Bacteria - what diseases they cause, names and types. Microbiology

At this very moment, man, when you read these lines, you are benefiting from the work of bacteria. From the oxygen we breathe in to the nutrients our stomachs extract from our food, we have bacteria to thank for thriving on this planet. In our body there are about ten times more microorganisms, including bacteria, than our own cells. Essentially, we are more microbes than people.

It's only recently that we've begun to understand a little about microscopic organisms and their impact on our planet and health, but history shows that centuries ago our ancestors were already harnessing the power of bacteria to ferment foods and drinks (whoever heard of bread and beer?).

In the 17th century, we began to study bacteria directly in our bodies in close connection with us - in the mouth. Antoni van Leeuwenhoek's curiosity led to the discovery of bacteria when he examined a plaque between his own teeth. Van Leeuwenhoek waxed poetic about the bacteria, describing the bacterial colony on his teeth as “a little white substance, like hardened dough.” Placing the sample under a microscope, van Leeuwenhoek saw that the microorganisms were moving. So they are alive!

You should know that bacteria have played a critical role on Earth, being key to the creation of breathable air and the biological richness of the planet we call home.

In this article, we will provide you with an overview of these tiny but very influential microorganisms. We'll look at the good, the bad, and the downright bizarre ways that bacteria shape human and environmental history. First, let's look at how bacteria differ from other types of life.

Bacteria Basics

Well, if bacteria are invisible to the naked eye, how can we know so much about them?

Scientists have developed powerful microscopes to look at bacteria - which range in size from one to a few microns (millionths of a meter) - and figure out how they relate to other life forms, plants, animals, viruses and fungi.

As you may know, cells are the building blocks of life, from the tissues of our body to the tree that grows outside our window. Humans, animals and plants have cells with genetic information contained in a membrane called the nucleus. These types of cells, called eukaryotic cells, have specialized organelles, each of which has a unique job to help the cell function.

Bacteria, however, do not have a nucleus, and their genetic material (DNA) floats freely inside the cell. These microscopic cells have no organelles and have other methods of reproduction and transfer of genetic material. Bacteria are considered prokaryotic cells.

Do bacteria survive in an environment with or without oxygen?

Their shape: rods (bacillus), circles (cocci) or spirals (spirillum)

Are the bacteria gram-negative or gram-positive, that is, do they have an outer protective membrane that prevents staining of the cell interior?

How bacteria move and explore their environment (many bacteria have flagella, tiny whip-like structures that allow them to move around in their environment)

Microbiology - the study of all types of microbes, including bacteria, archaea, fungi, viruses and protozoa - distinguishes bacteria from their microbial cousins.

Bacteria-like prokaryotes, now classified as archaea, were once together with bacteria, but as scientists learned more about them, they gave bacteria and archaea their own categories.

Microbial nutrition (and miasma)

Like people, animals and plants, bacteria need food to survive.

Some bacteria—autotrophs—use basic resources like sunlight, water, and environmental chemicals to create food (think of cyanobacteria, which have been converting sunlight into oxygen for 2.5 million years). Other bacteria are called heterotrophs by scientists because they get their energy from existing organic matter as food (for example, dead leaves on forest floors).

The truth is that what may be tasty to bacteria will be disgusting to us. They have evolved to absorb all types of products, from oil spills and nuclear byproducts to human waste and decomposition products.

But a bacteria's affinity for a particular food source could benefit society. For example, art experts in Italy turned to bacteria that can eat excess layers of salt and glue, reducing the durability of priceless works of art. The ability of bacteria to process organic matter is also very beneficial for the Earth, both in soil and in water.

From daily experience, you're well aware of the odor caused by bacteria as they consume the contents of your trash can, digesting leftover food and emitting their own gaseous byproducts. However, this is not all. You can also blame bacteria for causing those awkward moments when you pass gas yourself.

One big family

Bacteria grow and form colonies when given the chance. If food and environmental conditions are favorable, they reproduce and form sticky clumps called biofilms to survive on surfaces ranging from rocks to the teeth of your mouth.

Biofilms have their pros and cons. On the one hand, they are mutually beneficial to natural objects (mutualism). On the other hand, they can be a serious threat. For example, doctors who treat patients with medical implants and devices have serious concerns about biofilms because they provide real estate for bacteria. Once colonized, biofilms can produce byproducts that are toxic—and sometimes fatal—to humans.

Like people in cities, cells in a biofilm communicate with each other, exchanging information about food and potential dangers. But instead of calling neighbors on the phone, bacteria send notes using chemicals.

Also, bacteria are not afraid to live on their own. Some species have developed interesting ways to survive in harsh environments. When there is no more food and conditions become unbearable, bacteria preserve themselves by creating a hard shell, an endospore, which puts the cell into a state of dormancy and preserves the genetic material of the bacterium.

Scientists find bacteria in such time capsules that were stored for 100 and even 250 million years. This suggests that the bacteria can self-storage for a long time.

Now that we know what opportunities colonies provide to bacteria, let's figure out how they get there - through division and reproduction.

Bacteria reproduction

How do bacteria create colonies? Like other life forms on Earth, bacteria need to replicate themselves in order to survive. Other organisms do this through sexual reproduction, but not bacteria. But first, let's discuss why diversity is good.

Life undergoes natural selection, or the selective forces of a certain environment allow one type to flourish and reproduce more than another. You may remember that genes are the machinery that instructs a cell what to do and determines what color your hair and eyes will be. You get genes from your parents. Sexual reproduction results in mutations, or random changes in DNA, which creates diversity. The more genetic diversity there is, the greater the chance that an organism will be able to adapt to environmental constraints.

For bacteria, reproduction does not depend on meeting the right microbe; they simply copy their own DNA and divide into two identical cells. This process, called binary fission, occurs when one bacterium splits into two, copying DNA and passing it on to both parts of the divided cell.

Since the resulting cell will ultimately be identical to the one from which it was born, this method of propagation is not the best for creating a diverse gene pool. How do bacteria acquire new genes?

It turns out that bacteria use a clever trick: horizontal gene transfer, or the exchange of genetic material without reproducing. There are several ways that bacteria use to do this. One method involves collecting genetic material from the environment outside the cell - from other microbes and bacteria (through molecules called plasmids). Another way is viruses, which use bacteria as a home. When viruses infect a new bacterium, they leave the genetic material of the previous bacterium in the new one.

The exchange of genetic material gives bacteria the flexibility to adapt, and they adapt if they sense stressful changes in the environment, such as food shortages or chemical changes.

Understanding how bacteria adapt is extremely important for fighting them and creating antibiotics for medicine. Bacteria can exchange genetic material so frequently that sometimes treatments that worked before no longer work.

No high mountains, no great depths

If you ask the question “where are the bacteria?”, it is easier to ask “where are there no bacteria?”

Bacteria are found almost everywhere on Earth. It is impossible to imagine the number of bacteria on the planet at any one time, but some estimates put their number (bacteria and archaea together) at 5 octillion - a number with 27 zeros.

Classifying bacterial species is extremely difficult for obvious reasons. There are now approximately 30,000 officially identified species, but the knowledge base is constantly growing, and there are opinions that we are just the tip of the iceberg of all types of bacteria.

The truth is that bacteria have been around for a very long time. They produced some of the oldest fossils, dating back 3.5 billion years. Scientific research suggests that cyanobacteria began creating oxygen approximately 2.3-2.5 billion years ago in the world's oceans, saturating the Earth's atmosphere with the oxygen we breathe to this day.

Bacteria can survive in the air, water, soil, ice, heat, on plants, in the intestines, on the skin - everywhere.

Some bacteria are extremophiles, meaning they can withstand extreme conditions that are either very hot or cold, or lack the nutrients and chemicals we typically associate with life. Researchers found such bacteria in the Mariana Trench, the deepest point on Earth at the bottom of the Pacific Ocean, near hydrothermal vents in water and ice. There are also bacteria that like high temperatures, such as those that color the opalescent pool in Yellowstone National Park.

Bad (for us)

While bacteria make important contributions to human and planetary health, they also have a dark side. Some bacteria can be pathogenic, meaning they cause illness and disease.

Throughout human history, certain bacteria have (understandably) gotten a bad rap, causing panic and hysteria. Take the plague, for example. The bacterium that causes the plague, Yersinia pestis, not only killed more than 100 million people, but may have contributed to the collapse of the Roman Empire. Before the advent of antibiotics, drugs that help fight bacterial infections, they were very difficult to stop.

Even today, these pathogenic bacteria seriously scare us. Thanks to the development of resistance to antibiotics, bacteria that cause anthrax, pneumonia, meningitis, cholera, salmonellosis, tonsillitis and other diseases that still remain close to us always pose a danger to us.

This is especially true for Staphylococcus aureus, the bacterium responsible for staph infections. This “superbug” causes numerous problems in clinics, since patients very often contract this infection when implanting medical implants and catheters.

We've already talked about natural selection and how some bacteria produce a variety of genes that help them cope with environmental conditions. If you have an infection and some of the bacteria in your body are different from others, antibiotics may affect most of the bacterial population. But those bacteria that survive will develop resistance to the drug and remain, waiting for the next chance. Therefore, doctors recommend completing the course of antibiotics to the end, and in general using them as rarely as possible, only as a last resort.

Biological weapons are another frightening aspect of this conversation. Bacteria can be used as a weapon in some cases, in particular anthrax was used at one time. In addition, not only people suffer from bacteria. A separate species, Halomonas titanicae, has shown an appetite for the sunken ocean liner Titanic, eating away at the metal of the historic ship.

Of course, bacteria can cause more than just harm.

Heroic bacteria

Let's explore the good side of bacteria. After all, these microbes gave us delicious foods like cheese, beer, sourdough and other fermented elements. They also improve human health and are used in medicine.

Individual bacteria can be thanked for shaping human evolution. Science is collecting more and more data about microflora - microorganisms that live in our bodies, especially in the digestive system and intestines. Research shows that bacteria, new genetic materials, and the diversity they bring to our bodies allow humans to adapt to new food sources that have not been exploited before.

Let's look at it this way: by lining the surface of your stomach and intestines, bacteria “work” for you. When you eat, bacteria and other microbes help you break down and extract nutrients from your food, especially carbohydrates. The more diverse the bacteria we consume, the more diversity our bodies gain.

Although our knowledge of our own microbes is very limited, there is reason to believe that the absence of certain microbes and bacteria in the body may be associated with human health, metabolism and susceptibility to allergens. Preliminary studies in mice have shown that metabolic diseases like obesity are associated with a diverse and healthy microbiota, rather than our prevailing “calories in, calories out” mentality.

The possibility of introducing certain microbes and bacteria into the human body that may provide certain benefits is currently being actively explored, but at the time of writing, general recommendations for their use have not yet been established.

In addition, bacteria played an important role in the development of scientific thought and human medicine. Bacteria played a leading role in the development of Koch's 1884 postulates, which led to the general understanding that disease is caused by a specific type of microbe.

Researchers studying bacteria accidentally discovered penicillin, an antibiotic that saved many lives. Also, quite recently, in connection with this, an easy way to edit the genome of organisms was discovered, which could revolutionize medicine.

In fact, we are just beginning to understand how to benefit from our cohabitation with these little friends. In addition, it is not clear who is the true owner of the Earth: people or microbes.

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

In the absence of any type of beneficial bacteria, a person begins to get sick, the functioning of the gastrointestinal tract and respiratory tract is disrupted. Beneficial bacteria for humans are concentrated on the skin, in the intestines, and on the mucous membranes of the body. The number of microorganisms is regulated by the immune system.

Normally, the human body contains both beneficial and pathogenic microflora. Bacteria can be beneficial or pathogenic.

There are many more beneficial bacteria. They make up 99% of the total number of microorganisms.

In this situation, the necessary balance is maintained.

Among the different types of bacteria that live on the human body are:

• bifidobacteria;
• lactobacilli;
• enterococci;
• coli.

Bifidobacteria

This type of microorganism is the most common and is involved in the production of lactic acid and acetate. It creates an acidic environment, thereby neutralizing most pathogenic microbes. Pathogenic flora ceases to develop and cause processes of rotting and fermentation.

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

The synthesis of vitamin C is not complete without the participation of bifidobacteria. In addition, there is information that bifidobacteria help to absorb vitamins D and B, which are necessary for a person to function normally. If there is a deficiency of bifidobacteria, even taking synthetic vitamins of this group will not bring any results.

Lactobacilli

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

Lactobacilli are involved in the formation of lactic acid, lysocine, and bacteriocins. This is a great help for the immune system. If there is a deficiency of these bacteria in the intestines, then dysbiosis develops very quickly.

Lactobacilli populate not only the intestines, but also the mucous membranes. So these microorganisms are important for women's health. They maintain the acidity of the vaginal environment and prevent development.

Escherichia coli

Not all types of E. coli are pathogenic. Most of them, on the contrary, perform a protective function. The usefulness of the genus lies in the synthesis of cocilin, which actively resists the bulk of pathogenic microflora.

These bacteria are useful for the synthesis of various groups of vitamins, folic and nicotinic acid. Their role in health should not be underestimated. For example, folic acid is essential for the production of red blood cells and maintaining normal hemoglobin levels.

Enterococci

They help absorb sucrose. Living mainly in the small intestine, they, like other beneficial non-pathogenic bacteria, provide protection against excessive proliferation of harmful elements. At the same time, enterococci are considered to be relatively safe bacteria.

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

Positive effects of bacteria on the body

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

Most bacteria are involved in the synthesis and breakdown of vitamins. Without their presence, B vitamins are not absorbed by the intestines, which leads to disorders of the nervous system, skin diseases, and decreased hemoglobin.

The bulk of undigested food components that reach the large intestine are broken down precisely by bacteria. In addition, microorganisms ensure the constancy of water-salt metabolism. More than half of all microflora is involved in the regulation of the absorption of fatty acids and hormones.

The intestinal microflora forms local immunity. It is here that the bulk of pathogenic organisms are destroyed and the harmful microbe is blocked.

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

Beneficial non-pathogenic microorganisms have a positive effect on the walls of the small and large intestines. They maintain a constant level of acidity there, stimulate the lymphoid apparatus, the epithelium becomes resistant to various carcinogens.

Intestinal peristalsis also largely depends on what microorganisms are in it. Suppressing the processes of decay and fermentation is one of the main tasks of bifidobacteria. Many microorganisms develop for many years in symbiosis with pathogenic bacteria, thereby controlling them.

Biochemical reactions that constantly occur with bacteria release a lot of thermal energy, maintaining the overall thermal balance of the body. Microorganisms feed on undigested residues.

Dysbacteriosis

Dysbacteriosis is a change in the quantitative and qualitative composition of bacteria in the human body . In this case, beneficial organisms die, and harmful ones actively reproduce.

Dysbacteriosis affects not only the intestines, but also the mucous membranes (there may be dysbiosis of the oral cavity, vagina). The names that will prevail in the analyzes are: streptococcus, staphylococcus, micrococcus.

In normal conditions, beneficial bacteria regulate the development of pathogenic microflora. The skin and respiratory organs are usually under reliable protection. When the balance is disturbed, a person experiences the following symptoms: intestinal flatulence, bloating, abdominal pain, frustration.

Later, weight loss, anemia, and vitamin deficiency may begin. From the reproductive system there is abundant discharge, often accompanied by an unpleasant odor. Irritation, roughness, and cracks appear on the skin. Dysbacteriosis is a side effect after taking antibiotics.

If you notice such symptoms, you should definitely consult a doctor, who will prescribe a set of measures to restore normal microflora. This often requires taking probiotics.

People are trying to find new ways to protect themselves from their harmful influence. But there are also beneficial microorganisms: they promote the ripening of cream, the formation of nitrates for plants, decompose dead tissue, etc. Microorganisms live in water, soil, air, on the body of living organisms and inside them.

Shapes of bacteria

There are main 4 forms of bacteria, namely:

1. Micrococci – located separately or in irregular clusters. They are usually motionless.
2. Diplococci are arranged in pairs and can be surrounded by a capsule in the body.
3. Streptococci occur in the form of chains.
4. Sarcines form clusters of cells shaped like packets.
5. Staphylococci. As a result of the division process, they do not diverge, but form clusters (clusters).

The bacterium has a complex structure:

• Wall cells protect a single-celled organism from external influences, give it a certain shape, provide nutrition and preserve its internal contents.
• Cytoplasmic membrane contains enzymes, participates in the process of reproduction and biosynthesis of components.
• Cytoplasm serves to perform vital functions. In many species, the cytoplasm contains DNA, ribosomes, various granules, and a colloidal phase.
• Nucleoid is the irregularly shaped nuclear region in which DNA is located.
• Capsule is a surface structure that makes the shell more durable and protects against damage and drying out. This mucous structure is more than 0.2 microns thick. With a smaller thickness it is called microcapsule. Sometimes around the shell there is slime, has no clear boundaries and is soluble in water.
• flagella are called surface structures that serve to move cells in a liquid environment or on a solid surface.
• Drank- thread-like formations, much thinner and fewer flagella. They come in various types, differ in purpose and structure. Pili are needed to attach the organism to the affected cell.
• Controversy. Sporulation occurs when unfavorable conditions arise and serves to adapt the species or preserve it.

We suggest considering the main types of bacteria:

Nutrients enter the cell through its entire surface. Microorganisms have become widespread due to the existence of different types of nutrition. To live, they need a variety of elements: carbon, phosphorus, nitrogen, etc. The supply of nutrients is regulated using a membrane.

The type of nutrition is determined by how carbon and nitrogen are absorbed and by the type of energy source. Some of them can obtain these elements from the air and use solar energy, while others require substances of organic origin to exist. They all need vitamins and amino acids that can act as catalysts for reactions occurring in their body. The removal of substances from the cell occurs through the process of diffusion.

In many types of microorganisms, oxygen plays an important role in metabolism and respiration. As a result of respiration, energy is released, which they use to form organic compounds. But there are bacteria for which oxygen is lethal.

Reproduction occurs by dividing the cell into two parts. After it reaches a certain size, the separation process begins. The cell elongates and a transverse septum is formed in it. The resulting parts disperse, but some species remain connected and form clusters. Each of the newly formed parts feeds and grows as an independent organism. When placed in a favorable environment, the reproduction process occurs at high speed.

Microorganisms are able to decompose complex substances into simple ones, which can then be used again by plants. Therefore, bacteria are indispensable in the cycle of substances; without them, many important processes on Earth would be impossible.

Do you know?

Conclusion: Don't forget to wash your hands every time you come home after going outside. When you go to the toilet, also wash your hands with soap. A simple rule, but so important! Keep it clean and bacteria won't bother you!

To reinforce the material, we invite you to complete our exciting assignments. Good luck!

Task No. 1

Look carefully at the picture and tell me which of these cells is bacterial? Try to name the remaining cells without looking at the clues:

They surround us everywhere. Many of them are very necessary and useful for humans, but many, on the contrary, cause terrible diseases.
Do you know what forms bacteria come in? How do they reproduce? What do they eat? Do you want to know?
.site) will help you find in this article.

Shapes and sizes of bacteria

Bacteria are not at all large, their sizes range from half to five micrometers. The largest bacterium measures seven hundred and fifty micrometers. After the discovery of nanobacteria, it turned out that their size is much smaller than scientists previously imagined. However, to date, nanobacteria have not been well studied. Some scientists even doubt their existence.

Aggregates and multicellular organisms

How do they move?

Nutrition

Reproduction

Bacteria undoubtedly deserve your attention not only because they cause many diseases. These microorganisms were the first living beings to inhabit our planet. The history of bacteria on Earth goes back almost four billion years! The most ancient cyanobacteria existing today are cyanobacteria; they appeared three and a half billion years ago.

You can experience the beneficial properties of bacteria for yourself thanks to the specialists of the Tiens Corporation, who have developed for you