Saccharomyces cerevisiae

Saccharomyces cerevisiae

Saccharomyces cerevisiae
S. cerevisiae under DIC microscopy
Scientific classification
Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Saccharomycotina
Class: Saccharomycetes
Order: Saccharomycetales
Family: Saccharomycetaceae
Genus: Saccharomyces
Species: S. cerevisiae
Binomial name
Saccharomyces cerevisiae
Meyen ex E.C. Hansen

Saccharomyces cerevisiae is a species of fermentation. S. cerevisiae cells are round to ovoid, 5–10 μm in diameter. It reproduces by a division process known as budding.[1]

Many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. S. cerevisiae is currently the only yeast cell known to have Berkeley bodies present, which are involved in particular secretory pathways. Antibodies against S. cerevisiae are found in 60–70% of patients with Crohn's disease and 10–15% of patients with ulcerative colitis (and 8% of healthy controls).[2]

Contents

  • Etymology 1
  • History 2
  • Biology 3
    • Ecology 3.1
    • Life cycle 3.2
    • Nutritional requirements 3.3
    • Mating 3.4
    • Cell cycle 3.5
  • In biological research 4
    • Model organism 4.1
    • In the study of aging 4.2
    • Meiosis, recombination and DNA repair 4.3
    • Genome sequencing 4.4
    • Gene function and interactions 4.5
    • Other tools in yeast research 4.6
    • Astrobiology 4.7
  • In commercial applications 5
    • Brewing 5.1
    • Baking 5.2
    • Uses in aquaria 5.3
  • See also 6
  • References 7
  • Further reading 8
  • External links 9

Etymology

"Saccharomyces" derives from Latinized Greek and means "sugar-mold" or "sugar-fungus", saccharo (σάκχαρις) being the combining form "sugar" and myces (μύκης, genitive μύκητος) being "fungus". Cerevisiae comes from Latin and means "of beer". Other names for the organism are:

  • S. cerevisiae short form of the scientific name
  • Brewer's yeast, though other species are also used in brewing[3]
  • Ale yeast
  • Top-fermenting yeast
  • Baker's yeast[3]
  • Ragi yeast, in connection to making Tapai
  • Budding yeast

This species is also the main source of nutritional yeast and yeast extract.

History

In the 19th century, bread bakers obtained their yeast from beer brewers, and this led to sweet-fermented breads such as the Imperial "Kaiser-Semmel" roll,[4] which in general lacked the sourness created by the acidification typical of Lactobacillus. However, beer brewers slowly switched from top-fermenting to bottom-fermenting yeast (both S. cerevisiae) and this created a shortage of yeast for making bread, so the Vienna Process was developed in 1846.[5] 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[6]), 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.

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 century centrifuges were used for concentrating the yeast,[7] making modern commercial yeast possible, and turning yeast production into a major industrial endeavor. The slurry yeast made by small bakers and grocery shops became cream yeast, a suspension of live yeast cells in growth medium, and then compressed yeast, the fresh cake yeast that became the standard leaven for bread bakers in much of the Westernized world during the early 20th century.

During World War II, Fleischmann's developed a 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. 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.

Biology

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).[8] Since S. cerevisiae is not airborne, it requires a vector to move. In fact, 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.[9]

The optimum temperature for growth of S. cerevisiae is 30–35 °C.[9]

Life cycle

Two forms of fungal 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, in general, die. This is the asexual form of the fungus. The diploid cells (the preferential 'form' of yeast) similarly undergo a simple lifecycle of mitosis and growth. The rate at which the mitotic cell cycle progresses often differs substantially between haploid and diploid cells.[10] Under conditions of stress, diploid cells can undergo sporulation, entering meiosis and producing four haploid spores, which can subsequently mate. This is the sexual form of the fungus. Under optimal conditions, yeast cells can double their population every 100 minutes.[11][12] However, growth rates vary enormously both between strains and between environments.[13] Mean replicative lifespan is about 26 cell divisions.[14][15]

Nutritional requirements

All strains of S. cerevisiae can grow aerobically on glucose, maltose, and trehalose 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.

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. cerevisiae does not excrete proteases, so extracellular protein cannot be metabolized.

amino acids 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. Indeed, a S. cerevisiae-based growth assay laid the foundation for the isolation, crystallisation, and later structural determination of biotin. Most strains also require pantothenate for full growth. In general, S. cerevisiae is prototrophic vitamins.

Mating

Yeast has two mating types, a and α (alpha), which show primitive aspects of sex differentiation.[16] 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 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.

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.

Cell cycle

Growth in yeast is synchronised with the growth of the bud, which reaches the size of the mature cell by the time it separates from the parent cell. In well nourished, rapidly growing yeast cultures, all the cells can be seen to 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.

In biological research

Model organism

Saccharomyces cerevisiae
Numbered ticks are 10 micrometers apart.

When researchers look for an organism to use in their studies, they look for several traits. Among these are size, generation time, accessibility, manipulation, genetics, conservation of mechanisms, and potential economic benefit. The yeast species S. pombe and S. cerevisiae are both well studied; these two species diverged approximately , and are significant tools in the study of DNA damage and repair mechanisms.[17]

S. cerevisiae has developed as a model organism because it scores favorably on a number of these criteria.

  • As a single-cell organism, S. cerevisiae is small with a short generation time (doubling time 1.25–2 hours[18] at 30 °C or 86 °F) and can be easily 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 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 knockouts strains.
  • As a 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

S. cerevisiae has been highly studied as a model organism to better understand aging for more than five decades and has contributed to the identification of more mammalian genes affecting aging than any other model organism.[19] Some of the topics studied using yeast are

  • Cerevisiae Dissection Video
  • Saccharomyces Genome Database
  • Yeast Resource Center Public Data Repository
  • Munich Information Center for Protein Sequences
  • UniProtSaccharomyces cerevisiae

External links

  • Arroyo-López FN, Orlić S, Querol A, Barrio E (2009). "Effects of temperature, pH and sugar concentration on the growth parameters of Saccharomyces cerevisiae, S. kudriavzevii and their interspecific hybrid" (PDF). Int. J. Food Microbiol. 131 (2–3): 120–7.  
  • Jansma, David B. (1999). Saccharomyces cerevisiaeRegulation and variation of subunits of RNA polymerase II in (PDF) (Ph.D.). University of Toronto. 

Further reading

  1. ^ Feldmann, Horst (2010). Yeast. Molecular and Cell bio. Wiley-Blackwell.  
  2. ^ Walker LJ, Aldhous MC, Drummond HE, Smith BR, Nimmo ER, Arnott ID, Satsangi J (2004). "Anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease are associated with disease severity but not NOD2/CARD15 mutations". Clin. Exp. Immunol. 135 (3): 490–6.  
  3. ^ a b Moyad MA (2008). "Brewer's/baker's yeast (Saccharomyces cerevisiae) and preventive medicine: Part II". Urol Nurs 28 (1): 73–75.  
  4. ^ Eben Norton Horsford (1875). Report on Vienna bread – Google Books. Washington: Government Printing Office. p. 86. 
  5. ^ Kristiansen, B.; Ratledge, Colin (2001). Basic biotechnology. Cambridge, UK: Cambridge University Press. p. 378.  
  6. ^ Eben Norton Horsford (1875). Report on Vienna bread – Google Books. Washington: Government Printing Office. pp. 31–32. 
  7. ^ Marx, Jean & Litchfield, John H. (1989). A Revolution in biotechnology. Cambridge, UK: Cambridge University Press. p. 71.  
  8. ^ Marshall, Charles, ed. (June 1912). Microbiology. P. Blakiston's son & Company. p. 420. Retrieved November 5, 2014. 
  9. ^ a b Stefanini I, Dapporto L, Legras JL, Calabretta A, Di Paola M, De Filippo C, Viola R, Capretti P, Polsinelli M, Turillazzi S, Cavalieri D (2012). "Role of social wasps in Saccharomyces cerevisiae ecology and evolution". Proc. Natl. Acad. Sci. U.S.A. 109 (33): 13398–403.  
  10. ^ Zörgö E, Chwialkowska K, Gjuvsland AB, Garré E, Sunnerhagen P, Liti G, Blomberg A, Omholt SW, Warringer J (2013). "Ancient evolutionary trade-offs between yeast ploidy states". PLoS Genet. 9 (3): e1003388.  
  11. ^ Herskowitz I (1988). "Life cycle of the budding yeast Saccharomyces cerevisiae". Microbiol. Rev. 52 (4): 536–553.  
  12. ^ Friedman, Nir (January 3, 2011). "The Friedman Lab Chronicles". Growing yeasts (Robotically).  
  13. ^ 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 (2011). "Trait variation in yeast is defined by population history". PLoS Genet. 7 (6): e1002111.  
  14. ^ Kaeberlein M, Powers RW, Steffen KK, Westman EA, Hu D, Dang N, Kerr EO, Kirkland KT, Fields S, Kennedy BK (2005). "Regulation of yeast replicative life span by TOR and Sch9 in response to nutrients". Science 310 (5751): 1193–1196.  
  15. ^ Kaeberlein M (2010). "Lessons on longevity from budding yeast". Nature 464 (7288): 513–519.  
  16. ^ Saccharomyces cerevisiae http://bioweb.uwlax.edu/bio203/s2007/nelson_andr/
  17. ^ Nickoloff, Jac A.; Haber, James E. (2011). "Saccharomyces cerevisiae"Mating-Type Control of DNA Repair and Recombination in . In Nickoloff, Jac A.; Hoekstra, Merl F. DNA Damage and Repair. Contemporary Cancer Research. pp. 107–24.  
  18. ^ T. Boekhout; V. Robert, eds. (2003). Yeasts in Food: Beneficial and Detrimental aspects. Behr's Verlag. p. 322.  
  19. ^ a b c d e Longo VD, Shadel GS, Kaeberlein M, Kennedy B (2012). "Replicative and chronological aging in Saccharomyces cerevisiae". Cell Metab. 16 (1): 18–31.  
  20. ^ a b c d Kaeberlein M, Burtner CR, Kennedy BK (2007). "Recent developments in yeast aging". PLoS Genet. 3 (5): 655–660.  
  21. ^ Wei M, Fabrizio P, Hu J, Ge H, Cheng C, Li L, Longo VD (2008). "Life span extension by calorie restriction depends on Rim15 and transcription factors downstream of Ras/PKA, Tor, and Sch9". PLoS Genet. 4 (1): 139–149.  
  22. ^ "10-Fold Life Span Extension Reported". University of Southern California. 
  23. ^ Unal E, Kinde B, Amon A (2011). "Gametogenesis eliminates age-induced cellular damage and resets life span in yeast". Science 332 (6037): 1554–7.  
  24. ^ Herskowitz I (1988). "Life cycle of the budding yeast Saccharomyces cerevisiae". Microbiol. Rev. 52 (4): 536–53.  
  25. ^ a b c Ruderfer DM, Pratt SC, Seidel HS, Kruglyak L (2006). "Population genomic analysis of outcrossing and recombination in yeast". Nat. Genet. 38 (9): 1077–81.  
  26. ^ a b  
  27. ^ a b Game JC, Zamb TJ, Braun RJ, Resnick M, Roth RM (1980). "The Role of Radiation (rad) Genes in Meiotic Recombination in Yeast". Genetics 94 (1): 51–68.  
  28. ^ Malone RE, Esposito RE (1980). "The RAD52 gene is required for homothallic interconversion of mating types and spontaneous mitotic recombination in yeast". Proc. Natl. Acad. Sci. U.S.A. 77 (1): 503–7.  
  29. ^ Henriques, J. A. P.; Moustacchi, E. (1980). "Sensitivity to Photoaddition of Mono-And Bifunctional Furocoumarins of X-Ray Sensitive Mutants of Saccharomyces Cerevisiae". Photochemistry and Photobiology 31 (6): 557–63.  
  30. ^ Birdsell, John A.; Wills, Christopher (2003). "The Evolutionary Origin and Maintenance of Sexual Recombination: A Review of Contemporary Models". Evolutionary Biology. pp. 27–138.  
  31. ^ Bernstein, Harris; Bernstei, Carol (2013). "Evolutionary Origin and Adaptive Function of Meiosis". Meiosis.  
  32. ^ Hrandl, Elvira (2013). "Meiosis and the Paradox of Sex in Nature". Meiosis.  
  33. ^ 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 (1996). "Life with 6000 genes". Science 274 (5287): 546, 563–7.  
  34. ^ Botstein D, Chervitz SA, Cherry JM (1997). "Yeast as a model organism". Science 277 (5330): 1259–60.  
  35. ^ "YeastDeletionWeb". Retrieved 2013-05-25. 
  36. ^ a b c 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 (2010). "The genetic landscape of a cell". Science 327 (5964): 425–31.  
  37. ^ 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 (2004). "Global mapping of the yeast genetic interaction network". Science 303 (5659): 808–13.  
  38. ^ a b Warmflash, David; Ciftcioglu, Neva; Fox, George; McKay, David S.; Friedman, Louis; Betts, Bruce; Kirschvink, Joseph (November 5–7, 2007). Living interplanetary flight experiment (LIFE): An experiment on the survivalability of microorganisms during interplanetary travel (PDF). Workshop on the Exploration of Phobos and Deimos.  
  39. ^ a b "Projects: LIFE Experiment: Phobos".  
  40. ^ Anatoly Zak (1 September 2008). "Mission Possible".  
  41. ^ "Designates Saccharomyces cerevisiae as official microbe of State of Oregon". Oregon State Legislature. 

References

See also

Owing to the high cost of commercial CO2 cylinder systems, CO2 injection by yeast is one of the most popular DIY approaches followed by aquaculturists for providing CO2 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.

Uses in aquaria

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.

Baking

In May 2013, the Oregon legislature made S. cerevisiae the official state microbe in recognition of the impact craft beer brewing has had on the state economy and the state's identity as the craft beer-brewing capital of the United States.[41]

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 flocs to adhere to CO2 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 than the same beverage fermented with a lager yeast. "Fruity esters" may be formed if the yeast undergoes temperatures near 21 °C (70 °F), or if the fermentation temperature of the beverage fluctuates during the process. Lager yeast normally ferments at a temperature of approximately 5 °C (41 °F), where Saccharomyces cerevisiae becomes dormant.

Brewing

In commercial applications

Among other microorganisms, a sample of living S. cerevisiae was included in the List of microorganisms tested in outer space)

Astrobiology

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 for studying protein interactions and tetrad analysis. Other resources, include a gene deletion library including ~4700 viable haploid single gene deletion strains. A GFP fusion strain library used to study protein localisation and a TAP tag library used to purify protein from yeast cell extracts.

Other tools in yeast research

[36] as a model for understanding the regulation of eukaryotic cells. A project underway to analyze the genetic interactions of all double-deletion mutants through S. cerevisiae has further enhanced the power of [35] genome sequence and a set of deletion mutants covering 90% of the yeast genomeS. cerevisiae The availability of the

Gene function and interactions

  • Examples
    YBR134C (aka SUP45 encoding 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.
Systematic gene names for Baker's yeast
Example gene name YGL118W
Y the Y to show this is a yeast gene
G chromosome on which the gene is located
L left or right arm of the chromosome
118 sequence number of the gene/ORF on this arm, starting at the centromere
W whether the coding sequence is on the Watson or Crick strand

S. cerevisiae was the first eukaryotic homologs in the human genome.[34] 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.

Genome sequencing

since this benefit is realized during each meiosis, whether or not out-crossing occurs. [32][31][30] strains and concluded that S. cerevisiae (2006) analyzed the ancestry of natural [25] Ruderfer et al.

Evidence from studies of S. cerevisiae bear on the adaptive function of meiosis and recombination. Mutations defective in genes essential for meiotic and mitotic recombination in S. cerevisiae cause increased sensitivity to radiation or DNA damaging chemicals.[25][26] For instance, gene rad52 is required for both meiotic recombination[27] and mitotic recombination.[28] Rad52 mutants have increased sensitivity to killing by X-rays, Methyl methanesulfonate and the DNA cross-linking agent 8-methoxypsoralen-plus-UVA, and show reduced meiotic recombination.[26][27][29] These findings suggest that recombination repair during meiosis and mitosis is needed for repair of the different damages caused by these agents.

S. cerevisiae reproduces by mitosis as diploid cells when nutrients are abundant. However, when starved, these cells undergo meiosis to form haploid spores.[24]

Meiosis, recombination and DNA repair

Mother cells give rise to progeny buds by mitotic divisions, but undergo replicative aging over successive generations and ultimately die. However, when a mother cell undergoes meiosis and gametogenesis, lifespan is reset.[23] 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. However, the nature of these damages remains to be established.

[22][21]