in developing countries, bacterial diseases still collect their deadly tribute.

Scientific and Technical Encyclopedic Dictionary.

Watch what is "bacteria" in other dictionaries:

Intestinal wand (Escherichia coli) ... Wikipedia

Bacteria - Bacteria. Contents: * Total morphology bacteria ........ 6 70 Degeneration of bacteria ............ 675 Biology bacteria .............. 676 Acidophilic bacillos ........... 677 Pigment-forming bacteria ....... 681 bacteria glowing ..... ....... 682 ... ... Big medical encyclopedia

- (from Greek. Bakterion wand), microorganisms with a prokaryotic type of the structure of the cell. Traditionally, under Actually B. imply unicellular or combined in organized groups of sticks and cocci, fixed or with flagella, opposing ... ... Biological Encyclopedic Dictionary

- (from Greek. Bakterion Wand) A group of microscopic, mostly single-cell organisms. Refer to the milking forms of prokaryotam. The basis of the modern classification of bacteria, according to which all bacteria are divided into eubacteria (gram-negative ... ... Big Encyclopedic Dictionary

A group of unicellular microscope, organisms. Together with a blue green algae, B. represent the kingdom and the talent of the prokaryotes (see), which consists of photos of photobacteria (photosynthesis) and cobster (chemosyntheses). A type… … Dictionary of microbiology

- (from Greek. Bakteria stick). Microscopic single-celled organisms having, more part, shape of sticks. A dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. Buckteria Greek, from Bakteria, stick. Passing ... ... Dictionary of foreign words of the Russian language

Modern encyclopedia

bacteria - microorganisms with the prokaryotic type of the structure of the cell, i.e. there is no nuclear sheath, the present core; dying from the effects of sun rays; Have sense of smell. Cockki spherical bacteria. Diplococci. Micrococci. Streptococci. Staffillococci. ... ... The ideographic dictionary of the Russian language

Bacteria - (from the Greek Bakterion wand), a group of microscopic predominantly single-celled organisms. Possessed the cell wall, but do not have a clearly decorated kernel. We multiply divide. In the form of cells, bacteria can be spheroid (cocci), ... ... Illustrated Encyclopedic Dictionary

- (from Greek. Bakterion stick), a group of microscopic unicellular organisms. According to the type of breathing, they are divided into aerobic and anaerobic, by type of power on autotrophic and heterotrophic. Participate in the cycle of substances in nature, performing a function ... ... Ecological Dictionary

Study history

The basics of general microbiology and studying the role of bacteria in nature were laid by Beierink Martinus Villem and Vinogradsky Sergey Nikolaevich.

The study of the structure of a bacterial cell began with the invention of an electron microscope in the 1930s. In 1937, E. Chatton proposed to share all organisms on the type of cellular structure on prokaryotm and eukaryota, and in 1961, Steinier and Van Nile finally issued this separation. The development of molecular biology led to the discovery in 1977 by K. Esid of indigenous differences and among the prokaryotes themselves: between bacteria and arches.

Structure

The overwhelming majority of bacteria (with the exception of actinomycetes and nichtal cyanobacteria) are unicellular. In the form of cells, they can be rounded (cocci), rods (bacillos, clostridium, pseudomonads), convulsions (vibrions, spirillas, spirochetes), less often with stars, tetrahedral, cubic, c- or o-shaped. The form defines the abilities of bacteria as attachment to the surface, mobility, absorption of nutrients. It is noted, for example, that oligotrophs, that is, bacteria living at low nutrient content in the medium, seek to increase the surface ratio to the volume, for example, using the formation of growth (so-called. Proshet).

Mandatory cellular structures distinguish three:

From the outside of the CPM there are several layers (cell wall, capsule, mucous case), called cell sheath, as well as surface structures (flagella, villi). CPM and cytoplasm unite together into the concept protoplast.

Structure of Protoplasta

CPM limits the contents of the cell (cytoplasm) from the external environment. Homogeneous cytoplasm fraction containing a set of soluble RNAs, proteins, products and substrates of metabolic reactions, named cytozole. Another part of the cytoplasm is represented by various structural elements.

All the genetic information necessary for life, genetic information is contained in one DNA (bacterial chromosome), most often having the shape of a covalently closed ring (linear chromosomes detected from Streptomyces. and Borrelia.). It is attached to the CPM at one point and is placed in a structure, isolated, but not separated by a membrane from the cytoplasm, and called nucleoid. DNA in an expanded state has a length of more than 1 mm. The bacterial chromosome is usually represented in a single copy, that is, almost all the prokaryotes of haploid, although under certain conditions one cell may contain several copies of its chromosome, and Burkholderia Cepacia. It has three different ring chromosomes (3.6; 3.2 and 1.1 million pairs of nucleotides). The ribosomes of prokaryitis are also different from those in eukaryotes and have a 70 S sedimentation constant (80 s in eukaryota).

In addition to these structures, spare substances can also be included in the cytoplasm.

Cell sheath and surface structures

In bacteria, there are two main types of structure of the cell wall, characteristic of gram-positive and gram-negative species.

The cell wall of gram-positive bacteria is a homogeneous layer with a thickness of 20-80 nm, built mainly of peptidoglycan with fewer Teichoic acids and a small amount of polysaccharides, proteins and lipids (the so-called lipopolysaccharide). In the cell wall there are pores with a diameter of 1-6 nm, which make it permeable for a number of molecules.

In gram-negative bacteria, the peptideoglycane layer is easily adjacent to the CPM and has a thickness of only 2-3 nm. It is surrounded by an outer membrane having, as a rule, an uneven, curved shape. Between the CPM, the layer of peptidoglycan and the external membrane there is a space called periplasmic and a solution filled with a solution that includes transport proteins and enzymes.

From the outside of the cell wall, the capsule can be - an amorphous layer that keeps the wall connection. The mucous layers do not have communication with the cell and are easily separated, the covers are not amorphous, but have a thin structure. However, between these three idealized cases there are many transitional forms.

Dimensions

The size of bacteria averages 0.5-5 microns. Weight - 4⋅10 -13. Escherichia Coli., for example, has dimensions of 0.3-1 per 1-6 microns, Staphylococcus aureus. - diameter 0.5-1 μm, Bacillus subtilis - 0.75 by 2-3 microns. The largest of the famous bacteria is Thiomargarita Namibiesisreaching a size of 750 μm (0.75 mm). The second is Epulopiscium Fishelsoni.having a diameter of 80 μm and length up to 700 microns and surgery fish digestive tract Acanthurus Nigrofuscus. Achromatium Oxaliferum reaches sizes 33 per 100 microns, Beggiatoa Alba. - 10 at 50 microns. Spioctuettes can grow up to 250 μm in length with a thickness of 0.7 microns. At the same time, bacteria belongs the smallest of organisms having the cellular structure. Mycoplasma Mycoides It has dimensions of 0.1-0.25 μm, which corresponds to the size of large viruses, for example, tobacco mosaic, cow's sieves or influenza. According to theoretical calculations, a spherical cell with a diameter of less than 0.15-0.20 microns becomes unable to independently playback, since it does not physically fit all the necessary biopolymers and structures in sufficient quantities.

With a linear increase in the radius of the cell, its surface increases in proportion to the square of the radius, and the volume is proportional to the cube, so in small organisms the surface ratio to the volume is higher than that of larger, which means for the first more active metabolism with the environment. Metabolic activity measured by different indicators per unit biomass in small forms is higher than that of large ones. Therefore, small even for microorganisms sizes give bacteria and arches advantages at the rate of growth and reproduction compared to more complex eukaryotes and determine their important environmental role.

Large milk at bacteria

The multicellular body must meet the following conditions:

• its cells must be aggregated
• between the cells the functions should be separated,
• sustainable specific contacts must be installed between aggregated cells.

The multicellularity in prokaryotm is known, the most highly organized multicellular organisms belong to groups of cyanobacteria and actinomycetes. In the thread cyanobacteria, structures in the cell wall, which ensure the contact of two adjacent cells - microplazmodesma. The possibility of exchanging between cells of substance (dye) and energy (electrical component of transmembrane potential) is shown. Some of the nital cyanobacterias contain in addition to conventional vegetative cells functionally differentiated: acintes and heterocysts. The latter carry out nitrogen fixation and are intensively exchanged metabolites with vegetative cells.

Methods of movement and irritability

Many bacteria are movable. There are several fundamentally different types of motion of bacteria. The most common movement with the help of flagella: single bacteria and bacterial associations (rod). A special case of this is the movement of spirochetes, which are wriggled due to axial threads close to the structure of flavors, but located in periplasm. Another type of movement is the slip of bacteria that do not have flavors, on the surface of solid media and the movement in the water of unagreable bacteria of the genus Synechococcus. . Its mechanism is not yet sufficiently studied; It is intended to participate in the release of mucus (pushing the cell) and in the cell wall of fibrillar yarns causing a "running wave" on the surface of the cell. Finally, bacteria can pop up and dive into liquids by changing their density, filling with gases or devastating aerosomas.

Bacteria are actively moving in the direction determined by those or other stimuli. This phenomenon got the name Taxis. They distinguish Chemotaxis, Aerhataxis, Phototaxis, etc.

Metabolism

Constructive metabolism

With the exception of some specific points, the biochemical paths for which proteins, fats, carbohydrates and nucleotides are being carried out, while bacteria are similar to those in other organisms. However, according to the number of possible variants of these paths and, accordingly, according to the degree of dependence on the receipt of organic substances from the outside they differ.

Some of these can synthesize all the organic molecules from inorganic compounds (autotrophy), others require ready-made organic compounds that they can only transform (heterotrophs).

Satisfying the need for nitrogen bacteria can be due to its organic compounds (like heterotrophic eukaryotes) and due to molecular nitrogen (like some archaea). Most bacteria are used to synthesize amino acids and other nitrogen-containing organic substances inorganic nitrogen compounds: ammonia (incoming in cells in the form of ammonium ions), nitrites and nitrates (which are pre-restored to ammonium ions). Phosphorus they are able to absorb in the form of phosphate, sulfur - as sulfate or less often sulfide.

Energy metabolism

The ways of obtaining energy in bacteria are distinguished by uniqueness. There are three types of energy production (and all three are known for bacteria): fermentation, breathing and photosynthesis.

Bacteria exercising only oxygen-free photosynthesis, do not have photosystems II. First, it is purple and green nichly bacteria, which only functions only the cyclic path of electron transfer, aimed at creating a transmembrane proton gradient, due to which the ATP (photo phosphorylation) is synthesized, and is also restored over (f) + used for CO 2 assimilation. . Secondly, these are green sulfur and heliobacteria, having both cyclic, and non-cyclic electron transport, which makes direct recovery over (f) +. As a donor of an electron filling the "vacancy" in the pigment molecule in an oxless photosynthesis, reduced sulfur compounds (molecular, hydrogen sulfide, sulfite) or molecular hydrogen are used.

There are also bacteria with very specific energy metabolism. So, in October 2008, a message about the detection of an ecosystem consisting of representatives of one single previously unknown type of bacteria appeared in the SCIENCE journal Desulforudis audaxviatorwhich receive energy for their livelihoods from chemical reactions with the participation of hydrogen formed by the decay of water molecules under the influence of radiation of the uranium ores near the colony. Some colonies of bacteria living at the bottom of the ocean are used to transmit energy to their collections electric current.

Types of Life

You can combine the types of constructive and energy metabolism in the following table:

From the table, it can be seen that the variety of pricing types is much larger than that of eukaryotes (the latter are only capable of chemorganoometerotrophy and photoolithoautrophy).

Reproduction and genetic device

Reproduction of bacteria

Some bacteria do not have a sexual process and multiply only an equilibrium binary transverse division or kill. For one group of unicellular cyanobacteria, multiple division is described (a number of fast consecutive binary divisions, leading to formation from 4 to 1024 new cells). To ensure necessary for evolution and adaptation to the changeable environment of the plasticity of the genotype, they have other mechanisms.

Genetic apparatus

The genes necessary for life and determining species specificity are located in bacteria most often in a single covalently closed DNA molecule - chromosome (sometimes to designate bacterial chromosomes to emphasize their differences from eukaryotic, the term gene to be used (English Genophore)). The area where the chromosome is localized is called a nucleoid and is not surrounded by a membrane. In this regard, new-seated mRNA is immediately available for binding to ribosomes, and transcription and broadcast are conjugate.

A separate cell may contain only 80% of the amount of genes existing in all strains of its form (t. N. "Collective genome").

In addition to chromosome, there are often plasmids in bacteria cells - also closed in a DNA ring capable of independent replication. They can be so great that it becomes indistinguishable from chromosome, but contain additional genes necessary only in specific conditions. Special distribution mechanisms ensure the preservation of plasmids in child cells so that they are lost at a frequency of less than 10 -7 in the recalculation of the cell cycle. The specificity of the plasmid can be very diverse: from the presence of only one type of owner to the plasmid RP4, which occurs in almost all gram-negative bacteria. The plasmids are encoded by mechanisms for antibiotics, the destruction of specific substances, etc., the NiF-genes needed for nitrogenation are also located in plasmids. The plasmid gene can be included in a chromosome with a frequency of about 10 -4 - 10 -7.

In DNA of bacteria, as in DNA of other organisms, transposons are distinguished - mobile segments that can move from one part of the chromosome to the other, or in extrachromosomal DNA. Unlike plasmid, they are incapable of autonomous replication and contain IS-segments - plots that encode their transfer inside the cell. The IS segment can act as a separate transposon.

Horizontal transfer of genes

Prokaryotes may occur a partial combination of genomes. When conjugation, the donor cell during direct contact transmits the recipient cell part of its genome (in some cases all). DONOR DNA sections can exchange for homologous sections of the recipient DNA. The probability of such an exchange is significant only for bacteria of one species.

Similarly, the bacterial cell can absorb and freely located in the DNA environment, including it in its genome in the event of a high degree of homology with its own DNA. This process is called transformation. In natural conditions, the exchange of genetic information is trained with moderate phages (transduction). In addition, non-chromosomal genes are possible with the help of a defined type plasmide encoding this process, the process of exchanging other plasmids and transmission transposon.

With horizontal transfer of new genes, it is not formed (as it takes place during mutations), but the creation of different gene combinations is made. This is important for the reason that natural selection is valid for the entire set of signs of the body.

Cell Differentiation

Cell differentiation is a change in protein set (usually also manifested in a change in morphology) with a constant genotype.

Education of resting forms

The formation of particularly stable forms with slow metabolism serving to conserve in adverse conditions and distribution (less often for reproduction) is the most common type of differentiation in bacteria. The most resistant of them are endospores formed by representatives Bacillus., Clostridium., Sporohalobacter., Anaerobacter. (forms 7 endospores from one cell and can multiply with their help) and Heliobacterium.. The formation of these structures begins as usual division and at the first stages can be converted into it with some antibiotics. Endospores of many bacteria are able to withstand 10-minute boiling at 100 ° C, drying for 1000 years and, according to some data, are stored in soils and rocks in a viable state of millions of years.

Less steady are exospores, cysts ( Azotobacter., sliding bacteria, etc.), acintes (cyanobacteria) and myxospheri (mix acid).

Other types of morphologically differentiated cells

Actinomycetes and cyanobacteria form differentiated cells that serve for breeding (disputes, as well as hormagonia and bayocytes, respectively). It is also necessary to note the structures similar to the bacteroids of nodule bacteria and heterocysts of cyanobacteria, which serve to protect nitrogenase from the effects of molecular oxygen.

Classification

The greatest fame received a phenotypic classification of bacteria based on the structure of their cell wall, included, in particular, in the IX edition of Berjja bacteria (1984-1987). The largest taxonomic groups in it were 4 departments: Gracilicutes. (gram-negative), Firmicutes. (gram-positive), Tenericutes. (mycoplasma) and Mendosicutes. (Archaei).

Recently, the phylogenetic classification of bacteria is obtained more and more and it is used in Wikipedia), based on molecular biology data. One of the first methods for assessing Rodance in the similarity of the genome was the method of comparing the content of guanine and cytosine in DNA in the 1960s in the 1960s. Although the same values \u200b\u200bof their content and cannot give any information about the evolutionary proximity of organisms, their differences are 10% meaning that the bacteria do not belong to one genus. Another method that produced in the 1970s real revolution in microbiology was the analysis of the sequence of genes in 16S RRNA, which made it possible to allocate several phylogenetic branches of eubacteria and evaluate the relationship between them. For a classification at the level level, a hybridization DNA DNA method is used. An analysis of the sample of well-studied species suggests that 70% of the level of hybridization characterizes one species, 10-60% is one genus, less than 10% - different genera.

Phylogenetic classification partly repeats phenotypic, so, group Gracilicutes. present in both the other. At the same time, the systematics of gram-negative bacteria has been completely revised, the archaebacteria is allocated to an independent taxon of higher rank, part of taxonomic groups are divided into parts and regrouped, organisms with completely different environmental functions are combined into one groups, which causes a number of inconvenience and discontent part of the scientific community . The object of complaints becomes also the fact that the classification of molecules is actually carried out, and not organisms.

Origin, evolution, place in the development of life on earth

Bacteria Along with Arches were one of the first living organisms on Earth, appeared about 3.9-3.5 billion years ago. Evolutionary relationships between these groups have not yet been studied, there is at least three main hypotheses: N. Pace suggests the presence of a general ancestor of protobacteria, Zavarzin considers the arche of the dead-end branch of the evolution of eubacteria that has mastered extremal habitats; Finally, according to the third hypothesis of Archai - the first living organisms from which bacteria occurred.

Pathogenic bacteria

Pathogenic is called bacteria parasitizing on other organisms. Bacteria cause a large number of human diseases such as plague ( Yersinia Pestis), anthrax ( Bacillus Anthracis), leprecha (leprosy, pathogen: Mycobacterium leprae.), diphteria ( Corynebacterium Diphtheriae.), syphilis ( Treponema Pallidum), cholera ( Vibrio Cholerae.), tuberculosis ( Mycobacterium tuberculosis), lickeriosis ( Listeria monocytogenes) and others. Opening of pathogenic properties in bacteria continues: in 1976, the disease of the legionnaires caused by Legionella Pneumophila., in the 1980s, it was shown that Helicobacter pylori. causes ulcerative disease and even stomach cancer, as well as chronic

In our world there are a huge number of bacteria. Among them are good, and there are bad. What we know better, other worse. In our article, we picked up a list of the most famous bacteria living among us and in our body. The article is written with the share of humor, so do not judge strictly.

Provides "Fais - control" in your internships

Lactobacillus (Lactobacillus Plantarum) Living in the digestive tract of a person from prehistoric times, make a big and important thing. As a garlic of vampires, they scare path-making bacteria, not letting them settle in your abdomen and bring the intestine to the disorder. Welcome! Salt cucumbers and tomatoes, sauerkraut strengthen the strength bounced, but know that heavy workouts and stress on physical exercise reduce their ranks. Add a little black currant to a protein cocktail. These berries reduce fitness stress due to antioxidants contained in them.

2. Defender Pylori Pause

Stops the attacks of hunger at 3 o'clock

Another bacteria living in the digestive tract, Helicobacter pylori, are developing with your childhood and help maintain healthy weight throughout life, controlling hormones responsible for feeling hunger! Eat 1 apple every day.

These fruits are produced in the stomach of lactic acid, in which most of the harmful bacteria does not survive, but who adore Helicobacter pylori. However, keep N. pylori in the framework, they can go against you and cause the stomach ulcers. Prepare for breakfast scrambled eggs with spinach: nitrates from these green leaves in the vests of the stomach wall, protecting it from excess of lactic acid.

3. Heat Pseudomonas Aeruginosa

Loves shower, hot tubs and pools

Living in warm water Pseudomonas Aeruginosa bacterium is closed under the skin of the skull through the pores of the hair follicles, causing an infection accompanied by itching and pain in the affected areas.

Do not want to spit a hat for swimming every time you take a bath? Reflect the invasion of a chicken chicken chicken or salmon and eggs. A large amount of protein needs folliclauses to be healthy and effectively fight in the thorny bodies. Do not forget about fatty acids that are absolutely necessary for healthy scalp. This will help you with 4 canned tuna banks or 4 medium avocado per week. No more.

4. Harmful Bacteria Corynebacterium Minutissimum

High-tech simplest

Harmful bacteria can be buried in the most unexpected places. Here, for example, Corynebacterium minutissimum, causing rash, loves to live on touchscreen phones and tablet computers. Destroy them!

Strange, but no one has yet developed a free app that fights with these microbes. But many companies produce covers for phones and tablets with antibacterial coating, which is guaranteed to stop the reproduction of bacteria. And try not to rub your hands on each other when you dry them after washing - it can reduce the population of bacteria by 37%.

5. Noble Scounding Escherichia Coli

Good bad bacteria

Escherichia coli bacterium is considered the cause of tens of thousands of infectious diseases annually. But she gives us a problem only when it finds a way to leave the colon and mutilate into the pathogenic strain. Normally, it is quite useful for life and provides the body with vitamin K, which supports the health of the arteries, preventing cardiac attacks.

To keep this frequently flashing in the titles of news, the bacteria is included in the news headers, including legumes in its diet five times a week. The fiber of beans is not cleaving, but moves into a thick intestine, where E. coli can sink on it and continue the normal cycle of reproduction. The richer fiber is black beans, then go away, or lounted and only then the usual red usual. The legumes not only hold bacteria under control, but also limit your invened appetite with their tissue, and also increase the effectiveness of nutrients to the organism.

6. Raping staphylococcusaureus

Eats youth of your skin

Most often, furuncules and acne are caused by the bacterium Staphylococcusaureus, which lives on the skin of most people. Acne is, of course, causing, but, penetrating the damaged skin inside the body, this bacterium may cause more serious diseases: pneumonia and meningitis.

Natural antibiotic dermicidin, toxic to these bacteria, is contained in the human sweat. At least once a week, include high-intensity exercises in training, trying to work 85% of the maximum possibilities. And always use a clean towel.

7. Microbe - Bifidobacterium Animalis

® lives in ferocular products

Bacteria Bifidobacterium Animalis inhabit the contents of cans with yogurt, bottles with kefir, spoken, rippled and other similar products. They reduce the time of the meal in the colon 21%. Food is not stirred, the formation of extra gases does not occur - you are less likely to know the problem under the codenate name "Pir Spirit".

Forged bacteria, for example, banana - eat it after lunch. And the lunch itself will exceed a paste with artichokes and garlic. All these foods are rich in fruitoligo - saccharides - Bifidobacterium Animalis loves this kind of carbohydrates and eat them with pleasure, after which there are multiplied with less pleasure. And with the growth of the population, your chances of normal digestion increase.

We try to give the most relevant and useful information for you and your health. Materials posted on this page are informational and are intended for educational purposes. Website visitors should not use them as medical recommendations. Determination of the diagnosis and the choice of treatment technique remains an exceptional prerogative of your attending physician! We are not responsible for the possible negative consequences resulting from the use of information posted on the site website.