Microbiology 1

Microbiology

An agar plate streaked with microorganisms

Microbiology (from Greek μῑκρος, mīkros, "small"; βίος, bios, "life";and -λογία, -logia) is the study of microorganisms, which aremicroscopic, unicellular, and cell-cluster organisms.[1] This includeseukaryotes such as fungi and protists, and prokaryotes. Viruses[2] andprions, though not strictly classed as living organisms, are also studied.Microbiology typically includes the study of the immune system, orImmunology. Generally, immune systems interact with pathogenicmicrobes; these two disciplines often intersect which is why manycolleges offer a paired degree such as "Microbiology andImmunology".

Microbiology is a broad term which includes virology, mycology, parasitology, bacteriology and other branches. Amicrobiologist is a specialist in microbiology and these other topics.

Microbiology is researched actively, and the field is advancing continually. It is estimated only about one percent ofall of the microbe species on Earth have been studied.[3] Although microbes were directly observed over threehundred years ago, the field of microbiology can be said to be in its infancy relative to older biological disciplinessuch as zoology and botany.

History

AncientThe existence of microorganisms was hypothesized for many centuries before their actual discovery. The existenceof unseen microbiological life was postulated by Jainism which is based on Mahavira’s teachings as early as 6thcentury BCE.[4] . Paul Dundas notes that Mahavira asserted existence of unseen microbiological creatures living inearth, water, air and fire.[5] Jain scriptures also describe nigodas which are sub-microscopic creatures living in largeclusters and having a very short life and are said to pervade each and every part of the universe, even in tissues ofplants and flesh of animals.[6] The Roman Marcus Terentius Varro made references to microbes when he warnedagainst locating a homestead in the vicinity of swamps "because there are bred certain minute creatures which cannotbe seen by the eyes, which float in the air and enter the body through the mouth and nose and there cause seriousdiseases."[7]

In 1546 Girolamo Fracastoro proposed that epidemic diseases were caused by transferable seedlike entities thatcould transmit infection by direct or indirect contact, or even without contact over long distances.However, early claims about the existence of microorganisms were speculative, and not based on any data orobservation. Actual observation and discovery of microbes had to await the invention of the microscope in the 17thcentury.

Microbiology 2

Modern

Antonie van Leeuwenhoek, was considered to bethe first to observe microorganisms using a

microscope.

in 1676, Antonie van Leeuwenhoek observed bacteria and othermicroorganisms, using a single-lens microscope of his own design.[1]

While Van Leeuwenhoek is often cited as the first to observe microbes,Robert Hooke made the first recorded microscopic observation, of thefruiting bodies of molds, in 1665.[8] . The first observation of microbesusing a microscope is generally credited to the Dutch draper andhaberdasher, Antonie van Leeuwenhoek, who lived for most of his lifein Delft, Holland. It has, however, been suggested that a Jesuit priestcalled Athanasius Kircher was the first to observe microorganisms.[9]

He was among the first to design magic lanterns for projectionpurposes, so he must have been well acquainted with the properties oflenses.[9] One of his book contains a chapter in Latin, which reads intranslation – ‘Concerning the wonderful structure of things in nature,investigated by Microscope. Here, he wrote ‘who would believe thatvinegar and milk abound with an innumerable multitude of worms.’ Healso noted that putrid material is full of innumerable creepinganimalculae. These observations antedate Robert Hooke’sMicrographia by nearly 20 years and were published some 29 years before van Leeuwenhoek saw protozoa and 37years before he described having seen bacteria.[9]

The field of bacteriology (later a subdiscipline of microbiology) was founded in the 19th century by Ferdinand Cohn,a botanist whose studies on algae and photosynthetic bacteria led him to describe several bacteria including Bacillusand Beggiatoa. Cohn was also the first to formulate a scheme for the taxonomic classification of bacteria anddiscover spores.[10] Louis Pasteur and Robert Koch were contemporaries of Cohn’s and are often considered to bethe father of Microbiology[9] and medical microbiology, respectively.[11] Pasteur is most famous for his series ofexperiments designed to disprove the then widely held theory of spontaneous generation, thereby solidifyingmicrobiology’s identity as a biological science.[12] Pasteur also designed methods for food preservation(pasteurization) and vaccines against several diseases such as anthrax, fowl cholera and rabies.[1] Koch is best knownfor his contributions to the germ theory of disease, proving that specific diseases were caused by specific pathogenicmicroorganisms. He developed a series of criteria that have become known as the Koch's postulates. Koch was oneof the first scientists to focus on the isolation of bacteria in pure culture resulting in his description of several novelbacteria including Mycobacterium tuberculosis, the causative agent of tuberculosis.[1]

While Pasteur and Koch are often considered the founders of microbiology, their work did not accurately reflect thetrue diversity of the microbial world because of their exclusive focus on microorganisms having direct medicalrelevance. It was not until the late 19th century and the work of Martinus Beijerinck and Sergei Winogradsky, thefounders of general microbiology (an older term encompassing aspects of microbial physiology, diversity andecology), that the true breadth of microbiology was revealed.[1] Beijerinck made two major contributions tomicrobiology: the discovery of viruses and the development of enrichment culture techniques.[13] While his work onthe Tobacco Mosaic Virus established the basic principles of virology, it was his development of enrichmentculturing that had the most immediate impact on microbiology by allowing for the cultivation of a wide range ofmicrobes with wildly different physiologies. Winogradsky was the first to develop the concept of chemolithotrophyand to thereby reveal the essential role played by microorganisms in geochemical processes.[14] He was responsiblefor the first isolation and description of both nitrifying and nitrogen-fixing bacteria.[1]

Microbiology 3

FieldsThe field of microbiology can be generally divided into several subdisciplines:• Microbial physiology: The study of how the microbial cell functions biochemically. Includes the study of

microbial growth, microbial metabolism and microbial cell structure.• Microbial genetics: The study of how genes are organized and regulated in microbes in relation to their cellular

functions. Closely related to the field of molecular biology.• Cellular microbiology: A discipline bridging microbiology and cell biology.• Medical microbiology: The study of the pathogenic microbes and the role of microbes in human illness. Includes

the study of microbial pathogenesis and epidemiology and is related to the study of disease pathology andimmunology.

• Veterinary microbiology: The study of the role in microbes in veterinary medicine or animal taxonomy.• Environmental microbiology: The study of the function and diversity of microbes in their natural environments.

Includes the study of microbial ecology, microbially-mediated nutrient cycling, geomicrobiology, microbialdiversity and bioremediation. Characterization of key bacterial habitats such as the rhizosphere and phyllosphere,soil and groundwater ecosystems, open oceans or extreme environments (extremophiles).

• Evolutionary microbiology: The study of the evolution of microbes. Includes the study of bacterial systematicsand taxonomy.

• Industrial microbiology: The exploitation of microbes for use in industrial processes. Examples includeindustrial fermentation and wastewater treatment. Closely linked to the biotechnology industry. This field alsoincludes brewing, an important application of microbiology.

• Aeromicrobiology: The study of airborne microorganisms.• Food microbiology: The study of microorganisms causing food spoilage and foodborne illness. Using

microorganisms to produce foods, for example by fermentation.• Pharmaceutical microbiology: the study of microorganisms causing pharmaceutical contamination and spoil• Agricultural microbiology: The study of agriculturaly important microorganisms.(Jobs with the Center For Disease Control and Prevention requires a degree in microbiology for most positions)• Soil Microbiology: The study of those microorganisms that are found in soil.• Water microbiology: The study of those microorganisms that are found in water.• Generation microbiology: The study of those microorganisms that have the same characters as their parents.• Nano microbiology: The study of those microorganisms at nano level.

Benefits

Fermenting tanks with yeast being used to brewbeer

Whilst there are undoubtedly some who fear all microbes due to theassociation of some microbes with various human illnesses, manymicrobes are also responsible for numerous beneficial processes suchas industrial fermentation (e.g. the production of alcohol, vinegar anddairy products), antibiotic production and as vehicles for cloning inmore complex organisms such as plants. Scientists have also exploitedtheir knowledge of microbes to produce biotechnologically importantenzymes such as Taq polymerase, reporter genes for use in othergenetic systems and novel molecular biology techniques such as theyeast two-hybrid system.

Bacteria can be used for the industrial production of amino acids. Corynebacterium glutamicum is one of the mostimportant bacterial species with an annual production of more than two million tons of amino acids, mainlyL-glutamate and L-lysine.[15]

Microbiology 4

A variety of biopolymers, such as polysaccharides, polyesters, and polyamides, are produced by microorganisms.Microorganisms are used for the biotechnological production of biopolymers with tailored properties suitable forhigh-value medical application such as tissue engineering and drug delivery. Microorganisms are used for thebiosynthesis of xanthan, alginate, cellulose, cyanophycin, poly(gamma-glutamic acid), levan, hyaluronic acid,organic acids, oligosaccharides and polysaccharide, and polyhydroxyalkanoates.[16]

Microorganisms are beneficial for microbial biodegradation or bioremediation of domestic, agricultural andindustrial wastes and subsurface pollution in soils, sediments and marine environments. The ability of eachmicroorganism to degrade toxic waste depends on the nature of each contaminant. Since sites typically have multiplepollutant types, the most effective approach to microbial biodegradation is to use a mixture of bacterial species andstrains, each specific to the biodegradation of one or more types of contaminants.[17]

There are also various claims concerning the contributions to human and animal health by consuming probiotics(bacteria potentially beneficial to the digestive system) and/or prebiotics (substances consumed to promote thegrowth of probiotic microorganisms).[18]

Recent research has suggested that microorganisms could be useful in the treatment of cancer. Various strains ofnon-pathogenic clostridia can infiltrate and replicate within solid tumors. Clostridial vectors can be safelyadministered and their potential to deliver therapeutic proteins has been demonstrated in a variety of preclinicalmodels.[19]

References[1] Madigan M, Martinko J (editors) (2006). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.[2] Rice G (2007-03-27). "Are Viruses Alive?" (http:/ / serc. carleton. edu/ microbelife/ yellowstone/ viruslive. html). . Retrieved 2007-07-23.[3] Amann RI, Ludwig W, Schleifer KH (1995). "Phylogenetic identification and in situ detection of individual microbial cells without

cultivation". Microbiol. Rev. 59 (1): 143–169. PMC 239358. PMID 7535888.[4] Mahavira is dated 599 BCE - 527 BC. See. Dundas, Paul; John Hinnels ed. (2002). The Jain. London: Routledge. ISBN 0-415-26606-8. p. 24[5] Dundas, Paul (2002) p. 88[6] *Jaini, Padmanabh (1998). The Jaina Path of Purification. New Delhi: Motilal Banarsidass. ISBN 81-208-1578-5. p. 109[7] Varro on Agriculture 1, xii Loeb.[8] Gest H (2005). "The remarkable vision of Robert Hooke (1635-1703): first observer of the microbial world". Perspect. Biol. Med. 48 (2):

266–72. doi:10.1353/pbm.2005.0053. PMID 15834198.[9] Wainwright, Milton (2003). An Alternative View of the Early History of Microbiology. 52. pp. 333–55. doi:10.1016/S0065-2164(03)01013-X.

PMID 12964250.[10] Drews G (1999). "Ferdinand Cohn, among the Founder of Microbiology". ASM News 65 (8): 547.[11] Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.[12] Bordenave G (2003). "Louis Pasteur (1822-1895)". Microbes Infect. 5 (6): 553–60. doi:10.1016/S1286-4579(03)00075-3. PMID 12758285.[13] Johnson J (2001). "Martinus Willem Beijerinck" (http:/ / www. apsnet. org/ Education/ feature/ TMV/ intro. html). APSnet. American

Phytopathological Society. . Retrieved May 2, 2010.[14] Paustian T, Roberts G (2009). "Beijerinck and Winogradsky Initiate the Field of Environmental Microbiology" (http:/ / www.

microbiologytext. com/ index. php?module=Book& func=displayarticle& art_id=32). Through the Microscope: A Look at All Things Small(3rd ed.). Textbook Consortia. § 1–14. . Retrieved May 2, 2010.

[15] Burkovski A (editor). (2008). Corynebacteria: Genomics and Molecular Biology (http:/ / www. horizonpress. com/ cory). Caister AcademicPress. ISBN 1904455301. . .

[16] Rehm BHA (editor). (2008). Microbial Production of Biopolymers and Polymer Precursors: Applications and Perspectives (http:/ / www.horizonpress. com/ biopolymers). Caister Academic Press. . .

[17] Diaz E (editor). (2008). Microbial Biodegradation: Genomics and Molecular Biology (http:/ / www. horizonpress. com/ biod) (1st ed.).Caister Academic Press. ISBN 1904455174. . .

[18] Tannock GW (editor). (2005). Probiotics and Prebiotics: Scientific Aspects (http:/ / www. horizonpress. com/ pro3). Caister AcademicPress. . .

[19] Mengesha et al. (2009). "Clostridia in Anti-tumor Therapy". Clostridia: Molecular Biology in the Post-genomic Era. Caister AcademicPress. ISBN 978-1-904455-38-7.

Microbiology 5

External links• Microbiology (http:/ / www. bbc. co. uk/ programmes/ b007753d) on In Our Time at the BBC. ( listen now (http:/

/ www. bbc. co. uk/ iplayer/ console/ b007753d/ In_Our_Time_Microbiology))• Online lectures in microbiology (http:/ / media. med. sc. edu/ microbiology2007/ ) University of South Carolina• Microbiology Online (http:/ / www. ocean. edu/ academics/ programs_of_study/ science/ MicrobiologyOnline.

htm)• Online Microbiology textbook (http:/ / www. microbiologytext. com/ index. php?module=Book& func=toc&

book_id=4)• Online Medical Microbiology textbook (http:/ / pathmicro. med. sc. edu/ book/ welcome. htm)• Institute of Microbiology of the Swiss Federal Institute of Technology (http:/ / www. micro. biol. ethz. ch/ )• Annual Review of Microbiology (http:/ / arjournals. annualreviews. org/ loi/ micro/ )

Article Sources and Contributors 6

Article Sources and ContributorsMicrobiology  Source: http://en.wikipedia.org/w/index.php?oldid=416994643  Contributors: 5 albert square, AJCann, AJim, APH, Achaemenes, AdRock, AdamRetchless, Adodda05, Advanced,Afluent Rider, Alan Liefting, Alpha male wolf, AlphaEta, Anclation, Andreadb, AnmaFinotera, Antandrus, Anypodetos, April kathleen, Arcadian, ArcadianOnUnsecuredLoc, Arjuna316, ArtLaPella, Athenean, Aua, Azaroonus, Bact, Bamskamp, Barras, Barrylb, BatteryIncluded, Bdekker, Bennybp, Bluemask, Bluerasberry, Boing! said Zebedee, Bomac, Brebacon, Brianga,Brighterorange, Brya, Bryan Derksen, Bubbachuck, CERminator, CanadianLinuxUser, Capricorn42, Cassandro, Catslayer, Causa sui, Centrx, Cforrester101, Chaos, Chiefmanzzz, ChrisCapoccia, Cinderelly007, Clarkiegirl12, Clicketyclack, CliffC, Cmcnicoll, Colenso, Conversion script, Crabula, D climacus, D6, DVD R W, Danieloke, Darkinho, Darnell-mote, Davidruben,DerHexer, Deviator13, Diberri, DonSiano, Dr Gangrene, DrSculerati, Drdcsharma, Dusis, Edward, Eeekster, El C, ElAmericano, Elassint, Eleassar777, Emuzesto, Eog1916, Epbr123, ErkanYilmaz, Espresso Addict, Etacar11, Eubulides, Euryalus, Excirial, Extransit, Fbarw, Feydey, Fhm42194, Fieldday-sunday, Finell, Flaviolin, Franamax, FrancoGG, Frazzydee, Gabbe, Genius101,Geologist, Ghenzmitz, Giftlite, Gilliam, Ginajanota, GiollaUidir, Giraffedata, Girdi, Glenn, GodDog, GraemeL, Graham87, Grasyop, Grendelkhan, Griffinhg, Gsteinberg, Gzli888, Herk1955,Heron, Hughbl, Hyacinth, Indian Chronicles, Indon, Irandill, J.delanoy, JaGa, Jagged 85, Jcwsoton, Jethero, Jlk3, Jmeppley, Jncraton, JonHarder, Jonel, JuanitaJP, Kaarel, Katieh5584,Knight1993, Koortrook, Kostisl, Krich, Kubra, LadyofHats, Lakshwadeep, Laurenautomatic, Leafyplant, Lexor, Little Mountain 5, Loser987, Lquilter, Luna Santin, MER-C, MacTire02, MagnusManske, Makemi, MarcoTolo, Martial75, Maurreen, MaxSem, Maxis ftw, Mayumashu, McDogm, McSly, Menaga gp, Mendaliv, Methcub, Miaow Miaow, Microbiologyprocedure.com, MikaelHäggström, MillarbankStreet, Mlpearc, Moocha, Mormegil, Mr.Bip, MrOllie, Mrkedwds, Mtiedemann, Muijz, Munita Prasad, Mushin, Nandutg, Napra12345, NawlinWiki, NewEnglandYankee,No Guru, Noclaf, Norm, Noutschko, Nucleophilic, Oatmeal batman, Ocaasi, Oli Filth, Oliver12, Onco p53, Oni Ookami Alfador, Opabinia regalis, Ozmaweezer, Padreilly, Perfectlover, Phgao,Philip Trueman, Photaling, Pigsonthewing, Pinethicket, Pixie, Plommespiser, Pol098, Prashantbioinfo, Pro bug catcher, Prof77, Pscott22, Puchiko, R'n'B, RHaworth, RUL3R, Raguks,Ranainam5343, Reaper Eternal, Recycled.jack, Remi0o, Reo On, Rharris401, Rhunt2188, Riana, Rich Farmbrough, Richard D. LeCour, Rmckay630, Ronhjones, RoyBoy, Ryanpiquette, ST47,Sabedon, Sadisticxxsammeh, Sam Clark, Scarecroe, Scharks, Seaphoto, Shanata, Shizhao, SilkTork, Silver4, Simhq, SiobhanHansa, Skier Dude, Smelialichu, Smoggyrob, Someone else,Souad27, Spitshine, SpuriousQ, Steinsky, Stephenb, Stupid Corn, SuperHamster, Supertouch, Swatjester, Tail, Tawker, Tbannist, Technidata, Teflon Don, Template namespace initialisationscript, Terrx, Tide rolls, TimBentley, TimVickers, Titoxd, Tomasz Prochownik, Tomtom3, Touchstone42, Trevor Johns, Utcursch, VMarie, Van helsing, Vanka5, Violask81976, Viriditas,Vsmith, Wallace2oo7, Wavelength, Wayward, WereSpielChequers, Whispering, Wiki alf, Yahel Guhan, Zeehun, Милан Јелисавчић, ملاع بوبحم, आशीष भटनागर, 492 anonymous edits

Image Sources, Licenses and ContributorsImage:Agar plate with colonies.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Agar_plate_with_colonies.jpg  License: Public Domain  Contributors: Ies, Phyzome, Roomba,Wickey-nl, WstImage:Anton van Leeuwenhoek.png  Source: http://en.wikipedia.org/w/index.php?title=File:Anton_van_Leeuwenhoek.png  License: Public Domain  Contributors: Jan Verkolje (1650—1693)Image:Samadams2.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Samadams2.jpg  License: GNU Free Documentation License  Contributors: Original uploader was Kafziel aten.wikipedia

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