日
関

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/19 20:29:38」(JST)

wiki en

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 nutrient, essential amino acid, essential fatty acid).

The complex pattern of evolution of vitamin auxotrophy across the eukaryotic tree of life is intimately connected with the interdependence between organisms.^[1]

Footnotes

^ Helliwell, Katherine E. et al. (2013). Widespread decay of vitamin-related pathways: coincidence or consequence?. Trends in Genetics, Volume 29, Issue 8, 469-478

External links

"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
"Auxotrophy and Organic Compounds in the Nutrition of Marine Phytoplankton"

References

English Journal

Biosynthetic incorporation of tryptophan analogs in proteins.

Broos J.SourceLaboratory of Biophysical Chemistry and Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
Methods in molecular biology (Clifton, N.J.).Methods Mol Biol.2014;1076:359-70. doi: 10.1007/978-1-62703-649-8_15.
Biosynthetic incorporation of Trp analogs in a protein can help in its characterization using fluorescence spectroscopy and other methodologies like NMR and phosphorescence. Here a protocol is presented resulting in the efficient incorporation of Trp analogs in a recombinant protein, using an Escher
PMID 24108634

A set of genetically diverged Saccharomyces cerevisiae strains with markerless deletions of multiple auxotrophic genes.

Louvel H, Gillet-Markowska A, Liti G, Fischer G.SourceUPMC, UMR7238, Génomique des Microorganismes, 15 rue de l'École de Médecine, 75006, Paris, France; CNRS, UMR7238, Génomique des Microorganismes, Paris, France.
Yeast (Chichester, England).Yeast.2013 Nov 29. doi: 10.1002/yea.2991. [Epub ahead of print]
Genome analysis of over 70 Saccharomyces strains revealed the existence of five groups of genetically diverged S. cerevisiae wild-type isolates, which feature distinct genetic backgrounds and reflect the natural diversity existing among the species. The strains originated from different geographical
PMID 24288298

Diversity of Cobalamin Riboswitches in the Corrinoid-Producing Organohalide Respirer Desulfitobacterium hafniense.

Choudhary PK, Duret A, Rohrbach-Brandt E, Holliger C, Sigel RK, Maillard J.SourceInstitute of Inorganic Chemistry, University of Zurich, Zurich, Switzerland.
Journal of bacteriology.J Bacteriol.2013 Nov;195(22):5186-95. doi: 10.1128/JB.00730-13. Epub 2013 Sep 13.
The strategic adaptation of prokaryotes in polluted niches involves the efficient regulation of their metabolism. The obligate anaerobe and metabolically versatile Desulfitobacterium hafniense reductively dechlorinates halogenated organic compounds (so-called organohalides). Some D. hafniense strain
PMID 24039263

Japanese Journal

Enhancement of L-phenylalanine production by engineered Escherichia coli using phased exponential L-tyrosine feeding combined with nitrogen source optimization(MICROBIAL PHYSIOLOGY AND BIOTECHNOLOGY)

Journal of bioscience and bioengineering 120(1), 36-40, 2015-07
NAID 110009973282

Construction of a <i>URA5.3</i> deletion strain of the unicellular red alga <i>Cyanidioschyzon merolae</i>: A backgroundless host strain for transformation experiments