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An agar plate streaked with microorganisms

Microbiology (from

Ancient Greek μῑκρος (mīkros) 'small', βίος (bíos) 'life', and -λογία (-logía) 'study of') is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells).[1][2] Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology

protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea.[3][4] Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means.[5] Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA
gene sequence used for bacteria identification.

, never considered as microorganisms, have been investigated by virologists, however, as the clinical effects traced to them were originally presumed due to chronic viral infections, and virologists took search—discovering "infectious proteins".

The existence of microorganisms was predicted many centuries before they were first observed, for example by the

microscopic organisms in the 1670s, using simple microscopes of his own design. Scientific microbiology developed in the 19th century through the work of Louis Pasteur and in medical microbiology Robert Koch


The existence of microorganisms was hypothesized for many centuries before their actual discovery. The existence of unseen microbiological life was postulated by

Jain scriptures describe nigodas which are sub-microscopic creatures living in large clusters and having a very short life, said to pervade every part of the universe, even in tissues of plants and flesh of animals.[8] The Roman Marcus Terentius Varro made references to microbes when he warned against locating a homestead in the vicinity of swamps "because there are bred certain minute creatures which cannot be seen by the eyes, which float in the air and enter the body through the mouth and nose and thereby cause serious diseases."[9]

Persian scientists hypothesized the existence of microorganisms, such as

Al-Razi who gave the earliest known description of smallpox in his book The Virtuous Life (al-Hawi).[10]

In 1546,

diseases were caused by transferable seedlike entities that could transmit infection by direct or indirect contact, or vehicle transmission.[11]

Schematic drawings
Van Leeuwenhoek's microscopes by Henry Baker[12]
Martinus Beijerinck is often considered as a founder of virology

In 1676,

moulds, in 1665.[14] It has, however, been suggested that a Jesuit priest called Athanasius Kircher was the first to observe microorganisms.[15]

Kircher was among the first to design magic lanterns for projection purposes, so he must have been well acquainted with the properties of lenses.[15] He wrote "Concerning the wonderful structure of things in nature, investigated by Microscope" in 1646, stating "who would believe that vinegar and milk abound with an innumerable multitude of worms." He also noted that putrid material is full of innumerable creeping animalcules. He published his Scrutinium Pestis (Examination of the Plague) in 1658, stating correctly that the disease was caused by microbes, though what he saw was most likely red or white blood cells rather than the plague agent itself.[15]

The birth of bacteriology

The field of

pure culture resulting in his description of several novel bacteria including Mycobacterium tuberculosis, the causative agent of tuberculosis.[2]

While Pasteur and Koch are often considered the founders of microbiology, their work did not accurately reflect the true diversity of the microbial world because of their exclusive focus on microorganisms having direct medical relevance. It was not until the late 19th century and the work of

Felix d'Herelle co-discovered bacteriophages in 1917 and was one of the earliest applied microbiologists.[22]

Joseph Lister was the first to use phenol disinfectant on the open wounds of patients.[23]


The branches of microbiology can be classified into applied sciences, or divided according to taxonomy, as is the case with bacteriology, mycology, protozoology, virology, phycology, and microbial ecology. There is considerable overlap between the specific branches of microbiology with each other and with other disciplines, and certain aspects of these branches can extend beyond the traditional scope of microbiology[24][25] A pure research branch of microbiology is termed cellular microbiology.


While some people have

dairy products), antibiotic production and act as molecular vehicles to transfer DNA to complex organisms such as plants and animals. Scientists have also exploited their knowledge of microbes to produce biotechnologically important enzymes such as Taq polymerase,[26] reporter genes for use in other genetic systems and novel molecular biology techniques such as the yeast two-hybrid system.[citation needed

Bacteria can be used for the industrial production of

Fermenting tanks with yeast being used to brew beer

A variety of

alginate, cellulose, cyanophycin, poly(gamma-glutamic acid), levan, hyaluronic acid, organic acids, oligosaccharides polysaccharide and polyhydroxyalkanoates.[29]

Microorganisms are beneficial for

contaminant. Since sites typically have multiple pollutant types, the most effective approach to microbial biodegradation is to use a mixture of bacterial and fungal species and strains, each specific to the biodegradation of one or more types of contaminants.[30]

prebiotics (substances consumed to promote the growth of probiotic microorganisms).[31][32] The ways the microbiome influences human and animal health, as well as methods to influence the microbiome are active areas of research.[33]

Research has suggested that microorganisms could be useful in the treatment of

tumors. Clostridial vectors can be safely administered and their potential to deliver therapeutic proteins has been demonstrated in a variety of preclinical models.[34]

Some bacteria are used to study fundamental mechanisms. An example of model bacteria used to study motility[35] or the production of polysaccharides and development is Myxococcus xanthus.[36]

See also


  1. ^ "Microbiology". Nature.com. Nature Portfolio (of Springer Nature). Retrieved 2020-02-01.
  2. ^ .
  3. .
  4. .
  5. .
  6. ^ Rice G (2007-03-27). "Are Viruses Alive?". Retrieved 2007-07-23.
  7. ^ .
  8. .
  9. ^ Varro MT (1800). The three books of M. Terentius Varro concerning agriculture. Vol. 1. Charing Cross, London: At the University Press. p. xii.
  10. ^ "فى الحضارة الإسلامية - ديوان العرب" [Microbiology in Islam]. Diwanalarab.com (in Arabic). Retrieved 14 April 2017.
  11. ^ Fracastoro G (1930) [1546]. De Contagione et Contagiosis Morbis [On Contagion and Contagious Diseases] (in Latin). Translated by Wright WC. New York: G.P. Putnam.
  12. microbial life
    . He actually measured the multiplication of the bugs. What is more amazing is that he published his discoveries.
  13. ^
    PMID 25750239
  14. .
  15. ^ .
  16. ^ Drews G (1999). "Ferdinand Cohn, among the Founder of Microbiology". ASM News. 65 (8): 547.
  17. .
  18. .
  19. .
  20. ^ Johnson J (2001) [1998]. "Martinus Willem Beijerinck". APSnet. American Phytopathological Society. Archived from the original on 2010-06-20. Retrieved May 2, 2010. Retrieved from Internet Archive January 12, 2014.
  21. ^ Paustian T, Roberts G (2009). "Beijerinck and Winogradsky Initiate the Field of Environmental Microbiology". Through the Microscope: A Look at All Things Small (3rd ed.). Textbook Consortia. § 1–14.
  22. PMID 23231482
  23. .
  24. ^ "Branches of Microbiology". General MicroScience. 2017-01-13. Retrieved 2017-12-10.
  25. .
  26. .
  27. . Retrieved 2016-03-25.
  28. .
  29. . Retrieved 2016-03-25.
  30. . Retrieved 2016-03-25.
  31. .
  32. . Retrieved 2016-03-25.
  33. ^ Wenner M (30 November 2007). "Humans Carry More Bacterial Cells than Human Ones". Scientific American. Retrieved 14 April 2017.
  34. .
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  36. .

Further reading

External links