Dorothy FarrarBacteria
Bacteria are the simplest creatures on earth. Bacteria (Latin: bacteria or Greek: bakterion : “sticks”) are unicellular organisms that are microscopic and do not have a real cell nucleus. Therefore, bacteria are also called prokaryotes. All living things can be grouped together with the archaea and eukaryotes. The average size of bacteria is 0.1-20 µm.
What are bacteria?
Bacteria are unicellular microorganisms that reproduce by simple cell division. In 1676 reports were first written on bacteria observed by Antoni van Leeuwenhoek in human saliva and in water.
Despite countless species having been discovered and described for over 300 years, it is believed that the majority, at over 95 percent of the planet’s bacterial species, are still unknown.
People often see bacteria only as illness and poor hygiene, although people could not live at all without bacteria, which also have important protective mechanisms for them.
Characteristics
Bacteria can be classified from different points of view. In terms of shape, bacteria have three typical shapes:
- spherical cocci (e.g. streptococci),
- Rod bacteria (such as the well-known intestinal bacterium Escherichia Coli)
- helical spirillae (spirochetes).
In addition, bacteria can also be divided into three different groups in terms of their growth at different temperatures.
- Psychrophilic bacteria (in short: psychrophiles) are cold-loving and multiply best at a temperature of -5 to +20 °C
- mesophilic bacteria (short: mesophiles), these have their optimal temperature at 32 to 42 °C.
- thermophilic bacteria (thermophiles) are heat-loving and prefer high temperatures of 45 – 80 °C
With regard to their diet, the bacteria can be divided into two groups:
- autotrophic bacteria: These bacteria get their energy from sunlight, which means they can exist without organic foreign substances. For example the cyanobacteria (also blue-green algae)
- heterotrophic bacteria: They feed exclusively on organic matter. Many bacteria of this type can even exist without oxygen (anaerobic bacteria)
An important method for distinguishing bacteria is Gram stain. It was developed by the Danish bacteriologist Hans Christian Gram (1853-1938) and stains 2 large groups of bacteria differently based on their cell membrane structure.
A distinction is thus made between gram-positive bacteria (turn blue when stained) and gram-negative bacteria (red). This distinction is particularly important when diagnosing infectious diseases, since the two bacteria can often only be combated with different antibiotics .
Gene transfer and movement
Bacteria can exchange DNA products with each other with the help of so-called sexpili (tubes made of protein). There is horizontal and vertical gene transfer. In horizontal gene transfer, the transfer of genes occurs outside of sexual reproduction. Vertical gene transfer is sexual.
In the liquid medium, bacteria usually swim with flagella (flagella). These are rotated like a propeller. Other bacteria move by rotating (spirochetes) or by crawling (cyanobacteria).
Theorie der Endosymbiontensynthese
The theory of endosymbiont synthesis states that in the course of the development of life, the cell of one unicellular creature was absorbed by the cell of another unicellular creature and became part of the cell of the resulting higher creature.
Evolution has created ever more complex living beings. Thus it is said that components of human cells also originally go back to single-celled living beings, which became a component of the cells. For example the mitochondria.
Meaning
Soil bacteria are indispensable in many material cycles because they work as decomposers. This means that it breaks down organic matter and reduces it to inorganic material, which can then be absorbed by plants, for example. Fungi are also decomposers.
A very important example are the cyanobacteria, which carry out photosynthesis and therefore only need light and no organic food. Together with the green algae and other groups of algae, these bacteria form the plankton, which is the food basis of many ecosystems both in the sea and in fresh water.
Bacteria in humans
Bacteria are of great importance to the human body. Humans are about 1013 cells and have ten times as many bacteria in and on them. The Escherichia Coli live in the intestines and produce the digestive flora.
Even the skin of a healthy person is covered all over with bacteria that protect the skin from external influences. They feed on fats, minerals and dander. The number of bacteria in the mouth is particularly high at 1010.
However, there are also a large number of bacteria that are pathogenic. Bacteria cause a lot of inflammation , such as purulent infections, blood poisoning (sepsis) or inflammation of individual parts of the body (organs -> cystitis ).
Protection against infectious diseases
The field of medicine – hygiene – has developed two effective methods to prevent disease-causing bacteria.
On the one hand with disinfection, which drastically reduces the number of bacteria during use, and on the other hand with sterilization. In this regard, due to this method, the materials and the equipment becomes germ-free.
However, as soon as bacteria have penetrated the body and triggered a disease there, antibiotics are currently the most effective and best remedy against them.
Unfortunately, due to the large number of different antibiotics that are used very quickly, dangerous resistances are also developing more and more frequently.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.