Genetic Improvement of Industrial Yeasts

Spencer, J. F. T.; Spencer, Dorothy M.

doi:10.1146/annurev.mi.37.100183.001005

Cited by 77 publications

(23 citation statements)

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“…Protoplast fusion is a valuable technique for the improvement of industrial yeast strains (Soencer and Spencer, 1983) and has been used to introduce the dextrin degradation characteristic of $accharo~yc~s dZastat~cus into S. uvarum and S. c~r~vfsZa~ (de Figueroa ~t a~., Ig84). However, S° dfastaticus is rather unattractive as a fusion partner as no m-amylase and debranching activity are produced …”

Section: Resultsmentioning

confidence: 99%

“…Economical utilization of these and other amylolytic species probably is not feasible due to their limited ethanol tolerance De ~ot e~ a~., 1984a). This problem could be circumvented by the construction of an active amylolyt~o Saccharomyces strain with excellent fermentation characteristics (Stewart ~t e~., 1982;Spencer and Spencer, 1983;Tubb~ 1983).…”

Section: : Wilson Et E~01982) the Potential Application Ofmentioning

confidence: 99%

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Production of extracellular debranching activity by amylolytic yeasts

1984

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Section: Resultsmentioning

confidence: 99%

Section: : Wilson Et E~01982) the Potential Application Ofmentioning

confidence: 99%

Production of extracellular debranching activity by amylolytic yeasts

1984

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“…With the exception of a single strain of unknown origin, all of the [PIN+]-infected isolates originated from human-associated environments with at least 40% coming from factories or large-scale manufacturing plants. Commercialized settings, like modern breweries or bakeries, regularly utilize multiple yeast strains concurrently (e.g., blended strains) (White 2003;White and White 2013), and industrial improvement of yeast often involves hybridizing genetically diverse isolates (Anderson and Martin 1975; Spencer and Spencer 1983;Steensels et al 2012). Commercial strains had complex patterns of genetic mosaicism, indicating that they are highly outcrossed.…”

Section: Risk Factors For [Pin+] Infectionmentioning

confidence: 99%

Effect of Domestication on the Spread of the [PIN+] Prion inSaccharomyces cerevisiae

2014

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Prions (infectious proteins) cause fatal neurodegenerative diseases in mammals. In the yeast Saccharomyces cerevisiae, many toxic and lethal variants of the [PSI+] and [URE3] prions have been identified in laboratory strains, although some commonly studied variants do not seem to impair cell growth. Phylogenetic analysis has revealed four major clades of S. cerevisiae that share histories of two prion proteins and largely correspond to different ecological niches of yeast. The [PIN+] prion was most prevalent in commercialized niches, infrequent among wine/vineyard strains, and not observed in ancestral isolates. As previously reported, the [PSI+] and [URE3] prions are not found in any of these strains. Patterns of heterozygosity revealed genetic mosaicism and indicated extensive outcrossing among divergent strains in commercialized environments. In contrast, ancestral isolates were all homozygous and wine/vineyard strains were closely related to each other and largely homozygous. Cellular growth patterns were highly variable within and among clades, although ancestral isolates were the most efficient sporulators and domesticated strains showed greater tendencies for flocculation.[PIN+]-infected strains had a significantly higher likelihood of polyploidy, showed a higher propensity for flocculation compared to uninfected strains, and had higher sporulation efficiencies compared to domesticated, uninfected strains. Extensive phenotypic variability among strains from different environments suggests that S. cerevisiae is a niche generalist and that most wild strains are able to switch from asexual to sexual and from unicellular to multicellular growth in response to environmental conditions. Our data suggest that outbreeding and multicellular growth patterns adapted for domesticated environments are ecological risk factors for the [PIN+] prion in wild yeast. P RIONS cause a variety of transmissible spongiform encephalopathies (TSEs) in mammals, including scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in cervids, and CreutzfeldtJakob disease (CJD) in humans. With all TSEs, endogenous prion protein (PrP) misfolds into an altered, usually proteaseresistant, isoform, termed "PrP res " (" res" for protease resistant). Several prions have been described in fungi (Wickner 1994), with many prion variants of the [PSI+] and [URE3] prions showing toxic or even lethal effects in Saccharomyces cerevisiae (McGlinchey et al. 2011). The [PSI+] prion of S. cerevisiae is formed from the cytosolic protein Sup35p. There are three distinct regions of Sup35p: a glutamine/ asparagine-rich N-terminal domain (amino acids 1-123) that is necessary and sufficient for prion formation (TerAvanesyan et al. 1994) and that facilitates deadenylation and decay of messenger RNA (Hosoda et al. 2003); a middle M domain (amino acids 124-253) of unknown function; and an essential C-terminal domain that functions during translation termination (reviewed by Wickner et al. 2004 (Derkatch et ...

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“…'1984). In addition, preliminary reports have been made on alcohol tolerance (Korhola~1983)., hydrogen sulphide production (Takahashi, Hojito and Sakai, 1980) and diketone production (Holmberg, 1984 Johnston and Oberrnan (1979), Rose (1.979) and Spencer and Spencer (1983). For example_ distillers' yeast \yould be capable of using 6 S. L.…”

Section: Introductionmentioning

confidence: 99%