Microbiological culture
541900
210142702
2008-05-04T17:48:51Z
AlleborgoBot
3813685
robot Adding: [[it:Coltura di microrganismi]]
[[Image:Anthrax_01.jpg|thumb|200px|right|A culture of ''[[Bacillus anthracis]]'']]
A '''microbiological culture''', AKA '''microbial culture''', is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested, or both. It is one of the primary [[diagnosis|diagnostic]] methods of [[microbiology]] and used as a tool to determine the cause of [[infectious disease]]. Microbial cultures are also used extensively as a research tool in [[molecular biology]]. It is often essential to isolate a pure culture of microorganisms. A pure (or ''axenic'') culture is a population of [[Cell (biology)|cell]]s or [[multicellular organisms]] growing in the absence of other [[species]] or types. A pure culture may originate from a single cell or single organism, in which case the cells are genetic [[clones]] of one another.
== Bacterial culture ==
The most common evolution of microbiological culture uses [[petri dish|petri dishes]] with a layer of [[agar plate|agar]]-based growth medium in them to grow bacterial cultures. This is generally done inside of an [[incubator (microbiology)|incubator]]. Another method is ''liquid culture'', where the bacteria are grown suspended in a liquid nutrient medium. Bottles of liquid culture are often placed in shakers in order to introduce [[oxygen]] to the liquid and maintaining the uniformity of the culture.
=== Isolation of pure cultures ===
Pure cultures of single-celled organisms usually must be isolated and grown under aseptic conditions, requiring sterilized instruments and filtered or still air. Isolated colonies of [[microorganism]]s are usually obtained by growth on the surface of a petri dish. The petri dish (or ''plate'') contains an appropriate growth medium for the microorganism of interest, usually gelled with [[agar]]. To isolate a pure culture, the initial sample (inoculum) is manipulated using with an inoculation loop or needle to spread and dilute the cells on the surface of the plate. The objective is to eventually have some areas of the petri dish with isolated single cells. The culture is incubated under appropriate environmental conditions until the cells have grown and visible colonies appear. Well-isolated colonies have a high probability of having grown from single cells and therefore being pure cultures.
Pure cultures can also be prepared by high dilution from a liquid culture into a liquid medium. At sufficient dilution only a fraction of the inoculated culture tubes grow, and the probability is high that those cultures originated from a single cell.
== Virus and phage culture ==
Virus or phage cultures require host cells for the virus or phage to multiply in. For [[bacteriophage]]s, cultures are grown by infecting bacterial cells. The phage can then be isolated from the resulting plaques in a lawn of bacteria on a plate. [[Virus]] cultures are obtained from their appropriate eukaryotic host cells.
== Eukaryotic cell culture ==
{{main|Cell culture}}
The term ''culture'' can also apply to [[eukaryote|eukaryotic]] microorganisms such as [[yeast]] and be used as a synonym for [[tissue culture]], which involves the growth of cells or tissues explanted from a [[multi-cellular]] organism.
=== Isolation of pure cultures ===
For single-celled eukaryotes, such as yeast, the isolation of pure cultures uses the same techniques as for bacterial cultures. Pure cultures of multicellular organisms are often more easily isolated by simply picking out a single individual to initiate a culture. This is a useful technique for pure culture of [[fungi]], multicellular [[algae]], and small [[metazoa]], for example.
== See also ==
* [[Blood culture]]
* [[Sputum culture]]
* [[Screening cultures]]
{{pathology}}
{{micro-stub}}
[[Category:Microbiology techniques]]
[[Category:Microbiology terms]]
[[Category:Cell cultures]]
[[cs:Kultura (biologie)]]
[[de:Bakterienkultur]]
[[es:Cultivo (microbiología)]]
[[fr:Culture microbiologique]]
[[it:Coltura di microrganismi]]
[[ja:培養]]
[[pt:Cultura bacteriana]]
[[sv:Bakterieodling]]
[[tr:Kültür (biyoloji)]]
[[uk:Чиста культура]]