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Research work

Bacteria:

enemies or friends?

Completed:

Gradusov Maxim Alexandrovich,

student of 2"E" class

municipal autonomous

educational institution

"Schools No. 187 with in-depth study

individual items, Nizhny Novgorod

Scientific adviser:

Sapunova Olga Alexandrovna,

primary school teacher of the highest category

MAOU "Schools No. 187"

Scientific consultant:

Levakova Elvira Yurievna,

Candidate of Chemical Sciences, teacher of chemistry of the highest category

MAOU "Schools No. 187"

Nizhny Novgorod

Introduction			………………………………………………………………..
		Theoretical part………………………………………...
		History of the study of bacteria…………………………...
		The structure of bacteria………………………………………….
		Types of bacteria………………………………………………
		Reproduction of bacteria……………………………………...
		Habitat of bacteria…………………………………..
		The benefits of bacteria………………………………………….
		Danger to humans…………………………………….
		Practical part…………………………………………
		Student survey………………………………….
		Analysis of the conducted questionnaire……………………………….
		Experiment………………………………………………...
Conclusion			………………………………………………………………..
List of sources and literature used…………………………
Application………………………………………………………………….

Introduction

From early childhood, we all know that after the street you need to wash your hands with soap and dirty objects should not be taken into your mouth. There are a huge number of microscopic organisms around us, invisible to the naked eye, and they can cause serious diseases. But on the TV screen and on the Internet, we are told about healthy products that contain ... bacteria! It turns out that not all microorganisms are harmful to humans. In our research work, we decided to find an answer to the question: who are bacteria for humans - enemies or friends? This question can be answered by microbiology - a science that studies microorganisms, their types and structure, the importance that they have in nature and human life. The topic of my research is also of concern to adult scientists; at present, metagenomics is actively developing - a new branch of genetics that studies the gene composition of entire communities of organisms. Analysis of the bacterial communities of human organisms will reveal how microorganisms prevent or increase the risk of developing diseases.

Relevance and the significance of the work lies in the fact that all children know why bacteria are necessary for people, why they are dangerous, and apply this knowledge in practice.

Subject of study: bacteria, their structure, forms and types

Purpose of the study: find out what role bacteria play in nature and human life

Research objectives:

Examine the scientific literature on the subject;

Analyze the effect of bacteria on human and animal organisms;

Develop a questionnaire and conduct a survey among the students of the class on the subject of research;

Conduct an experiment on growing bacteria at home.

Hypothesis is that human life is inextricably linked with bacteria, they bring not only harm, but also benefit.

CHAPTER 1. Theoretical part

1.1 History of the study of bacteria

The amazing world of bacteria, invisible to the eye, envelops our planet with a “living film”.

Bacteria are considered the most ancient creatures on Earth. They formed more than 3.5 billion years ago and for a very long time (about a billion years) were the only organisms on our planet.

Bacteria are living organisms that surround us everywhere. They live everywhere: in the air, in water, on the surface of our body, in the mouth, on all objects, plants and animals.

Bacteria are so small that they can only be seen with a microscope.

For the first time, bacteria were seen through an optical microscope and described in 1676 by the Dutch naturalist Anthony van Leeuwenhoek. Like all microscopic creatures, he called them "animalcules".

Figure 1. Anthony van Leeuwenhoek, his microscope and bacteria

The name "bacteria" was introduced in 1828 by the German scientist Christian Ehrenberg, which in Greek meant "little stick".

Figure 2. German scientist Christian Ehrenberg.

In the 1850s, the French microbiologist Louis Pasteur initiated the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties.

Figure 3. French microbiologist Louis Pasteur.

Medical microbiology was further developed in the works of Robert Koch, who formulated the general principles for determining the causative agent of the disease (Koch's postulates). In 1905 he was awarded the Nobel Prize for tuberculosis research.

Figure 4. German microbiologist Robert Koch.

The study of the structure of the bacterial cell began with the invention of the electron microscope in the 1930s.

Figure 5. Scanning electron microscope.

1.2 The structure of bacteria

The bacterium is covered with a strong shell - the cell wall. Its main function is to protect the body from external influences and give it a certain shape. Very often, an additional protective layer is formed over the cell wall of the bacterium - a capsule, which protects the bacterium from drying out.

Inside the cell is filled with cytoplasm. Bacteria do not have a nucleus, its place is taken by DNA, which carries the genetic information of the cell.

On the surface of some bacteria are flagella or short hairs that help the body move.

The plasma membrane is permeable and metabolism takes place through it.

Figure 6. Structure of a bacterium.

1.3 Types of bacteria

By way of nutrition, bacteria are divided into:

Figure 6. Types of bacteria by way of feeding.

Bacteria, depending on the shape of the cells, are divided into several groups:

spherical - cocci,

rod-shaped - bacilli or rods,

spiral - spirochetes

Figure 7. Types of bacteria by shape

Blue-green algae are also bacteria. They are capable of photosynthesis, like plants, and do not need organic matter for nutrition.

Figure 8. Blue-green algae.

There are motile and non-motile bacteria. Among the mobile ones, some swim freely with the help of special tails - flagella, while others simply glide due to the wave-like contractions of their own body.

Figure 9. Non-motile and non-motile bacteria.

Bacteria are useful and harmful:

Figure 10. Beneficial and harmful bacteria.

Reproduction of bacteria

Under favorable conditions, bacterial cells multiply very quickly, dividing in two. If a cell doubles every half an hour, then in a day it is capable of producing 281,474,976,710,656 descendants. And some bacteria can multiply even faster.

Figure 11. Reproduction of bacteria.

Habitat for bacteria

Bacteria live everywhere: in the air, in water, on the surface of our body, in the mouth, on all objects, plants and animals.

Figure 12. Habitat for bacteria.

Benefits of bacteria

The circulation of matter occurs with the participation of bacteria: if these little workers once disappeared, the planet would very quickly be littered with the remains of dead plants and dead animals.

Figure 13. The role of bacteria in nature.

Souring milk into a variety of fermented milk products.

Figure 14. Dairy products

Bacteria made bread from yeast dough fluffy, better baked.

Figure 15. Bread from yeast dough.

Without bacteria, there would be no pickled vegetables.

Figure 16. Pickled vegetables.

Pharmacists produce a variety of antibiotics, vaccines, enzymes, vitamins.

Figure 17. Manufacture of drugs.

Bacteria live on man and in man. Most bacteria live in the intestines, where they work for the benefit of man. Some help digest food, others produce vitamins, and others kill harmful microbes.

Figure 18. Bacteria in the human gut.

Human danger

Bacteria cause various infectious diseases.

Figure 19. Dangerous bacteria.

They lead to food spoilage: lactic acid bacteria ferment fresh milk.

Figure 20. Sour milk.

To protect yourself from harmful bacteria and make friends with useful ones, you need to:

Wash hands before eating and after returning home, from wherever;

wash vegetables and fruits;

monitor the expiration dates of products;

during epidemics, limit contact with possible carriers of the infection.

Figure 21. Protection from harmful bacteria.

CHAPTER 2. Practical part

2.1 Questionnaire

As a whole class, we attend the “Biologist of the Future” circle, which is led by a Ph.D. N.I. Lobachevsky Makeev Igor Serafimovich. In these classes, we study microorganisms, we examine them under a microscope.

To find out the idea of ​​bacteria in students, we conducted a survey of 26 students in the class.

2.2 Analysis of the conducted questionnaire

For the first question, the following data was obtained:

Data for the second question:

The data for the third question is as follows:

Data for the fourth question:

The data for the fifth question is as follows:

And finally, these are the data for the sixth question:

After analyzing the questionnaire, we can conclude that 80% of students have information, and 20% find it difficult to answer. For a more complete acquaintance with the new information, information booklets will be issued to students.

In the next circle sessions, we will study other microorganisms, such as molds. Let's try to grow bread mold on our own and examine it under a microscope.

2.3 Experiment

I also decided to try growing bacteria at home.

Figure 22. Petri dishes

I washed three Petri dishes, gas sterilized them.

Figure 23. Sterilization of Petri dishes

Then he prepared a nutrient medium from the substance Agar-agar.

Figure 24. Culture medium preparation

I poured the nutrient medium into the lower half of the Petri dishes with a thin layer, only covering the bottom.

Agar-agar is solid, the Petri dish is at room temperature - everything is ready to continue the experiment! Next, we plant the bacteria in a nutrient medium! Lightly touch the surface of the culture medium with your fingers (before and after washing your hands).

Figure 25. Planting bacteria from dirty hands in the 1st Petri dish

Figure 26. Planting bacteria after washing hands in the 2nd Petri dish

After placing the bacteria on a nutrient medium, I closed the Petri dishes with a lid, sealed them with masking tape, signed and placed the Petri dishes in a warm and dark place (under the battery).

Figure 27. Three Petri dishes with culture medium and bacteria in two dishes.

Figure 28. Three Petri dishes placed in a warm and dark place

On the fifth day of the experiment, colonies of bacteria, barely visible to the eye, began to appear.

Figure 29. Bacteria from dirty hands

In this Petri dish, where I touched the nutrient medium with clean hands, on the fifth day the bacteria are almost invisible.

Figure 30. Bacteria from clean hands

In this Petri dish, where I did not plant bacteria, everything is perfectly clean!

Figure 31. Pure culture medium

Conclusion:

Figure 32. Washing hands with soap

Conclusion

I collected and analyzed scientific information about bacteria, conducted a sociological survey to find out the idea of ​​bacteria in class students, and prepared booklets on the role of bacteria in nature and human life. In the course of my research work, I discovered for myself that bacteria are an integral part of life on our planet, and without them, life on Earth would be impossible. There are dangerous bacteria, but they also perform a certain function. I learned that bacteria are our helpers, first of all, they are symbionts, without which many processes of our body would be impossible. Beneficial bacteria restore the body's defenses and strengthen the human immune system. Bacteria play a positive role in human economic activity, they are widely used in medicine and biotechnology, and are the object of scientific research.

The negative role belongs to pathogenic or pathogenic bacteria. They are able to penetrate the tissues of plants, animals and humans and release substances that depress the body's defenses. A number of human diseases of bacterial origin are known. In the course of my work, I really learned a lot about bacteria, how to cultivate and study them. I made sure that all the materials support the hypothesis that bacteria can be both harmful to humans and beneficial. Summing up my work, I came to the conclusion that bacteria are our friends, and they become enemies only through the fault of the person himself.

In conclusion, I will quote the words of our contemporary, research scientist Wilhelm Boland: “This result once again confirms the assumption that all higher organisms, such as plants, insects and animals (including humans), coexist with microbiological symbionts. Without these beneficial microorganisms, we would not be able to live and survive. They should be considered an integral part of our body.”

List of used sources and literature

https://ru.wikipedia.org/wiki/Bacteria

http://jbio.ru/istoriya-issledovaniya-bakterij

Vaitkene L.D. Biology, M.: AST Publishing House, 2017. - 256 p.: ill.

Vakhrushev A.A., The world around. (Inhabitants of the Earth). Grade 3: textbook, M.: Balass, 2013. - 144 p.: ill.

Pleshakov A.A., Biology. Introduction to biology. 5th grade: textbook, M.: Bustard, 2016. - 158 p.: ill.

Sergeev B.F., I know the world: Biology, M.: AST Publishing House, 2004. - 398 p.: ill.

Annex 1.

Do you know about the existence of bacteria on our planet?

□ difficult to answer

Do you think bacteria can cause various diseases?

□ difficult to answer

Do you think all bacteria are harmful to humans?

□ difficult to answer

Do you think bacteria live in the human body?

□ difficult to answer

What are the benefits of bacteria living in the human body?

□ Helps digest food

□ Restore the body's defenses and strengthen the immune system

□ Not useful

How does a person use bacteria in economic activities?

□ Certain types of bacteria are used in cooking

□ Bacteria are used in the production of medicines and vitamins

□ Bacteria are used in the production of plant fertilizers

□ Bacteria are used to produce chemicals

Hanno Charisius and Richard Friebe

BUND FÜRS LEBEN.

Warum Bakterien unsere Freunde sind

Attention! The information contained in this book is not a substitute for medical advice. It is necessary to consult a specialist before applying any of the recommended actions.

© Carl Hanser Verlag Munich 2014

© Bochkareva K.E., Politikova A.V., translation into Russian, 2018

© Design. Eksmo Publishing LLC, 2019

Introduction

The dependence of bacteria in the gut on food opens up the possibility for us to influence the intestinal flora and replace pathogenic microbes with beneficial microbes.

Ilya Mechnikov, 1908

Bacteria are our friends.

They are the causative agents of many diseases. Contribute to unpleasant odors. Where they are, there is no purity, and what is not pure cannot be good.

“Antibacterial” is one of the few words with an “anti” prefix that sounds good to our ears. And for some time now we have been able to destroy bacteria with the help of antibacterial agents and antibiotics more effectively than ever before in the history of mankind. Antibiotics, since they were first used during World War II, have helped countless people with acute infections, even saved lives, and are now commonly prescribed medicines.

We disinfect and keep it as clean as possible. And wherever we are, we avoid contact with microorganisms.

Despite this, today we are by no means healthier than in the days when hygiene consisted solely of water and soap. On the contrary, since we began waging a large-scale war against bacteria, diseases - and health problems that used to be quite rare - have increased: diabetes, morbid obesity, allergies, autoimmune diseases, to name but a few. Is this simultaneity purely coincidental? Or maybe the successful eradication of micro-organisms has given us some sort of unintended risks and side effects? Are we violating the balance between us and the microbes in us, on us and around us, arranged for millennia, millions of years? And maybe we get sick because of it? Or maybe bacteria are not our enemies, but, on the contrary, our friends?

In our book, we want to try to answer these questions.

Transplantation without a scalpel

Today, the Internet is no less important meeting place for many patients than a family doctor. People with chronic bowel disease in 2012 and 2013 frequently visited the website of the Grabenstätt Musical Society. Entrepreneurial musicians on Lake Chiemsee are calling for a "chair donation" there to help fund the construction of their new laboratory building. Stool donation meant that for a nominal fee of 50 euros, someone else's feces in the laboratory could be purchased and transferred to someone in need.

However, this is unlikely to be of interest to someone who suffers from chronic inflammation of the intestine.

Anyone who searches the Internet for information about "stool donation" is likely to suffer from abdominal pain, diarrhea, fever, and food sensitivities. Sometimes he complains of immunodeficiency up to heart disorders. Stool donation simply consists of transferring a small amount of the intestinal content of a healthy person into the intestines of a sick person and is intended to alleviate his condition or perhaps even lead to a complete recovery.

In medical parlance, gut-to-gut transmission is called a fecal transplant.

How does it work? In a healthy person's stool, that is, in his feces, there is probably a mixture of healthy bacteria, in a sick person's stool - a mixture of unhealthy bacteria. And if you successfully put a mixture of healthy bacteria into an unhealthy gut, it should recover. It's like replacing the whole team in football. It is as if the weary footballers quarreling with each other and the coach are being removed, as if the Hamburg Sports Association in the fall of 2013 released eleven new ones from the well-played, individually strong, well-trained Borussia-Dortmund or Bayern-Munich squad on the football field.

Several years have passed, but doctors still do not fully recognize the effectiveness of stool donation and transplantation of fecal microflora. But in the meantime, scientific and medical specialty journals are writing about it more and more, and pharmaceutical companies see natural product as competition for their old and new gut drugs and are already having difficulty with the concept of distributing such drugs.

New discoveries

A look at the edition of an old German medical journal "Deutsches Erzteblatt"(Deutsches Ärzteblatt) dated February 15, 2013. A group of general practitioners from Ulm in a special publication for the first time described "transplantation of fecal microflora in treatment-resistant pseudomembranous colitis" in Germany.

Colitis means inflammation of the large intestine.

Resistant to treatment - that is, inflammation of the intestine occurs again after treatment.

Clostridium difficile is a bacterium that causes pseudomembranous colitis.

Transplantation of fecal microflora is ... but we have already mentioned this.

Even from the boring medical, professional language of these eight pages, one can easily understand how desperate a 73-year-old patient must be after constant courses of antibiotic therapy. After a short-term relief of symptoms - from abdominal pain to diarrhea - there was always a deterioration in the general condition. You can also imagine how confused the doctors were. Optimal clinical examination, new medications, then improvement and laboratory tests that no longer detect Clostridium, and then a couple of weeks later the return of the pathogen, an exacerbated recurrence of symptoms - and the patient's return to the clinic.

“Such people are in despair and often cannot lead a full life. They are very tense mentally, for example, they are afraid to accept any invitation and then eat something there,” says Thomas Seufferlein, head of the Internal Medicine Clinic of the First University Hospital Ulm. He took part in the first observation documented in Germany in a special journal.

Looking ahead, the 73-year-old patient has since been doing well, feels like a newborn, and to some extent, in fact, she is: what is new is her microbiome in the intestines, a community of many billions of bacteria that eat with us and provide us with food at the same time.

After the patient's intestines had been cleaned and she had been properly re-treated with antibiotics, she received stools through a colonoscope, donated by her 15-year-old granddaughter. She immediately felt better.

Genetic tests could show, says Seufferlein, that her intestines now actually contain a mix of bacteria that matches her stool donor's mix of bacteria. Unlike previous treatments, the old, unfavorable mixture of bacteria has thus not come back and clostridium difficile is no longer found.

Report on the topic:

Are bacteria friends or foes?

Safonov Alexey

3 "B" class

The human body is inhabited by millions of microorganisms, which are normal microflora. They help fight various diseases, improve digestion, accelerating the absorption of nutrients from the intestines into the blood, synthesize vitamins and other biologically active substances.

Spread of bacteria.

Bacteria exist everywhere and everywhere: in the food we eat, especially if it is sloppily cooked in dirty dishes; on unwashed vegetables and fruits. There are even more of them in the air we breathe, especially in the dusty indoor air. Lots of bacteria in water and soil. Bacteria can be found on all objects with which we come into contact: on door handles, on money, on the handrails of buses and trolleybuses, on sheets of books and notebooks.

Reproduction of bacteria.

The rate at which bacteria multiply is amazing. One bacterium in 15-20 minutes turns into 2. If one bacterium, which fell into favorable conditions, could freely multiply, then in 2-3 days its offspring would fill all the seas and oceans of the Earth. What helps bacteria to spread? What's stopping you?

Bacteria control measures. The reproduction of bacteria is helped by: heat, moisture, darkness and good nutrition. They prevent bacteria from multiplying, destroy them: cold, dry room, sunlight, cleanliness, lack of food.

Ways of infection with pathogenic bacteria.

Each patient spreads a large number of pathogenic bacteria around him. During sneezing, droplets from the mouth are sprayed 4-5 meters, while coughing - 6-8. You can get infected through the air, through a handshake.

Infection can occur through the patient's things: dishes, towels, books, clothes, toys. Carriers of microbes can serve as dogs, cats, mice, rats, flies, lice, mosquitoes.

Wounds, abrasions, and other skin lesions are the gates through which microbes enter our body. organism.

Microbes are carried by unwashed vegetables and fruits.

Curious facts.

Most of the time our hands get dirty. Together with dirt, dust, many infectious microbes accumulate on the hands. From the hands they are transferred to the face, eyes, lips, fall into the mouth. Through dirty hands they become infected with worms, typhus and other diseases.

Even more microbes accumulate under the nails.

The face is always open. A lot of dust, soot, microbes sit on it. They can fester and hurt the eyes.

Hair accumulates a lot of dust and germs. To prevent bacteria-enemies from attacking you, you need to wash your hands often and take a shower or bath, eat healthy food, play sports.

What are beneficial bacteria

Foaming kvass, soft porous bread - we would not have tasted them if it were not for our friends - microorganisms. Let's find out together what are beneficial bacteria?

You have probably already paid your attention to the multi-colored spots of mold, miraculously “blooming” on a forgotten crust of bread or in a jar of jam.

For children, this may indeed seem like a miracle: yesterday a piece of bread looked quite ordinary, but today ... it was covered with gray, yellow, blue spots! "What it is? Where did it come from? Is it possible to eat such bread?" - asks the little why, or maybe it did not start with mold, but with illness: "In the evening I was completely healthy, but today?" Or the child saw how the mother rolled out the yeast dough: “Why does it squeak under the rolling pin? Why does it come out of the package? And who made holes in the dough?" The children can't wait to find out everything!

And really, what do we really know about these and other microorganisms that surround us every day?

Debunking the Myths

Most people are sure that microbes are only harmful and they should be destroyed by all available means: from washing hands with antibacterial soap to treating every square centimeter of an apartment with chlorine-containing products. Someone even buys ultraviolet lamps for the children's room, while rubbing their hands contentedly: “Well, now hold on! How it will be in the hospital: cleanliness and sterility! "But, meanwhile, scientists have long known that microbes, or, as it is more correct to call them, microorganisms, are everywhere, so it is useless to fight them. They literally surround us and even abundantly inhabit our country. your own organism.

Many people wonder what beneficial bacteria are. Moreover, without microorganisms, life on Earth would not be possible at all!

global circulation substances occurs precisely with their active participation: if these little workers once disappeared, the planet would very quickly be littered with the remains of dead plants and dead animals. It is they who return the mineral substances once "carried out" from it by plants to the soil, thus regulating its fertility. And what about the food that is on our table every day?

Why, again, microorganisms have worked hard: fermented milk into a variety of fermented milk products, made bread from yeast dough lush, better baked and easily digestible, preserved fermented and pickled foods for us, even took care of our leisure by makingalcoholic drinks , tried to provide us with delicacies - for example, Roquefort and Camembert cheeses with noble mold. Cooks use citric acid extracted from mold fungi (which also belong to the microcosm), agronomists use bacterial preparations to combat diseases and pests of cultivated plants, livestock specialists prepare nutritious and long-term stored feed for farm animals (such as silage), pharmacists use a variety of antibiotics , vaccines, enzymes, vitamins... We encounter microbial end products several times a day without even thinking about it.

And invisible satellites dwelling on us and in us? There are, of course, unexpected visitors, but most of them are included in the honorary club "Normal human microflora": microorganisms inhabit the skin and mucous membranes in many, but most microbes live in the intestines, where they work for the benefit of the human body. Some produce enzymes, helping to more fully assimilate nutrients from incoming food, others produce vitamins that are absorbed by the intestinal wall and used by the body - the owner of all this fraternity.Third ones (acidophilic and bifidobacteria, as well as E. coli) have antibiotic (i.e., suppressing vital activity) properties in relation to to putrefactive and pathogenic microbes.

Now you understand what beneficial bacteria are and why it is important to use fermented milk products, especially with the prefix "Bio" in the name (they contain bifidobacteria in addition to ordinary lactic acid bacteria)? Those of them who reach the intestines safe and sound (and many will succeed), they will remain there and temporarily take root for the benefit of man.

A spoon of tar

However, not everything is so rosy. Like any creature in nature, microbes are diverse and do not fall under the definition of "absolutely harmful" or "absolutely useful". You can not discount the diverse and often dangerous infectious diseases - again they are to blame, invisible microorganisms. Of course, scientists have learned how to deal with many of them - in some places they even won a planetary victory, with some a temporary truce was concluded (for example, with leprosy, or, as it is called differently, with leprosy, the number of cases in the world is decreasing year by year, but it is too early to talk about the victory of man over the disease). Other infectious agents still pose a serious danger, despite the current level of development of medicine, such as tuberculosis. Yes, and new diseases appear with sad regularity: remember at least AIDS or swine flu (although many of them can only be called new conditionally - most often it is a long-known to science, but now a modified, mutated microbe with new properties).

Besides that microorganisms cause various infectious diseases, many of them cause other damage to humans - for example, lead to spoilage of food. And often it turns out to be the same friends: lactic acid bacteria ferment fresh milk; yeast leads to fermentation and souring of juices and fruits; mold... However, everything is clear with mold. Fortunately, a person has learned to deal with this kind of trouble - it’s not without reason that now there are many ways to preserve and sterilize products: from banal boiling to sonication, from simple drying to the introduction of chemical preservatives that increase the shelf life several times or even an order of magnitude.

Who should be afraid

To protect yourself from really harmful microbes and make friends with useful (or harmless), it is enough to follow simple, well-known rules: wash your hands before eating and after going to the toilet, after returning home from anywhere, wash vegetables bought in the market or in the store and fruits, monitor the expiration dates of products, during epidemics, limit contact with possible carriers of the infection. And in general, no one has yet canceled the general rules of hygiene and sanitation, but it seems superfluous to widespread and regular destruction of microbes at home. There are several reasons for this. Firstly, as mentioned, bacteria and mold spores are everywhere, so the use of the treatment does not last very long. Secondly, not only harmful microbes are destroyed, but also all the rest (useful and indifferent to the body), and after all, scientists have already proven that for the formation of a normalimmunity to the child constant meetings with representatives of the microworld are necessary. And thirdly, disinfectants are usually quite aggressive substances that act not only on microorganisms, but also on householdanimals and humans .

(Project "Microorganisms - enemies or friends?") Table of contents Page

Introduction 3 - 4

Main part 5 - 8

1. 1. 2.1. The concept of microorganisms 2.2. The role of the first bacteria 2.3. The most beneficial bacteria

2.4. Dangerous microorganisms

Practical part 9 - 10

3.1. Experience #1

3.2. Experience #2

Conclusion

List of sources used 11

Introduction

What are microorganisms? How much do we know about them?

“Invisible, they constantly accompany a person, invading his life either as friends or as enemies,” said Academician V. L. Omelyansky.

Microbiologists have long proven that microbes are all around us. They are in the air, in water and in the soil, in the organisms of all living beings. They can be useful: modern humanity has learned to use microorganisms to treat previously incurable diseases. And they can be very harmful: cause outbreaks of deadly diseases that can destroy an entire population.

I want to analyze the properties of microbes with the help of a project. Empirically make sure where they are friends to us, and where are enemies.

Project relevance

Every person from childhood should take care of their health. Most schoolchildren know very little about their body, so they make mistakes, which leads to serious diseases. From early childhood, we know that we need to wash our hands more often with soap and dirty objects should not be taken into the mouth, because there are many microorganisms around us that can harm our health.

Then why is it not forbidden to eat foods that contain bacteria, but on the contrary they say that they are useful???

Problematic issues

To answer all questions, we first understand the need

wash your hands after the street and before eating. It is necessary to understand why it is worth abandoning the bad habits of biting your nails and dragging dirty objects into your mouth (for example, a ballpoint pen).

Therefore, let's get acquainted with the bacteria that love to live on our hands and under our nails. And we will find out what their harm is.

Objective of the project:

Find out what role bacteria play in human life and health.

Increase attention to a healthy lifestyle.

Project objectives:

Introduction to microorganisms. How they grow, reproduce, eat and breathe.

Find out which bacteria are harmful and which are beneficial.

Understand the importance of taking care of your health.

Learn simple ways to fight pathogenic bacteria.

Main part

The concept of microorganisms.

Microorganism (microbe) - a combination of two Greek words "small" and "bios" - life.

Microbes - bacteria, viruses, fungi, yeast.

How are microorganisms identified?

Microbes are very small living organisms that can only be seen with a microscope at hundreds of times magnification.

It is interesting to see a drop of water under a microscope

Surprised by the number of microbes!!!

Microbes are distinguished by structure, shape and life features:

unicellular

multicellular

non-cellular

mobile, with the help of cilia or ponytails

motionless

useful

harmful

Here are some microbes under the microscope:

The very first bacteria

Traces of bacteria have been found in the oldest sedimentary deposits, which are already 3.9 billion years old.

There are suggestions that there are later rocks in which there may also be traces of bacteria.

Molecules of the first microorganisms began to multiply, receiving energy from the environment from the very beginning of the planet.

From the history

Stromatolites (cyanobacteria) are the oldest traces of life on Earth. They were discovered by Australian geologists led by Alain Nutman.

The role of the first bacteria

formed a fertile layer of soil;

saturate the atmosphere with oxygen;

created the prerequisites for the emergence of nuclear organisms (eukaryotes), which subsequently developed into two kingdoms: plants and animals.

The most beneficial bacteria

Modern bacteria, which are being studied for the purpose of treating a person, feeding him and cleaning up his waste products, have nothing to do with the first bacteria that lived on Earth.

Azotobacter ( Azotobacter )

These bacteria are useful to humans in areas such as:

Agriculture. In addition to the fact that they themselves increase soil fertility, they are used to obtain biological nitrogen fertilizers.

Medicine. Used to obtain medicines for gastrointestinal diseases.

food industry. Used in food additives to creams, puddings, ice cream, etc.

bifidobacteria

They are extremely useful for humans due to the following properties:

supply the body with vitamins, amino acids and proteins;

prevent the development of pathogenic microbes;

protect the body from the ingress of toxins from the intestines;

speed up the digestion of food.

lactic acid bacteria

They get their energy from the process of lactic acid fermentation. Their areas of application:

Food industry - production of kefir, sour cream, fermented baked milk, cheese; fermentation of vegetables and fruits; preparation of kvass, dough, etc.

Agriculture - slows down the development of mold and promotes better preservation of animal feed.

Traditional medicine - treatment of wounds and burns. That is why it is recommended to lubricate sunburn with sour cream.

Medicine - obtaining antibiotics, manufacturing drugs for the treatment of beriberi, gastrointestinal diseases, to improve metabolic processes.

Streptomycetes

They are manufacturers of a wide variety of drugs, including:

antifungal;

antibacterial;

antitumor.

Dangerous microorganisms

Penetrating into the body, pathogenic microbes can cause irreparable harm to a person. Microorganisms can enter the body both through water and food, and by airborne droplets. Often, unaware of what pathogenic bacteria are actually dangerous for, people neglect the simple rules of hygiene.

Harmful microbes

Some microorganisms cause food poisoning.

Even a small amount of microbes that enter our body can cause serious illness.

Pathogenic microbes are always found in the human body, but certain diseases, long-term use of antibiotics can provoke a beneficial habitat for dangerous bacteria.

Group A Streptococcus

Cause the development of purulent diseases, pharynx, respiratory tract; can provoke complications in the form of lesions of internal organs.

Protozoa

The simplest mushrooms can be not only dangerous, but also useful. The same mold is used in industry to produce certain varieties of cheese or citric acid; in medicine, a powerful antibiotic is obtained from it. Everyone knows about the use of yeast.

I want to demonstrate the harm and benefit of microorganisms using the example of lower fungi (Micromycetes group). This group includes types of mold and yeast. They are microscopic in size, in nature they cannot be detected with the naked eye.

With the help of experiments, I will show how dangerous mold develops from spores that can get on food through dirty hands and the properties of yeast during cooking.

Practical part

Test #1 shows that hand washing with soap kills most germs.

She put one piece of bread in a gloved “control” bag, then washed her hands and placed the second piece in a bag labeled “clean hands”. I passed another piece around in the hands of friends and after each child touched it, I put it in the third bag.

Result

Bread molds faster in the Dirty Hands sample due to germs.

Experiment No. 2: The beneficial use of microorganisms using the example of yeast

Knead the dough from flour, water, salt, sugar:

A) We kneaded one portion without yeast.

The buns were baked in the oven.

A) A yeast-free dough bun is very small, tough, not tasty.

B) The second yeast bun turned out to be lush, fragrant, very tasty.

Result

Experience No. 2 revealed to us the beneficial properties of yeast.

Yeast does the right job: they produce carbon dioxide and the dough rises, becomes lush.

Conclusion

The world of microbes is interesting and diverse!

Among microbes there are our friends and enemies.

Being in our body, beneficial microbes help it to be healthy and prevent harmful bacteria from harming a person.

List of used sources and literature.

1. 1. • https :// probacterii . en https :// mel . fm / news /2856340- hands www.grandars.ru › Medicine › Microbiology www.gribomaniya.ru/1-1

Afanasyeva Daria

This work is an independent research work with a selection of the necessary material from various sources. The student in her work showed the diversity of bacteria that surround a person in everyday life. She visited the Department of Microbiology of ChSMA, where she independently grew colonies of bacteria on various nutrient media and examined them under a microscope. This work can be used for extracurricular activities.

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City scientific and practical conference "Step into Science"

« Bacteria are our enemies and friends»

Section Biology

Made by Afanasyeva

Daria, student of grade 7 A, MBOU "Secondary School No. 19"

Head of Popykin

Olga Anatolyevna, teacher of biology and chemistry, MBOU "Secondary School No. 19"

Chita 2013

1. Introduction

It is difficult to find a place on Earth where there would be no bacteria. I was interested in the fact that they are so small that we cannot see them without a microscope. And at the same time, they can be very useful and harmful, as we were told in biology lessons. In addition, at present, the media very often mentions different types of bacteria contained in a huge variety of fermented milk products, which are very tasty and extremely beneficial to human health. We also often hear from TV screens and see different types of soap labeled “Antibacterial” on store shelves. So who are these our neighbors - bacteria?

In this project, I set myself the goal of proving that everyday human life is inextricably linked with bacteria, the significance of which cannot be unambiguously characterized. To achieve this goal, it is necessary to solve a number of tasks:

1. To study literature from various sources, where there is information about the features of the representatives of the first living beings that appeared many millions of years ago on our planet,
2. Meet the experts who are engaged in their cultivation,
3. Grow some strains of bacteria on your own.

In my work, I used different methods and techniques: search: I studied the scientific literature on this issue, analytical: I analyzed the information received, research: meetings with experts in the field, monitoring the processes of taking material, sowing on a nutrient medium, preparing various nutrient media, staining of preparations, comparison of results, conclusions.

2.1. History of the discovery of bacteria

Bacteria are the oldest known organisms. Traces of vital activity of bacteria and blue-green algae (stromatolites) belong to the Archean and date back to 3.5 billion years.

Bacteria are the smallest of the organisms with a cellular structure; their sizes range from 0.1 to 10 µm. A typical printing point can accommodate hundreds of thousands of medium-sized bacteria.

The name of the bacteria comes from the Greek word BAKTNOL, which means STICK. Bacteria are living microorganisms, often unicellular, relatively simple in structure.

Bacteriology is the branch of microbiology that deals with the study of bacteria. And specialists are called bacteriologists.

Bacteria were first seen through an optical microscope and described in 1676 by the Dutch naturalist Anthony van Leeuwenhoek. Like all microscopic creatures, he called them "animalcules".

The name "bacteria" was coined in 1828 by Christian Ehrenberg.

In the 1850s, Louis Pasteur initiated the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties.

Medical microbiology was further developed in the works of Robert Koch, who formulated the general principles for determining the causative agent of the disease (Koch's postulates). In 1905 he was awarded the Nobel Prize for tuberculosis research.

2.2. Classification of bacteria

Bacteria are classified according to their cell shape.

• spherical cocci,
• rod-shaped bacilli,
• comma curved vibrios,
• spiral spirilla.

Very often, bacteria form clusters in the form of long curved chains, groups and films. Some bacteria have one or more flagella. Among bacteria there are mobile and immobile forms. Mobile move due to wave-like contractions or with the help of flagella.

According to the method of respiration, bacteria are divided into aerobes (most bacteria) and anaerobes (causative agents of tetanus, botulism, gas gangrene). The former need oxygen to breathe, for the latter oxygen is useless or even poisonous.

2.3. Spread of bacteria

There is almost no place on earth where bacteria do not occur. Especially a lot of them in the soil. 1 gram of soil can contain hundreds of millions of bacteria. The human body also contains a large number of bacteria. Man is made up of human cells as well as bacterial, fungal and viral life forms. There are several trillion cells and more than 100 trillion bacteria in the human body, there are five hundred species of them. There are especially a lot of them in the intestines, they help to cope with food: they digest it, as well as in the respiratory tract, on the skin, and the urinary system. They live in the air, water of the seas and oceans, withstand deep freezing and high temperatures.

2.4. Feature of life processes

Most bacteria are colorless. Only a few of them are colored purple or green.

Bacterial cells are surrounded by a dense membrane, thanks to which it retains a constant shape. The composition and structure of the shell of bacteria differ significantly from plants and animals. There is no nucleus separated from the cytoplasm by a membrane. The nuclear substance in most bacteria is distributed in the cytoplasm.

Bacteria reproduce by dividing approximately every 20 minutes (under favorable conditions). Each daughter cell is a copy of the parent. Reproduction is prevented by the sun's rays and the products of their own vital activity.

The behavior of bacteria is not particularly complex. Chemical receptors register changes in the acidity of the environment and the concentration of various substances: sugars, amino acids, oxygen. Many bacteria react to changes in temperature or light, and some bacteria can sense the Earth's magnetic field.

Under unfavorable conditions, the bacterium is covered with a dense shell, the cytoplasm is dehydrated, and vital activity almost stops. In this state, spores of bacteria can stay for hours in a deep vacuum, endure temperatures from -240 ° C to +100 ° C. The number of bacteria is different in the air of ventilated and unventilated rooms. The living conditions of bacteria are varied. Some of them need air oxygen, others do not need it and are able to live in an oxygen-free environment.

2.5. Importance of bacteria

Man propagates certain types of bacteria because he needs and uses them. For example, bacteria are useful in curdling milk and fermenting sweet fruit juices. Many cheeses get their exquisite flavor from bacteria. The main mass of "friendly" microbes in the intestines are bifidobacteria (85-95%). Among the rest are lactic acid bacteria, E. coli, enterococci and other non-pathogenic or conditionally pathogenic bacteria. If dysbacteriosis occurs, the number of bifidobacteria is most often reduced.

For the prevention of dysbacteriosis, kefirs and yogurts enriched with bifidobacteria (bifidok and bioyogurts), as well as live yogurts, are used.
Probiotics are used for treatment. They contain more than 10 million bacteria, and in the most powerful - up to several billion.

For thousands of years, humans have used lactic bacteria to create many dairy products. If you add different bacteria to milk, you get cheese, yogurt, kefir, yogurt, cottage cheese.

Bacteria are widely used in the food industry for sauerkraut (in this case, organic acids are formed). Bacteria are used to leach ores (primarily copper and uranium), to treat wastewater from organic remains, in the processing of silk and leather, to control agricultural pests, and to produce medicines (for example, interferon). Some bacteria settle in the digestive tract of herbivorous mammals, ensuring the digestion of fiber. The two most important ecological functions of bacteria are nitrogen fixation and mineralization of organic remains. The binding of molecular nitrogen by bacteria to form ammonia (nitrogen fixation) and the subsequent nitrification of ammonia is a vital process, since plants cannot absorb nitrogen gas. Approximately 90% of the bound nitrogen is produced by nodule bacteria living in symbiosis with leguminous plants.

Bacteria bring not only benefits, but also harm. They multiply in food products, thereby causing spoilage. To stop reproduction, products are pasteurized (kept for half an hour at a temperature of 61–63 ° C), stored in the cold, dried (drying or smoking), salted or pickled.

Bacteria cause serious diseases in humans (tuberculosis, anthrax, tonsillitis, food poisoning, gonorrhea, etc.), animals and plants (for example, bacterial blight of apple trees). Favorable external conditions increase the rate of bacterial reproduction and can cause epidemics. Pathogenic bacteria enter the body by airborne droplets, through wounds and mucous membranes, the digestive tract. Symptoms of diseases caused by bacteria are usually due to the action of poisons produced by these microorganisms or formed during their destruction. The natural defense of human organisms and higher animals is based on the phagocytosis of bacteria by white blood cells and the immune system, which produces antibodies that bind and remove foreign proteins and carbohydrates from the bloodstream. In addition, there are natural and synthetic drugs against bacteria (for example, penicillin, which destroys the bacterial cell membrane, or streptomycin, which inactivates bacterial ribosomes).

3. Research results

Goal of the work: The study of the microbial landscape on the surface of objects and hands of students.

To achieve this goal, we have set ourselves a number of tasks:

1. Acquaintance with the work of the microbiological laboratory, methods of bacteriological research.

2. Carrying out crops on nutrient media of smears taken from the "dirty" hands and mobile phones of students.

3. Microscopic examination of cultures of microorganisms obtained after cultivation on nutrient media in the laboratory.

The work was carried out on the basis of the microbiological laboratory of the Department of Microbiology of the Chita State Medical Academy. The laboratory is equipped with modern equipment. Performs a wide range of microbiological studies on the study of bacteria and the diagnosis of many human diseases.

To obtain a pure culture of microorganisms, it is necessary:

1. Taking the material with a sterile object (tampon or dart) from a person.

2. Sowing on a nutrient medium.

3. Cultivation under certain conditions in a thermostat, for the accumulation of microorganisms.

4. Carrying out smears on glass slides, staining with special dyes (methylene blue), studying under a microscope.

The nutrient medium is a substance with the addition of sugar, protein, chocolate, agar-agar, etc., is the optimal substrate for the reproduction of bacteria. The thermostat creates optimal temperature conditions for the growth of bacteria (the required temperature and humidity). On average, the accumulation of bacteria occurs on the 5th day. For study, a light microscope can be used, which allows you to determine the shape, size of the bacterium, their ability to stain with various dyes.

To solve the second problem, with the help of a laboratory assistant, we cultured smears taken from dirty hands and the surface of mobile phones, without prior washing or processing. The inoculations were carried out on special nutrient media. Cultivation was carried out in a thermostat at a temperature of 34 degrees, 5 days. 5 days after smears on glass slides and their staining with dyes, which can be used as the following substances: methylene blue, Lugol's solution, methylene violet, fuchsin, we observed the growth of a large number of different bacteria, which were both pathogenic and normal, t .e. not causing disease.

The following bacteria were found: cocci - staphylococci, streptococci, enterococci; bacilli - Escherichia coli.

4. Conclusions.

In the course of working on this project, I learned a lot about bacteria, how to cultivate and study them. I visited the microbiological laboratory, where, with the help of specialists, I grew up and saw these creatures in a modern microscope.

As a result of our research, we found a large number of different bacteria on the surface of a mobile phone and dirty hands, some of which can cause diseases. The practical significance of the work lies in the need to wash hands and disinfect mobile phones, to prevent diseases among students and the need to multiply bacteria that bring invaluable benefits to human health.

From the results of our research, we suggest:

1. Ventilate classrooms and student gathering areas.

2. Treat and wipe items of use (books, notebooks, pens…)

3. Wash your hands more often, especially after school, outside, eating, and before eating

4. Have green plants in the classes that secrete phytoncides, which have a depressing effect on microorganisms. Plants with phytoncidal properties include different types of chlorophytum.

Literature

1. Biology textbook "On those who grow, but do not run"
2. Vavilov S.I. Great Soviet Encyclopedia. 2nd edition. M.: "BES", 1950
3. Vorobyov A.A., Krivosheina D.S. Fundamentals of immunology. Moscow: Masterstvo, 2001 https://accounts.google.com
   

   Slides captions:

   Bacteria Afanas'eva D. Supervisor Popykina O.A.

   bacteria

   History of the study Microscope 1751

   Anthony Van Leeuwenhoek

   Christian Ehrenberg

   Louis Pasteur

   Robert Koch

   Cocci, bacilli, vibrio, spirilla.

   Flagella in bacteria

   The structure of bacteria The structure of a gram-positive bacterium: A - pili, B - ribosomes, C - capsule, D - peptidoglycan layer, E - flagellum, F - cytosol, G - storage substances, H - plasmid, I - nucleoid, J - cytoplasmic membrane

   Bacteria on earth If there were no bacteria, there would be no life on earth.

   Microbiological laboratory

   Modern equipment

   Tampon or dart

   Nutrient medium

   thermostat

   examination under a microscope

   After sowing on a nutrient medium, various bacteria appeared:

   Prevention measures Wash your hands disinfect your phones

   Thank you for attention!