Conclusion on the topic of the history of the development of microbiology. Stages of development of microbiology. Ministry of Education of the Russian Federation
Microbes appeared on our planet earlier than animals and humans. It has been proven that pathogenic microbes existed in ancient times. This is evidenced by the detection of antigens of pathogenic bacteria, for example the causative agent of plague, in the remains of ancient burials (mummies). Even before the discovery of microbes, people suspected the existence of external factors that cause disease. Therefore, we can say that microbiology arose before our era and has gone through a long development path. In accordance with the level of knowledge about microbes, with the advent of new discoveries and methods, as well as the formation of new directions, the history of microbiology can be divided into five periods: 1) heuristic; 2) morphological; 3) physiological; 4) immunological; 5) molecular genetic.
Heuristic period
This period begins from the moment when Hippocrates (III - IV centuries BC) made a guess (heuristic - guess) that diseases transmitted from person to person are caused by invisible, inanimate substances. He called these substances “miasmas.” It must be said that in ancient times, not knowing about the existence of microbes, people used the fruits of the activity of microbes - winemaking, brewing, baking bread, etc.
Only in the XV - XVI centuries. Italian physician and poet Geralimo Fracastoro (1476 - 1553) substantiated the opinion that diseases are caused by “living contagions” that transmit diseases through the air or through objects, that these creatures live in the environment and to combat diseases it is necessary to isolate the patient and destroy contagion, etc. By the way, Fracastoro is considered the founder of epidemiology for these works.
Thus, over two millennia, scientists have gone from guesses and assumptions to the conviction that human diseases are caused by some invisible living beings.
Morphological period
This period begins from the end of the 17th - beginning of the 18th century, when the Dutch naturalist Anthony van Leeuwenhoek (1632 - 1723) discovered bacteria. The microscope he created magnified objects 150-300 times. Looking at everything (water, blood, plaque from teeth, etc.), Leeuwenhoek discovered many living “little animals”, which he called “animalculi”. Systematically making sketches and descriptions, he sent letters to the Royal Scientific Society of London. These letters were published in scientific journals, and then, in 1695, a book was published entitled “The Secrets of Nature, the Discoveries of Antonie van Leeuwenhoek Using a Microscope.” Thus, Leeuwenhoek marked the beginning of a morphological period that continues to this day. The first Russian to see microbes was Peter the Great, who visited Leeuwenhoek in Holland; He also brought the microscope to Russia, and the first researcher was the doctor M.M. Terekhovsky (1740 - 0796).
After the discovery of Leeuwenhoek, the victorious march of microbiology began. New bacteria, fungi, protozoa were discovered, and at the end of the 19th century. viruses were discovered. To prove the etiological role of microbes in human pathology, animal studies were conducted, as well as experiments on self-infection. It should be noted the bold experiments of the Russian epidemiologist Danila Samoilovich (1724 - 1810), who infected himself with the discharge of a bubo from a plague patient. Historically, a number of experiments on self-infection with materials or cultures of pathogens taken from a patient with cholera (Petenhofer, I.I. Mechnikov, D.K. Zabolotny, N.F. Gamaleya), typhus (G.N. Minkh), plague (B P. Smirnov), polio virus (M. N. Chumakov), etc.
End of the 19th century marked by the discovery of viruses. In 1892, Russian botanist D.I. Ivanovsky (1864 – 1920) discovered the kingdom of viruses while studying tobacco mosaic disease. Then many viruses were discovered that infect humans, animals, plants and bacteria. In the first half of the 20th century. an independent discipline - virology - took shape, and in 1992 the whole world celebrated the 100th anniversary of the discovery of viruses by D.I. Ivanovsky.
The discovery and emergence of new species of microbes, as well as changes in the pathogenic properties of already known microbes, is quite natural, since, on the one hand, microbiological methods are being improved, and on the other, representatives of the microcosm are evolving with the general laws of biology and genetics. In the last 20–30 years alone, more than three dozen new and modified variants of known microbes have been discovered. All of them are combined into a group of dangerous unpredictable infections.
In the future, humans will also expect the emergence of new or changed pathogens of infectious diseases. An example is the increasing role of T-cell leukemia viruses, hepatitis viruses, prions, etc. in human pathology.
Physiological period
Since the discovery of microbes, naturally, the question arose not only about their role in human pathology, but also about the structure biological properties, life processes, ecology, etc.
Therefore, from the middle of the 19th century, intensive study of the physiology of bacteria began. This period, which began in the 19th century and continues to this day, was conventionally called the physiological period in the development of microbiology.
The works of the outstanding French scientist Louis Pasteur (1822 – 1895) played a major role during this period. Being a chemist by training, possessing broad erudition, talent as an experimenter and the wisdom of an organizer of science, L. Pasteur made a number of fundamental fundamental discoveries in many fields of science, which allowed him to become the founder of a number of sciences: microbiology, biotechnology, disinfectology, stereochemistry.
L. Pasteur discovered:
1. The nature of fermentation;
2. Anaerobiosis;
3. Refuted the theory of spontaneous generation;
4. Justified the principle of sterilization;
5. Developed the principle of vaccination and methods of obtaining vaccines.
At the age of 26, L. Pasteur defended his doctoral dissertation “On arsenic compounds of potassium, sodium and ammonia,” in which he proved that when growing mushrooms, only certain stereoisomers are assimilated. Thus, L. Pasteur became the founder of stereochemistry.
Before Pasteur, Liebig's chemical theory of fermentation reigned. Pasteur made a discovery, proving that fermentation (lactic acid, alcoholic, acetic) is a biological phenomenon that is caused by microbes and their enzymes, i.e. Pasteur became the founder of biotechnology.
Before Pasteur, there was a theory of spontaneous generation of all living things, i.e. it was believed that animals not only descended from each other, but also arise spontaneously (frogs are born from mud, etc.). Thus, microbes also self-generated. Pasteur refuted this position with his experiments. He proved that if a sterile broth is left in an open flask, it will germinate, but if a sterile broth is placed in a flask that communicates with air through a spiral glass tube, then the broth will not germinate, since bacteria with dust particles from the air will be deposited on the curved parts of the spiral tube and will not fall into the broth.
Pasteur also proved that some bacteria not only cannot tolerate oxygen, but live and reproduce only in an oxygen-free environment. Thus, the phenomenon of anaerobiosis was discovered, and the group of microbes was called anaerobes.
Proof of the role of microbes in enzymatic processes led Pasteur to solve a number of practical problems, in particular, to develop a method of combating diseases of wine by heating it at 50 - 60˚C in order to destroy bacteria. This method, then called pasteurization, is widely used today in the food industry.
A significant contribution to the development of microbiology during this period was made by the German bacteriologist Robert Koch (1843 - 1910), who proposed staining bacteria, microphotography, a method for obtaining pure cultures, as well as the famous Henle-Koch triad for establishing the etiological role of microbes in infectious diseases. According to the triad, to prove the role of microbes in the occurrence of a specific disease, three conditions are necessary:
1. So that the microbe is detected only in the patient and is not detected in healthy people and patients with other diseases;
2. A pure culture of the microbe must be obtained;
3. The microbe must cause a similar disease when infecting animals.
Henle put forward these principles before Koch; Koch formulated and developed them. Nowadays, this triad is of relative importance, since it is sometimes difficult to reproduce the disease in animals (for example, HIV infection) and the pathogen is often found in healthy individuals (carriage).
Thus, the study of the biological and physiological properties of microorganisms since the end of the 19th century. and throughout the 20th century. led to knowledge of the deep life processes of bacteria, viruses and protozoa.
Immunological period
This period in the development of microbiology is associated primarily with the names of the French scientist L. Pasteur, Russian biologist I.I. Mechnikov (1843 – 1916) and the German chemist Paul Ehrlich (1854 – 1915). These scientists can rightfully be called the founders of immunology.
L. Pasteur discovered and developed the principle of vaccination, I.I. Mechnikov - the phagocytic theory, P. Ehrlich put forward a hypothesis about antibodies and developed the humoral theory of immunity.
It should be noted that more than 200 years ago, the English physician Edward Jenner (1749 - 1823) found a way to create immunity to the smallpox pathogen by inoculating a person with the cowpox virus. It was a great discovery, but it was of an empirical nature. And only L. Pasteur scientifically substantiated the principle of vaccination, the method of obtaining vaccines, and spread it to many countries. In the summer of 1886, the created by I.I. began to work in Odessa and Perm. Mechnikov and his talented student N.F. Gamaleya's first Pasteur stations.
Grateful humanity for the discoveries made, using funds raised through international subscription, built the Pasteur Institute in Paris in 1888, which still operates today. Such scientists worked at the Pasteur Institute as the first Pasteur’s student N.I. to obtain smallpox in humans by inoculating humans (for example, HIV-infection I.I. Mechnikov, E. Roux, A. Calmette (created the VCG vaccine), A .M. Bezredka (proposed a method of desensitization), J. Bordet (immunochemist), G. Ramon (developed a method for producing toxoids) and many others.
A huge contribution was made by I.I. Mechnikov, who received the Nobel Prize in 1908 for developing the theory of phagocytosis. In addition, I.I. Mechnikov was interested in the aging process and the role of normal human microflora; he is rightfully considered the founder of gerontology and the doctrine of dysbacteriosis. Opponent I.I. Mechnikov, P. Ehrlich was also awarded the Nobel Prize in 1908 for the humoral theory of immunity.
In 1900, R. Koch discovered delayed-type hypersensitivity, in 1902 - 1905. C. Richet, J. Portier, G.P. Sakharov described immediate hypersensitivity; in the 1950s, tolerance to antigens was discovered (P. Medovar, M. Hasek), immunological memory (F. Burnet). At the same time, the structure of immunoglobulins was studied (R. Porter and E. Edelman), interferon was discovered (A. Isaacs and J. Lindeman) and other immunomodulators. In addition, numerous studies have been devoted to the study of lymphocytes and their role in immunity, cooperative cell interactions, etc.
In the mid-20th century, immunology emerged as an independent science with goals, objectives, structure and classification.
Molecular genetic period
Development in the second half of the 20th century molecular biology, genetics, genetic and protein engineering and other sciences gave impetus to the development of molecular and genetic aspects of microbiology.
During this period, the molecular structure of bacteria and viruses, the structure and composition of their genome, pathogenicity factors and immune defense factors were deciphered.
Deciphering the genes of bacteria and viruses and their synthesis made it possible to artificially create recombinant DNA and, on their basis, obtain recombinant strains of microorganisms that are widely used to obtain biologically active substances (hormones, medicines, food proteins, sugars, etc.). Genetic engineering has made it possible to obtain vaccine and diagnostic drugs (vaccine against hepatitis B, monoclonal antibodies, etc.).
Immunogenetics is being developed, the purpose of which is gene prevention and gene therapy of immunodeficiencies. Gene diagnostics (polymerase chain reaction) is widely used in microbiology.
Great strides have been made in the study of the histocompatibility system, which has solved problems in transplantology during organ and tissue transplantation, and problems of maternal-fetal incompatibility in obstetrics and gynecology.
Chemotherapy and antibiotic therapy for infectious diseases has undergone evolution. A huge number of antiviral and antibacterial drugs have been created.
Thus, advances in microbiology and immunology have not only ensured success in the fight against infectious diseases, but have also opened up new ways and methods for diagnosing and treating non-infectious diseases.
Microbiology plays a vital role in human history. The origin of this science dates back to the 6th - 5th centuries BC. e. In those distant times, people were already beginning to realize that diseases do not appear just like that. And this happens due to microscopic, invisible to the eye, microorganisms. How did science arise and take shape?
What is microbiology?
Microbiology is a science that deals with the research and study of the life processes of various microorganisms that cannot be seen without special equipment. They can have different types of origin: plant, animal. One of the fundamental sciences is microbiology. For its in-depth study, many other sciences are used, namely:
- chemistry;
- physics;
- cytology;
- biology, etc.
There are only two types of microbiology: general, individual. General microbiology deals with the study of the structure and life processes of small microorganisms at various levels. And individual microbiology (or private) is engaged in research individual species microbes
In the 19th century, advances in the field of medicine, in particular microbiology, contributed to the formation of immunology, which today is considered a general biological discipline. In the development of microbiology, three main stages can be distinguished:
- Revealing the fact that there really are small microorganisms in nature that cannot be detected without special equipment.
- Differentiation of species.
- Study of immunity and diseases (infectious).
The main task of microbiology is the detailed study of the properties of microorganisms. For this purpose, special equipment is used, for example, microscopes. With their help, you can see small organisms and determine their shape and location. In medicine, an experiment is practiced when small microorganisms are deliberately implanted into a healthy animal. This helps to reconstruct and study each stage of infection.
French explorer Louis Pasteur
On December 27, 1822, the future great scientist Louis Pasteur was born in eastern France. At an early age he was interested in the field of art. But later he became interested natural sciences. He studied in Paris at the Ecole Superieure. After completing his studies, he was destined to become a science teacher.
B 48 year XIX century, Louis presented the results of his own scientific research. It was he who provided evidence that tartaric acid contains 2 types of crystals that polarize light in completely different ways. This significant event marked the beginning of his brilliant success in science.
Louis Pasteur is the creator of microbiology. Before his work began, scientists only assumed that chemical process yeast forms. And Louis Pasteur, after conducting a series of studies, was able to prove this fact. He discovered that there are 2 types of such microorganisms: some form alcohol, while others destroy it. Later he was able to find out that with slow heating, unnecessary bacteria are destroyed, which significantly increased the quality of alcohol-containing products.
The scientist was also interested in the formation of mold on food. He later proved that moldiness is caused by spores in the environment. The fewer of them there are in space, the slower the food spoils.
His research helped save the silk industry in France. And also many human lives, since it was he who invented the rabies vaccine.
German scientist Robert Koch
Koch Robert is considered a contemporary of Pastser. His birth occurred in December 1843. At the age of 23, he graduated from medical university and received a diploma, after which he worked in several medical institutions.
His significant career began with work as a bacteriologist. He studied anthrax on sick animals. His research revealed that infected individuals have a lot of foreign microorganisms that healthy animals do not have. These bacteria were rod-shaped.
Koch later became interested in tuberculosis. The first studies were carried out on the corpse of a worker who died of consumption. A detailed study of the organs did not lead to the identification of pathogenic bacteria. Koch then suggested that the samples should be colored. And indeed, the scientist noticed some sticks between the lung tissues. Afterwards, Robert Koch developed a vaccine against tuberculosis, but it could not cure the disease, but it determined 100% whether the patient was infected or not. This vaccine is still in use today.
The emergence of the science of microbiology
Man encountered the effects of the vital activity of microorganisms much earlier than their official discovery. People deliberately fermented milk, fermented dough and wine. Even in the works of the ancient Greek scientist, lines were found about what he suggests about the relationship between diseases and dangerous pathogenic fumes.
Anthony van Leeuwenhoek confirmed these guesses with the help of a magnifying glass he invented. With its help, Anthony was able to examine the surrounding objects. It turned out that small organisms live on these objects that are invisible to the naked eye. But he was never able to prove their participation in infecting people with dangerous diseases.
Preventive treatment of the home in order to prevent diseases was provided for by the Hindus. In 1771, in Moscow, a military doctor first used disinfection of the belongings of people infected with the plague, and also vaccinated those who had contact with those infected.
The most fascinating story is about the discovery of smallpox vaccination. It was also used by the Persians, Turks, and Chinese. It happened like this: weakened bacteria were introduced to a person, because it was believed that the disease would be easier this way. The English doctor Edward Jenner noted that most people who do not have smallpox did not become infected through close contact with infected people. This fact was noticed in milkmaids who were in contact with cows infected with smallpox. The study of this fact lasted about 10 years. As a result, the scientist injected the diseased cow's blood into a healthy boy. Later, Jenner inoculated the young man with the germs of a sick person. This is how a vaccine was discovered, thanks to which people were freed from this terrible disease.
Research by domestic scientists
The most famous discoveries in the field of microbiology, made by scientific researchers from all over the world, make it clear that almost any disease can be overcome. Domestic researchers have made a huge investment in the formation of modern science. Peter I in 1698 made acquaintance with Leeuwenhoek, who, in turn, showed him the operation of a microscope.
L.S. Tsenkovsky published his Scientific research, in which microorganisms were classified as organisms of plant origin. He also used Pasteur's methods in the fight against anthrax.
I.I. Mechnikov formed the theory of immunity. He made strong arguments that numerous cells of the body have every chance of suppressing viral bacteria on their own. His studies became the basis for the study of inflammation. Mechnikov studied the human body and sought to understand why it ages. The professor wanted to find a method that would increase life expectancy. He believed that toxic elements arising during the activity of putrefactive microorganisms poison the human body. According to Mechnikov, the body should be populated with fermented milk microorganisms that suppress harmful microorganisms. The professor believed that in this way life expectancy could be significantly increased.
Mechnikov studied a large number of serious diseases: tuberculosis, typhoid, cholera and many others.
Technical microbiology
Technical microbiology studies bacteria that are used in the production of vitamins and certain substances. The main problem in this area is considered to be the growth of scientific and technical techniques in manufacturing (especially in the food sector).
Mastering industrial microbiology directs a specialist to the need for painstaking compliance with absolutely all generally accepted sanitary standards in production. By studying this science, you can prevent spoilage of many products. The subject is being studied more by future experts in the food industry.
Innovative technologies
Microbiology is the basis of innovative technologies. Microorganisms and their world have not yet been fully studied. Most scientists are confident that with the help of microorganisms it is possible to develop technologies that will have no analogues. It is biotechnology that will become the basis for the latest technological discoveries.
When exploring oil and coal deposits, bacteria are used. It is no secret that fuel reserves are already running out. Therefore, scientists are already recommending the use of microbiological methods for extracting alcohols from renewable sources.
Microbiological technologies will help overcome environmental and energy problems. Incredibly, however, microbiological processing of organic residues makes it possible to clean the environment, as well as obtain biogas that is not inferior to natural gas. This type of fuel extraction method does not require large expenses. Today, in nature there is a large amount of used material for processing around.
Numerous modern scientists believe that in the future, it is biology that will make it possible to overcome many energy and environmental difficulties that have every chance of appearing in the shortest possible time.
TOPIC 1. INTRODUCTION. MORPHOLOGY, PHYSIOLOGY AND CLASSIFICATION OF BACTERIA.
1. Subject and tasks of medical microbiology.
2. History of the development of microbiology.
3. Morphology of bacteria.
4. Physiology of bacteria.
5. Classification of bacteria.
6. Methods for studying the morphology and properties of bacteria.
Subject and tasks of medical microbiology.
Microbiology(from Greek micros– small, bios- life, logos– teaching) – the science of microorganisms, the patterns of their development and the changes they cause in the habitat and in the environment.
Sizes of microorganisms< 0,1 мм, величина их измеряется в мкм.
Microbiology includes sections:
o General- is studying general patterns microorganisms.
o Technical– is developing biotechnology for the synthesis of biologically active substances by microorganisms: proteins, vitamins, enzymes, antibiotics, alcohols.
o Agricultural– studies microorganisms that participate in the cycle of substances, are used to prepare fertilizers, cause plant diseases, etc.
o Veterinary– studies pathogens of animal diseases, develops methods for diagnosis, prevention and treatment of animals.
o Sanitary– studies the sanitary and microbiological state of environmental objects, its impact on human health and develops measures to prevent the adverse effects of pathogenic microbes.
o Marine– studies the microflora of the seas and oceans.
o Space– studies the microflora of outer space, the influence of space conditions on the properties of microorganisms and the microflora of the human body.
o Medical– studies microorganisms pathogenic and opportunistic for humans, their ecology and prevalence, methods for their isolation and identification, and also develops methods microbiological diagnostics, specific prevention and treatment of diseases caused by them.
History of the development of microbiology.
There are five historical periods of development and formation of microbiology as a science.
I. Heuristic period associated more with logical and methodological methods of finding the truth than with any experiments and evidence.
Hippocrates, Paracelsus(VI century BC) suggested the nature of infectious diseases, miasmas, small invisible animals.
The idea was formulated in its most complete form by Girolamo Fracostoro in the work “On Contagions, Contagious Diseases and Treatment” (1546), where he expressed the idea of a living contagion of “seeds of disease” that causes diseases. Moreover, each disease is caused by its own contagion. To prevent diseases, they were recommended to isolate the patient, quarantine, wear masks, and treat objects with vinegar. However, these were hypotheses for which they had no evidence.
II.Descriptive period(morphological) associated with the creation of the microscope and the discovery of microscopic creatures invisible to the human eye. The first microscope was created in 1590 by Dutch scientists Hans And Zachary Jansen, but it only had a 32x magnification. Dutch naturalist Antonio Leeuwenhoek(1632 - 1723) constructed a microscope with a magnification of 160-300 times, with the help of which he was able to detect the smallest “living animals” (“animalcules”, from lat. animalcula, animal) in rainwater, dental plaque and other materials.
During the same period in 1771, a Russian doctor Danilo Samoilovich(1744 – 1805), in the experience of self-infection with pus of plague patients, proved the role of microorganisms in the etiology of the plague and the possibility of protecting people from the plague through vaccinations. To prove that the plague was caused by a special pathogen, he infected himself with the secretions of the bubo of a person suffering from the plague and became ill with the plague. Fortunately, D. Samoilovich survived.
Edward Jenner(1749 – 1823) created and successfully used a vaccine to prevent smallpox, taking material from a milkmaid with cowpox.
III.Physiological period(Pasterovsky)– “golden age” of microbiology.
L. Pasteur(1822 – 1895) – founder of the French school of microbiology, his main achievements:
Fermentation and rotting are a microbial process;
Spontaneous generation is not possible;
Diseases of wine and beer;
Silkworm diseases;
Rabies vaccine anthrax in animals and chicken cholera;
Proposal of a soft method of sterilization - pasteurization.
R. Koch(1843 – 1910) – founder of the school of German microbiologists, his achievements:
Isolated the anthrax bacillus;
Isolated the causative agent of tuberculosis and cholera;
Introduced aniline dyes, immersion system, dense nutrient media.
IV. Immunological period associated with the works of I. I. Mechnikov and P. Ehrlich.
I. I. Mechnikov(1845-1916) - one of the founders of immunology, described the phenomenon of phagocytosis (cellular theory of immunity).
Paul Ehrlich(1854-1915) formulated the theory of humoral immunity, explaining the origin of antibodies and their interaction with antigens.
IN 1908 I. I. Mechnikov and P. Ehrlich were awarded Nobel Prize for work in the field of immunology.
D. I. Ivanovsky(1864-1920) – discoverer of viruses. As a member of the Department of Botany at St. Petersburg University in 1892 While studying tobacco mosaic disease, he came to the conclusion that the disease was caused by a filterable agent, later called a virus.
1928 – A. Fleming While studying the phenomena of microbial antagonism, he obtained unstable penicillin.
And in 1940 – G. Flory and E. Chain obtained a stable form of penicillin.
V. Modern period (molecular genetic) associated with the scientific and technological revolution in natural science.
1944 – The role of DNA in transmission has been proven hereditary information. (O. Avery, K. McLeod, K. McCarthy)
1953 – Decoding the structure of DNA D. Watson and F. Crick .
1958 – Description of the phenomenon of immunological tolerance ( P. Medavar and Hasek)
1959 – We modeled an immunoglobulin molecule ( R. Porter and D. Edelman) .
IN 60-70 Work appeared on the genetics of bacteria and the emergence of genetic engineering.
1982 – HIV was discovered( R. Gallo, 1883 L. Montagnier).
Morphology of bacteria.
Based on their shape, the following main groups of microorganisms are distinguished.
1. Globular or cocci.
2. Rod-shaped.
3.Crimped.
4.Branching.
I. Coccoid bacteria (cocci) according to the nature of their relative positions after division, they are divided into:
1.Micrococci- cells located alone. They are part of the normal microflora and are found in the external environment. They do not cause diseases in humans.
2.Diplococcus - these are paired cells, these include gonococci, meningococci, pneumococci.
3.Streptococci - multiplying cells maintain connection (do not diverge), forming chains. There are many pathogenic microorganisms - causative agents of sore throats, scarlet fever, purulent inflammatory processes.
4.Tetracocci - have the form of tetrads (i.e. four cells). They have no medical significance.
5.Sarcin - have the form of packets of 8, 16 or more cocci. Often found in the air. There are no pathogenic forms.
6.Staphylococcus - form clusters resembling bunches of grapes. They cause numerous diseases, primarily purulent-inflammatory ones.
II. Rod-shaped microorganisms (rods):
1.Bacteria- rods that do not form spores (Escherichia coli, dysentery, tuberculosis, diphtheria, etc.).
2.bacilli- aerobic spore-forming microbes. The diameter of the spore usually does not exceed the size (“width”) of the cell (anthrax bacillus).
3.Clostridia- anaerobic spore-forming microbes. The diameter of the spore is larger than the diameter of the cell, and therefore the cell resembles a spindle or a tennis racket (the causative agent of tetanus, botulism, gas gangrene).
It must be borne in mind that the term “bacteria” is often used to refer to all microbes - prokaryotes. In a narrower (morphological) sense, bacteria are rod-shaped forms of prokaryotes that do not have spores.
III. Twisted forms of microorganisms:
1.Vibrios- have one bend, can be in the shape of a comma, a short curl (vibrio cholerae).
2.Spirilla- have 2-3 curls (causative agent Sodoku - rat bite disease).
3.Spirochetes- have a different number of curls. Of the large number of spirochetes, representatives of three genera are of greatest medical importance - Treptonema, Borrelia, Leptospira.
IV. Branching bacteria - rod-shaped bacteria that may have Y-shaped branches found in bifidobacteria. They can also be presented in the form of thread-like branched cells that can intertwine, forming mycelium, as observed in actinomycete.
In addition to true bacteria, there are others more or less different from them. These are spirochetes, rickettsia, chlamydia, actinomycetes and mycoplasmas.
Spirochetes - thin, long, convoluted (spiral-shaped), gram-negative bacteria. They are mobile, moving by wave-like contraction of the body. Some spirochetes cause human diseases (relapsing fever, syphilis).
In humans, chlamydia causes chlamydia, which manifests itself as damage to the eyes (trachoma, conjunctivitis), urogenital tract, lungs, etc.
Actinomycetes ( or radiant mushrooms) have the appearance of small or long branched thin threads. Pathogenic forms cause actinomycosis.
Mycoplasmas- small bacteria (0.15-1 µm), surrounded only by a cytoplasmic membrane and without a cell wall. They have a variety of shapes: coccoid, filamentous, flask-shaped. Mycoplasmas cause atypical pneumonia and lesions of the genitourinary tract in humans.
Physiology of bacteria.
Nutrition of bacteria
Respiration of bacteria.
Through respiration (or biological oxidation), microorganisms obtain energy.
With respect to molecular oxygen, bacteria can be divided into three main groups:
1) obligate (obligatory) aerobes can grow only in the presence of oxygen (mycobacterium tuberculosis);
2) obligate anaerobes grow in a medium without oxygen, which is toxic to them (clostridium botulism, gas gangrene, tetanus, bacteroides);
3) facultative anaerobes (aerobes) can grow both in the presence of oxygen and without it (Escherichia coli, pathogens of typhoid fever, paratyphoid fever).
MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION
TULA STATE UNIVERSITY
Department of Sanitary, Hygienic and Preventive Disciplines
CHESTNOVA T.V., SMOLYANINOVA O.L.
MEDICAL MICROBIOLOGY, VIRUSOLOGY
AND IMMUNOLOGY
(Educational and practical manual for students medical universities).
TULA – 2008
UDC 576.8
Reviewers:…………
Medical microbiology, virology and immunology: Educational and practical manual / Ed. M422 T.V. Chestnovoy, O.L. Smolyaninova, –….., 2008. -….p.
The educational and practical manual was written by employees of the Department of Sanitary, Hygienic and Preventive Disciplines of Tula state university in accordance with officially approved programs for teaching microbiology (bacteriology, virology, mycology, protozoology) and immunology for students of medical universities of all faculties.
The educational and practical manual describes the bacteriological laboratory, outlines microscopic research methods, the basics of preparing nutrient media, and contains information about the morphology, systematics and physiology of bacteria, fungi, protozoa and viruses. Characteristics of various pathogenic microorganisms, viruses and methods of their laboratory research are also given.
GENERAL MICROBIOLOGY
Introduction…………………………………………………………………………………………………………
Short story development of microbiology…………………………………………………………
Topic 1. Morphology and classification of microorganisms……………………………………..
1.1. Microbiological laboratories, their equipment, basic safety precautions and rules of work in them…………………………………………………………………………………..
1.2. Structure and classification of microorganisms……………………………………………………………………
1.3. Structure and classification of bacteria (prokaryotes)……………………………………………………….
1.4. Structure and classification of mushrooms……………………………………………………………..
1.5. Structure and classification of protozoa……………………………………………………….
1.6. Structure and classification of viruses………………………………………………………………
Test on the topic………………………………………………………………………………………..
Topic 2. Microscopy………………………………………………………………………………..
2.1. Microscopes, their structure, types of microscopy, microscopy techniques for microorganisms, rules for handling a microscope………………………………………………………….
2.2. Methods for preparing and staining microscopic preparations……………………..
Test on the topic………………………………………………………………………………………….
Topic 3. Physiology of microorganisms……………………………………………………………….
3.1. Growth and reproduction of bacteria. Reproduction phases…………………………………………………………….
3.2. Nutrient media, principles of their classification, requirements for nutrient media, methods of cultivating microorganisms…………………………………………..
3.3. Nutrition of bacteria………………………………………………………………………………….
3.4. Metabolism of the bacterial cell……………………………………………………………….
3.5. Types of plastic exchange…………………………………………………………………………………………
3.6. Principles and methods of isolating pure cultures. Bacterial enzymes, their identification. Intraspecific identification (epidemiological marking)……………………………..
3.7. Features of the physiology of fungi, protozoa, viruses and their cultivation………………
3.8. Bacteriophages, their structure, classification and application………………………………………………………..
Test on the topic…………………………………………………………………………………………
Topic 4. The influence of environmental conditions on microorganisms……………………………………..
4.1. The effect of physical, chemical and biological factors on microorganisms………….
4.2. The concept of sterilization, disinfection, asepsis and antiseptics. Sterilization methods, equipment. Disinfection quality control…………………………………………………………..
Topic 5. Normal microflora of the human body……………………………………………………………….
5.1. Normoflora, its significance for microorganisms. The concept of transient flora, dysbiotic conditions, their assessment, methods of correction……………………………………………………..
Topic 6. Genetics of microbes. …………………………………………………………………………………………..
6.1. Structure of the bacterial genome. Phenotypic and genotypic variability. Mutations. Modifications……………………………………………………………………………………..
Genetic recombinations of microorganisms. Fundamentals of genetic engineering, practical application…………………………………………………………………………………………………………….
Test on the topic………………………………………………………………………………………..
Topic 7. Antimicrobials………………………………………………………………………………….
7.1. Antibiotics natural and synthetic. Classification of antibiotics by chemical structure, mechanism, spectrum and type of action. Methods of obtaining…………………………….
7.2. Drug resistance of bacteria, ways to overcome it. Methods for determining sensitivity to antibiotics………………………………………………………………………………………..
Topic 8. The doctrine of infection……………………………………………………………………………………..
8.1. Concept of infection. Forms of infection and periods of infectious diseases. Pathogenicity and virulence. Pathogenicity factors. Bacterial toxins, their nature, properties, production…………………………………………………………………………………………….
8.2. The concept of epidemiological surveillance of the infectious process. The concept of the reservoir, source of infection, routes and factors of transmission………………………………………………………………
Test on the topic………………………………………………………………………………………..
GENERAL IMMUNOLOGY……………………………………………………………………………………….
Topic 9. Immunology…………………………………………………………………………………
9.1. The concept of immunity. Types of immunity. Nonspecific protective factors…………….
9.2. Central and peripheral organs immune system. Cells of the immune system. Forms of immune response…………………………………………………………………………………
9.3. Complement, its structure, functions, activation pathways. Role in immunity…………………..
9.4. Antigens, their properties and types. Antigens of microorganisms…………………………………..
9.5. Antibodies and antibody formation. Structure of immunoglobulins. Classes of immunoglobulins and their properties …………………………………………………………………………………………………………
96. Serological reactions and their application……………………………………………………….
9.7. Immunodeficiency states. Allergic reactions. Immunological memory. Immunological tolerance. Autoimmune processes………………………………………………………………
9.8. Immunoprophylaxis, immunotherapy………………………………………………………..
PRIVATE MICROBIOLOGY……………………………………………………………………………….
Topic 10. Pathogens of intestinal infections………………………………………………………….
10.1. Salmonella……………………………………………………………………………………..
10.2. Shigella……………………………………………………………………………………….
10.3. Escherichia………………………………………………………………………………………………………….
10.4. Vibrio cholerae……………………………………………………………………………….
10.5. Yersinia………………………………………………………………………………….
Topic 11. Foodborne toxic infections. Food toxicoses……………………………………………………………
11.1. general characteristics and pathogens of PTI…………………………………………………….
11.2. Botulism…………………………………………………………………………………………..
Topic 12. Pathogens of purulent-inflammatory diseases…………………………………………………………
12.1. Pathogenic cocci (streptococci, staphylococci)………………………………………………………………..
12.2. Gram-negative bacteria (Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella, Proteus)…
12.3. Wound anaerobic clostridial and non-clostridial infections………………………
Topic 13. Pathogens of bacterial airborne infections…………………………….
13.1. Corynebacteria……………………………………………………………………………………
13.2. Bordetella……………………………………………………………………………………………………………
13.3. Meningococci……………………………………………………………………………………..
13.4. Mycobacteria…………………………………………………………………………………..
13.5. Legionella………………………………………………………………………………………..
Topic 14. Pathogens of sexually transmitted diseases (STDs)………………………
14.1. Chlamydia…………………………………………………………………………………………..
14.2. The causative agent of syphilis…………………………………………………………………………………….
14.3. Gonococci……………………………………………………………………………………….
Topic 15. Pathogens of rickettsial diseases…………………………………………………………………………………..
Topic 16. Causative agents of bacterial zoonotic infections……………………………….
16.1. Francisella………………………………………………………………………………………
16.2. Brucella……………………………………………………………………………………….
16.3. The causative agent of anthrax…………………………………………………………………………………..
16.4. The causative agent of the plague…………………………………………………………………………………
16.5. Leptospira…………………………………………………………………………………..
Topic 17. Pathogenic protozoa………………………………………………………………………………..
17.1. Plasmodium malaria………………………………………………………………………………….
17.2. Toxoplasma……………………………………………………………………………………….
17.3. Leishmania………………………………………………………………………………………..
17.4. The causative agent of amoebiasis………………………………………………………………………….
17.5. Giardia……………………………………………………………………………………………………………
Topic 18. Diseases caused by pathogenic fungi………………………………………………………..
PRIVATE VIRUSOLOGY………………………………………………………………………………………..
Topic 19. Pathogens of acute respiratory viral infections…………………………………………………………………………………
19.1. Influenza viruses………………………………………………………………………………….
19.2. Parainfluenza. PC viruses………………………………………………………………………………………………
19.3. Adenoviruses…………………………………………………………………………………………………………
19.4. Rhinoviruses………………………………………………………………………………………..
19.5. Reoviruses……………………………………………………………………………………….
Topic 20. Pathogens of viral airborne infections……………………………………..
20.1. Measles and mumps viruses……………………………………………………………………………………..
20.2. Herpes virus……………………………………………………………………………………...
20.3. Rubella virus……………………………………………………………………………………
Topic 21. Poxyviruses………………………………………………………………………………….
21.1. The causative agent of smallpox…………………………………………………………………………………….
Topic 22. Enteroviral infections………………………………………………………………..
22.1. Poliovirus…………………………………………………………………………………
22.2. ECHO viruses. Coxsackie viruses…………………………………………………………………………………
Topic 23. Retroviruses……………………………………………………………………………….......
23.1. The causative agent of HIV infection………………………………………………………………………………………..
Topic 24. Arboviral infections……………………………………………………………………………………….
24.1.Rhabdoviruses……………………………………………………………………………………….
24.2. Flaviviruses…………………………………………………………………………………………………………
24.3. Hantaviruses……………………………………………………………………………………….
Topic 25. Causative agents of viral hepatitis…………………………………………………………………………………
25.1. Hepatitis A virus………………………………………………………………………………….
25.2. Hepatitis B virus…………………………………………………………………………………..
25.3. Hepatitis C virus…………………………………………………………………………………..
PART ONE. GENERAL MICROBIOLOGY
Introduction.
Microbiology is a science that studies microscopic creatures called microorganisms, their biological characteristics, systematics, ecology, and relationships with other organisms.
Microorganisms include bacteria, actinomycetes, fungi, including filamentous fungi, yeast, protozoa and non-cellular forms - viruses, phages.
Microorganisms play an extremely important role in nature - they carry out the circulation of organic and inorganic (N, P, S, etc.) substances, mineralize plant and animal residues. But they can bring great harm– causing damage to raw materials, food products, organic materials. This may result in the formation of toxic substances.
Many types of microorganisms are causative agents of diseases in humans, animals and plants.
At the same time, microorganisms are currently widely used in the national economy: with the help different types bacteria and fungi receive organic acids (acetic, citric, etc.), alcohols, enzymes, antibiotics, vitamins, and feed yeast. Baking, winemaking, brewing, production of dairy products, fermentation of fruits and vegetables, as well as other branches of the food industry operate on the basis of microbiological processes.
Currently, microbiology is divided into the following sections:
Medical microbiology - studies pathogenic microorganisms that cause human diseases and develops methods for diagnosing, preventing and treating these diseases. Studies the ways and mechanisms of their spread and methods of combating them. Adjacent to the course of medical microbiology is a separate course - virology.
Veterinary microbiology studies pathogenic microorganisms that cause diseases in animals.
Biotechnology examines the characteristics and conditions of development of microorganisms used to obtain compounds and drugs used in the national economy and medicine. She develops and improves scientific methods biosynthesis of enzymes, vitamins, amino acids, antibiotics and other biologically active substances. Biotechnology also faces the task of developing measures to protect raw materials, food, and organic materials from spoilage by microorganisms, and studying the processes that occur during their storage and processing.
Soil microbiology studies the role of microorganisms in the formation and fertility of soil and in plant nutrition.
Aquatic microbiology studies the microflora of water bodies, its role in food chains, in the cycle of substances, in the pollution and treatment of drinking and waste water.
Genetics of microorganisms, as one of the youngest disciplines, examines the molecular basis of heredity and variability of microorganisms, patterns of mutagenesis processes, develops methods and principles for controlling the life activity of microorganisms and obtaining new strains for use in industry, agriculture and medicine.
A brief history of the development of microbiology.
The credit for the discovery of microorganisms belongs to the Dutch naturalist A. Leeuwenhoek (1632-1723), who created the first microscope with a magnification of 300 times. In 1695 he published the book “Secrets of Nature” with drawings of cocci, rods, and spirilla. This aroused great interest among natural scientists. The state of science at that time allowed only to describe new species (morphological period).
The beginning of the physiological period is associated with the activities of the great French scientist Louis Pasteur (1822-1895). The name of Pasteur is associated with the largest discoveries in the field of microbiology: he investigated the nature of fermentation, established the possibility of life without oxygen (anaerobiosis), rejected the theory of spontaneous generation, and investigated the causes of spoilage of wines and beer. He proposed effective ways to combat pathogens of food spoilage (pasteurization), developed the principle of vaccination and methods for obtaining vaccines.
R. Koch, a contemporary of Pasteur, introduced sowing on solid nutrient media, counting microorganisms, isolating pure cultures, and sterilizing materials.
The immunological period in the development of microbiology is associated with the name of the Russian biologist I.I. Mechnikov, who discovered the doctrine of the body's immunity to infectious diseases (immunity), was the founder of the phagocytic theory of immunity, and discovered antagonism in microbes. Simultaneously with I.I. Mechnikov studied the mechanisms of immunity to infectious diseases by the major German researcher P. Ehrlich, who created the theory of humoral immunity.
Gamaleya N.F. – founder of immunology and virology, discovered bacteriophagy.
DI. Ivanovsky first discovered viruses and became the founder of virology. Working in Nikitsky botanical garden over the study of tobacco mosaic disease, which caused enormous damage to tobacco plantations, in 1892. found that this disease, widespread in Crimea, is caused by a virus.
N.G. Gabrichevsky organized the first bacteriological institute in Moscow. He owns works on the study of scarlet fever, diphtheria, plague and other infections. He organized the production of anti-diphtheria serum in Moscow and successfully used it to treat children.
P.F. Zdrodovsky is an immunologist and microbiologist, known for his fundamental work on the physiology of immunity, as well as in the field of rickettsiology and brucellosis.
V.M. Zhdanov is a major virologist, one of the organizers of the global eradication of smallpox on the planet, who stood at the origins of molecular virology and genetic engineering.
M.P. Chumakov is an immunobiotechnologist and virologist, organizer of the Institute of Poliomyelitis and Viral Encephalitis, author of an oral polio vaccine.
Z.V. Ermolyeva - the founder of domestic antibiotic therapy
The stages of development of microbiology are related to each other not so much chronologically as due to the main achievements and discoveries, therefore many researchers distinguish different periods, but most often the following: heuristic, morphological, physiological, immunological and molecular genetic.
HEURISTIC PERIOD (IV III centuries BC. XVI century)
It is associated more with logical and methodological methods of finding the truth, that is, heuristics, than with any experiments and evidence. Thinkers of this period (Hippocrates, the Roman writer Varro, Avicenna, etc.) made assumptions about the nature of infectious diseases, miasmas, and small invisible animals. These ideas were formulated into a coherent hypothesis many centuries later in the writings of the Italian physician D. Fracastoro (1478-1553), who expressed the idea of living contagium (contagium vivum), which causes diseases. Moreover, each disease is caused by its own contagion. To protect themselves from diseases, they were recommended to isolate the patient, quarantine, wear masks, and treat objects with vinegar.
MORPHOLOGICAL PERIOD (XVII - FIRST HALF of the XIX centuries)
It begins with the discovery of microorganisms by A. Leeuwenhoek. At this stage, the ubiquitous distribution of microorganisms was confirmed, the shapes of cells, the nature of movement, and the habitats of many representatives of the microcosm were described. The end of this period is significant in that the knowledge about microorganisms accumulated by this time and the scientific methodological level (in particular, the presence of microscopic technology) allowed scientists to solve three very important (basic) problems for all natural sciences: studying the nature of the processes of fermentation and decay, the causes of infectious diseases, the problem of the very origin of microorganisms.
Study of the nature of fermentation and decay processes. The term “fermentation” (fermentatio) to denote all processes involving the release of gas was first used by the Dutch alchemist J.B. Helmont (1579
1644). Many scientists have tried to define and explain this process. But the closest to understanding the role of yeast in the fermentation process was the French chemist A.L. Lavoisier (1743-1794) while studying the quantitative chemical transformations of sugar during alcoholic fermentation, but he did not have time to complete his work, as he became a victim of the terror of the French bourgeois revolution. Many scientists studied the fermentation process, but the French botanist C. Cagnard de Latour (studied the sediment during alcoholic fermentation and discovered living creatures) and the German naturalists F Kützing (during the formation of vinegar, he paid attention to the mucous film on the surface, which also consisted of living organisms) and T. Schwann. But their research was severely criticized by supporters of the theory of the physicochemical nature of fermentation. They were accused of “frivolity in their conclusions” and lack of evidence.
The second main problem about the microbial nature of infectious diseases was also solved during the morphological period of the development of microbiology. The first to suggest that diseases are caused by invisible creatures were the ancient Greek physician Hippocrates (c. 460-377 BC), Avicenna (c. 980-1037), etc. Despite the fact that the appearance of diseases is now had already been associated with discovered microorganisms, direct evidence was needed. And they were received by the Russian doctor, epidemiologist D.S. Samoilovich (1744 1805). Microscopes of that time had a magnification of approximately 300 times and did not allow detection of the plague causative agent, for the identification of which, as is now known, a magnification of 800-1000 times is necessary. To prove that the plague was caused by a special pathogen, he infected himself with the secretions of the bubo of a person suffering from the plague and fell ill with the plague. Fortunately, D.S. Samoilovich remained alive. Subsequently, heroic experiments on self-infection to prove the infectiousness of a particular microorganism were carried out by Russian doctors G.N. Minh and O.O. Mochutkovsky, I.I. Mechnikov and others. But priority in resolving the issue of the microbial nature of infectious diseases belongs to the Italian naturalist A. Basi (1773-1856), who was the first to experimentally establish the microbial nature of the disease of silkworms; he discovered the transmission of the disease when a microscopic fungus is transferred from a sick individual to a healthy one. But most researchers were convinced that the causes of all diseases are disturbances in the flow of chemical processes in the body.
The third problem, about the method of appearance and reproduction of microorganisms, was solved in a dispute with the then dominant theory of spontaneous generation. Despite the fact that the Italian scientist L. Spallanzani in the mid-18th century. observed the division of bacteria under a microscope, the opinion that they self-generate (arise from rot, dirt, etc.) was not refuted. This was done by the outstanding French scientist Louis Pasteur (1822-1895), who, with his work, laid the foundation for modern microbiology.
During the same period, the development of microbiology in Russia began. The founder of Russian microbiology is L.N. Tsenkovsky (1822-1887). The objects of his research are protozoa, algae, and fungi. He discovered and described big number protozoa, studied their morphology and development cycles, showed that there is no sharp boundary between the world of plants and animals. He organized one of the first Pasteur stations in Russia and proposed a vaccine against anthrax (live Tsenkovsky vaccine).
PHYSIOLOGICAL PERIOD (SECOND HALF of the 19th century) Rapid development of microbiology in the 19th century. led to the discovery of many microorganisms: nodule bacteria, nitrifying bacteria, causative agents of many infectious diseases (anthrax, plague, tetanus, diphtheria, cholera, tuberculosis, etc.), tobacco mosaic virus, foot-and-mouth disease virus, etc. The discovery of new microorganisms was accompanied by the study of not only their structure, but also their life activity, that is, to replace the morphological and systematic study of the first half of the 19th century. came the physiological study of microorganisms, based on precise experiment. Therefore the second half of XIX V. It is customary to call the physiological period in the development of microbiology.
This period is characterized by outstanding discoveries in the field of microbiology, and without exaggeration it could be called Pasteursky in honor of the brilliant French scientist L. Pasteur, because the scientific activity of this scientist covered all the main problems associated with the life of microorganisms. More about the main scientific discoveries L. Pasteur and their significance for protecting human health and economic activity person will be discussed in § 1.3.
The first of L. Pasteur's contemporaries to appreciate the significance of his discoveries was the English surgeon J. Lister (1827-1912), who, based on the achievements of L. Pasteur, first introduced into medical practice the treatment of all surgical instruments with carbolic acid, disinfection of operating rooms and achieved a reduction in the number of deaths after operations.
One of the founders of medical microbiology is Robert Koch (1843
1910), who developed methods for obtaining pure cultures of bacteria, staining bacteria during microscopy, and microphotography. The Koch triad formulated by R. Kokh is also known, which is still used to identify the causative agent of the disease. In 1877, R. Koch isolated the causative agent of anthrax, in 1882, the causative agent of tuberculosis, and in 1905 he was awarded the Nobel Prize for R. Koch's discovery of the causative agent of cholera.
During the physiological period, namely in 1867, M.S. Voronin described nodule bacteria, and almost 20 years later G. Gelriegel and G. Wilfart showed their ability to fix nitrogen. French chemists T. Schlesing and A. Münz substantiated the microbiological nature of nitrification (1877), and in 1882 P. Deguerin established the nature of denitrification, the nature of anaerobic decomposition of plant residues. Russian scientist P.A. Kostychev created a theory of the microbiological nature of soil formation processes.
Finally, in 1892, the Russian botanist D.I. Ivanovsky (1864-1920) discovered the tobacco mosaic virus. In 1898, regardless of D.I. Ivanovsky, the same virus was described by M. Beyerinck. Then the foot-and-mouth disease virus was discovered (F. Leffler, P. Frosh, 1897), yellow fever (W. Reed, 1901) and many other viruses. However, it became possible to see viral particles only after the invention of the electron microscope, since they are not visible in light microscopes. To date, the kingdom of viruses includes up to 1000 pathogenic species. Totally agree Lately A number of new viruses were discovered by D.I. Ivanovsky, including the virus that causes AIDS. There is no doubt that the period of discovery of new viruses and bacteria and the study of their morphology and physiology continues to the present day.
S.N. Winogradsky (1856-1953) and the Dutch microbiologist M. Beijerinck (1851-1931) introduced the microecological principle of studying microorganisms. S.N. Winogradsky proposed creating specific (elective) conditions that make it possible for the preferential development of one group of microorganisms, discovered in 1893 an anaerobic nitrogen fixer, which he named in honor of Pasteur Clostridium pasterianum, isolated microorganisms from the soil that represented a completely new type of life and were called chemolithoautotrophic .
The microecological principle was also developed by M. Beyerinck and applied to the isolation of various groups of microorganisms. 8 years after the discovery of S.N. Winogradsky, the nitrogen fixer M. Beijerinck, isolated Azotobacter chroococcum under aerobic conditions, studied the physiology of nodule bacteria, the processes of denitrification and sulfate reduction, etc. Both of these researchers are the founders of the ecological direction of microbiology, associated with the study of the role of microorganisms in the cycle of substances in nature.
TO end of the 19th century V. differentiation of microbiology into a number of special areas is planned: general, medical, soil.
IMMUNOLOGICAL PERIOD (EARLY XX century)
With the advent of the twentieth century. A new period in microbiology begins, which was led by the discoveries of the 19th century.
Works of L. Pasteur on vaccination, I.I. Mechnikov on phagocytosis, P. Ehrlich on the theory of humoral immunity constituted the main content of this stage in the development of microbiology, which rightfully received the title immunological.
Paul Ehrlich (1854-1915) German physician, bacteriologist and biochemist, one of the founders of immunology and chemotherapy, who put forward the humoral (from the Latin humor liquid) theory of immunity. He believed that immunity arises as a result of the formation of antibodies in the blood that neutralize the poison. This was confirmed by the discovery of antitoxin antibodies that neutralize toxins in animals that were injected with diphtheria or tetanus toxin (E. Behring, S. Kitazato).
In 1883, he formulated the phagocytic theory of immunity. Human immunity to re-infection has been known for a long time, but the nature of this phenomenon was unclear even after
I.I. Swordsmen of how vaccination against many diseases became widely used. I.I. Mechnikov showed that the body’s defense against pathogenic bacteria is a complex biological reaction, which is based on the ability of phagocytes (macro and microphages) to capture and destroy foreign bodies that enter the body, including bacteria. Research by I.I. Mechnikov’s work on phagocytosis convincingly proved that, in addition to humoral, there is cellular immunity.
I.I. Mechnikov and P. Ehrlich were scientific opponents for many years, each experimentally proving the validity of his theory. Subsequently, it turned out that there is no contradiction between humoral and phagocytic immunity, since these mechanisms protect the body together. And in 1908 I.I. Mechnikov, together with P. Ehrlich, was awarded the Nobel Prize for developing the theory of immunity.
The immunological period is characterized by the discovery of the main reactions of the immune system to genetically foreign substances (antigens): antibody formation and phagocytosis, delayed-type hypersensitivity (DTH), immediate-type hypersensitivity (IHT), tolerance, immunological memory.
Microbiology and immunology developed especially rapidly in the 50s and 60s. twentieth century. This was facilitated by the most important discoveries in the field of molecular biology, genetics, and bioorganic chemistry; the emergence of new sciences: genetic engineering, molecular biology, biotechnology, computer science; creation of new methods and use of scientific equipment.
Immunology is the basis for the development of laboratory methods for diagnosis, prevention and treatment of infectious and many non-infectious diseases, as well as the development of immunobiological drugs (vaccines, immunoglobulins, immunomodulators, allergens, diagnostic drugs). The development and production of immunobiological preparations is carried out by immunobiotechnology, an independent branch of immunology. Modern medical microbiology and immunology have achieved great success and play a huge role in the diagnosis, prevention and treatment of infectious and many non-infectious diseases associated with a disorder of the immune system (oncological, autoimmune diseases, organ and tissue transplantation, etc.).
MOLECULAR GENETIC PERIOD (Since the 50s of the twentieth century)
It is characterized by a number of fundamentally important scientific achievements and discoveries:
1. Deciphering the molecular structure and molecular biological organization of many viruses and bacteria; discovery of the simplest life forms of the “infectious” prion protein.
2. Deciphering the chemical structure and chemical synthesis of some antigens. For example, the chemical synthesis of lysozyme (D. Sela, 1971), peptides of the AIDS virus (R.V. Petrov, V.T. Ivanov, etc.).
3. Deciphering the structure of immunoglobulin antibodies (D. Edelman, R. Porter, 1959).
4. Development of a method for culturing animal and plant cells and growing them on an industrial scale in order to obtain viral antigens.
5. Obtaining recombinant bacteria and recombinant viruses.
6. Creation of hybridomas by fusion of immune B lymphocytes producing antibodies and cancer cells to produce monoclonal antibodies (D. Keller, Ts. Milshtein, 1975).
7. Discovery of immunomodulators immunocytokinins (interleukins, interferons, myelopeptides, etc.) endogenous natural regulators of the immune system and their use for the prevention and treatment of various diseases.
8. Production of vaccines using biotechnology methods and genetic engineering techniques (hepatitis B, malaria, HIV antigens and other antigens) and biologically active peptides (interferons, interleukines, growth factors, etc.).
9. Development of synthetic vaccines based on natural or synthetic antigens and their fragments.
10. Discovery of viruses that cause immunodeficiencies.
11. Development of fundamentally new methods for diagnosing infectious and non-infectious diseases (enzyme immunoassays, radioimmunoassays, immunoblotting, nucleic acid hybridization). Creation of test systems based on these methods for indication, identification of microorganisms, diagnosis of infectious and non-infectious diseases.
In the second half of the twentieth century. The formation of new directions in microbiology continues, new disciplines with their own objects of research (virology, mycology) are sprouting from it, directions that differ in research objectives are being identified (general microbiology, technical, agricultural, medical microbiology, genetics of microorganisms, etc.) . Many forms of microorganisms were studied and by about the mid-50s. last century by A. Kluiver (1888
1956) and K. Neel (1897-1985) formulated the theory of the biochemical unity of life.
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