Both in the course of the school curriculum and within the framework of specialized university education, examples from the kingdom of bacteria are necessarily considered. This oldest form of life on our planet appeared earlier than any other known to man. For the first time, as scientists estimate, bacteria formed about three and a half billion years ago, and for about a billion years there were no other forms of life on the planet. Examples of bacteria, our enemies and friends, are necessarily considered within the framework of any educational program, because it is these microscopic life forms that make possible the processes characteristic of our world.
Features of prevalence
Where in the living world can examples of bacteria be found? Yes, almost everywhere! They are in spring water, and in desert dunes, and elements of soil, air and rocky rocks. In Antarctic ice, for example, bacteria live at a frost of -83 degrees, but high temperatures do not interfere with them - life forms have been found in sources where the liquid is heated to +90. The population density of the microscopic world is evidenced by the fact that, for example, bacteria in a gram of soil is innumerable hundreds of millions.
Bacteria can live on any other form of life - on a plant, an animal. Many people know the phrase "intestinal microflora", and on TV they constantly advertise products that improve it. In fact, it is, for example, just formed by bacteria, that is, normally in the human body, there are also innumerable microscopic life forms. They are also on our skin, in the mouth - in a word, anywhere. Some of them are really harmful and even life-threatening, which is why antibacterial agents are so widespread, but without others it would be simply impossible to survive - our species coexist in symbiosis.
living conditions
Whatever the example of bacteria, these organisms are exceptionally resistant, can survive in adverse conditions, easily adapt to negative factors. Some forms need oxygen to survive, while others can do just fine without it. There are many examples of representatives of bacteria that survive excellently in an anoxic environment.
Studies have shown that microscopic life forms can survive in severe frost, they are not afraid of very high dryness or high temperatures. The spores by which bacteria multiply can easily cope even with prolonged boiling or processing at low temperatures.
What are there?
When examining examples of bacteria (enemies and friends of man), it must be remembered that modern biology introduces a classification system that somewhat simplifies the understanding of this diverse kingdom. It is customary to talk about several different forms, each of which has a specialized name. So, bacteria in the form of a ball are called cocci, streptococci are balls collected in a chain, and if the formation looks like a bunch, then it belongs to the group of staphylococci. Such microscopic forms of life are known when two bacteria live at once in one capsule covered with a mucous membrane. These are called diplococci. Bacilli are rod-shaped, spirilla are spirals, and vibrios are an example of a bacterium (any student who responsibly passes the program should be able to bring it), which is similar in shape to a comma.
This name was adopted for microscopic life forms that, when analyzed by Gram, do not change color when exposed to crystal violet. For example, pathogenic and harmless gram-positive bacteria retain a purple hue even when washed with alcohol, but gram-negative ones are completely discolored.
When examining a microscopic lifeform after a Gram wash, a contract stain (safranin) should be used, which will cause the bacterium to turn pink or red. This reaction is due to the structure of the outer membrane, which prevents the dye from penetrating inside.
Why is this needed?
If, as part of a school course, a student is given the task of giving examples of bacteria, he can usually remember those forms that are considered in the textbook, and their key features are already indicated for them. The stain test was invented precisely to detect these specific parameters. Initially, the study was aimed at classifying representatives of the microscopic life form.
The results of the Gram test allow conclusions to be drawn regarding the structure of the cell walls. Based on the information received, all identified forms can be divided into two groups, which is further taken into account in the work. For example, pathogenic bacteria from the Gram-negative class are much more resistant to the influence of antibodies, since the cell wall is impenetrable, protected, and powerful. But for gram-positive resistance is characterized by a markedly lower.
Pathogenicity and features of interaction
A classic example of a disease caused by bacteria is an inflammatory process that can develop in a variety of tissues and organs. Most often, such a reaction is provoked by gram-negative life forms, since their cell walls cause a reaction from the human immune system. The walls contain LPS (lipopolysaccharide layer), in response to which the body generates cytokines. This provokes inflammation, the host body is forced to cope with the increased production of toxic components, which is due to the struggle between the microscopic life form and the immune system.
Which ones are known?
In medicine, at present, special attention is paid to three forms that provoke serious diseases. The bacterium Neisseria gonorrhoeae is transmitted sexually, symptoms of respiratory pathologies are observed when the body is infected with Moraxella catarrhalis, and one of the very dangerous diseases for humans - meningitis - is provoked by the bacterium Neisseria meningitidis.
Bacilli and diseases
Considering, for example, bacteria, the diseases that they provoke, it is simply impossible to ignore bacilli. This word is currently known to any layman, even very poorly imagining the features of microscopic life forms, and it is this variety of gram-negative bacteria that is extremely important for modern doctors and researchers, as it provokes serious problems of the human respiratory system. There are also known examples of diseases of the urinary system, provoked by such an infection. Some bacilli adversely affect the functioning of the gastrointestinal tract. The degree of damage depends both on the immunity of the person and on the specific form that infected the body.
A certain group of Gram-negative bacteria is associated with an increased likelihood of nosocomial infection. The most dangerous of the relatively widespread cause secondary meningitis, pneumonia. The most accurate should be employees of medical institutions of the intensive care unit.
Lithotrophs
Considering examples of bacterial nutrition, special attention should be paid to the unique group of lithotrophs. This is such a microscopic form of life, which for its activity receives energy from an inorganic compound. Metals, hydrogen sulfide, ammonium, and many other compounds are used, from which the bacterium receives electrons. An oxygen molecule or another compound that has already passed the oxidation stage acts as an oxidizing agent in the reaction. The transfer of an electron is accompanied by the production of energy stored by the body and used in metabolism.
For modern scientists, lithotrophs are of interest primarily because they are living organisms rather atypical for our planet, and the study allows us to significantly expand our understanding of the possibilities that some groups of living beings have. Knowing the examples, the names of bacteria from the class of lithotrophs, examining the features of their vital activity, it is possible to some extent restore the primary ecological system of our planet, that is, the period when there was no photosynthesis, oxygen did not exist, and even organic matter has not yet appeared. The study of lithotrophs gives a chance to know life on other planets, where it can be realized due to the oxidation of inorganic matter, in the complete absence of oxygen.
Who and what?
What are lithotrophs in nature? An example is nodule bacteria, chemotrophic, carboxytrophic, methanogens. Currently, scientists cannot say for sure that they have been able to detect all the varieties belonging to this group of microscopic life forms. It is assumed that further research in this direction is one of the most promising areas of microbiology.
Lithotrophs take an active part in cyclic processes that are important for the conditions for the existence of life on our planet. Often, the chemical reactions provoked by these bacteria have a rather strong effect on the space. So, sulfur bacteria can oxidize hydrogen sulfide in sediments at the bottom of a reservoir, and without such a reaction, the component would react with oxygen contained in the water layers, which would make life in it impossible.
Symbiosis and opposition
Who does not know examples of viruses, bacteria? As part of the school course, everyone is told about pale treponema, which can provoke syphilis, flambesia. There are also viruses of bacteria, which are known to science as bacteriophages. Studies have shown that in just one second they can infect 10 to the 24th degree of bacteria! This is both a powerful tool for evolution and a method applicable to genetic engineering, which is currently being actively studied by scientists.
Importance of life
There is a misconception in the philistine environment that bacteria are only the cause of human disease, and there is no more benefit or harm from them. This stereotype is due to the anthropocentric picture of the surrounding world, that is, the idea that everything somehow correlates with a person, revolves around him, and exists only for him. In fact, we are talking about constant interaction without any specific center of rotation. Bacteria and eukaryotes have been interacting for as long as both these kingdoms exist.
The first way to fight bacteria, invented by mankind, was associated with the discovery of penicillin, a fungus that can destroy microscopic life forms. Fungi belong to the kingdom of eukaryotes and, from the point of view of the biological hierarchy, are more closely related to humans than plants. But studies have shown that fungi are far from the only and not even the first thing that has become an enemy of bacteria, because eukaryotes appeared much later than microscopic life. Initially, the struggle between bacteria (and other forms simply did not exist) was using the components that these organisms produced in order to win a place for themselves to exist. At present, a person, trying to discover new ways to fight bacteria, can only discover those methods that have been known to nature for a long time and were used by organisms in the struggle for life. But drug resistance, which scares so many people so much, is a normal resistance reaction that has been inherent in microscopic life for many millions of years. It was she who determined the ability of bacteria to survive all this time and continue to develop and multiply.
Attack or die
Our world is a place where only those who are adapted to life, capable of defending, attacking, surviving, can survive. At the same time, the ability to attack is closely related to the options for protecting oneself, one's life, and interests. If a certain bacterium could not escape antibiotics, that species would die out. Currently existing microorganisms have quite developed and complex defense mechanisms that are effective against a wide variety of substances and compounds. The most applicable method in nature is the redirection of danger to another target.
The appearance of an antibiotic is accompanied by an impact on the molecule of a microscopic organism - on RNA, protein. If you change the target, then the place where the antibiotic can bind will change. A point mutation, which makes one organism resistant to the action of an aggressive component, becomes the reason for the improvement of the whole species, since it is this bacterium that continues to actively reproduce.
Viruses and bacteria
This topic is currently causing a lot of talk among both professionals and laymen. Almost every second considers himself a specialist in viruses, which is connected with the work of mass media systems: as soon as the flu epidemic approaches, they talk and write about viruses everywhere and everywhere. A person, having become acquainted with these data, begins to believe that he knows everything that is possible. Of course, it is useful to get acquainted with the data, but do not be mistaken: not only ordinary people, but also professionals, at present, have yet to discover most of the information about the features of the vital activity of viruses and bacteria.
By the way, in recent years, the number of people convinced that cancer is a viral disease has increased significantly. Many hundreds of laboratories around the world have conducted studies from which such a conclusion can be drawn regarding leukemia, sarcoma. However, so far these are only assumptions, and the official evidence base is not enough to make a precise conclusion.
Virology
This is a rather young branch of science, which originated eight decades ago, when it was discovered that it provokes tobacco mosaic disease. Noticeably later, the first image was obtained, although very inaccurate, and more or less correct research has been carried out only in the last fifteen years, when the technologies available to mankind made it possible to study such small life forms.
At present, there is no exact information about how and when viruses appeared, but one of the main theories is that this life form originated from bacteria. Instead of evolution, degradation took place here, development turned back, and new unicellular organisms were formed. A group of scientists argue that viruses were previously much more complex, but a number of features have been lost over time. The state that is available for study by modern man, the diversity of the data of the genetic fund are only echoes of different degrees, stages of degradation, characteristic of a particular species. How correct this theory is is still unknown, but the existence of a close relationship between bacteria and viruses cannot be denied.
Bacteria: so different
Even if a modern person understands that bacteria surround him everywhere and everywhere, it is still difficult to realize how much the processes of the surrounding world depend on microscopic life forms. Only recently, scientists have found that live bacteria even fill the clouds, where they rise with steam. The abilities given to such organisms are surprising and inspiring. Some provoke the transformation of water into ice, which causes precipitation. As the pellet begins to fall, it melts again, and a shower of water—or snow, depending on the climate and season—falls onto the ground. Not so long ago, scientists suggested that through bacteria, you can achieve an increase in precipitation.
The described abilities have so far been discovered in the study of a species that has received the scientific name Pseudomonas Syringae. Scientists have previously assumed that clouds that are clear for the human eye are filled with life, and modern means, technologies and tools have made it possible to prove this point of view. According to rough estimates, a cubic meter of cloud is filled with microbes at a concentration of 300-30,000 copies. Among others, the mentioned form of Pseudomonas Syringae is present here, provoking the formation of ice from water at a rather high temperature. It was first discovered several decades ago while studying plants and grown in an artificial environment - it turned out to be quite simple. Currently, Pseudomonas Syringae are actively working for the benefit of mankind in ski resorts.
How does this happen?
The existence of Pseudomonas Syringae is associated with the production of proteins that cover the surface of a microscopic organism in a mesh. When a water molecule approaches, a chemical reaction begins, the lattice is leveled, a grid appears, which causes the formation of ice. The core attracts water, increases in size and mass. If all this happened in a cloud, then the increase in weight leads to the impossibility of further soaring and the pellet falls down. The form of precipitation is determined by the air temperature near the earth's surface.
Presumably, Pseudomonas Syringae can be resorted to during a period of drought, for which it is necessary to introduce a colony of bacteria into the cloud. Currently, scientists do not know exactly what concentration of microorganisms can provoke rain, so experiments are being carried out, samples are taken. At the same time, it is necessary to find out why Pseudomonas Syringae moves by clouds, if the microorganism normally lives on the plant.