We explain what microbes or microorganisms are and the characteristics of bacteria, viruses, protozoa, fungi and yeasts.
Some microbes are pathogenic but others are harmless or even beneficial.What are microbes?
Microbes o microorganisms are the tiniest forms of life known, which are also the most abundant in the entire planet Earth. They cannot be viewed or identified without the help of a microscope.
Many of them coexist with us without posing any threat, while others have learned over the millennia to lead an existence parasite or pathogenic, that is, as infectious agents of other organisms, especially multicellular.
The term microbe comes from the Greek voices mikros ("Tiny") and bios ("Life"), and was coined during the nineteenth century, to give name to the invisible beings responsible for diseases.
The idea of these beings had already appeared in the philosophical and prescientific realm of the humanity in the 13th century. For this reason, we still tend to associate the word microbe with pathogenic microorganisms, that is, those that carry parasitic stocks.
However, it was not until the seventeenth century that its existence, with the emergence of the microbiology as an organized field of scientific knowledge. Thus the vast fauna and Flora existing microscope, whose species they are not, as was initially thought, directly related.
Microbes are found literally all over the world, both on the ground, in the waters and the air, and both inside and outside of our own bodies. Our intestines, for example, are home to a ecosystem whole microbiotic, which live with us and help us digest the food.
Microbes are also responsible for the breakdown of organic material in the open, of the fermentation of beer, of the intense flavor of certain cheeses, and even of producing certain antibiotics.
They are essential to perpetuate life on the planet, although from time to time some get out of control and can cause damage to others populations from living beings. But everything is part of the processes of life on our planet.
There are many types of microbe, as we have said, but in this case we will focus on the best known: bacteria, virus, parasites, mushrooms Y yeast, which we will see below separately.
Bacteria
Bacteria (and to some extent, archaebacteria or archaea) are single-celled organisms prokaryotes very few micrometers in size (between 0.5 and 5 μm). They present diverse but recognizable shapes, such as spheres (cocci), bars (bacilli), spirals (vibrios) or helices (spirillae).
They are the most abundant organisms on the entire planet, adapted to all types of habitat in practically any type of conditions, both in free life (dedicated to photosynthesis, chemosynthesis or decomposition processes) as in parasitic life (dedicated to infecting other organisms).
The existence of bacteria is essential for the ecological balance of the world, since they deal with fundamental processes of recycling of organic matter and intervene in different biogeochemical cycles.
Bacteria can also cause deadly diseases, such as cholera, diphtheria, leprosy, syphilis, typhus or gonorrhea, and in these cases they are fought with various antibiotic compounds.
Virus
Viruses are acellular infectious agents, that is, they are so simple that they do not even consist of a single cell. cell, but they need to invade foreign cells in order to reproduce.
They are so simple that from a certain point of view it is impossible to know if they are really alive. However, they have their own genetic material that they inject into the cells they invade, to force them to synthesize new viruses instead of their own. protein usual.
When the invaded cell no longer supports the number of young viruses inside, it explodes. Thus, the viruses are released and infect other similar cells.
A virus is such a tiny and simple structure that it cannot be seen through ordinary microscopes (that is, they are submicroscopic beings). However, some species can reach exceptionally large sizes.
Your body consists of a molecule from DNA or RNA, encapsulated in a more or less simple protein envelope, and a layer of lipids that allows them to resist while searching for their host cell.
Viruses are in almost every ecosystems of the world and can have very different shapes and sizes, as well as very different methods of transmission. In the case of human being, viruses can transmit from common illnesses like the flu to incurable diseases like AIDS or HPV.
Protozoa
Protozoa or protozoa (from the Greek protos, "first", zoon, "Animal"), is the name coined in 1818 by the German naturalist Georg Goldfuss (1782-1848) for what were then considered primal animals, that is, the simplest that exist. They were then classified within the protist kingdom, or as his own kingdom apart from beings eukaryotes and unicellular.
Protozoa are a very diverse group of microscopic beings that can sometimes be as small as a few millimeters. About 30,000 species are known.
They tend to abound in aqueous media and in the soil itself, playing various roles within the food chain: heterotrophs, predators, detritivores, and even myxotrophs (as some are partially autotrophic through the photosynthesis).
Protozoa generally have a single-celled body endowed with a membrane permeable and vacuoles to digest their food, as well as flagella or other means of transport. Depending on the species, they can survive encyst to difficult environmental conditions to reactivate when the time is right.
In some cases they can lead a parasitic life, causing infections of different levels of danger. That is the case of amoebas, giardias or trichomonas. Other species, such as paramecium, live in pools of rainwater and are totally harmless to humans.
Fungi and yeasts
Located in a region intermediate between plants and animals, fungi and yeasts constitute a kingdom whole of life, of which many species are microscopic in size.
Fungi have cells endowed with chitin cell walls, different from those of plants, and they proliferate in humid environments. reproducing through spores, generally asexual. In many cases, its spores serve as an infectious agent and infect living beings with parasitic fungi, thus causing disease.
Of course, microscopic fungi do not have the traditional hypha shape of mushrooms or other ordinary fungal species, but are unicellular, devoid of flagella and mobility.
In some cases they are of great benefit to humans, such as the yeasts that are used to make bread, for the fermentation of certain liquors, or to produce biochemical substances, such as the antibiotic penicillin, produced by the fungus. penicillium.