Preparation for the OGE in biology. Bacteria and viruses: theory and practice

Currently, more than 2.5 million species of living organisms have been described on Earth. However, the actual number of species on Earth is several times greater, since many types of microorganisms, insects, etc. are not taken into account. In addition, it is believed that the modern species composition is only about 5% of the species diversity of life during the period of its existence on Earth.
Systematics, classification and taxonomy serve to streamline such a variety of living organisms.

Systematics - a branch of biology that deals with the description, designation and classification of existing and extinct organisms by taxa.
Classification - the distribution of the entire set of living organisms according to a certain system of hierarchically subordinate groups - taxa.
Taxonomy - a section of systematics that develops the theoretical foundations of classification. A taxon is a group of organisms artificially isolated by man, related to one degree or another, and at the same time sufficiently isolated so that it can be assigned a certain taxonomic category of one or another rank.

In the modern classification, there is the following hierarchy of taxa:

kingdom;
department (type in animal taxonomy);
Class;
order (order in animal taxonomy);
family;

In addition, intermediate taxa are distinguished: over- and sub-kingdoms, over- and subdivisions, over- and subclasses, etc.

The taxonomy of living organisms is constantly changing and updating. It currently looks like this:

Non-cellular forms

Kingdom Viruses

Cell forms

The kingdom of Prokaryota (Procariota):

kingdom of bacteria Bacteria, Bacteriobionta),
kingdom of Archaebacteria Archaebacteria, Archaebacteriobionta),
kingdom Prokaryotic algae

department Blue-green algae, or Cyanei ( Cyanobionta);
department Prochlorophyte algae, or Prochlorophytes ( Prochlororhyta).

Kingdom of Eukaryotes (Eycariota)

plant kingdom ( Vegetabilia, Phitobiota or Plantae):

subkingdom of Bagryanka ( Rhodobionta);
sub-kingdom True algae ( Phycobionta);
sub-kingdom Higher plants ( Embryobionta);

Kingdom of Mushrooms Fungi, Mycobionta, Mycetalia or Mycota):

subkingdom Lower fungi (unicellular) ( Myxobionta);
subkingdom Higher fungi (multicellular) ( Mycobionta);

animal kingdom ( Animalia, Zoobionta)

subkingdom Protozoa, or Unicellular ( Protozoa, Protozoobionta);
subkingdom Multicellular ( Metazoa, Metazoobionta).

A number of scientists single out one kingdom of Drobyanka in the super-kingdom of Prokaryotes, which includes three sub-kingdoms: Bacteria, Archaebacteria and Cyanobacteria.

Viruses, bacteria, fungi, lichens

Kingdom of viruses

Viruses exist in two forms: resting(extracellular), when their properties as living systems do not manifest themselves, and intracellular when viruses replicate. Simple viruses (for example, tobacco mosaic virus) consist of a nucleic acid molecule and a protein shell - capsid.

Some more complex viruses (influenza, herpes, etc.), in addition to capsid proteins and nucleic acids, may contain a lipoprotein membrane, carbohydrates, and a number of enzymes. Proteins protect the nucleic acid and determine the enzymatic and antigenic properties of viruses. The shape of the capsid can be rod-shaped, filiform, spherical, etc.

Depending on the nucleic acid present in the virus, RNA-containing and DNA-containing viruses are distinguished. Nucleic acid contains genetic information, usually about the structure of the proteins of the capsid. It can be linear or circular, in the form of single or double stranded DNA, single or double stranded RNA.

The virus that causes AIDS (Acquired Immune Deficiency Syndrome) infects the blood cells that provide immunity to the body. As a result, an AIDS patient can die from any infection. AIDS viruses can enter the human body during sexual intercourse, during injections or operations if sterilization conditions are not followed. Prevention of AIDS consists in avoiding casual sex, using condoms, and using disposable syringes.

bacteria

All prokaryotes belong to the same kingdom of Drobyanka. It contains bacteria and blue-green algae.

The structure and activity of bacteria.

Prokaryotic cells do not have a nucleus, the location of DNA in the cytoplasm is called a nucleoid, the only DNA molecule is closed in a ring and is not associated with proteins, cells are smaller than eukaryotic cells, the cell wall contains a glycopeptide - murein, a mucous layer is located on top of the cell wall, which performs a protective function, there are no membrane organelles (chloroplasts, mitochondria, endoplasmic reticulum, Golgi complex), their functions are performed by invaginations of the plasma membrane (mesosomes), ribosomes are small, microtubules are absent, therefore the cytoplasm is motionless, there are no centrioles and division spindle, cilia and flagella have a special structure. Cell division is carried out by constriction (there is no mitosis and meiosis). This is preceded by DNA replication, then the two copies diverge, carried along by the growing cell membrane.

There are three groups of bacteria: archaebacteria, eubacteria and cyanobacteria.

archaebacteria- the most ancient bacteria (methane-forming, etc., about 40 species are known in total). They have common structural features of prokaryotes, but differ significantly in a number of physiological and biochemical properties from eubacteria. eubacteria- true bacteria, a later form in evolutionary terms. Cyanobacteria (cyanoea, blue-green algae)- phototrophic prokaryotic organisms that carry out photosynthesis like higher plants and algae with the release of molecular oxygen.

The following groups of bacteria are distinguished according to the shape of the cells: spherical - cocci, rod-shaped - bacilli, arcuately curved - vibrios, spiral - spirilla and spirochetes. Many bacteria are capable of independent movement due to flagella or due to cell contraction. Bacteria are unicellular organisms. Some are able to form colonies, but the cells in them exist independently of each other.

Under unfavorable conditions, some bacteria are able to form spores due to the formation of a dense shell around the DNA molecule with a portion of the cytoplasm. Bacterial spores are not used for reproduction, as in plants and fungi, but to protect the body from the effects of adverse conditions (drought, heating, etc.).

In relation to oxygen, bacteria are divided into aerobes(requires oxygen) anaerobes(dying in the presence of oxygen) and optional forms.

According to the mode of nutrition, bacteria are divided into autotrophic(carbon dioxide is used as a carbon source) and heterotrophic(using organic matter). Autotrophic, in turn, are divided into phototrophs(use the energy of sunlight) and chemotrophs(use the energy of oxidation of inorganic substances). The phototrophs are cyanobacteria(blue-green algae), which carry out photosynthesis, like plants, with the release of oxygen, and green and purple bacteria which carry out photosynthesis without the release of oxygen. Chemotrophs oxidize inorganic substances ( nitrifying bacteria, nitrogen-fixing bacteria, iron bacteria, sulfur bacteria, etc.).

Reproduction of bacteria.

Bacteria reproduce asexually - cell division(prokaryotes do not have mitosis and meiosis) with the help of constrictions or partitions, less often by budding. These processes are preceded by the duplication of the circular DNA molecule.

In addition, bacteria are characterized by a sexual process - conjugation. When conjugated through a special channel formed between two cells, a DNA fragment of one cell is transferred to another cell, that is, the hereditary information contained in the DNA of both cells changes. Since the number of bacteria does not increase, for correctness, the concept of "sexual process" is used, but not "sexual reproduction".

The role of bacteria in nature and the importance for humans

Thanks to a very diverse metabolism, bacteria can exist in a variety of environmental conditions: in water, air, soil, and living organisms. The role of bacteria is great in the formation of oil, coal, peat, natural gas, in soil formation, in the cycles of nitrogen, phosphorus, sulfur and other elements in nature. Saprotrophic bacteria participate in the decomposition of organic remains of plants and animals and in their mineralization to CO 2 , H 2 O, H 2 S, NH 3 and other inorganic substances. Together with fungi, they are decomposers. Nodule bacteria(nitrogen-fixing) form a symbiosis with leguminous plants and are involved in the fixation of atmospheric nitrogen into mineral compounds available to plants. Plants themselves do not have this ability.

A person uses bacteria in microbiological synthesis, in sewage treatment plants, to obtain a number of drugs (streptomycin), in everyday life and in the food industry (obtaining fermented milk products, winemaking).

kingdom mushrooms

General characteristics of mushrooms. Mushrooms are isolated in a special kingdom, numbering about 100 thousand species.

Differences between mushrooms and plants:

heterotrophic mode of nutrition
storage nutrient glycogen
the presence of chitin in the cell walls

Differences between mushrooms and animals:

unlimited growth
absorption of food by suction
reproduction by spores
the presence of a cell wall
inability to actively move
The structure of mushrooms is diverse - from unicellular forms to complex hat forms.

Lichens

The structure of lichens. Lichens number more than 20 thousand species. These are symbiotic organisms formed by a fungus and an algae. At the same time, lichens are a morphologically and physiologically integral organism. The body of the lichen consists of intertwined hyphae of the fungus, between which algae (green or blue-green) are located. Algae carry out the synthesis of organic substances, and fungi absorb water and mineral salts. Depending on body structure thallus ) distinguish three groups of lichens: scale , or cortical(thallus has the appearance of plaques or crusts, tightly growing together with the substrate); foliate (in the form of plates attached to the substrate with bunches of hyphae); bushy (in the form of stems or ribbons, usually branched and growing together with the substrate only at the base). Lichen growth is extremely slow - only a few millimeters per year.

Lichen reproduction carried out either sexually (due to the fungal component), or asexually (formation of spores or breaking off pieces of the thallus).
The meaning of lichens. Due to their "dual" nature, lichens are very hardy. This is due to the possibility of both autotrophic and heterotrophic nutrition, as well as the ability to fall into a state of suspended animation, in which the body is severely dehydrated. In this state, lichens can tolerate the action of various adverse environmental factors (severe overheating or hypothermia, the almost complete absence of moisture, etc.). Biological features allow lichens to populate the most unfavorable habitats. They are often pioneers in the settlement of a particular land area, destroy rocks and form the primary soil layer, which is then mastered by other organisms.
At the same time, lichens are very sensitive to environmental pollution by various chemicals, which allows them to be used as bioindicators environmental conditions.
Lichens are used to obtain medicines, litmus, tannins and dyes. Yagel (reindeer moss) is the main food for reindeer. Some peoples eat lichens for food. Since the growth of lichens is very slow, measures are needed to protect it: regulation of reindeer grazing, orderly movement of vehicles, etc.

About which Gwyneth Paltrow's lifestyle resource Goop wrote - the most impossible from the world of healthy lifestyle at the moment, then you thought not quite right. Simply because now we will talk about something even stranger. What is most interesting is that Goop is not involved in the “new probiotics” business. And only science is involved.

According to Live Science, recent experiments have shown that types of bacteria isolated from children's feces can promote the production of short-chain fatty acids (SCFA) in mice and in an environment that mimics the human intestine.

SCFA molecules, recall, are a subset that are produced by certain types of microorganisms in the gut during the fermentation process. According to numerous studies, they should be associated with maintaining intestinal health and protection against a number of diseases.

"Short-chain fatty acids are a key component of normal gut function," lead study author Hariom Yadav, a molecular medicine specialist at the Wake Forest School of Medicine, wrote in Scientific Reports. - Patients with diabetes, obesity, autoimmune disorders and cancer often have fewer short-chain fatty acids. Increasing them may be beneficial in maintaining or even restoring a normal intestinal environment and hopefully improving health.”

Fecal microbiota transplants (or “fecal transplants”), the researchers suggest, can treat a wide variety of gut disorders by addressing imbalances in microbial diversity. The scientists explain that they chose to use infant microbes for the simple reason that infants' gut microbiome is generally free of . And also, the authors of the study add half-jokingly, because this material is always in abundance.

During the experiments, they isolated 10 bacterial strains - five species of Lactobacillus and five species of Enterococcus, obtained from 34 "candidates". They then tested different doses of the 10-bacterial probiotic blend in mice and found that even low doses maintained a healthy microbial balance by increasing SCFA production.

"Our results suggest that human-derived probiotics can be used to treat diseases associated with gut microbiome imbalances and short-chain fatty acid deficiencies in the gut," comments Yadav. However, much more research will be needed before unusual probiotics hit store shelves. But this seems to be a good thing.

Vaccination

Remembering the heated debates on the issues of evolution and vitalism, we must not forget that people's interest in theoretical biology arose as a result of intensive medical studies, persistent study of functional disorders in the body. No matter how fast biological science developed in theoretical terms, no matter how far it moved away from the daily needs of practice, sooner or later it had to return to the needs of medicine.
The study of theory is by no means something abstract and unjustified, since the introduction of the achievements of theoretical science allows practice to move forward rapidly. And although applied science can develop purely empirically, without theory this development is much slower and more uncertain.
As an example, consider the history of the study of infectious diseases. Until the beginning of the 19th century. doctors, in fact, were completely helpless during epidemics of plague or other infectious diseases that flared up on our planet from time to time. Smallpox is one of the diseases from which mankind suffered. It was tragic that it spread like a real natural disaster, every third of the sick died, and the survivors remained disfigured for life: faces covered with mountain ash repelled even loved ones.
However, it has been observed that the past illness provided immunity in the next outbreak. Therefore, many considered it more expedient not to avoid the disease, but to endure it, but in a very weak form that would not be life-threatening and would not disfigure the patient. In this case, the person would be guaranteed against repeated diseases. In countries such as Turkey and China, they have long tried to infect people with the contents of pustules from patients with a mild form of smallpox. The risk was great, because sometimes the disease proceeded in a very severe form. At the beginning of the XVIII century. similar vaccinations were carried out in England, but it is difficult to say whether they brought more benefit or harm. Being engaged in practical medical activities, the Englishman Edward Jenner (1749–1823) studied the protective properties of cowpox known in folk medicine: people who have had it become immune to both cowpox and human smallpox. After long and careful observation, on May 14, 1796, Jenner performed the first cowpox inoculation on an eight-year-old boy, using material taken from a woman with cowpox. The vaccination was accompanied by malaise. And two months later, the boy was infected with pus from the pustule of a smallpox patient - and remained healthy. In 1798, after repeating this experience many times, Jenner published the results of his work. He suggested calling the new method vaccination (from the Latin vaccinia - cowpox).
The fear of smallpox was so great that Jenner's method was accepted with enthusiasm, and the resistance of the most conservative was quickly broken. Vaccination spread throughout Europe and the disease receded. In countries with highly developed medicine, doctors no longer felt helpless in the fight against smallpox. In the history of mankind, this was the first case of a quick and radical victory over a dangerous disease.
But only the development of the theory could bring further success. At that time, no one knew the causative agents of infectious diseases; it was not necessary to count on the use of mild forms for vaccination purposes. The task for biologists was to learn how to "make" their own "variants" of milder forms of the disease, but this required knowing much more than was known in Jenner's day.

germ theory of disease

Bacteriology

It is impossible to hope that someday it will be possible to completely isolate people from pathogenic microbes. Sooner or later, a person is at risk of infection. How to treat the patient? Of course, the body has its own means of fighting microbes: after all, as you know, sometimes a patient recovers even without assistance. The outstanding Russian biologist Ilya Ilyich Mechnikov (1845–1916) succeeded in illustrating such an “antibacterial struggle” of the organism. He showed that leukocytes perform the function of protection against pathogenic agents that have entered the body of animals and humans: they leave the blood vessels and rush to the site of infection, where a real battle of white blood cells with bacteria unfolds. Cells that perform a protective role in the body, Mechnikov called phagocytes.
In addition, recovery from many diseases is accompanied by the development of immunity (immunity), although no visible changes are found. This could be quite logically explained by the fact that antibodies are formed in the body of the ill person that have the ability to kill or neutralize the invading microbes. This view also explains the effect of vaccination; in the body of the vaccinated, antibodies are formed that are active against both the cowpox microbe and the smallpox microbe, which is very similar to it. Now victory is assured, but not over the disease itself, but over the microbe that causes it.
Pasteur outlined ways to fight anthrax, a deadly disease that was destroying herds of domestic animals. He found the causative agent of the disease and proved that it belongs to a special type of bacteria. Pasteur heated a preparation of bacteria to destroy their ability to cause disease (pathogenicity). The introduction of weakened (attenuated) bacteria into the body of an animal led to the formation of antibodies capable of resisting the original pathogenic bacteria.
In 1881, Pasteur staged an extremely revealing experiment. For the experiment, a herd of sheep was taken, one part of which was injected with weakened anthrax bacteria, and the other remained unvaccinated. After some time, all the sheep were infected with pathogenic strains. The vaccinated sheep showed no signs of the disease; unvaccinated sheep contracted anthrax and died.
Similar methods were used by Pasteur to fight chicken cholera and, most significantly, with one of the most terrible diseases - rabies (or rabies), transmitted to humans from infected wild or domestic animals.
The success of Pasteur's germ theory revived interest in bacteria. The German botanist Ferdinand Julius Kohn (1828–1898) studied plant cells under a microscope. He showed, for example, that the protoplasms of plant and animal cells are essentially identical. In the 60s of the XIX century, he turned to the study of bacteria. Cohn's greatest merit was the establishment of the vegetable nature of bacteria. He was the first to clearly separate bacteria from protozoa and tried to systematize bacteria according to genera and species. This allows us to consider Kohn the founder of modern bacteriology.
Cohn was the first to notice the talent of the young German physician Robert Koch (1843–1910). In 1876, Koch isolated the bacterium that causes anthrax and learned how to grow it. The support of Cohn, who became acquainted with the work of Koch, played an important role in the life of the great microbiologist. Koch cultivated bacteria on a solid medium - gelatin (which was later replaced by agar, extracted from seaweed), and not in a liquid poured into test tubes. This technical improvement has brought many advantages. In a liquid environment, bacteria of different types mix easily, and it is difficult to determine which one causes a particular disease. If the culture is applied as a smear on a solid medium, individual bacteria, dividing many times, form colonies of new cells, strictly fixed in their position. Even if the initial culture consists of a mixture of different types of bacteria, each colony is a pure cell culture, which allows you to accurately determine the type of pathogenic microbes. Koch first poured the medium onto a flat piece of glass, but his assistant Julius Richard Petri (1852–1921) replaced the glass with two flat, shallow glass cups, one of which served as a lid. Petri dishes are still widely used in bacteriology. Using the developed method for isolating pure microbial cultures, Koch and his collaborators isolated the causative agents of many diseases, including tuberculosis (1882).

Insects

Nutrition Factors

During the last third of the last century, the germ theory dominated the minds of most doctors, but there were those who held a different opinion. The German pathologist Virchow - the most famous opponent of Pasteur's theory - believed that diseases were caused by a disorder in the body itself rather than external agents. Virchow's merit was that over several decades of work in the Berlin municipality and national legislatures, he achieved such serious improvements in the field of hygiene as the purification of drinking water and the creation of an effective system for the disinfection of wastewater. Another scientist, Pettenkofer, did a lot in this area. He and Virchow can be considered the founders of modern social hygiene (the study of disease prevention in human society).
Such measures to prevent the spread of epidemics, of course, were no less important than the direct impact on the microbes themselves.
Naturally, the concern for cleanliness, which Hippocrates preached, retained its significance even when the role of microbes became clear to everyone. The advice of Hippocrates regarding the need for a full and varied diet remained in force, and their importance was revealed not only for maintaining health in general, but also as a specific method for preventing certain diseases. The idea that malnutrition could be the cause of disease was considered "old-fashioned" - scientists were obsessed with microbes - but it was supported by fairly strong evidence.
During the Age of Discovery, people spent long months on board ships, eating only those foods that could be well preserved, since the use of artificial cold was not yet known. The terrible scourge of sailors was scurvy. The Scottish physician James Lind (1716-1794) drew attention to the fact that diseases are found not only on board ships, but also in besieged cities and prisons - everywhere where food is monotonous. Perhaps the disease is caused by the absence of any product in the diet? Lind tried to diversify the diet of sailors suffering from scurvy, and soon discovered the healing effect of citrus fruits. The great English navigator James Cook (1728–1779) introduced citrus fruits into the diet of the crew of his Pacific expeditions in the 70s of the 18th century. As a result, only one person died of scurvy. In 1795, during the war with France, the sailors of the British Navy began to give lemon juice, and not a single case of scurvy was recorded.
However, such purely empirical achievements, in the absence of the necessary theoretical justifications, were introduced very slowly. In the 19th century major discoveries in the field of nutrition related to the role of protein. It was found that some proteins, "complete", present in the diet, can support life, others, "inferior", like gelatin, are not able to do this. The explanation came only when the nature of the protein molecule was better known. In 1820, having treated a complex molecule of gelatin with acid, a simple molecule was isolated from it, which was called glycine. Glycine belongs to the class of amino acids. Initially, it was assumed that it serves as a building block for proteins, just as a simple sugar, glucose, is a building block from which starch is built. However, by the end of the XIX century. this theory was found to be untenable. Other simple molecules were obtained from a wide variety of proteins - all of them, differing only in details, belonged to the class of amino acids. The protein molecule turned out to be built not from one, but from a number of amino acids. By 1900, dozens of different amino acid building blocks were known. Now it no longer seemed incredible that proteins differ in the ratio of amino acids they contain. The first scientist to show that a particular protein may not have one or more amino acids that play an essential role in the life of an organism was the English biochemist Frederick Gowland Hopkins (1861–1947). In 1903, he discovered a new amino acid - tryptophan - and developed methods for its detection. Zein, a protein isolated from corn, was negative and therefore did not contain tryptophan. It turned out to be an inferior protein, since, being the only protein in the diet, it did not provide the vital activity of the organism. But even a small addition of tryptophan made it possible to prolong the life of experimental animals.
Subsequent experiments, carried out in the first decade of the 20th century, clearly showed that certain amino acids are synthesized in the mammalian organism from substances normally found in tissues. However, some of the amino acids must be supplied with food. The absence of one or more of these "essential" amino acids makes the protein defective, leading to illness and sometimes death. Thus, the concept of additional nutritional factors was introduced - compounds that cannot be synthesized in the body of animals and humans and must be included in food to ensure normal life.
Strictly speaking, amino acids are not a serious medical problem for nutritionists. Lack of amino acids usually occurs only with artificial and monotonous nutrition. Natural food, even if it is not very rich, provides the body with a sufficient variety of amino acids.
Since a disease such as scurvy is cured by lemon juice, it is reasonable to assume that lemon juice supplies the body with some missing nutritional factor. It is unlikely that it is an amino acid. Indeed, all known biologists of the XIX century. the ingredients of lemon juice, taken together or separately, could not cure scurvy. This food factor had to be a substance needed only in very small quantities and chemically different from the usual components of food.
Finding the mysterious substance was not so difficult. After the development of the doctrine of essential amino acids for life, more subtle nutritional factors were identified that the body needs only in trace amounts, but this did not happen in the process of studying scurvy.

vitamins

In 1886, the Dutch physician Christian Eijkman (1858–1930) was sent to Java to fight beriberi. There were reasons to think that this disease arises as a result of malnutrition. Japanese sailors suffered greatly from beriberi and stopped getting sick only when, in the 80s of the 19th century, milk and meat were introduced into their diet, which consisted almost exclusively of rice and fish. Aikman, however, being captivated by Pasteur's germ theory, was convinced that beriberi was a bacterial disease. He brought chickens with him, hoping to infect them with germs. But all his attempts were unsuccessful. True, in 1896, chickens suddenly fell ill with a disease similar to beriberi. Finding out the circumstances of the disease, the scientist found that just before the outbreak of the disease, chickens were fed polished rice from the hospital food warehouse. When they were transferred to the old food, recovery began. Gradually, Aikman became convinced that this disease could be caused and cured by a simple change in diet.
At first, the scientist did not appreciate the true significance of the data obtained. He suggested that the grains of rice contain some kind of toxin, which is neutralized by something contained in the shell of the grain, and since the shell is removed when the rice is peeled, unneutralized toxins remain in the polished rice. But why create a hypothesis about the presence of two unknown substances, a toxin and an antitoxin, when it is much easier to assume that there is some kind of nutritional factor needed in negligible amounts? This opinion was shared by Hopkins and the American biochemist Casimir Funk (born in 1884). They suggested that not only beriberi, but also such diseases as scurvy, pellagra and rickets, are explained by the absence of the smallest amounts of certain substances in food.
Still under the impression that these substances belong to the class of amines, Funk proposed in 1912 to call them vitamins (the amines of life). The name has taken root and has been preserved to this day, although it has since become clear that they have nothing to do with amines.
Vitamin hypothesis Hopkins - Funk was fully formulated, and the first third of the XX century. showed that various diseases can be cured by the appointment of a reasonable diet and diet. For example, the American physician Joseph Goldberger (1874–1929) discovered (1915) that the pellagra disease common in the southern states of the United States was by no means of microbial origin. In fact, it was caused by the absence of some vitamin and disappeared as soon as milk was added to the diet of patients. Initially, vitamins were known only that they were able to prevent and treat certain diseases. In 1913, the American biochemist Elmer Vernon McCollum (born in 1879) suggested that vitamins be called letters of the alphabet; this is how vitamins A, B, C and D appeared, and then vitamins E and K were added to them. It turned out that food containing vitamin B actually contains more than one factor that can affect more than one symptom complex. Biologists started talking about vitamins B1, B2, etc.
It turned out that it was the lack of vitamin B1 that caused beriberi, and the lack of vitamin B2 caused pellagra. Lack of vitamin C led to scurvy (the presence of small amounts of vitamin C in citrus juice explains their healing effect, which allowed Lind to cure scurvy), lack of vitamin D to rickets. Lack of vitamin A affected vision and caused night blindness. Vitamin B12 deficiency caused malignant anemia. These are the main diseases caused by vitamin deficiency. With the accumulation of knowledge about vitamins, all these diseases ceased to be a serious medical problem. Since the 30s of the 20th century, vitamins in their pure form began to be isolated and synthesized.

Morphology of bacteria, structure of a prokaryotic cell.

In prokaryotic cells there is no clear boundary between the nucleus and the cytoplasm, there is no nuclear membrane. The DNA in these cells does not form structures similar to eukaryotic chromosomes. Therefore, prokaryotes do not undergo the processes of mitosis and meiosis. Most prokaryotes do not form membrane-bound intracellular organelles. In addition, prokaryotic cells do not have mitochondria and chloroplasts.

bacteria, as a rule, are unicellular organisms, their cell has a rather simple shape, it is a ball or cylinder, sometimes curved. Bacteria reproduce mainly by dividing into two equivalent cells.

spherical bacteria called cocci and can be spherical, ellipsoidal, bean-shaped, and lanceolate.

According to the arrangement of cells relative to each other after division, cocci are divided into several forms. If, after cell division, the cells diverge and are located one by one, then such forms are called monococci. Sometimes cocci, when dividing, form clusters resembling a bunch of grapes. Similar forms are staphylococcus. Cocci remaining in the same plane after division in bound pairs are called diplococci, and generators of different chain lengths - streptococci. Combinations of four cocci that appear after cell division in two mutually perpendicular planes are tetracocci. Some cocci divide in three mutually perpendicular planes, which leads to the formation of peculiar clusters of a cubic shape called sardines.

Most bacteria have cylindrical, or rod-shaped, shape. Rod-shaped bacteria that form spores are called bacilli, and not forming disputes - bacteria.

Rod-shaped bacteria differ in shape, size in length and diameter, the shape of the ends of the cell, as well as in mutual arrangement. They can be cylindrical with straight ends or oval with rounded or pointed ends. Bacteria are also slightly curved, filamentous and branching forms are found (for example, mycobacteria and actinomycetes).

Depending on the mutual arrangement of individual cells after division, rod-shaped bacteria are divided into rods proper (single arrangement of cells), diplobacteria or diplobacilli (paired arrangement of cells), streptobacteria or streptobacilli (form chains of various lengths). Often there are convoluted, or spiral, bacteria. This group includes spirilla (from lat. spira - a curl), having the form of long curved (from 4 to 6 turns) sticks, and vibrios (lat. vibrio - I bend), which are only 1/4 of a spiral coil, similar to a comma .

Filamentous forms of bacteria living in water bodies are known. In addition to those listed, there are multicellular bacteria that carry ethical outgrowths on the surface of protoplasmic cells - prostecs, triangular and star-shaped bacteria, as well as worm-shaped bacteria that have the shape of a closed and open ring.

Bacterial cells are very small. They are measured in micrometers, while fine structure details are measured in nanometers. Cocci usually have a diameter of about 0.5-1.5 microns. The width of rod-shaped (cylindrical) forms of bacteria in most cases ranges from 0.5 to 1 microns, and the length is several micrometers (2-10). Small sticks have a width of 0.2-0.4 and a length of 0.7-1.5 microns. Among bacteria, real giants can also be found, the length of which reaches tens and even hundreds of micrometers. The shapes and sizes of bacteria vary significantly depending on the age of the culture, the composition of the medium and its osmotic properties, temperature, and other factors.

Of the three main forms of bacteria, cocci are the most stable in size, rod-shaped bacteria are more variable, and the length of the cells changes especially significantly.

A bacterial cell placed on the surface of a solid nutrient medium grows and divides, forming a colony of progeny bacteria. After a few hours of growth, the colony already consists of such a large number of cells that it can be seen with the naked eye. Colonies may have a slimy or pasty consistency, in some cases they are pigmented. Sometimes the appearance of the colonies is so characteristic that it makes it possible to identify microorganisms without much difficulty.

Fundamentals of bacterial physiology.

The chemical composition of microorganisms differs little from other living cells.

Water is 75-85%, chemicals are dissolved in it.

Dry matter 15-25%, composed of organic and mineral compounds

Nutrition of bacteria. The entry of nutrients into a bacterial cell is carried out in several ways and depends on the concentration of substances, the size of the molecules, the pH of the medium, the permeability of membranes, etc. By type of food microorganisms are divided into:

autotrophs - synthesize all carbon-containing substances from CO2;

heterotrophs - organic matter is used as a carbon source;

saprophytes - feed on organic matter of dead organisms;

Breath bacteria. Respiration, or biological oxidation, is based on redox reactions that take place with the formation of an ATP molecule. In relation to molecular oxygen, bacteria can be divided into three main groups:

obligate aerobes - can grow only in the presence of oxygen;

obligate anaerobes - grow in an environment without oxygen, which is toxic to them;

facultative anaerobes - can grow both with oxygen and without it.

Growth and reproduction of bacteria. Most prokaryotes reproduce by binary fission in half, less often by budding and fragmentation. Bacteria, as a rule, are characterized by a high rate of reproduction. The time of cell division in various bacteria varies quite widely: from 20 minutes in Escherichia coli to 14 hours in Mycobacterium tuberculosis. On dense nutrient media, bacteria form clusters of cells called colonies.

bacterial enzymes. Enzymes play an important role in the metabolism of microorganisms. Distinguish:

endoenzymes - localized in the cytoplasm of cells;

exoenzymes - released into the environment.

Enzymes of aggression destroy tissue and cells, causing a wide distribution of microbes and their toxins in the infected tissue. The biochemical properties of bacteria are determined by the composition of enzymes:

saccharolytic - breakdown of carbohydrates;

proteolytic - the breakdown of proteins,

lipolytic - breakdown of fats,

and are an important diagnostic feature in the identification of microorganisms.

For many pathogenic microorganisms, the optimum temperature is 37°C and pH 7.2-7.4.

Water. Importance of water for bacteria. Water makes up about 80% of the mass of bacteria. The growth and development of bacteria are obligately dependent on the presence of water, since all chemical reactions occurring in living organisms are realized in an aquatic environment. For the normal growth and development of microorganisms, the presence of water in the environment is necessary.

For bacteria, the water content in the substrate should be more than 20%. Water must be in an accessible form: in the liquid phase in the temperature range from 2 to 60 °C; this interval is known as the biokinetic zone. Although water is very stable chemically, its ionization products - H + and OH ions - have a very large effect on the properties of almost all cell components (proteins, nucleic acids, lipids, etc.). Thus, the catalytic activity of enzymes is largely depends on the concentration of H+ and OH ions.

Fermentation is the main source of energy for bacteria.

Fermentation is a metabolic process that produces ATP, and electron donors and acceptors are products formed during fermentation itself.

Fermentation is the process of enzymatic breakdown of organic substances, mainly carbohydrates, proceeding without the use of oxygen. It serves as a source of energy for the life of the body and plays an important role in the circulation of substances and in nature. Some types of fermentation caused by microorganisms (alcohol, lactic, butyric, acetic) are used in the production of ethyl alcohol, glycerin and other technical and food products.

Alcoholic fermentation(carried out by yeast and some types of bacteria), during which pyruvate is broken down into ethanol and carbon dioxide. One molecule of glucose results in two molecules of alcohol (ethanol) and two molecules of carbon dioxide. This type of fermentation is very important in the production of bread, brewing, winemaking and distillation.

lactic acid fermentation, during which pyruvate is reduced to lactic acid, lactic acid bacteria and other organisms carry out. When milk is fermented, lactic acid bacteria convert lactose into lactic acid, turning milk into fermented milk products (yogurt, curdled milk, etc.); lactic acid gives these products a sour taste.

Lactic acid fermentation also occurs in the muscles of animals when the energy demand is higher than that provided by respiration, and the blood does not have time to deliver oxygen.

Burning sensations in the muscles during heavy exercise are correlated with the production of lactic acid and a shift to anaerobic glycolysis, since oxygen is converted to carbon dioxide by aerobic glycolysis faster than the body replenishes oxygen; and soreness in the muscles after exercise is caused by microtrauma of the muscle fibers. The body shifts to this less efficient, but faster, method of producing ATP when oxygen is deficient. The liver then gets rid of the excess lactate, converting it back into an important glycolysis intermediate, pyruvate.

Acetic fermentation carried out by many bacteria. Vinegar (acetic acid) is a direct result of bacterial fermentation. When pickling foods, acetic acid protects food from disease-causing and rotting bacteria.

Butyric fermentation leads to the formation of butyric acid; its causative agents are some anaerobic bacteria of the genus Clostridium.

Reproduction of bacteria.

Some bacteria do not have a sexual process and reproduce only by equal-sized binary transverse fission or budding. For one group of unicellular cyanobacteria, multiple division has been described (a series of fast successive binary divisions, leading to the formation of 4 to 1024 new cells). To ensure the plasticity of the genotype necessary for evolution and adaptation to a changing environment, they have other mechanisms.

When dividing, most gram-positive bacteria and filamentous cyanobacteria synthesize a transverse septum from the periphery to the center with the participation of mesosomes. Gram-negative bacteria divide by constriction: at the site of division, a gradually increasing curvature of the CPM and the cell wall inward is found. When budding, a kidney is formed and grows at one of the poles of the mother cell, the mother cell shows signs of aging and usually cannot produce more than 4 daughter cells. Budding occurs in different groups of bacteria and, presumably, arose several times in the course of evolution.

In other bacteria, in addition to reproduction, a sexual process is observed, but in the most primitive form. The sexual process of bacteria differs from the sexual process of eukaryotes in that bacteria do not form gametes and cell fusion does not occur. The mechanism of recombination in prokaryotes. However, the main event of the sexual process, namely the exchange of genetic material, occurs in this case as well. This is called genetic recombination. Part of the DNA (very rarely all of the DNA) of the donor cell is transferred to the recipient cell, whose DNA is genetically different from that of the donor. In this case, the transferred DNA replaces part of the recipient's DNA. DNA replacement involves enzymes that break down and rejoin DNA strands. This produces DNA that contains the genes of both parental cells. Such DNA is called recombinant. The offspring, or recombinants, show marked diversity in traits caused by gene shifts. Such a variety of characters is very important for evolution and is the main advantage of the sexual process.

There are 3 ways to obtain recombinants. These are, in the order of their discovery, transformation, conjugation, and transduction.

Origin of bacteria.

Bacteria, along with archaea, were among the first living organisms on Earth, appearing about 3.9-3.5 billion years ago. The evolutionary relationships between these groups have not yet been fully studied, there are at least three main hypotheses: N. Pace suggests that they have a common ancestor of protobacteria; Zavarzin considers archaea to be a dead-end branch of eubacteria evolution that has mastered extreme habitats; finally, according to the third hypothesis, archaea are the first living organisms from which bacteria originated.

Eukaryotes arose as a result of symbiogenesis from bacterial cells much later: about 1.9-1.3 billion years ago. The evolution of bacteria is characterized by a pronounced physiological and biochemical bias: with a relative poverty of life forms and a primitive structure, they have mastered almost all currently known biochemical processes. The prokaryotic biosphere already had all the currently existing ways of substance transformation. Eukaryotes, having penetrated into it, changed only the quantitative aspects of their functioning, but not the qualitative ones; at many stages of the cycles of elements, bacteria still retain a monopoly position.

One of the oldest bacteria are cyanobacteria. In the rocks formed 3.5 billion years ago, products of their vital activity - stromatolites - were found, indisputable evidence of the existence of cyanobacteria dates back to 2.2-2.0 billion years ago. Thanks to them, oxygen began to accumulate in the atmosphere, which 2 billion years ago reached concentrations sufficient to start aerobic respiration. The formations characteristic of the obligately aerobic Metallogenium belong to this time.

The appearance of oxygen in the atmosphere (oxygen catastrophe) dealt a serious blow to anaerobic bacteria. They either die out or go to locally preserved anoxic zones. The total species diversity of bacteria at this time is reduced.

It is assumed that due to the lack of a sexual process, the evolution of bacteria follows a completely different mechanism than that of eukaryotes. Constant horizontal gene transfer leads to ambiguities in the picture of evolutionary relationships, evolution proceeds extremely slowly (and, perhaps, with the advent of eukaryotes, it stopped altogether), but under changing conditions, a rapid redistribution of genes between cells occurs with an unchanged common genetic pool.

Systematics of bacteria.

The role of bacteria in nature and in human life.

Bacteria play an important role on Earth. They take an active part in the cycle of substances in nature. All organic compounds and a significant part of inorganic ones undergo significant changes with the help of bacteria. This role in nature is of global importance. Appearing on Earth before all organisms (more than 3.5 billion years ago), they created the living shell of the Earth and continue to actively process living and dead organic matter, involving their metabolic products in the circulation of substances. The cycle of substances in nature is the basis for the existence of life on Earth.

The decay of all plant and animal remains and the formation of humus and humus are also produced mainly by bacteria. Bacteria are a powerful biotic factor in nature.

The soil-forming work of bacteria is of great importance. The first soil on our planet was created by bacteria. However, in our time, the condition and quality of the soil depend on the functioning of soil bacteria. Particularly important for soil fertility are the so-called nitrogen-fixing nodule bacteria-symbionts of leguminous plants. They saturate the soil with valuable nitrogen compounds.

Bacteria purify dirty wastewater by breaking down organic matter and converting it into harmless inorganic matter. This property of bacteria is widely used in the operation of wastewater treatment plants.

In many cases, bacteria can be harmful to humans. So, saprotrophic bacteria spoil food products. To protect products from spoilage, they are subjected to special treatment (boiling, sterilization, freezing, drying, chemical cleaning, etc.). If this is not done, food poisoning may occur.

Among bacteria, there are many disease-causing (pathogenic) species that cause diseases in humans, animals or plants. Typhoid fever is caused by the Salmonella bacterium, and dysentery by the Shigella bacterium. Pathogenic bacteria are carried through the air with droplets of the saliva of a sick person when sneezing, coughing, and even during normal conversation (diphtheria, whooping cough). Some disease-causing bacteria are very resistant to desiccation and persist in the dust for a long time (tuberculosis bacillus). Bacteria of the genus Clostridium live in dust and soil - the causative agents of gas gangrene and tetanus. Some bacterial diseases are transmitted through physical contact with a sick person (venereal disease, leprosy). Often, pathogenic bacteria are transmitted to humans through so-called vectors. For example, flies, crawling through sewage, collect thousands of pathogenic bacteria on their paws, and then leave them on the products consumed by humans.

To begin with, it is worth understanding what immunity is and how it is related to the state of human blood. To do this, we recommend that you carefully read the article “HOW PEOPLE KILL THEIR BLOOD… DO YOU KILL YOUR BLOOD?” (about the connection between blood and immunity, what doctors are silent about):

Next, watch this video, which opens the veil of secrets associated with the infectious theory of diseases. It talks about the Ebola virus, etc. You will understand that in order not to get sick with infectious diseases, it is enough to lead a healthy lifestyle. There is no reason to be afraid to pick up an infection from someone. Even the most terrible viruses and bacteria do not live in a healthy body and a bright soul.

Bacteria are servants given to Man by nature to cleanse our internal environment from toxins.

Primary disease is a natural cleansing of the body.

To clean the internal environment, our body can use microorganisms. He kind of hires microbes to clean up when he can't do it himself. Approximately such a conclusion can be drawn from the hypothesis of Professor A.V. Rusakova, about which A.N. Chuprun spoke about in 1991 in his book “What is a raw food diet and how to become a raw foodist (naturist)”.

The main cause of all our diseases is the slagging of the body. It was noticed that if in this state a person catches some kind of infection, his production of interferon decreases - the defenses seem to be turned off on purpose, allowing the disease to develop. During an illness, our body deliberately turns off the immune system so that bacteria can destroy all the toxins in the body. And we just do not understand the purpose of bacteria on Earth. The bacterium is not interested in our muscles, heart, eyes or brain, but only in our toxins in our tissues. The more waste and toxins we accumulate in our body, the more bacteria we attract.

Another interesting fact is that bacteria will never touch something that is still alive. Giant sequoia trees live up to 2,000 years with very little bacteria in their sap. Despite the fact that sequoia roots have been in the ground for literally thousands of years, bacteria do not touch them. However, as soon as the tree dies, the bacteria immediately begin their work of turning the tree back into earth. Bacteria know what lives and what has died, and they are only interested in dead matter.

Can a bacterium cause disease in humans?
Yes and no.
Yes, if the human body is filled with toxins.
Not if the body is clean inside.
Therefore, those who eat mainly boiled food get sick easily. If you don't want to get sick, keep your intestines clean.

The process of purification by bacteria in humans can be schematically represented as follows.

Alien residues from distorted cooked food molecules that have accumulated in the body are a breeding ground for some microorganisms and, in addition, they are a significant hindrance to the functioning of the immune system. With an additional weakening of local immunity, for example, in the case of cooling, or with a massive viral infection, favorable conditions are created in some place of the human body for the reproduction of some of the ubiquitous microorganisms.

A focus of inflammation is formed, where microbes intensively process the accumulated foreign residues into other substances that our body can already remove on its own, for example, in the form of secretions during a runny nose, cough, skin manifestations, etc. After the completion of this work, the immune system, in an already cleansed organism, restores its activity and suppresses the microflora that has expired. This is the primary natural protective and adaptive reaction of a normal organism to a polluted state of the internal environment.

This cleansing reaction is called the word "disease", since its manifestations are unpleasant for a person and usually painful. Specific names for such inflammatory diseases are given, as already mentioned, by the name of the place in which the focus of inflammation was formed. Microorganisms there can also be different, but the essence of these processes is the same: the internal environment of the body is cleaned.

These diseases share many common symptoms. Usually the temperature rises, soreness of the inflamed area of the body occurs, appetite decreases, weakness appears, later skin phenomena or other excretory processes may occur - runny nose, cough .... All these symptoms do not mean the defeat of the organism, but, on the contrary, its rational wise behavior, which ensures its victorious completion of purification. For the body, such a procedure is also “not honey”, but it chooses the lesser evil. It is more important for him to get rid of pollution quickly and with minimal damage. Nature is wise, she knows her business well.

When, for example, antibiotics or other medicines are used in these harmless primary cleansing diseases, the unpleasant symptoms decrease, the runny nose or cough stops, the temperature decreases and the situation seems to have improved. Outwardly, this looks like helping a person, like restoring health, therefore, in such cases, this is traditionally done so far. But this is self-deception, or rather, an erroneous understanding of the situation. This is harmful, because as a result of such interference in the work of the body, the purification process stops or becomes a protracted chronic form. But the main task - to return the natural purity of the internal environment - remains unfulfilled.

Moreover, each such "treatment" dulls the body's sensitivity to pollution and deprives it of its primary cleansing reactions. Such an organism is in completely abnormal conditions, it is doomed to exist at a high level of internal pollution, and this grossly distorts its life processes and further leads to more severe disorders, to the emergence of secondary and tertiary diseases.

In such “healed” people, pathological processes gradually develop, which, due to differences in hereditary and acquired properties, manifest themselves in the form of a variety of diseases: allergies, diabetes, hypertension, heart failure, etc., and in some “for no apparent reason” unexpected heart attack or stroke. There is an opinion that cancer also occurs due to many disorders in the body, caused by a large pollution of the internal environment.

The body's ability to maintain a clean internal environment can serve as one of the generalized indicators of human health. When medicine will be able to reliably measure the "slagging" of the body and its sensitivity to various types of pollution, i.e. ability to self-cleaning, then it will be possible to approach the direct measurement of the parameter that Academician N.M. Amosov called "the amount of health." Then it will be possible to objectively assess the results of the impact on the body of various medicines and reasonably decide on the appropriateness of their use.

Unfortunately, doctors who use medications do not always care about long-term consequences. It is more important for them to get a momentary reduction in unpleasant symptoms, to get a “treatment effect”. The position of physicians can be understood: they usually have to deal with patients whose organism is so damaged by repeated use of drugs and so heavily polluted that its natural cleansing reactions proceed in a distorted, severe form. Doctors are forced, reinsured, to use medicines again, despite the fact that in most cases such treatment distorts the body's natural defense reactions even more, reduces its reactivity and reduces the “amount of health”.

IMPORTANT! HOW FLOUR AFFECTS IMMUNITY? WHY IS BREAD HARMFUL!

Another helpful video HOW TO RESTORE THE INTESTINAL MICROFLORA AND IMMUNE:

IMPORTANT INFORMATION!BASIC ALGORITHM AND METHODS OF TREATMENT OF ANY DISEASES:

To better understand the causes and mechanisms of the occurrence of diseases, be sure to study the articles:

* BLOOD OXIDATION LEADS TO DISEASE OF THE ORGANISM! WHY BLOOD ACIDIFICATION IS A HEALTH THREAT. ACID-BALANCE BALANCE OF THE BODY (acid-base balance) - THE PHYSICAL BASIS OF HUMAN HEALTH!

* ATTENTION! THE RESULTS OF THE LARGEST LONG-TERM NUTRITION STUDIES PROVE A DIRECT LINK BETWEEN DEADLY DISEASES AND THE CONSUMPTION OF "FOOD" OF ANIMAL ORIGIN (any meat and dairy products)!

* HOW CHRONIC DISEASES APPEAR. HOW DIFFERENT ORGANIS IN THE ORGANISM ARE INTERRELATED (what influences what). How to find the cause of your diseases. Video compilation A.T. Ogulov:

* MUSCLE-FREE NUTRITION - THE WAY TO HEALTH AND LONGEVITY!

IMPORTANT ARTICLE! DON'T LET THE LYMPH STAY! Licorice is the best lymphostimulator, a plant created to cleanse and renew the lymphatic system!

HEALING COLDS AND FLU BY EFFECTIVE NATURAL METHODS! AND PREVENTION, HOW TO STAY HEALTHY!