Saccharomyces cerevisiae 237704 219062313 2008-06-13T11:48:13Z Amire80 210028 adding interwiki - he. [[:en:WP:WPIW/HE|You can help!]] {{Taxobox | name = ''Saccharomyces cerevisiae'' | image = S cerevisiae under DIC microscopy.jpg | image_width = 280px | regnum = [[Fungus|Fungi]] | phylum = [[Ascomycota]] | subphylum = [[Saccharomycotina]] | classis = [[Saccharomycetes]] | ordo = [[Saccharomycetales]] | familia = [[Saccharomycetaceae]] | genus = ''[[Saccharomyces]]'' | species = '''''S. cerevisiae''''' | binomial = ''Saccharomyces cerevisiae'' | binomial_authority = [[Franz Meyen|Meyen]] ex [[Emil Christian Hansen|E.C. Hansen]] }} '''''Saccharomyces cerevisiae''''' is a [[species]] of [[budding]] [[yeast]]. It is perhaps the most useful [[yeast]] owing to its use since ancient times in [[baking]] and [[brewing]]. It is believed that it was originally isolated from the skins of grapes (one can see the yeast as a component of the thin white film on the skins of some dark-colored fruits such as plums; it exists among the [[Wax#Vegetable waxes|waxes]] of the [[Plant cuticle|cuticle]]). It is one of the most intensively studied [[Eukaryote|eukaryotic]] [[model organism]]s in [[molecular biology|molecular]] and [[cell biology]], much like ''[[Escherichia coli]]'' as the model [[prokaryote]]. It is the microorganism behind the most common type of [[fermentation (biochemistry)|fermentation]]. ''Saccharomyces cerevisiae'' cells are round to ovoid, 5–10 [[micrometre]]s in diameter. It reproduces by a division process known as [[budding]]. It is useful in studying the [[cell cycle]] because it is easy to culture, but, as a [[eukaryote]], it shares the complex internal cell structure of plants and animals. ''S. cerevisiae'' was the first [[eukaryotic]] [[genome]] that was completely sequenced. The yeast genome database [http://www.yeastgenome.org/] is highly annotated and remains a very important tool for developing basic knowledge about the function and organization of eukaryotic cell genetics and physiology. Another important ''S. cerevisiae'' database is maintained by the Munich Information Center for Protein Sequences [http://mips.gsf.de/genre/proj/yeast/index.jsp]. The genome is composed of about 13,000,000 [[base pair]]s and 6,275 [[gene]]s, compactly organised on 16 chromosomes. Only about 5,800 of these are believed to be true functional genes. It is estimated that yeast shares about 23% of its genome with that of [[human]]s. "''Saccharomyces''" derives from [[Greek language|Greek]], and means "sugar mold". "''Cerevisiae''" comes from [[Latin]], and means "of beer". Other names for the organism are: * '''Brewer's yeast''' (the apostrophe may be after the ''s'' or missing), though other species are also used in brewing * '''Ale yeast''' * '''Top-fermenting yeast''' * '''[[Baker's yeast]]''' (the apostrophe may be after the ''s'' or missing) * '''Budding yeast''' This species is also the main source of [[nutritional yeast]] and [[yeast extract]]. ==Life cycle== There are two forms in which yeast cells can survive and grow, [[haploid]] and [[diploid]]. The [[haploid]] cells undergo a simple lifecycle of [[mitosis]] and growth, and under conditions of high stress will generally simply die. The [[diploid]] cells (the preferential 'form' of yeast) similarly undergo a simple lifecycle of [[mitosis]] and [[cell growth|growth]], but under conditions of [[Stress (medicine)|stress]] can undergo sporulation, entering [[meiosis]] and producing a variety of haploid [[spores]], which can go on to mate ([[Sexual reproduction|conjugate]]), reforming the [[diploid]]. ==Mating== {{main|Mating of yeast}} Yeast has two mating types, '''a''' and α, which show primitive aspects of sex differentiation, and are hence of great interest. For more information on the biological importance of these two cell types, where they come from (from a molecular biology point of view), and details of the process of mating type switching, see the main article. ==In science== ''Saccharomyces cerevisiae'' is a widely used model organism in science, and therefore also one of the most studied (along with ''[[E. coli]]''). ''S. cerevisiae'' has obtained this important position because of its established use in industry (e.g. beer, bread and wine fermentation, ethanol production). Additionally, yeasts are comparatively similar in structure to human cells, both being eukaryotic, in contrast to the prokaryotes (bacteria and archaea). Many proteins important in human biology were first discovered by studying their [[Homology_(biology)|homologs]] in yeast; these proteins include [[cell cycle]] proteins, signaling proteins, and protein-processing enzymes. The [[petite mutation]] in ''S. cerevisiae'' is of particular interest. ==Top-fermenting yeast== ''Saccharomyces cerevisiae'' is known as a top-fermenting yeast, so called because during the fermentation process its hydrophobic surface causes the flocs to adhere to CO2 and rise to the top of the fermentation vessel. It is one of the major types of yeast used in the [[brewing]] of [[beer]], along with ''[[Saccharomyces pastorianus]]''. Some beers that use top-fermenting yeast are called ''[[ale]]s'', and for that reason these yeasts are also sometimes called "ale yeast". Top-fermenting yeasts are often fermented at higher temperatures than lager yeasts and the resulting beers are normally "fruitier." ==Uses in Aquaria== Owing to the high cost of commercial CO<sub>2</sub> cylinder systems, [[CO2#Uses|CO<sub>2</sub> injection]] by yeast is one of the most popular [[DIY]] approaches followed by aquaculturists for providing CO<sub>2</sub> to underwater aquatic plants. The yeast culture is generally maintained in plastic bottles and typical systems provide one bubble every 3-7 seconds. Various approaches have been devised to allow proper absorption of the gas into the water. ==Virus L-A== ''Saccharomyces cerevisiae'' [[Saccharomyces cerevisiae virus L-A|Virus L-A]] is a [[Double-stranded RNA viruses|double-stranded RNA]] (dsRNA) virus ''Saccharomyces cerevisiae'' with similarity to animal [[Double-stranded RNA viruses|double-stranded RNA viruses]].<ref name=wickner>{{cite book |chapterurl=http://www.horizonpress.com/rnav|author=Wickner et al|year=2008|chapter=The Yeast dsRNA Virus L-A Resembles Mammalian dsRNA Virus Cores|title=Segmented Double-stranded RNA Viruses: Structure and Molecular Biology|publisher=Caister Academic Press|id=[http://www.horizonpress.com/rnav ISBN 978-1-904455-21-9]}}</ref> ==See also== *[[Ale]] *[[Beer]] *''[[Saccharomyces pastorianus]]'' *[[Killer yeasts]] ==References== <!-- ---------------------------------------------------------- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a discussion of different citation methods and how to generate footnotes using the <ref>, </ref> and <reference /> tags ----------------------------------------------------------- --> <div class="references-small"> <references /> </div> {{citations missing|date=April 2007}} ==External links== {{Commons|Saccharomyces cerevisiae|Saccharomyces cerevisiae}} * [http://www.yeastgenome.org/ Saccharomyces Genome Database] * [http://www.sceptrans.org/ Cell cycle and metabolic cycle regulated transcription in yeast] * [http://www.yeastrc.org/pdr/ Yeast Resource Center Public Data Repository] * [http://mips.gsf.de/genre/proj/yeast/index.jsp Munich Information Center for Protein Sequences] - [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8849441&dopt=Abstract abstract of the paper describing the genome] * [http://www.yeastgenome.org/VL-what_are_yeast.html What are Yeast] * [http://pixie.princeton.edu/pixie/ BioPIXIE] * [http://www.thebiogrid.org BioGRID: A General Repository for Saccharomyces cerevisiae Interactions] * [http://www.yeastract.com: YEASTRACT (Yeast Search for Transcriptional Regulators And Consensus Tracking)] ==CO2 injection by Yeast for Planted Aquaria== * [http://www.thekrib.com/Plants/CO2/co2-narten.html Fairly detailed discussion with plans] * [http://www.csd.net/~cgadd/aqua/diy_reactor.htm DIY CO2 reactor] {{Model Organisms}} <!-- Use http://vs.aka-online.de/globalwpsearch/ to find interwikis--> {{Dietary supplement}} [[Category:Bacteriology]] [[Category:Digestive system]] [[Category:Probiotics]] [[Category:Ascomycota]] [[Category:Model organisms]] [[Category:Baking]] [[Category:Brewing]] [[Category:Leavening agents]] [[Category:Oenology]] [[Category:Yeasts]] [[Category:Microbiology]] [[ca:Saccharomyces cerevisiae]] [[an:Saccharomyces cerevisiae]] [[bg:Дрожди]] [[cs:Saccharomyces cerevisiae]] [[de:Backhefe]] [[et:Pinnakääritamine]] [[es:Saccharomyces cerevisiae]] [[fr:Saccharomyces cerevisiae]] [[he:שמר האפייה]] [[it:Saccharomyces cerevisiae]] [[lt:Alaus mieliagrybis]] [[hu:Élesztőgomba]] [[nl:Bovengisting]] [[ja:出芽酵母]] [[pl:Drożdże piekarnicze]] [[pt:Saccharomyces cerevisiae]] [[qu:Aqha qunchu]] [[ru:Пивоваренные дрожжи]] [[sk:Kvasinka pivná]] [[sl:Saccharomyces cerevisiae]] [[fi:Hiiva]] [[sv:Saccharomyces cerevisiae]] [[tr:Saccharomyces cerevisiae]] [[zh:釀酒酵母]]