Bacteria are the most numerous inhabitants of planet Earth. They settled it in ancient times and continue to exist today. Some species have not changed much since then. Bacteria useful and harmful literally surround us everywhere (and even penetrate other organisms). With a rather primitive unicellular structure, they are one of the most likely effective forms of living nature and stand out in a special kingdom.
Margin of safety
These microorganisms, as they say, do not drown in water and do not burn in fire. Literally: they withstand temperatures up to plus 90 degrees, freezing, lack of oxygen, pressure - high and low. We can say that nature has invested a huge margin of safety in them.
Bacteria beneficial and harmful to the human body
As a rule, the bacteria that inhabit our bodies in abundance are not given due attention. After all, they are so small that they seem to have no significant significance. Those who think so are largely mistaken. Bacteria useful and harmful for a long time and reliably “colonized” other organisms, successfully coexist with them. Yes, they cannot be seen without the help of optics, but they can benefit or harm our body.
Who lives in the intestines?
Doctors say that if you put together only the bacteria that live in the intestines and weigh them, you get something like three kilograms! Such a huge army cannot be ignored. Many of the microorganisms continuously enter the human intestines , but only a few species find favorable conditions for living and living there. And in the process of evolution, they even formed a constant microflora, which is designed to perform important physiological functions.
Wise neighbors
Bacteria have long played an important role in human life , although until very recently, humans had no idea about this. They help their master in digestion and a number of other functions. What are these invisible neighbors?
Constant microflora
99% of the population live permanently in the intestines. They are ardent adherents and helpers of man.
- The main beneficial bacteria. Names: bifidobacteria and bacteroids. Their overwhelming majority.
- Concomitant beneficial bacteria. Names: E. coli, Enterococci, Lactobacillus. Their number should be 1-9% of the total.
You must also know that under appropriate negative conditions, all these representatives of the intestinal flora (with the exception of bifidobacteria) can cause diseases.
What are they doing?
The main functions of these bacteria are to help us in the digestion process. It is noted that a person with improper nutrition can experience dysbiosis. As a result, congestion and poor health, constipation and other inconveniences. With a normalized nutritional balance, the disease usually recedes.
Another function of these bacteria is watchdog. They monitor which bacteria are beneficial. To ensure that "outsiders" do not penetrate into their community. If, for example, the pathogen of dysentery tries to enter the intestine - Shigella Sonne, 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
About 1% in the body of a healthy individual are the so-called opportunistic microbes. They relate to unstable microflora. Under normal conditions, they perform certain functions that do not harm the person, work for the good. But in a certain situation they can prove themselves as pests. These are mainly staphylococci and various kinds of mushrooms.
Dislocation in the digestive tract
In fact, the entire digestive tract has a heterogeneous and unstable microflora - the bacteria are useful and harmful. The esophagus contains the same inhabitants as in the oral cavity. There are only a few acid-resistant in the stomach: lactobacilli, Helicobacter pylori, streptococci, fungi. In the small intestine, microflora is also not numerous. Most bacteria are in the colon. So, defecating, a person is able to secrete over 15 trillion microorganisms per day!
The role of bacteria in nature
She is also certainly great. There are several global functions, without which all life on the planet would probably have ceased to exist long ago. The most important is sanitary. Bacteria eat dead organisms in nature. They, in essence, work as original janitors, not allowing deposits of dead cells to accumulate. Scientifically, they are called saprotrophs.
Another important role of bacteria is participation in the global circulation of substances on land and at sea. On planet Earth, all substances in the biosphere pass from one organism to another. Without some bacteria, this transition would simply be impossible. 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 nitrogen in the air nitrogenous fertilizers for plants (microorganisms live right in their roots). Such a symbiosis between plants and bacteria is being studied by science.
Participation in food chains
As already mentioned, bacteria are the most numerous inhabitants of the biosphere. And accordingly, they can and should participate in food chains that are characteristic of the nature of animals and plants. Of course, for humans, for example, bacteria are not the main part of the diet (unless you can use it as a dietary supplement). However, there are organisms that feed on bacteria. These organisms, in turn, feed on other animals.
Cyanobacteria
These blue-green algae (an outdated name for these bacteria, fundamentally wrong from a scientific point of view) are capable of producing a huge amount of oxygen as a result of photosynthesis. Once upon a time, it was they who began to saturate our atmosphere with oxygen. Cyanobacteria continue to successfully do this to this day, forming a certain part of oxygen in the modern atmosphere!