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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/14 23:26:43」(JST)

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Auxotrophy (Gr. αὐξάνω "to increase"; τροφή "nourishment") is the inability of an organism to synthesize a particular organic compound required for its growth (as defined by IUPAC). An auxotroph is an organism that displays this characteristic; auxotrophic is the corresponding adjective. Auxotrophy is the opposite of prototrophy, which is characterized by the ability to synthesize all the compounds needed for growth.

The method of replica plating implemented by Esther Lederberg included auxotrophs that were temperature-sensitive; that is, their ability to synthesize was temperature-dependent. (Auxotrophs are usually not temperature-dependent. They can also depend on other factors.) Multiple auxotrophs can also coexist at the same time, within the same organism.

In genetics, a strain is said to be auxotrophic if it carries a mutation that renders it unable to synthesize an essential compound. For example, a yeast mutant with an inactivated uracil synthesis pathway gene is a uracil auxotroph. (E.g., if the yeast Orotidine 5'-phosphate decarboxylase gene is inactivated, the resultant strain is a uracil auxotroph.) Such a strain is unable to synthesize uracil and will only be able to grow if uracil can be taken up from the environment. This is the opposite of a uracil prototroph, or in this case a wild-type strain, which can still grow in the absence of uracil. Auxotrophic genetic markers are often used in molecular genetics; they were famously used in Beadle and Tatum's Nobel prize-winning work on the one gene-one enzyme hypothesis.

Researchers have used strains of E. coli auxotrophic for specific amino acids to introduce non-natural amino acid analogues into proteins. For instance cells auxotrophic for the amino acid phenylalanine can be grown in media supplemented with an analogue such as para-azido phenylalanine.

Many living things, including humans, are auxotrophic for large classes of compounds required for growth and must obtain these compounds through diet (see vitamin, essential amino acid, essential fatty acid).

Footnotes[edit]

External links[edit]

"Regulation of endosomal clathrin and retromer-mediated endosome to Golgi retrograde transport by the J-domain protein RME-8" - The EMBO Journal
"Pleiotropic effects of purine auxotrophy inRhizobium meliloti on cell surface molecules" - Springerlink
http://mic.sgmjournals.org/cgi/reprint/16/1/286.pdf "Auxotrophy and Organic Compounds in the Nutrition of Marine Phytoplankton"

English Journal

New families of single integration vectors and gene tagging plasmids for genetic manipulations in budding yeast.

Wosika V1, Durandau E1, Varidel C1, Aymoz D1, Schmitt M1, Pelet S2.
Molecular genetics and genomics : MGG.Mol Genet Genomics.2016 Dec;291(6):2231-2240. Epub 2016 Sep 16.
The tractability of the budding yeast genome has provided many insights into the fundamental mechanisms regulating cellular life. With the advent of synthetic biology and single-cell measurements, novel tools are required to manipulate the yeast genome in a more controlled manner. We present, here,
PMID 27637489

A set of isogenic auxotrophic strains for constructing multiple gene deletion mutants and parasexual crossings in Aspergillus niger.

Niu J1, Arentshorst M1, Seelinger F1, Ram AF2, Ouedraogo JP1,3.
Archives of microbiology.Arch Microbiol.2016 Nov;198(9):861-8. doi: 10.1007/s00203-016-1240-6. Epub 2016 Jun 1.
To construct a set of isogenic auxotrophic strains in Aspergillus niger suited for creating multiple gene deletion mutants and executing parasexual crossings, we have combined mutations in genes involved in colour pigmentation (fwnA and olvA) with well-selectable auxotrophic markers (pyrG, nicB, arg
PMID 27251039

Arginase is Essential for Survival of Leishmania donovani Promastigotes but not Intracellular Amastigotes.

Boitz JM1, Gilroy CA, Olenyik TD1,2, Paradis D2, Perdeh J2, Dearman K2, Davis MJ2, Yates PA1, Li Y3, Riscoe MK3,4, Ullman B1, Roberts SC5.
Infection and immunity.Infect Immun.2016 Oct 24. pii: IAI.00554-16. [Epub ahead of print]
Studies in Leishmania donovani have shown that both ornithine decarboxylase and spermidine synthase, two enzymes of the polyamine biosynthetic pathway, are critical for promastigote proliferation and required for maximum infection in mice. However, the importance of arginase (ARG), the first enzyme
PMID 27795357

Japanese Journal

Differences in infectivity between endosymbiotic Chlorella variabilis cultivated outside host Paramecium bursaria for 50 years and those immediately isolated from host cells after one year of reendosymbiosis