View source for Saccharomyces cerevisiae

{{Short description|Species of yeast}}
{{Speciesbox
| image = Saccharomyces cerevisiae SEM.jpg
| image_caption = ''S. cerevisiae'', [[Scanning electron microscope|electron micrograph]]
| genus = Saccharomyces
| species = cerevisiae
| authority = [[Franz Meyen|Meyen]] ''ex'' [[Emil Christian Hansen|E.C. Hansen]]
}}
<!--{{redirect|cerevisiae}}-->

'''''Saccharomyces cerevisiae''''' ({{IPAc-en|ˌ|s|ɛr|ə|ˈ|v|ɪ|s|i|.|iː}}) ('''brewer's yeast''' or '''baker's yeast''') is a species of [[yeast]] (single-celled [[fungus|fungal]] microorganisms). The species has been instrumental in [[winemaking]], [[baking]], and [[brewing]] since ancient times. It is believed to have been originally isolated from the skin of [[grape]]s.{{efn|The yeast can be seen 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 [[eukaryotic]] [[model organism]]s in [[molecular biology|molecular]] and [[cell biology]], much like ''[[Escherichia coli]]'' as the model [[bacteria|bacterium]]. It is the microorganism which causes many common types of [[fermentation (biochemistry)|fermentation]]. ''S.&nbsp;cerevisiae'' cells are round to ovoid, 5–10&nbsp;[[micrometre|μm]] in diameter. It reproduces by [[budding]].<ref>{{cite book|last=Feldmann|first=Horst|title=Yeast. Molecular and Cell bio|date=2010|publisher=Wiley-Blackwell|isbn=978-3-527-32609-9}}{{page needed|date=January 2014}}</ref>

Many [[protein]]s important in human biology were first discovered by studying their [[homology (biology)|homologs]] in yeast; these proteins include [[cell cycle]] proteins, [[signaling protein]]s, and protein-processing [[enzyme]]s. ''S. cerevisiae'' is currently the only yeast cell known to have [[Berkeley body|Berkeley bodies]] present, which are involved in particular secretory pathways. [[Antibodies]] against ''S.&nbsp;cerevisiae'' are found in 60–70% of patients with [[Crohn's disease]] and 10–15% of patients with [[ulcerative colitis]], and may be useful as part of a panel of serological markers in differentiating between inflammatory bowel diseases (e.g. between ulcerative colitis and Crohn's disease), their localization, and severity.<ref>{{cite journal |vauthors=Walker LJ, Aldhous MC, Drummond HE, Smith BR, Nimmo ER, Arnott ID, Satsangi J |title=Anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease are associated with disease severity but not NOD2/CARD15 mutations |journal=Clin. Exp. Immunol. |volume=135 |issue=3 |pages=490–96 |year=2004 |pmid=15008984 |pmc=1808965 |doi=10.1111/j.1365-2249.2003.02392.x}}</ref>

==Etymology==
"''Saccharomyces''" derives from [[Latin alphabet|Latinized]] [[Ancient Greek|Greek]] and means "sugar-mold" or "sugar-fungus", ''saccharon'' (σάκχαρον) being the combining form "sugar" and ''myces'' (μύκης) being "[[fungus]]".<ref>{{L&S|saccharon|ref}}</ref><ref>{{LSJ|mu/khs|μύκης|ref}}.</ref> ''Cerevisiae'' comes from Latin and means "of beer".<ref>{{L&S|cerevisia}}, {{L&S|cervisia|ref}}</ref>  Other names for the organism are:
* '''[[Yeast#Beer|Brewer's yeast]]''', though other species are also used in brewing<ref name="Baker'syeast">{{cite journal | vauthors = Moyad MA | title = Brewer's/baker's yeast (Saccharomyces cerevisiae) and preventive medicine: Part II | journal = Urol Nurs | volume = 28 | issue = 1 | pages = 73–75 | year = 2008 | pmid = 18335702 }}</ref>
* '''Ale yeast'''{{cn|date=July 2024}}
* '''Top-fermenting yeast'''{{cn|date=July 2024}}
* '''[[Baker's yeast]]'''<ref name="Baker'syeast" />
* '''Ragi yeast''', in connection to making [[tapai]]{{cn|date=July 2024}}
* '''Budding yeast'''{{cn|date=July 2024}}

This species is also the main source of [[nutritional yeast]] and [[yeast extract]].{{cn|date=November 2022}}

==History==
In antiquity, pure yeasts were unavailable due to a lack of understanding of microbiology necessary to produce them. Instead, mixtures of wild bacteria (especially [[Lactobacillus]]) and yeasts were used for brewing and leavening, resulting in acidic goods. However, empirical testing by beer makers around the 15th century led to the discovery that first boiling a [[wort]] containing [[hops]] gave a non acidic beverage. The reason for this was unknown at the time, but boiling killed unwanted bacteria, and the hops contain natural chemicals that suppressed the regrowth of acid-making bacteria while the yeast flourished.

Thus in the 19th century, bread bakers obtained their yeast from beer brewers, and this led to sweet-fermented breads such as the Imperial "[[Kaiser roll|Kaisersemmel]]" roll,<ref name="urlReport on Vienna bread, page 86 - Google Books">
{{Cite book
 | author= Eben Norton Horsford
 | title= Report on Vienna bread
 | page= [https://archive.org/details/bub_gb_6jRDAAAAIAAJ/page/n100 86]
 | publisher= U.S. Government Printing Office
 | year= 1875
 | url= https://archive.org/details/bub_gb_6jRDAAAAIAAJ
| quote= sweet.
 }}
</ref>
which in general lacked the sourness created by the acidification typical of ''Lactobacillus''. However, many beer brewers slowly switched from top-fermenting (''S. cerevisiae'') to bottom-fermenting (''[[Saccharomyces pastorianus|S. pastorianus]]'') yeast. The [[Vienna bread|Vienna Process]] was developed in 1846.<ref name="isbn0-521-77917-0">
{{cite book
 | last1= Kristiansen
 | first1= B.
 | last2= Ratledge
 | first2= Colin
 | title= Basic biotechnology
 | publisher= Cambridge University Press
 | location= Cambridge, UK
 | year= 2001
 | page= 378
 | isbn= 978-0-521-77917-3
}}
</ref>
While the innovation is often popularly credited for using steam in baking ovens, leading to a different crust characteristic, it is notable for including procedures for high milling of grains (see Vienna grits<ref name="urlReport on Vienna bread, page 31-32 - Google Books">
{{Cite book
 | url= https://archive.org/details/bub_gb_6jRDAAAAIAAJ
 | quote= sweet.
 | title= Report on Vienna bread
 | author= Eben Norton Horsford
 | pages= [https://archive.org/details/bub_gb_6jRDAAAAIAAJ/page/n44 31]–32
 | publisher= U.S. Government Printing Office
 | year= 1875
}}
</ref>),
cracking them incrementally instead of mashing them with one pass; as well as better processes for growing and harvesting top-fermenting yeasts, known as press-yeast.<ref>{{cite book |title=Report on Vienna bread |author=Eben Norton Horsford |page=87 |location=Washington|publisher=Government Printing Office |year=1875}}</ref>

Refinements in microbiology following the work of [[Louis Pasteur]] led to more advanced methods of culturing pure strains. In 1879, Great Britain introduced specialized growing vats for the production of ''S. cerevisiae'', and in the United States around the turn of the 20th century centrifuges were used for concentrating the yeast,<ref name="isbn0-521-32749-0">
{{cite book
 | last1= Marx
 | first1= Jean
 | last2= Litchfield
 | first2= John H.
 | name-list-style= amp
 | title= A Revolution in biotechnology
 | publisher= Cambridge University Press
 | location= Cambridge, UK
 | year= 1989
 | page= [https://archive.org/details/revolutioninbiot0000unse/page/71 71]
 | isbn= 978-0-521-32749-7
 | url= https://archive.org/details/revolutioninbiot0000unse/page/71
 }}
</ref>
turning yeast production into a major industrial process which simplified its distribution, reduced unit costs, and contributed to the commercialization and commoditization of bread and beer. Fresh "cake yeast" became the standard leaven for bread bakers in much of the Western world during the early 20th century.<ref>{{cite journal
| last1= Lahue
| first1= Caitlin
| last2= Madden
| first2= Anne A.
| last3= Dunn
| first3= Robert R.
| last4= Smukowski Heil
| first4= Caiti
| title= History and Domestication of Saccharomyces cerevisiae in Bread Baking
| date= 11 November 2020
| journal= Frontiers in Genetics
| volume= 11
| article-number= 584718
| doi= 10.3389/fgene.2020.584718
| pmid= 33262788
| pmc= 7686800
| doi-access= free}}</ref>

During [[World War II]], [[Fleischmann's Yeast|Fleischmann's]] developed a [[wikt:granulate|granulated]] active dry yeast for the United States armed forces, which did not require refrigeration and had a longer shelf-life and better temperature tolerance than fresh yeast; it is still the standard yeast for US military recipes. The company created yeast that would rise twice as fast, cutting down on baking time. [[Red Star Yeast|Lesaffre]] would later create instant yeast in the 1970s, which has gained considerable use and market share at the expense of both fresh and dry yeast in their various applications.{{Citation needed|date=January 2021}}

==Biology==
[[File:Laboratoorne pagaripärm (Saccharomyces cerevisiae) agariplaadil..JPG|thumb|Yeast colonies on an agar plate.]]

===Ecology===
In nature, yeast cells are found primarily on ripe fruits such as grapes (before maturation, grapes are almost free of yeasts).<ref>{{cite book |editor1-last=Marshall |editor1-first=Charles |date=June 1912 |title=Microbiology |url=https://books.google.com/books?id=VvI0AQAAMAAJ |publisher=P. Blakiston's son & Company |page=420 |access-date=November 5, 2014 }}</ref> ''S. cerevisiae'' can also be found year-round in the bark of [[Oak|oak trees]].<ref>{{Cite web|last=Young|first=Ed|date=2012-07-30|title=You can thank wasps for your bread, beer, and wine|url=https://www.nationalgeographic.com/science/article/you-can-thank-wasps-for-your-bread-beer-and-wine|archive-url=https://web.archive.org/web/20211102211512/https://www.nationalgeographic.com/science/article/you-can-thank-wasps-for-your-bread-beer-and-wine|archive-date=November 2, 2021|website=National Geographic|language=en}}</ref> Since ''S. cerevisiae'' is not airborne, it requires a vector to move.<ref>{{cite journal |vauthors= Mortimer R, Polsinelli M|title= On the origins of wine yeast|journal= Research in Microbiology|volume= 50|issue= 3|pages= 199–204|year= 1999|doi=10.1016/S0923-2508(99)80036-9|pmid= 10229949|doi-access= free}}</ref>

Queens of social wasps overwintering as adults (''[[Vespa crabro]]'' and ''[[Polistes]]'' spp.) can harbor yeast cells from autumn to spring and transmit them to their progeny.<ref name="ReferenceA">{{cite journal | vauthors = Stefanini I, Dapporto L, Legras JL, Calabretta A, Di Paola M, De Filippo C, Viola R, Capretti P, Polsinelli M, Turillazzi S, Cavalieri D | title = Role of social wasps in Saccharomyces cerevisiae ecology and evolution | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 109 | issue = 33 | pages = 13398–403 | year = 2012 | pmid = 22847440 | pmc = 3421210 | doi = 10.1073/pnas.1208362109 | bibcode = 2012PNAS..10913398S | doi-access = free }}</ref> The intestine of ''[[Polistes dominula]]'', a social wasp, hosts ''S. cerevisiae'' strains as well as ''S. cerevisiae'' × ''[[Saccharomyces paradoxus|S. paradoxus]]'' hybrids. Stefanini et al. (2016) showed that the intestine of ''Polistes dominula'' favors the mating of ''S. cerevisiae'' strains, both among themselves and with ''S. paradoxus'' cells by providing environmental conditions prompting cell [[Spore|sporulation]] and spores germination.<ref name="pmid26787874">{{cite journal |vauthors=Stefanini I, Dapporto L, Berná L, Polsinelli M, Turillazzi S, Cavalieri D |title=Social wasps are a Saccharomyces mating nest |journal=Proc. Natl. Acad. Sci. U.S.A. |volume= 113|issue= 8|pages= 2247–51|year=2016 |pmid=26787874 |doi=10.1073/pnas.1516453113 |pmc=4776513|bibcode=2016PNAS..113.2247S |doi-access=free }}</ref>

The optimum temperature for growth of ''S. cerevisiae'' is {{Convert|30|-|35|C}}.<ref name="ReferenceA"/>

===Life cycle===
Two forms of yeast cells can survive and grow: [[haploid]] and [[diploid]]. The haploid cells undergo a simple [[biological life cycle|lifecycle]] of [[mitosis]] and growth and, under conditions of high stress, will, in general, die. This is the [[asexual reproduction|asexual]] form of the fungus. The diploid cells (the preferential 'form' of yeast) similarly undergo a simple lifecycle of mitosis and [[cell growth|growth]]. The rate at which the mitotic cell cycle progresses often differs substantially between haploid and diploid cells.<ref>{{cite journal | vauthors = Zörgö E, Chwialkowska K, Gjuvsland AB, Garré E, Sunnerhagen P, Liti G, Blomberg A, Omholt SW, Warringer J | title = Ancient evolutionary trade-offs between yeast ploidy states | journal = PLOS Genet. | volume = 9 | issue = 3 | article-number = e1003388 | year = 2013 | pmid = 23555297 | pmc = 3605057 | doi = 10.1371/journal.pgen.1003388 | doi-access = free }}</ref> Under conditions of [[Stress (medicine)|stress]], diploid cells can undergo [[Spore|sporulation]], entering [[meiosis]] and producing four haploid [[spore]]s, which can subsequently mate. This is the [[sexual reproduction|sexual]] form of the [[fungus]]. Under optimal conditions, yeast cells can double their population every 100&nbsp;minutes.<ref>{{cite journal | vauthors = Herskowitz I | title = Life cycle of the budding yeast Saccharomyces cerevisiae | journal = Microbiol. Rev. | volume = 52 | issue = 4 | pages = 536–53 | year = 1988 | doi = 10.1128/MMBR.52.4.536-553.1988 | pmid = 3070323 | pmc = 373162 }}</ref><ref>{{cite web | last = Friedman | first = Nir | title = The Friedman Lab Chronicles | work = Growing yeasts (Robotically) | publisher = [[Nir Friedman]] Lab | date = January 3, 2011 | url = https://nirfriedmanlab.blogspot.com/2011/01/growing-yeasts-robotically.html | access-date = 2012-08-13 }}</ref> However, growth rates vary enormously between strains and between environments.<ref>{{cite journal | vauthors = Warringer J, Zörgö E, Cubillos FA, Zia A, Gjuvsland A, Simpson JT, Forsmark A, Durbin R, Omholt SW, Louis EJ, Liti G, Moses A, Blomberg A | title = Trait variation in yeast is defined by population history | journal = PLOS Genet. | volume = 7 | issue = 6 | article-number = e1002111 | year = 2011 | pmid = 21698134 | pmc = 3116910 | doi = 10.1371/journal.pgen.1002111 | doi-access = free }}</ref> Mean [[Self-replication|replicative]] lifespan is about 26&nbsp;cell divisions.<ref>{{cite journal | vauthors = Kaeberlein M, Powers RW, Steffen KK, Westman EA, Hu D, Dang N, Kerr EO, Kirkland KT, Fields S, Kennedy BK | title = Regulation of yeast replicative life span by TOR and Sch9 in response to nutrients | journal = Science | volume = 310 | issue = 5751 | pages = 1193–96 | year = 2005 | pmid = 16293764 | doi = 10.1126/science.1115535 | bibcode = 2005Sci...310.1193K }}</ref><ref>{{cite journal | vauthors = Kaeberlein M | title = Lessons on longevity from budding yeast | journal = Nature | volume = 464 | issue = 7288 | pages = 513–19 | year = 2010 | pmid = 20336133 | pmc = 3696189 | doi = 10.1038/nature08981 | bibcode = 2010Natur.464..513K }}</ref>

In the wild, recessive deleterious mutations accumulate during long periods of [[asexual reproduction]] of diploids, and are purged during [[selfing]]: this purging has been termed "genome renewal".<ref>{{cite journal|last1=Mortimer|first1=Robert K.|last2=Romano |first2=Patrizia|last3=Suzzi|first3=Giovanna|last4=Polsinelli|first4=Mario|title=Genome renewal: A new phenomenon revealed from a genetic study of 43 strains ofSaccharomyces cerevisiae derived from natural fermentation of grape musts |journal=Yeast |date=December 1994 |volume=10|issue=12 |pages=1543–52 |doi=10.1002/yea.320101203 |pmid=7725789 }}</ref><ref>{{cite journal |last1=Masel|first1=Joanna |author1-link=Joanna Masel |last2=Lyttle|first2=David N.|title=The consequences of rare sexual reproduction by means of selfing in an otherwise clonally reproducing species|journal=Theoretical Population Biology|date=December 2011|volume=80|issue=4|pages=317–22|doi=10.1016/j.tpb.2011.08.004|pmid=21888925|pmc=3218209|bibcode=2011TPBio..80..317M }}</ref>

===Nutritional requirements===
{{See also|Yeast assimilable nitrogen}}
{{Unreferenced section|date=January 2021}}
All [[strain (biology)|strains]] of ''S.&nbsp;cerevisiae'' can grow [[Aerobic respiration|aerobically]] on [[glucose]], [[maltose]],<ref>{{cite journal |last1=Bell |first1=P.J.L. |last2=Higgins |first2=V.J. |last3=Attfield |first3=P.V. |title=Comparison of fermentative capacities of industrial baking and wild-type yeasts of the species Saccharomyces cerevisiae in different sugar media |journal=Letters in Applied Microbiology |date=11 April 2001 |volume=32 |issue=4 |pages=224–229 |doi=10.1046/j.1472-765x.2001.00894.x |pmid=11298930 }}</ref> and [[trehalose]]<ref>{{cite journal |last1=Jules |first1=Matthieu |last2=Guillou |first2=Vincent |last3=François |first3=Jean |last4=Parrou |first4=Jean-Luc |title=Two Distinct Pathways for Trehalose Assimilation in the Yeast Saccharomyces cerevisiae |journal=Applied and Environmental Microbiology |date=May 2004 |volume=70 |issue=5 |pages=2771–2778 |doi=10.1128/AEM.70.5.2771-2778.2004 |pmid=15128531 |pmc=404389 |bibcode=2004ApEnM..70.2771J }}</ref> and fail to grow on [[lactose]] and [[cellobiose]]. However, growth on other [[sugars]] is variable. [[Galactose]] and [[fructose]] are shown to be two of the best fermenting sugars. The ability of yeasts to use different sugars can differ depending on whether they are grown aerobically or anaerobically. Some strains cannot grow anaerobically on [[sucrose]] and trehalose.{{fact|date=December 2024}}

All strains can use [[ammonia]] and [[urea]] as the sole [[nitrogen]] source, but cannot use [[nitrate]], since they lack the ability to reduce them to [[ammonium]] [[ions]]. They can also use most [[amino acids]], small [[peptides]], and nitrogen bases as nitrogen sources. [[Histidine]], [[glycine]], [[cystine]], and [[lysine]] are, however, not readily used. ''S.&nbsp;cerevisiae'' does not excrete [[proteases]], so extracellular protein cannot be metabolized.

[[Yeasts]] also have a requirement for [[phosphorus]], which is assimilated as a dihydrogen phosphate ion, and [[sulfur]], which can be assimilated as a [[sulfate]] ion or as organic sulfur compounds such as the [[amino acid]]s methionine and cysteine. Some metals, like [[magnesium]], [[iron]], [[calcium]], and [[zinc]], are also required for good growth of the yeast.

Concerning organic requirements, most strains of ''S. cerevisiae'' require [[biotin]].<ref>{{Cite journal |last1=Wu |first1=Hong |last2=Ito |first2=Kiyoshi |last3=Shimoi |first3=Hitoshi |date=November 2005 |title=Identification and Characterization of a Novel Biotin Biosynthesis Gene in Saccharomyces cerevisiae |journal=Applied and Environmental Microbiology |volume=71 |issue=11 |pages=6845–6855 |doi=10.1128/AEM.71.11.6845-6855.2005 |issn=0099-2240 |pmc=1287709 |pmid=16269718|bibcode=2005ApEnM..71.6845W }}</ref> Indeed, a ''S. cerevisiae''-based growth assay laid the foundation for the isolation, crystallization, and later structural determination of biotin. Most strains also require [[pantothenate]] for full growth. In general, ''S. cerevisiae'' is prototrophic for vitamins.

===Mating===
[[File:Shmoos s cerevisiae.jpg|thumb|''Saccharomyces cerevisiae'' mating type '''a''' with a cellular bulging called a [[Shmoo (yeast)|shmoo]] in response to '''α'''-factor]]
{{Main|Mating of yeast}}

Yeast has two mating types, '''a''' and α (''alpha''), which show primitive aspects of sex differentiation.<ref>Saccharomyces cerevisiae http://bioweb.uwlax.edu/bio203/s2007/nelson_andr/ {{Webarchive|url=https://web.archive.org/web/20111227083949/http://bioweb.uwlax.edu/bio203/s2007/nelson_andr/ |date=2011-12-27 }}</ref> As in many other eukaryotes, mating leads to [[genetic recombination]], i.e. production of novel combinations of chromosomes. Two [[haploid]] yeast cells of opposite mating type can mate to form [[diploid]] cells that can either [[sporulation|sporulate]] to form another generation of haploid cells or continue to exist as diploid cells. Mating has been exploited by biologists as a tool to combine genes, plasmids, or proteins at will.{{Citation needed|date=January 2021}}

The mating pathway employs a [[G protein-coupled receptor]], [[G protein]], [[RGS protein]], and three-tiered [[MAPK]] signaling cascade that is homologous to those found in humans. This feature has been exploited by biologists to investigate basic mechanisms of [[signal transduction]] and [[desensitization (medicine)|desensitization]].{{Citation needed|date=January 2021}}

===Cell cycle===
Growth in yeast is synchronized with the growth of the [[budding|bud]], which reaches the size of the mature cell by the time it separates from the parent cell. In well nourished, rapidly growing yeast [[microbiological culture|cultures]], all the cells have buds, since bud formation occupies the whole [[cell cycle]]. Both mother and daughter cells can initiate bud formation before cell separation has occurred. In yeast cultures growing more slowly, cells lacking buds can be seen, and bud formation only occupies a part of the cell cycle.{{Citation needed|date=January 2021}}

====Cytokinesis====
[[Cytokinesis]] enables budding yeast ''Saccharomyces cerevisiae'' to divide into two daughter cells. ''S. cerevisiae'' forms a bud which can grow throughout its cell cycle and later leaves its mother cell when mitosis has completed.<ref name = "morgan">Morgan, David (2007). The Cell Cycle: Principles of Control. Sinauer Associates.</ref>

''S. cerevisiae'' is relevant to cell cycle studies because it divides asymmetrically by using a polarized cell to make two daughters with different fates and sizes. Similarly, [[stem cell]]s use asymmetric division for self-renewal and differentiation.<ref name = "bi 2017">{{cite journal | last1 = Bi | first1 = Erfei | year = 2017 | title = Mechanics and regulation of cytokinesis in budding yeast | journal = Seminars in Cell & Developmental Biology | volume = 66 | pages = 107–18 | doi = 10.1016/j.semcdb.2016.12.010 | pmid = 28034796 | pmc = 5474357 }}</ref>

=====Timing=====
For many cells, M phase does not happen until S phase is complete. However, for entry into mitosis in ''S. cerevisiae'' this is not true. Cytokinesis begins with the budding process in late G1 and is not completed until about halfway through the next cycle. The assembly of the spindle can happen before S phase has finished duplicating the chromosomes.<ref name="morgan"/> Additionally, there is a lack of clearly defined G2 in between M and S. Thus, there is a lack of extensive regulation present in higher eukaryotes.<ref name="morgan"/>

When the daughter emerges, the daughter is two-thirds the size of the mother.<ref name = "wloka" >{{cite journal | last1 = Wloka | first1 = Carsten | year = 2012 | title = Mechanisms of cytokinesis in budding yeast | journal = Cytoskeleton | volume = 69 | issue = 10| pages = 710–26 | doi = 10.1002/cm.21046 | pmid = 22736599 }}</ref> Throughout the process, the mother displays little to no change in size.<ref name = "bi 2002">{{cite journal | last1 = Bi | first1 = Erfei | year = 2002 | title = Cytokinesis in Budding Yeast: the Relationship between Actomyosin Ring Function and Septum Formation | journal = Cell Structure and Function | volume = 26 | issue = 6| pages = 529–37 | doi = 10.1247/csf.26.529 | pmid = 11942606 | doi-access = free }}</ref> The RAM pathway is activated in the daughter cell immediately after cytokinesis is complete. This pathway makes sure that the daughter has separated properly.<ref name="wloka"/>

=====Actomyosin ring and primary septum formation=====
Two interdependent events drive cytokinesis in ''S. cerevisiae''. The first event is contractile [[actomyosin ring]] (AMR) constriction and the second event is formation of the primary [[septum]] (PS), a chitinous cell wall structure that can only be formed during cytokinesis. The PS resembles in animals the process of extracellular matrix remodeling.<ref name="wloka"/> When the AMR constricts, the PS begins to grow. Disrupting AMR misorients the PS, suggesting that both have a dependent role. Additionally, disrupting the PS also leads to disruptions in the AMR, suggesting both the actomyosin ring and primary septum have an interdependent relationship.<ref>{{cite journal | last1 = Fang | first1 = X | year = 2010 | title = Biphasic targeting and cleavage furrow ingression directed by the tail of a myosin-II | journal = J Cell Biol | volume = 191 | issue = 7| pages = 1333–50 | doi = 10.1083/jcb.201005134 | pmid = 21173112 | pmc = 3010076 }}</ref><ref name="bi 2002"/>

The AMR, which is attached to the cell membrane facing the cytosol, consists of actin and myosin II molecules that coordinate the cells to split.<ref name="morgan"/> The ring is thought to play an important role in ingression of the plasma membrane as a contractile force.{{Citation needed|date=January 2021}}

Proper coordination and correct positional assembly of the contractile ring depends on septins, which is the precursor to the septum ring. These GTPases assemble complexes with other proteins. The septins form a ring at the site where the bud will be created during late G1. They help promote the formation of the actin-myosin ring, although this mechanism is unknown. It is suggested they help provide structural support for other necessary cytokinesis processes.<ref name="morgan"/> After a bud emerges, the septin ring forms an hourglass. The septin hourglass and the myosin ring together are the beginning of the future division site.<ref>{{Cite journal |last1=Glomb |first1=Oliver |last2=Gronemeyer |first2=Thomas |date=2016-11-03 |title=Septin Organization and Functions in Budding Yeast |journal=Frontiers in Cell and Developmental Biology |volume=4 |page=123 |doi=10.3389/fcell.2016.00123 |doi-access=free |issn=2296-634X |pmc=5093138 |pmid=27857941}}</ref>

The septin and AMR complex progress to form the primary septum consisting of glucans and other chitinous molecules sent by vesicles from the Golgi body.<ref>{{cite journal | last1 = VerPlank | first1 = Lynn | year = 2005 | title = Cell cycle-regulated trafficking of Chs2 controls actomyosin ring stability during cytokinesis | journal = Mol. Biol. Cell | volume = 16 | issue = 5| pages = 2529–43 | doi = 10.1091/mbc.e04-12-1090 | pmid = 15772160 | pmc = 1087255 }}</ref> After AMR constriction is complete, two secondary septums are formed by glucans. How the AMR ring dissembles remains poorly unknown.<ref name="bi 2017"/>

Microtubules do not play as significant a role in cytokinesis compared to the AMR and septum. Disruption of microtubules did not significantly impair polarized growth.<ref>{{cite journal | last1 = Adams | first1 = A | year = 1984 | title = Relationship of actin and tubulin distribution to bud growth in wild-type and morphogenetic-mutant Saccharomyces cerevisiae | journal = J. Cell Biol. | volume = 98 | issue = 3| pages = 934–945 | doi = 10.1083/jcb.98.3.934 | pmid = 6365931 | pmc = 2113156 }}</ref> Thus, the AMR and septum formation are the major drivers of cytokinesis.{{Citation needed|date=January 2021}}

=====Differences from fission yeast=====
* Budding yeast form a bud from the mother cell. This bud grows during the cell cycle and detaches; fission yeast divide by forming a cell wall <ref name="morgan"/>
* Cytokinesis begins at G1 for budding yeast, while cytokinesis begins at G2 for fission yeast. Fission yeast "select" the midpoint, whereas budding yeast "select" a bud site <ref name="differences">{{cite journal | last1 = Balasubramanian | first1 = Mohan | year = 2004 | title = Comparative Analysis of Cytokinesis in Budding Yeast, Fission Yeast and Animal Cells | journal = Curr. Biology | volume = 14 | issue = 18| pages = R806–18 | doi = 10.1016/j.cub.2004.09.022 | pmid = 15380095 | doi-access = free | bibcode = 2004CBio...14.R806B }}</ref>
* During early anaphase the actomyosin ring and septum continues to develop in budding yeast, in fission yeast during metaphase-anaphase the actomyosin ring begins to develop <ref name="differences"/>

==In biological research==
{{More citations needed section|date=January 2021}}

===Model organism===
[[File:S cerevisiae under DIC microscopy.jpg|thumb|''S. cerevisiae'', [[Differential interference contrast microscopy|differential interference contrast]] image]]
[[Image:20100911 232323 Yeast Live.jpg|thumb|''Saccharomyces cerevisiae''<br />Numbered ticks are 11 micrometers apart.]]
<!-- This Paragraph appropriated from the Model Organisms Page -->When researchers look for an organism to use in their studies, they look for several traits. Among these are size,{{what?|date=August 2024}} short generation time, accessibility{{what?|date=August 2024}}, ease of manipulation, genetics,{{what?|date=August 2024}} conservation of mechanisms,{{what?|date=August 2024}} and potential economic benefit.{{cn|date=August 2024}} The yeast species ''[[Schizosaccharomyces pombe]]'' and ''S. cerevisiae'' are both well studied; these two species diverged approximately {{Ma|600|300}}, and are significant tools in the study of [[DNA damage (naturally occurring)|DNA damage]] and [[DNA repair|repair mechanisms]].<ref>{{cite book |first1= Jac A. |last1=Nickoloff |first2=James E. |last2=Haber |date=2011 |chapter=Mating-Type Control of DNA Repair and Recombination in ''Saccharomyces cerevisiae'' |doi=10.1007/978-1-59259-095-7_5 |pages=107–124 |editor1-first=Jac A. |editor1-last=Nickoloff |editor2-first=Merl F. |editor2-last=Hoekstra |title=DNA Damage and Repair |series=Contemporary Cancer Research |isbn=978-1-59259-095-7 | chapter-url=https://link.springer.com/chapter/10.1007/978-1-59259-095-7_5}}</ref>

''S. cerevisiae'' has developed as a [[model organism]] because it scores favorably on a number of criteria.
* As a single-cell organism, ''S. cerevisiae'' is small with a short generation time (doubling time 1.25–2 hours<ref>{{cite book |editor=Boekhout, T. |editor2=Robert, V. |date=2003 |title=Yeasts in Food: Beneficial and Detrimental aspects |publisher=Behr's Verlag |isbn=978-3-86022-961-3 |page=322 |url=https://books.google.com/books?id=GG-60Vtl81EC |access-date=January 10, 2011}}</ref> at {{convert|30|C|F|disp=or}}) and can be easily [[Cell culture|cultured]]. These are all positive characteristics in that they allow for the swift production and maintenance of multiple specimen lines at low cost.
* ''S. cerevisiae'' divides with meiosis, allowing it to be a candidate for sexual genetics research.
* ''S. cerevisiae'' can be [[Transformation (genetics)|transformed]] allowing for either the addition of new genes or deletion through [[homologous recombination]]. Furthermore, the ability to grow ''S. cerevisiae'' as a haploid simplifies the creation of [[gene knockout]] strains.
* As an [[eukaryote]], ''S. cerevisiae'' shares the complex internal cell structure of plants and animals without the high percentage of [[non-coding DNA]] that can confound research in higher eukaryotes.
* ''S. cerevisiae'' research is a strong economic driver, at least initially, as a result of its established use in industry.

===In the study of aging===
For more than five decades ''S. cerevisiae'' has been studied as a model organism to better understand aging and has contributed to the identification of more mammalian genes affecting aging than any other model organism.<ref name="Replicative">{{cite journal | vauthors = Longo VD, Shadel GS, Kaeberlein M, Kennedy B | title = Replicative and chronological aging in Saccharomyces cerevisiae | journal = Cell Metab. | volume = 16 | issue = 1 | pages = 18–31 | year = 2012 | pmid = 22768836 | pmc = 3392685 | doi = 10.1016/j.cmet.2012.06.002 }}</ref> Some of the topics studied using yeast are [[calorie restriction]], as well as in genes and cellular pathways involved in [[senescence]]. The two most common methods of measuring aging in yeast are Replicative Life Span (RLS), which measures the number of times a cell divides, and Chronological Life Span (CLS), which measures how long a cell can survive in a non-dividing stasis state.<ref name="Replicative" /> Limiting the amount of glucose or amino acids in the [[growth medium]] has been shown to increase RLS and CLS in yeast as well as other organisms.<ref name="Recent">{{cite journal | vauthors = Kaeberlein M, Burtner CR, Kennedy BK | title = Recent developments in yeast aging | journal = PLOS Genet. | volume = 3 | issue = 5 | pages = 655–60 | year = 2007 | pmid = 17530929 | pmc = 1877880 | doi = 10.1371/journal.pgen.0030084 | doi-access = free }}</ref> At first, this was thought to increase RLS by up-regulating the sir2 enzyme; however, it was later discovered that this effect is independent of [[sir2]]. Over-expression of the genes sir2 and fob1 has been shown to increase RLS by preventing the accumulation of [[extrachromosomal rDNA circle]]s, which are thought to be one of the causes of senescence in yeast.<ref name="Recent" /> The effects of dietary restriction may be the result of a decreased signaling in the TOR cellular pathway.<ref name="Replicative" /> This pathway modulates the cell's response to nutrients, and mutations that decrease TOR activity were found to increase CLS and RLS.<ref name="Replicative" /><ref name="Recent" /> This has also been shown to be the case in other animals.<ref name="Replicative" /><ref name="Recent" /> A yeast mutant lacking the genes {{visible anchor|Sch9}} and [[Ras2]] has recently been shown to have a tenfold increase in chronological lifespan under conditions of calorie restriction and is the largest increase achieved in any organism.<ref>{{cite journal | vauthors = Wei M, Fabrizio P, Hu J, Ge H, Cheng C, Li L, Longo VD | title = Life span extension by calorie restriction depends on Rim15 and transcription factors downstream of Ras/PKA, Tor, and Sch9 | journal = PLOS Genet. | volume = 4 | issue = 1 | pages = 139–49 | year = 2008 | pmid = 18225956 | pmc = 2213705 | doi = 10.1371/journal.pgen.0040013 | doi-access = free }}</ref><ref>{{cite web |title=10-Fold Life Span Extension Reported |url=http://www.usc.edu/uscnews/stories/14716.html |publisher=University of Southern California |archive-url=https://web.archive.org/web/20160304070340/http://www.usc.edu/uscnews/stories/14716.html |archive-date=2016-03-04}}</ref>

Mother cells give rise to progeny buds by mitotic divisions, but undergo replicative [[Ageing|aging]] over successive generations and ultimately die. However, when a mother cell undergoes [[meiosis]] and [[gametogenesis]], [[Maximum life span|lifespan]] is reset.<ref>{{cite journal | vauthors = Unal E, Kinde B, Amon A | title = Gametogenesis eliminates age-induced cellular damage and resets life span in yeast | journal = Science | volume = 332 | issue = 6037 | pages = 1554–57 | year = 2011 | pmid = 21700873 | pmc = 3923466 | doi = 10.1126/science.1204349 | bibcode = 2011Sci...332.1554U }}</ref> The replicative potential of [[gametes]] ([[spores]]) formed by aged cells is the same as gametes formed by young cells, indicating that age-associated damage is removed by meiosis from aged mother cells. This observation suggests that during meiosis removal of age-associated damages leads to [[Rejuvenation (aging)|rejuvenation]]. However, the nature of these damages remains to be established.

During starvation of non-replicating ''S. cerevisiae'' cells, [[reactive oxygen species]] increase leading to the accumulation of [[DNA oxidation|DNA damages]] such as apurinic/apyrimidinic sites and double-strand breaks.<ref name="pmid20223252">{{cite journal |vauthors=Steinboeck F, Hubmann M, Bogusch A, Dorninger P, Lengheimer T, Heidenreich E |title=The relevance of oxidative stress and cytotoxic DNA lesions for spontaneous mutagenesis in non-replicating yeast cells |journal=Mutat. Res. |volume=688 |issue=1–2 |pages=47–52 |date=June 2010 |pmid=20223252 |doi=10.1016/j.mrfmmm.2010.03.006|bibcode=2010MRFMM.688...47S }}</ref>  Also in non-replicating cells the ability to [[DNA repair|repair]] endogenous double-strand breaks declines during chronological [[ageing|aging]].<ref name="pmid30410502">{{cite journal |vauthors=Pongpanich M, Patchsung M, Mutirangura A |title=Pathologic Replication-Independent Endogenous DNA Double-Strand Breaks Repair Defect in Chronological Aging Yeast |journal=Front Genet |volume=9 |article-number=501 |date=2018 |pmid=30410502 |pmc=6209823 |doi=10.3389/fgene.2018.00501|doi-access=free }}</ref>

===Meiosis, recombination, and DNA repair===
''S. cerevisiae'' reproduces by mitosis as diploid cells when nutrients are abundant. However, when starved, these cells undergo meiosis to form haploid spores.<ref name="pmid3070323">{{cite journal | vauthors = Herskowitz I | title = Life cycle of the budding yeast Saccharomyces cerevisiae | journal = Microbiol. Rev. | volume = 52 | issue = 4 | pages = 536–53 | year = 1988 | doi = 10.1128/MMBR.52.4.536-553.1988 | pmid = 3070323 | pmc = 373162}}</ref>

Evidence from studies of ''S. cerevisiae'' bear on the adaptive function of meiosis and [[Genetic recombination|recombination]]. [[Mutation]]s defective in genes essential for meiotic and mitotic recombination in ''S. cerevisiae'' cause increased sensitivity to [[radiation]] or [[genotoxicity|DNA damaging chemicals]].<ref name=tripathi>{{cite journal | vauthors = Ruderfer DM, Pratt SC, Seidel HS, Kruglyak L | title = Population genomic analysis of outcrossing and recombination in yeast | journal = Nat. Genet. | volume = 38 | issue = 9 | pages = 1077–81 | year = 2006 | pmid = 16892060 | doi = 10.1038/ng1859 }}</ref><ref name=Haynes>{{cite book | last1 = Haynes | first1 = Robert H. | author1-link = Robert Haynes (geneticist) | last2 = Kunz | first2 = Bernard A. | date = 1981 | chapter = DNA repair and mutagenesis in yeast | chapter-url = https://cshmonographs.org/csh/index.php/monographs/article/viewArticle/4235 | editor1-first = Jeffrey N. | editor1-last = Strathern | editor2-first = Elizabeth W. | editor2-last = Jones | editor3-first = James R. | editor3-last = Broach | title = The Molecular Biology of the Yeast ''Saccharomyces'': Life Cycle and Inheritance | location = Cold Spring Harbor, N.Y. | publisher = [[Cold Spring Harbor Laboratory]] | pages = [https://archive.org/details/molecularbiology0000unse_w1g0/page/371 371–414] | isbn = 978-0-87969-139-4 | url = https://archive.org/details/molecularbiology0000unse_w1g0/page/371 }}</ref> For instance, gene [[RAD52|''rad52'']] is required for both meiotic recombination<ref name=Game>{{cite journal | vauthors = Game JC, Zamb TJ, Braun RJ, Resnick M, Roth RM | title = The Role of Radiation (rad) Genes in Meiotic Recombination in Yeast | journal = Genetics | volume = 94 | issue = 1 | pages = 51–68 | year = 1980 | doi = 10.1093/genetics/94.1.51 | pmid = 17248996 | pmc = 1214137}}</ref> and mitotic recombination.<ref name="pmid6987653">{{cite journal | vauthors = Malone RE, Esposito RE | title = The RAD52 gene is required for homothallic interconversion of mating types and spontaneous mitotic recombination in yeast | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 77 | issue = 1 | pages = 503–07 | year = 1980 | pmid = 6987653 | pmc = 348300 | doi = 10.1073/pnas.77.1.503 | bibcode = 1980PNAS...77..503M | doi-access = free }}</ref> ''Rad52'' mutants have increased sensitivity to killing by [[X-ray]]s, [[Methyl methanesulfonate]] and the DNA cross-linking agent [[Methoxsalen|8-methoxypsoralen-plus-UVA]], and show reduced meiotic recombination.<ref name=Haynes /><ref name=Game /><ref>{{cite journal |doi=10.1111/j.1751-1097.1980.tb03746.x |title=Sensitivity to Photoaddition of Mono-And Bifunctional Furocoumarins of X-Ray Sensitive Mutants of Saccharomyces cerevisiae |date=1980 |last1=Henriques |first1=J. A. P. |last2=Moustacchi |first2=E. |journal=Photochemistry and Photobiology |volume=31 |issue=6 |pages=557–63 }}</ref> These findings suggest that [[Homologous recombination|recombination repair]] during meiosis and mitosis is needed for repair of the different damages caused by these agents.

Ruderfer et al.<ref name="tripathi" /> (2006) analyzed the ancestry of natural ''S. cerevisiae'' strains and concluded that [[outcrossing]] occurs only about once every 50,000 cell divisions. Thus, it appears that in nature, mating is likely most often between closely related yeast cells. Mating occurs when haploid cells of [[Mating of yeast|opposite mating type]] MATa and MATα come into contact. Ruderfer et al.<ref name="tripathi" /> pointed out that such contacts are frequent between closely related yeast cells for two reasons. The first is that cells of opposite mating type are present together in the same [[ascus]], the sac that contains the cells directly produced by a single meiosis, and these cells can mate with each other. The second reason is that haploid cells of one mating type, upon cell division, often produce cells of the opposite mating type with which they can mate. The relative rarity in nature of meiotic events that result from [[outcrossing]] is inconsistent with the idea that production of [[genetic variation]] is the main selective force maintaining meiosis in this organism. However, this finding is consistent with the alternative idea that the main selective force maintaining meiosis is enhanced recombinational repair of DNA damage,<ref name=Birdsell>{{cite book |doi=10.1007/978-1-4757-5190-1_2 |chapter=The Evolutionary Origin and Maintenance of Sexual Recombination: A Review of Contemporary Models |title=Evolutionary Biology |date=2003 |last1=Birdsell |first1=John A. |last2=Wills |first2=Christopher |isbn=978-1-4419-3385-0 |pages=27–138}}</ref> since this benefit is realized during each meiosis, whether or not out-crossing occurs.

===Genome sequencing===
''S. cerevisiae'' was the first eukaryotic [[genome]] to be completely sequenced.<ref name="Reference44">{{cite journal | vauthors = Goffeau A, Barrell BG, Bussey H, Davis RW, Dujon B, Feldmann H, Galibert F, Hoheisel JD, Jacq C, Johnston M, Louis EJ, Mewes HW, Murakami Y, Philippsen P, Tettelin H, Oliver SG | title = Life with 6000 genes | journal = Science | volume = 274 | issue = 5287 | pages = 546, 563–67 | year = 1996 | pmid = 8849441 | doi = 10.1126/science.274.5287.546 | bibcode = 1996Sci...274..546G }}</ref> The genome sequence was released to the [[public domain]] on April 24, 1996. Since then, regular updates have been maintained at the [[Saccharomyces Genome Database|''Saccharomyces'' Genome Database]]. This [[database]] is a highly annotated and cross-referenced database for yeast researchers. Another important ''S.&nbsp;cerevisiae'' database is maintained by the Munich Information Center for Protein Sequences (MIPS). Further information is located at the [[Yeastract]] curated repository.<ref name="pmid16381908">{{cite journal |date=Jan 2006|title=The YEASTRACT database: a tool for the analysis of transcription regulatory associations in Saccharomyces cerevisiae|journal = Nucleic Acids Res.|volume=34|issue=Database issue|pages=D446–51|location = England| pmid = 16381908|doi = 10.1093/nar/gkj013| pmc = 1347376 |last1=Teixeira |first1=M. C. |last2=Monteiro |first2=P |last3=Jain |first3=P |last4=Tenreiro |first4=S |last5=Fernandes |first5=AR |last6=Mira |first6=NP |last7=Alenquer |first7=M |last8=Freitas |first8=AT |last9=Oliveira |first9=AL |last10=Sá-Correia |first10=I }}</ref>

The ''S. cerevisiae'' genome is composed of about 12,156,677 [[base pair]]s and 6,275 [[gene]]s, compactly organized on 16 chromosomes.<ref name="Reference44"/> Only about 5,800 of these genes are believed to be functional. It is estimated at least 31% of yeast genes have [[Homology (biology)|homologs]] in the human genome.<ref>{{cite journal | vauthors = Botstein D, Chervitz SA, Cherry JM | title = Yeast as a model organism | journal = Science | volume = 277 | issue = 5330 | pages = 1259–60 | year = 1997 | pmid = 9297238 | pmc = 3039837 | doi = 10.1126/science.277.5330.1259 }}</ref> Yeast genes are classified using gene symbols (such as Sch9) or systematic names. In the latter case the 16 chromosomes of yeast are represented by the letters A to P, then the gene is further classified by a sequence number on the left or right arm of the chromosome, and a letter showing which of the two DNA strands contains its coding sequence.<ref>{{cite book|vauthors=Stamm S, Smith CW, Lührmann R |title=Alternative Pre-mRNA Splicing: Theory and Protocols |publisher=Wiley-Blackwell |isbn=978-3-527-63677-8 |chapter=Yeast Nomenclature Systematic Open Reading Frame (ORF) and Other Genetic Designations |doi=10.1002/9783527636778.app1 |doi-access=free|pages=605–7}}</ref>

{|border="1" cellspacing="0"
|+ Systematic gene names for Baker's yeast
|-
| Example gene name
! scope="row" style="background:#efefef;"| YGL118W
|-
! scope="row" style="background:#efefef;" | Y
|the Y indicates this is a yeast gene
|-
! scope="row" style="background:#efefef;" | G
|chromosome on which the gene is located (chromosome 1 = A etc.)
|-
! scope="row" style="background:#efefef;" | L
|left or right arm of the chromosome
|-
! scope="row" style="background:#efefef;" | 118
|sequence number of the gene/ORF on this arm, starting at the centromere
|-
! scope="row" style="background:#efefef;" | W
|whether the coding sequence is on the Watson or Crick strand
|}

'''Examples:'''
* YBR134C (aka SUP45 encoding [[Sup45p|eRF1]], a translation termination factor) is located on the right arm of chromosome 2 and is the 134th [[open reading frame]] (ORF) on that arm, starting from the centromere. The coding sequence is on the Crick strand of the DNA.
* YDL102W (aka POL3 encoding a subunit of [[DNA polymerase delta]]) is located on the left arm of chromosome 4; it is the 102nd ORF from the centromere and codes from the Watson strand of the DNA.

===Gene function and interactions===
The availability of the ''S.&nbsp;cerevisiae'' genome sequence and a set of deletion mutants covering 90% of the yeast genome<ref>{{cite web |url=http://www-sequence.stanford.edu/group/yeast_deletion_project/deletions3.html |title=YeastDeletionWeb |access-date=2013-05-25 |archive-date=2012-09-29 |archive-url=https://web.archive.org/web/20120929010716/http://www-sequence.stanford.edu/group/yeast_deletion_project/deletions3.html }}</ref> has further enhanced the power of ''S.&nbsp;cerevisiae'' as a model for understanding the regulation of eukaryotic cells. A project underway to analyze the genetic interactions of all double-deletion mutants through [[synthetic genetic array]] analysis will take this research one step further. The goal is to form a functional map of the cell's processes.

{{As of|2010}} a model of genetic interactions is most comprehensive yet to be constructed, containing "the interaction profiles for ~75% of all genes in the Budding yeast".<ref name="Landscape">{{cite journal | vauthors = Costanzo M, Baryshnikova A, Bellay J, Kim Y, Spear ED, Sevier CS, Ding H, Koh JL, Toufighi K, Mostafavi S, Prinz J, St Onge RP, VanderSluis B, Makhnevych T, Vizeacoumar FJ, Alizadeh S, Bahr S, Brost RL, Chen Y, Cokol M, Deshpande R, Li Z, Lin ZY, Liang W, Marback M, Paw J, San Luis BJ, Shuteriqi E, Tong AH, van Dyk N, Wallace IM, Whitney JA, Weirauch MT, Zhong G, Zhu H, Houry WA, Brudno M, Ragibizadeh S, Papp B, Pál C, Roth FP, Giaever G, Nislow C, Troyanskaya OG, Bussey H, Bader GD, Gingras AC, Morris QD, Kim PM, Kaiser CA, Myers CL, Andrews BJ, Boone C | title = The genetic landscape of a cell | journal = Science | volume = 327 | issue = 5964 | pages = 425–31 | year = 2010 | pmid = 20093466 | pmc = 5600254 | doi = 10.1126/science.1180823 | bibcode = 2010Sci...327..425C }}</ref> This model was made from 5.4 million two-gene comparisons in which a double [[gene knockout]] for each combination of the genes studied was performed. The effect of the double knockout on the [[Fitness (biology)|fitness]] of the cell was compared to the expected fitness. Expected fitness is determined from the sum of the results on fitness of single-gene knockouts for each compared gene. When there is a change in fitness from what is expected, the genes are presumed to interact with each other. This was tested by comparing the results to what was previously known. For example, the genes Par32, Ecm30, and Ubp15 had similar interaction profiles to genes involved in the Gap1-sorting module cellular process. Consistent with the results, these genes, when knocked out, disrupted that process, confirming that they are part of it.<ref name="Landscape" />

From this, 170,000 gene interactions were found and genes with similar interaction patterns were grouped together. Genes with similar genetic interaction profiles tend to be part of the same pathway or biological process.<ref name="Mapping">{{cite journal | vauthors = Tong AH, Lesage G, Bader GD, Ding H, Xu H, Xin X, Young J, Berriz GF, Brost RL, Chang M, Chen Y, Cheng X, Chua G, Friesen H, Goldberg DS, Haynes J, Humphries C, He G, Hussein S, Ke L, Krogan N, Li Z, Levinson JN, Lu H, Ménard P, Munyana C, Parsons AB, Ryan O, Tonikian R, Roberts T, Sdicu AM, Shapiro J, Sheikh B, Suter B, Wong SL, Zhang LV, Zhu H, Burd CG, Munro S, Sander C, Rine J, Greenblatt J, Peter M, Bretscher A, Bell G, Roth FP, Brown GW, Andrews B, Bussey H, Boone C | title = Global mapping of the yeast genetic interaction network | journal = Science | volume = 303 | issue = 5659 | pages = 808–13 | year = 2004 | pmid = 14764870 | doi = 10.1126/science.1091317 | bibcode = 2004Sci...303..808T }}</ref> This information was used to construct a global network of gene interactions organized by function. This network can be used to predict the function of uncharacterized genes based on the functions of genes they are grouped with.<ref name="Landscape" />

===Other tools in yeast research===

Approaches that can be applied in many different fields of biological and medicinal science have been developed by yeast scientists. These include [[Yeast two hybrid|yeast two-hybrid]] for studying [[Protein–protein interaction|protein interactions]] and [[Tetrad (genetics)|tetrad analysis]]. Other resources, include a gene deletion library including ~4,700 viable haploid single gene deletion strains. A [[Green fluorescent protein|GFP fusion strain library]] used to study protein localisation and a [[Tandem affinity purification|TAP tag library]] used to purify protein from yeast cell extracts.{{citation needed|date=January 2014}}

Stanford University's [[yeast deletion project]] created [[knockout mutation]]s of every gene in the ''S.&nbsp;cerevisiae'' genome to determine their function.<ref>{{Cite journal|last1=Giaever|first1=Guri|last2=Nislow|first2=Corey|date=2014-06-01|title=The Yeast Deletion Collection: A Decade of Functional Genomics|journal=Genetics|language=en|volume=197|issue=2|pages=451–465|doi=10.1534/genetics.114.161620|issn=0016-6731|pmc=4063906|pmid=24939991}}</ref>

===Synthetic yeast chromosomes and genomes===
The yeast genome is highly accessible to manipulation, hence it is an excellent model for genome engineering.

The international Synthetic Yeast Genome Project (Sc2.0 or ''Saccharomyces cerevisiae version 2.0'') aims to build an entirely designer, customizable, synthetic ''S. cerevisiae'' genome from scratch that is more stable than the wild type. In the synthetic genome all [[transposon]]s, [[repeated sequence (DNA)|repetitive elements]], and many [[intron]]s are removed, all UAG [[stop codon]]s are replaced with UAA, and [[transfer RNA]] genes are moved to a novel [[neochromosome]]. {{As of|2017|3}}, 6 of the 16 chromosomes have been synthesized and tested. No significant fitness defects have been found.<ref>{{cite journal |title=Cover stories: Making the synthetic yeast chromosomes cover and introductory spread image |journal=Science |date=10 March 2017 |volume=355 |issue=6329 |article-number=eaan1126 |doi=10.1126/science.aan1126 |pmid=28280148 }}</ref>

All 16 chromosomes can be fused into one single chromosome by successive end-to-end chromosome fusions and [[centromere]] deletions. The single-chromosome and wild-type yeast cells have nearly identical [[transcriptome]]s and similar phenotypes. The giant single chromosome can support cell life, although this strain shows reduced growth across environments, competitiveness, [[gamete]] production and viability.<ref>{{cite journal |last1=Shao |first1=Yangyang |last2=Lu |first2=Ning |last3=Wu |first3=Zhenfang |last4=Cai |first4=Chen |last5=Wang |first5=Shanshan |last6=Zhang |first6=Ling-Li |last7=Zhou |first7=Fan |last8=Xiao |first8=Shijun |last9=Liu |first9=Lin |last10=Zeng |first10=Xiaofei |last11=Zheng |first11=Huajun |last12=Yang |first12=Chen |last13=Zhao |first13=Zhihu |last14=Zhao |first14=Guoping |last15=Zhou |first15=Jin-Qiu |last16=Xue |first16=Xiaoli |last17=Qin |first17=Zhongjun |title=Creating a functional single-chromosome yeast |journal=Nature |date=16 August 2018 |volume=560 |issue=7718 |pages=331–335 |doi=10.1038/s41586-018-0382-x |pmid=30069045 |bibcode=2018Natur.560..331S }}</ref>

===Astrobiology===
Among other microorganisms, a sample of living ''S.&nbsp;cerevisiae'' was included in the [[Living Interplanetary Flight Experiment]], which would have completed a three-year interplanetary round-trip in a small capsule aboard the Russian [[Fobos-Grunt]] spacecraft, launched in late 2011.<ref name="LIFE">{{cite conference |first1=David |last1=Warmflash |first2=Neva |last2=Ciftcioglu |first3=George |last3=Fox |first4=David S. |last4=McKay |first5=Louis |last5=Friedman |first6=Bruce |last6=Betts |first7=Joseph |last7=Kirschvink |url=http://www.lpi.usra.edu/meetings/phobosdeimos2007/pdf/7043.pdf |title=Living interplanetary flight experiment (LIFE): An experiment on the survivalability of microorganisms during interplanetary travel |conference=Workshop on the Exploration of Phobos and Deimos |date=November 5–7, 2007 |location=[[Ames Research Center]]}}</ref><ref name=planetary-life>{{cite web |url=http://www.planetary.org/programs/projects/innovative_technologies/life/ |title=Projects: LIFE Experiment: Phobos |publisher=[[The Planetary Society]] |access-date=2 April 2011 |archive-url=https://web.archive.org/web/20110316100755/http://www.planetary.org/programs/projects/innovative_technologies/life |archive-date=16 March 2011}}</ref> The goal was to test whether selected [[organism]]s could survive a few years in [[outer space|deep space]] by flying them through interplanetary space. The experiment would have tested one aspect of [[transpermia]], the hypothesis that [[life]] could survive space travel, if protected inside rocks blasted by impact off one planet to land on another.<ref name="LIFE"/><ref name="planetary-life" /><ref name=Zak1>{{cite web |url=http://www.airspacemag.com/space-exploration/Mission_Possible.html?c=y&page=4 |author=Anatoly Zak |title=Mission Possible |date=1 September 2008 |work=[[Air & Space Magazine]] |publisher=[[Smithsonian Institution]] |access-date=26 May 2009}}</ref> Fobos-Grunt's mission ended unsuccessfully, however, when it failed to escape low Earth orbit. The spacecraft along with its instruments fell into the Pacific Ocean in an uncontrolled re-entry on January 15, 2012. The next planned exposure mission in deep space using ''S. cerevisiae'' is [[BioSentinel]]. (see: [[List of microorganisms tested in outer space]])

==In commercial applications==
===Brewing===
{{Further|Yeast in winemaking}}
''Saccharomyces cerevisiae'' is used in brewing beer, when it is sometimes called a [[top-fermenting]] or top-cropping yeast. It is so called because during the fermentation process its hydrophobic surface causes the [[Yeast flocculation#Process|floc]]s to adhere to CO<sub>2</sub> and rise to the top of the fermentation vessel. Top-fermenting yeasts are fermented at higher temperatures than the lager yeast ''[[Saccharomyces pastorianus]]'', and the resulting beers have a different flavor from the same beverage fermented with a lager yeast. "Fruity esters" may be formed if the yeast undergoes temperatures near {{convert|21|C|F}}, or if the fermentation temperature of the beverage fluctuates during the process. Lager yeast normally ferments at a temperature of approximately {{convert|5|C|F}} or 278 k, where ''Saccharomyces cerevisiae'' becomes dormant. A variant yeast known as ''Saccharomyces cerevisiae'' var. ''diastaticus'' is a beer spoiler which can cause secondary fermentations in packaged products.<ref>{{Cite web|url=https://www.chaibio.com/beer-spoilage/diastaticus|title=Controlling Diastaticus in your Brewery|website=www.chaibio.com|access-date=9 April 2019|archive-date=30 April 2021|archive-url=https://web.archive.org/web/20210430084921/https://www.chaibio.com/beer-spoilage/diastaticus}}</ref>

In May 2013, the [[Oregon]] legislature made ''S. cerevisiae'' the [[List of Oregon state symbols|official state microbe]] in recognition of the impact craft beer brewing has had on the state economy and the state's identity.<ref>{{cite web |title=Designates Saccharomyces cerevisiae as official microbe of State of Oregon |url=https://olis.leg.state.or.us/liz/2013R1/Measures/Overview/HCR12 |publisher=Oregon State Legislature |date=29 May 2013 |access-date=9 April 2019 |archive-date=30 April 2021 |archive-url=https://web.archive.org/web/20210430084920/https://olis.leg.state.or.us/liz/2013R1/Measures/Overview/HCR12 }}</ref>

===Baking===
{{main|Baker's yeast}}

''S. cerevisiae'' is used in baking; the carbon dioxide generated by the fermentation is used as a [[leavening agent]] in bread and other baked goods. Historically, this use was closely linked to the brewing industry's use of yeast, as bakers took or bought the [[barm]] or yeast-filled foam from brewing [[ale]] from the brewers (producing the [[barm cake]]); today, brewing and baking yeast strains are somewhat different.{{cn|date=November 2022}}

===Nutritional yeast===
{{main|Nutritional yeast}}

''Saccharomyces cerevisiae'' is the main source of nutritional yeast, which is sold commercially as a food product. It is popular with [[vegan]]s and [[vegetarian]]s as an ingredient in [[cheese substitute]]s, or as a general [[food additive]] as a source of vitamins and minerals, especially [[amino acids]] and [[B-complex vitamins]].

===Selenium yeast===
{{main|Selenium yeast}}

''Saccharomyces cerevisiae'' is grown in [[selenium]]-rich media to produce a yeast rich in organic selenium compounds that can be more easily absorbed by animals including humans. At the levels used, random misincorporation of [[seleno amino acid]]s in lieu of [[sulfur amino acid]]s happen.<ref name="pmid26003453">{{cite journal |last1=Kieliszek |first1=M |last2=Błażejak |first2=S |last3=Gientka |first3=I |last4=Bzducha-Wróbel |first4=A |title=Accumulation and metabolism of selenium by yeast cells. |journal=Applied Microbiology and Biotechnology |date=July 2015 |volume=99 |issue=13 |pages=5373–82 |doi=10.1007/s00253-015-6650-x |pmid=26003453 |pmc=4464373}}</ref>

===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 [[Do it yourself|DIY]] approaches followed by aquaculturists for providing CO<sub>2</sub> to underwater aquatic plants. The yeast culture is, in general, 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.<ref>{{Cite web|url=http://www.thekrib.com/Plants/CO2/co2-narten.html|title=CO2 Injection: The Yeast Method|website=www.thekrib.com|access-date=2016-11-21}}</ref>

==Direct use in medicine==
{{missing information|non-boulardii (CBS 5926) strains, such as CNCM I-3856: might be a good idea to search the EMA database|date=January 2022}}
''Saccharomyces cerevisiae'' is used as a [[probiotic]] in humans and animals. The strain ''[[Saccharomyces cerevisiae var. boulardii]]'' is industrially manufactured and used clinically as a medication.

Several clinical and experimental studies have shown that ''S. cerevisiae var. boulardii'' is, to lesser or greater extent, is useful for prevention or treatment of several gastrointestinal diseases.<ref name=Kelesidis>{{cite journal |last1=Kelesidis |first1=Theodoros |last2=Pothoulakis |first2=Chralabos |date=November 11, 2011 |title=Efficacy and safety of the probiotic Saccharomyces boulardii for the prevention and therapy of gastrointestinal disorders |journal=Therapeutic Advances in Gastroenterology |volume=5 |issue=2 |pages=111–125 |doi=10.1177/1756283X11428502 |pmid=22423260 |pmc=3296087 }}</ref> Moderate quality evidence has shown ''S. cerevisiae var. boulardii'' reduces risk of antibiotic-associated diarrhoea both in adults<ref name=Szajewska1/><ref name=Kelesidis/><ref name=McFarland>{{cite journal |last1=McFarland |first1=Lynne V. |date=May 14, 2010 |title=Systematic review and meta-analysis of Saccharomyces boulardii in adult patients |journal=[[World Journal of Gastroenterology]] |volume=16 |issue=18 |pages=2202–2222 |doi=10.3748/wjg.v16.i18.2202 |pmid=20458757 |pmc=2868213 |doi-access=free }}</ref> and in children<ref name=Szajewska1>{{cite journal |last1=Szajewska |first1=H. |last2=Kolodziej |first2=M. |date=October 2015 |title=Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea |journal=Alimentary Pharmacology & Therapeutics |volume=42 |issue=7 |pages=793–801 |doi=10.1111/apt.13344 |pmid=26216624 |doi-access=free }}</ref><ref name=Kelesidis/> and to reduce risk of adverse effects of ''[[Helicobacter pylori]]'' eradication therapy.<ref name=Szajewska2>{{cite journal |last1=Szajewska |first1=H. |last2=Horvath |first2=A.|last3=Kolodziej |first3=M. |date=June 2015 |title=Systematic review with meta-analysis: Saccharomyces boulardii supplementation and eradication of Helicobacter pylori infection |journal=Alimentary Pharmacology & Therapeutics |volume=41 |issue=12 |pages=1237–1245 |doi=10.1111/apt.13214 |pmid=25898944 |doi-access=free }}</ref><ref name=Kelesidis/><ref name=McFarland/> There is some evidence to support efficacy of ''S. cerevisiae var. boulardii'' in prevention (but not treatment) of traveler's diarrhoea<ref name=Kelesidis/><ref name=McFarland/> and, at least as an adjunct medication, in treatment of acute diarrhoea in adults and children and of persistent diarrhoea in children.<ref name=Kelesidis/> It may also reduce symptoms of  allergic rhinitis.<ref>{{cite journal |last1=Moyad |first1=MA |title=Immunogenic yeast-based fermentation product reduces allergic rhinitis-induced nasal congestion: a randomized, double-blind, placebo-controlled trial. |journal=Adv Ther |year=2009 |volume=26 |issue=8 |pages=795–804 |doi=10.1007/s12325-009-0057-y |pmid=19672568 |doi-access=free |pmc=6822977 }}</ref>

Administration of ''S. cerevisiae var. boulardii'' is considered generally safe.<ref name=McFarland/> In clinical trials it was well tolerated by patients, and adverse effects rate was similar to that in control groups (i. e. groups with ''[[placebo]]'' or no treatment).<ref name=Szajewska1/> No case of ''S. cerevisiae var. boulardii'' fungemia has been reported during clinical trials.<ref name=McFarland/>

In clinical practice, however, cases of [[fungemia]], caused by ''S. cerevisiae var. boulardii'' are reported.<ref name=McFarland/><ref name=Kelesidis/> Patients with [[Immunodeficiency|compromised immunity]] or those with central vascular catheters are at special risk. Some researchers have recommended avoiding use of ''S. cerevisiae var. boulardii'' as treatment in such patients.<ref name=McFarland/> Others suggest only that caution must be exercised with its use in risk group patients.<ref name=Kelesidis/>

==As a human pathogen==
''Saccharomyces cerevisiae'' is proven to be an [[Opportunistic infection|opportunistic human pathogen]], though of relatively low [[virulence]].<ref name=Murphy/> Despite widespread use of this microorganism at home and in industry, contact with it very rarely leads to infection.<ref name=Canada-2017/>
''Saccharomyces cerevisiae'' was found in the skin, oral cavity, oropharinx, duodenal mucosa, digestive tract, and vagina of healthy humans<ref name=Anoop/> (one review found it to be reported for 6% of samples from human intestine<ref name=Hallen-Adams>{{cite journal |last1=Hallen-Adams |first1=Heather E. |last2=Suhr |first2=Mallory J. |date=November 1, 2016 |title=Fungi in the healthy human gastrointestinal tract
 |journal=Virulence |volume=8 |issue=3 |pages=352–358 |doi=10.1080/21505594.2016.1247140 |pmid=27736307 |pmc=5411236 }}</ref>). Some specialists consider ''S. cerevisiae'' to be a part of the [[Human microbiota|normal microbiota]] of the gastrointestinal tract, the respiratory tract, and the vagina of humans,<ref name=Pfaller/> while others believe that the species cannot be called a true [[commensal]] because it originates in food.<ref name=Hallen-Adams/><ref name=Enache-Angoulvant/> Presence of ''S. cerevisiae'' in the human digestive system may be rather transient;<ref name=Enache-Angoulvant/> for example, experiments show that in the case of oral administration to healthy individuals it is eliminated from the intestine within 5 days after the end of administration.<ref name=Hallen-Adams/><ref name=Canada-2017>{{cite book |author=<!--Staff writer(s); no by-line.--> |title=Final Screening Assessment of Saccharomyces cerevisiae strain F53 |url=http://publications.gc.ca/collections/collection_2017/eccc/En14-268-2017-eng.pdf |publisher=Government of Canada. |date=January 2017 |isbn=978-0-660-07394-1}}</ref>

Under certain circumstances, such as [[Immunodeficiency|degraded immunity]], ''Saccharomyces cerevisiae'' can cause infection in humans.<ref name=Canada-2017/><ref name=Murphy/> Studies show that it causes 0.45–1.06% of the cases of [[Vaginal yeast infection|yeast-induced vaginitis]]. In some cases, women suffering from ''S. cerevisiae''-induced vaginal infection were intimate partners of bakers, and the strain was found to be the same that their partners [[Baker's yeast|used for baking]]. As of 1999, no cases of ''S. cerevisiae''-induced vaginitis in women, who worked in bakeries themselves, were reported in scientific literature. Some cases were linked by researchers to the use of the yeast in home baking.<ref name=Murphy>{{cite journal |last1=Murphy |first1=Alan |last2=Kavanagh |first2=Kevin |date=June 15, 1999 |title=Emergence of Saccharomyces cerevisiae as a human pathogen. Implications for biotechnology |url=http://mural.maynoothuniversity.ie/7603/1/KK-Emergence-1999.pdf |journal=Enzyme and Microbial Technology |volume=25 |issue=7 |pages=551–557 |doi=10.1016/S0141-0229(99)00086-1 }}</ref> Cases of infection of [[oral cavity]] and [[pharynx]] caused by ''S. cerevisiae'' are also known.<ref name=Murphy/>

===Invasive and systemic infections===
Occasionally ''Saccharomyces cerevisiae'' causes [[invasive infection]]s (i. e. gets into the bloodstream or other normally sterile body fluid or into a deep site tissue, such as [[lungs]], [[liver]], or [[spleen]]) that can go [[systemic infection|systemic]] (involve multiple organs). Such conditions are life-threatening.<ref name=Murphy/><ref name=Enache-Angoulvant/> More than 30% cases of ''S. cerevisiae'' invasive infections lead to death even if treated.<ref name=Enache-Angoulvant/> ''S. cerevisiae'' invasive infections, however, are much rarer than invasive infections caused by ''[[Candida albicans]]''<ref name=Murphy/><ref name=Chitasombat>{{cite journal |last1=Chitasombat |first1=Maria |last2=Kofteridis |first2=Diamantis |last3=Jiang |first3=Ying |last4=Tarrand |first4=Jeffrey |last5=Lewis |first5=Russel|author-link6=Dimitrios Kontoyiannis |last6=Kontoyiannis |first6=Dimitrios |date=January 2012 |title=Rare opportunistic (non-Candida, non-Criptococcus) Yeast Bloodstream Infections in Patients with Cancer |journal=Journal of Infection |volume=64 |issue=1 |pages=68–75 |doi=10.1016/j.jinf.2011.11.002 |pmid=22101079 |pmc=3855381}}</ref> even in patients weakened by cancer.<ref name=Chitasombat/> ''S. cerevisiae'' causes 1% to 3.6% [[nosocomial]] cases of [[fungemia]].<ref name=Enache-Angoulvant/> A comprehensive review of ''S. cerevisiae'' invasive infection cases found all patients to have at least one predisposing condition.<ref name=Enache-Angoulvant/>

''Saccharomyces cerevisiae'' may enter the bloodstream or get to other deep sites of the body by translocation from [[Oral mucosa|oral]] or [[Gastrointestinal tract#Lower gastrointestinal tract|enteral]] [[mucosa]] or through contamination of intravascular catheters (e. g. [[central venous catheter]]s).<ref name=Pfaller>{{cite journal |last1=Pfaller |first1=Michael |last2=Diekema |first2=Daniel |date=February 2010 |title=Epidemiology of Invasive Mycoses in North America |journal=Critical Reviews in Microbiology  |volume=36 |issue=1 |pages= 1–53 |doi=10.3109/10408410903241444 |pmid=20088682 }}</ref> Intravascular catheters, antibiotic therapy and compromised immunity are major predisposing factors for ''S. cerevisiae'' invasive infection.<ref name=Enache-Angoulvant>{{cite journal |last1=Enache-Angoulvant |first1=Adela |last2=Hennequin |first2=Christophe |date=December 1, 2005 |title=Invasive Saccharomyces Infection: A Comprehensive Review |journal=Clinical Infectious Diseases  |volume=41 |issue=11 |pages=1559–1568 |doi= 10.1086/497832 |pmid=16267727 }}</ref>

A number of cases of [[fungemia]] were caused by intentional ingestion of living ''S. cerevisiae'' cultures for dietary or therapeutic reasons, including use of ''[[Saccharomyces boulardii]]'' (a strain of ''S. cerevisiae''  which is used as a [[probiotic]] for treatment of certain forms of [[diarrhea]]).<ref name=Murphy/><ref name=Enache-Angoulvant/> ''Saccharomyces boulardii'' causes about 40% cases of invasive ''Saccharomyces'' infections<ref name=Enache-Angoulvant/> and is more likely (in comparison to other ''S. cerevisiae'' strains) to cause invasive infection in humans without general problems with immunity,<ref name=Enache-Angoulvant/> though such adverse effect is very rare relative to ''Saccharomyces boulardii'' therapeutic administration.<ref name=Hennequin>{{cite journal |last1=Hennequin |first1=C. |last2=Cauffman-Lacroix |first2=C. |last3=Jobert |first3=A.|last4=Viard |first4=J.P.|last5=Ricour |first5=C.|last6=Jacquemin |first6=J.L.|last7=Berche |first7=P.|date=February 2000 |title=Possible Role of Catheters in Saccharomyces boulardii Fungemia |journal= European Journal of Clinical Microbiology and Infectious Diseases |volume=19 |issue=1 |pages=16–20 |doi= 10.1007/s100960050003 |pmid=10706174 }}</ref>

''S. boulardii'' may contaminate intravascular catheters through hands of medical personnel involved in administering probiotic preparations of ''S. boulardii'' to patients.<ref name=Enache-Angoulvant/>

Systemic infection usually occurs in patients who have their [[immunodeficiency|immunity compromised]] due to severe illness ([[HIV/AIDS]], [[leukemia]], other forms of [[cancer]]) or certain medical procedures ([[bone marrow transplantation]], [[abdominal surgery]]).<ref name=Murphy/>

A case was reported when a [[Solitary pulmonary nodule|nodule]] was [[Wedge resection (lung)|surgically excised]] from a lung of a man employed in baking business, and examination of the tissue revealed presence of ''Saccharomyces cerevisiae''. Inhalation of [[Baker's yeast|dry baking yeast powder]] is supposed to be the source of infection in this case.<ref name="Sridhar">{{cite journal |last1=Ren |first1=Ping |last2=Sridhar |first2=Sundara |last3=Chaturvedi |first3=Vishnu |date=June 2004 |title=Use of Paraffin-Embedded Tissue for Identification of Saccharomyces cerevisiae in a Baker's Lung Nodule by Fungal PCR and Nucleotide Sequencing|url= |journal=Journal of Clinical Microbiology  |volume=42 |issue=6 |pages=2840–2842 |doi= 10.1128/JCM.42.6.2840-2842.2004 |pmid=15184487 |pmc=427872 }}</ref><ref name=Enache-Angoulvant/>

===Virulence of different strains===
[[File:Hustopece 20210903 170948 Saccharomyces cerevisiae.jpg|thumb| Statue of ''Saccharomyces cerevisiae'' ([[Hustopeče]], [[Czech Republic]])]]
Not all strains of ''Saccharomyces cerevisiae'' are equally virulent towards humans. Most environmental strains are not capable of growing at temperatures above 35&nbsp;°C (i. e. at temperatures of living body of humans and other [[mammalian]]). Virulent strains, however, are capable of growing at least above 37&nbsp;°C  and often up to 39&nbsp;°C (rarely up to 42&nbsp;°C).<ref name=Anoop/> Some industrial strains are also capable of growing above 37&nbsp;°C.<ref name=Murphy/> [[European Food Safety Authority]] (as of 2017) requires that all ''S. cerevisiae'' strains capable of growth above 37&nbsp;°C that are added to the food or feed chain in viable form must, as to be qualified presumably safe, show no resistance to antimycotic drugs used for treatment of yeast infections.<ref name=QPS-2017>{{cite journal |last1=Ricci |first1=Antonia |display-authors=etal |date=March 14, 2017 |title=Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 5
 |journal=EFSA Journal |volume=15 |issue=3 |pages= e04663|doi=10.2903/j.efsa.2017.4663 |pmid=32625420 |pmc=7328882 |doi-access=free }}</ref>

The ability to grow at elevated temperatures is an important factor for strain's virulence but not the sole one.<ref name=Anoop>{{cite journal |last1=Anoop |first1=Valar |last2=Rotaru |first2=Sever |last3=Shwed |first3=Philip S. |last4=Tayabali |first4=Azam F. |last5=Arvanitakis |first5=George |date=July 20, 2015 |title=Review of current methods for characterizing virulence and pathogenicity potential of industrial Saccharomyces cerevisiae strains towards humans
 |journal=[[FEMS Yeast Research]]  |volume=15 |issue=6 |article-number= fov057|doi=10.1093/femsyr/fov057 |pmid=26195617 |doi-access=free }}</ref>

Other traits that are usually believed to be associated with virulence are: ability to produce certain enzymes such as [[proteinase]]<ref name=Murphy/> and [[phospholipase]],<ref name=Anoop/> invasive growth<ref name=Anoop/> (i.e. growth with intrusion into the nutrient medium), ability to adhere to mammalian cells,<ref name=Anoop/> ability to survive in the presence of [[hydrogen peroxide]]<ref name=Anoop/> (that is used by [[macrophage]]s to kill foreign microorganisms in the body) and other abilities allowing the yeast to resist or influence immune response of the host body.<ref name=Anoop/> Ability to form branching chains of cells, known as [[Hypha#Types|pseudohyphae]] is also sometimes said to be associated with virulence,<ref name=Murphy/><ref name=Anoop/> though some research suggests that this trait may be common to both virulent and non-virulent strains of ''Saccharomyces cerevisiae''.<ref name=Anoop/>

==See also==
* ''Saccharomyces cerevisiae'' extracts: [[Vegemite]], [[Marmite]], [[Cenovis]], [[Guinness Yeast Extract]], [[Mannan Oligosaccharide based nutritional supplements (MOS)|mannan oligosaccharides]], [[PGG-glucan|pgg-glucan]], [[zymosan]]
* ''Saccharomyces cerevisiae boulardii'' (''[[Saccharomyces boulardii]]'')
* [[Auto-brewery syndrome]]
* [[Biosprint]]
* [[BolA-like protein family]]
* [[Flora of Door County, Wisconsin#Hybrid yeast|Flora of Door County, Wisconsin § Hybrid yeast]]
* [[Saccharomyces cerevisiae virus L-A]]
* [[Yeast Promoter Atlas]] (2010)
* [[:Category:Saccharomyces cerevisiae genes|Category:''Saccharomyces cerevisiae'' genes]]

==References==
'''Footnotes'''
{{notelist}}

'''Citations'''
{{Reflist}}

==Further reading==
* {{cite journal | vauthors = Arroyo-López FN, Orlić S, Querol A, Barrio E | title = Effects of temperature, pH and sugar concentration on the growth parameters of Saccharomyces cerevisiae, S. kudriavzevii and their interspecific hybrid | journal = Int. J. Food Microbiol. | volume = 131 | issue = 2–3 | pages = 120–27 | year = 2009 | pmid = 19246112 | doi = 10.1016/j.ijfoodmicro.2009.01.035 | url = http://bib.irb.hr/datoteka/389483.Arroyo-Lopez_et_al.pdf | archive-date = 2021-07-30 | access-date = 2012-02-03 | archive-url = https://web.archive.org/web/20210730133544/http://bib.irb.hr/datoteka/389483.Arroyo-Lopez_et_al.pdf }}
* {{cite thesis |type=Ph.D. |last=Jansma |first=David B. |title=Regulation and variation of subunits of RNA polymerase II in ''Saccharomyces cerevisiae'' |date=1999 |publisher=University of Toronto |url=http://www.collectionscanada.gc.ca/obj/s4/f2/dsk1/tape7/PQDD_0003/NQ41179.pdf}}

==External links==
{{Commons|Saccharomyces cerevisiae}}
* [http://www.yeastgenome.org/ ''Saccharomyces'' Genome Database]
* [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] {{Webarchive|url=https://web.archive.org/web/20060823011533/http://mips.gsf.de/genre/proj/yeast/index.jsp |date=2006-08-23 }}
* [[UniProt]] – [https://www.uniprot.org/uniprot/?query=organism:4932+AND+reviewed:yes ''Saccharomyces cerevisiae'']
* {{UCSC genomes|sacCer3}}

{{Bread}}
{{Model organisms}}
{{Taxonbar|from=Q719725}}
{{Authority control}}

[[Category:Saccharomyces cerevisiae| ]]
[[Category:Baking]]
[[Category:Digestive system]]
[[Category:Edible fungi]]
[[Category:Fungal models]]
[[Category:Fungi described in 1883]]
[[Category:Fungi in cultivation]]
[[Category:Fungus species]]
[[Category:Leavening agents]]
[[Category:Oenology]]
[[Category:Osmophiles]]
[[Category:Probiotics]]
[[Category:Yeasts used in brewing]]