Bacteria are useful and harmful. Bacteria in human life

Bacteria are the most numerous inhabitants of the planet Earth. They inhabited it in ancient times and continue to exist until now. Some species have changed little since then. Bacteria useful and harmful literally surround us everywhere (and even penetrate into other organisms). With a fairly primitive unicellular structure, they are one of the most probably effective forms of living nature and stand out in a special kingdom.

Margin of safety

These microorganisms, as they say, do not sink in the water and do not burn in the fire. Literally: withstand temperatures of up to plus 90 degrees, freezing, lack of oxygen, pressure - high and low. We can say that in them nature has invested a huge margin of safety.

Bacteria useful and harmful to the human body

As a rule, the bacteria that abundantly inhabit our bodies are not given proper attention. After all, they are so small that they do not seem to matter. Those who think so, are largely mistaken. Bacteria that are useful and harmful have "colonized" other organisms in a long and reliable manner, successfully coexist with them. Yes, they can not be seen without the help of optics, but they can benefit or harm our body.

Who lives in the gut?

Doctors say that if you put together only bacteria that live in the intestines, and weigh - you will get something about three kilograms! With such a huge army can not be ignored. Many of the microorganisms continuously entered the human intestine , but only some species find favorable conditions for living and life. And in the process of evolution they even formed a constant microflora, which is called upon to perform important physiological functions.

"Wise" neighbors

Bacteria in human life have long played an important role, although until recently, a person about this and did not guess. They help their master in digestion and perform a number of other functions. What are these invisible neighbors?

Constant microflora

99% of the population permanently reside in the intestine. They are ardent followers and helpers of man.

• The main useful bacteria. Names: bifidobacteria and bacteroides. Their overwhelming majority.
• Associated beneficial bacteria. Names: E. coli, enterococci, lactobacilli. Their number should be 1-9% of the total.

It is also necessary to know that under appropriate negative conditions all these representatives of the intestinal flora (except for bifidobacteria) can cause diseases.

What are they doing?

The main function of these bacteria is to help us in the process of digestion. It is noticed that a person with an improper diet can experience dysbacteriosis. As a result - stagnation and poor health, constipation and other inconveniences. When the balance of nutrition is normal, the disease usually recedes.

Another function of these bacteria is the watchdog. They keep track of which bacteria are useful. To ensure that "outsiders" do not penetrate into their community. If, for example, the causative agent of dysentery, Shigella Sonne, tries to enter the intestine, they kill her. However, it is worth noting that this happens only in the body of a relatively healthy person, with good immunity. Otherwise - the risk of getting sick increases at times.

Unstable microflora

Approximately 1% in the body of a healthy individual is the so-called conditionally pathogenic microbes. They belong to the unstable microflora. Under normal conditions, they perform certain functions that do not harm a person, work for good. But in a certain situation they can prove themselves as pests. These are mainly staphylococci and various fungi.

Dislocation in the digestive tract

In fact, the entire digestive tract has a heterogeneous and unstable microflora - the bacteria are useful and harmful. Esophagus contains the same inhabitants as in the oral cavity. In the stomach are only some, resistant to acid: lactobacilli, Helicobacter, streptococcus, fungi. In the small intestine microflora is also few. The most bacteria is found in the large intestine. So, defecating, a person is able to allocate more than 15 trillion microorganisms per day!

The role of bacteria in nature

It is also, of course, great. There are several global functions, without which all living things on the planet probably would have long since ceased to exist. The most important is sanitary. Bacteria eat dead organisms that are in nature. They, in essence, work as original wipers, not allowing to accumulate deposits of dead cells. Scientifically they are called saprotrophs.

Another important role of bacteria is the participation in the global circulation of substances on land and at sea. On the planet Earth, all substances in the biosphere pass from one organism to another. Without some bacteria, this transition would simply not be possible. The role of bacteria is invaluable, for example, in the cycle and reproduction of such an important element as nitrogen. In the soil, there are certain bacteria that make nitrogenous nitrogen fertilizers for plants (microorganisms live right in their roots). Such symbiosis between plants and bacteria is studied by science.

Participation in food chains

As already mentioned, bacteria are the most numerous inhabitants of the biosphere. And accordingly, can and should participate in food chains inherent in the nature of animals and plants. Of course, for humans, for example, bacteria are not a major part of the diet (except that it can be used as a food supplement). However, there are organisms that feed on bacteria. These organisms, in turn, feed on other animals.

Cyanobacteria

These blue-green algae (the outdated name of these bacteria, fundamentally wrong from the scientific point of view) are able to produce a huge amount of oxygen as a result of photosynthesis. Once upon a time they started to saturate our atmosphere with oxygen. Cyanobacteria continue to do this successfully to this day, forming a certain part of oxygen in the modern atmosphere!