scholarly journals Aquaporin Expression Correlates with Freeze Tolerance in Baker's Yeast, and Overexpression Improves Freeze Tolerance in Industrial Strains

2002 ◽  
Vol 68 (12) ◽  
pp. 5981-5989 ◽  
Author(s):  
An Tanghe ◽  
Patrick Van Dijck ◽  
Françoise Dumortier ◽  
Aloys Teunissen ◽  
Stefan Hohmann ◽  
...  
Keyword(s):  
Freeze Tolerance ◽  
Baker’S Yeast ◽  
Yeast Cells ◽  
Northern Analysis ◽  
Freezing Process ◽  
Crystal Formation ◽  
Baker's Yeast ◽  
Freeze Resistance ◽  
Freeze Thaw ◽  
Yeast Strains

ABSTRACT Little information is available about the precise mechanisms and determinants of freeze resistance in baker's yeast, Saccharomyces cerevisiae. Genomewide gene expression analysis and Northern analysis of different freeze-resistant and freeze-sensitive strains have now revealed a correlation between freeze resistance and the aquaporin genes AQY1 and AQY2. Deletion of these genes in a laboratory strain rendered yeast cells more sensitive to freezing, while overexpression of the respective genes, as well as heterologous expression of the human aquaporin gene hAQP1, improved freeze tolerance. These findings support a role for plasma membrane water transport activity in determination of freeze tolerance in yeast. This appears to be the first clear physiological function identified for microbial aquaporins. We suggest that a rapid, osmotically driven efflux of water during the freezing process reduces intracellular ice crystal formation and resulting cell damage. Aquaporin overexpression also improved maintenance of the viability of industrial yeast strains, both in cell suspensions and in small doughs stored frozen or submitted to freeze-thaw cycles. Furthermore, an aquaporin overexpression transformant could be selected based on its improved freeze-thaw resistance without the need for a selectable marker gene. Since aquaporin overexpression does not seem to affect the growth and fermentation characteristics of yeast, these results open new perspectives for the successful development of freeze-resistant baker's yeast strains for use in frozen dough applications.

scholarly journals Aquaporin-Mediated Improvement of Freeze Tolerance of Saccharomyces cerevisiae Is Restricted to Rapid Freezing Conditions

2004 ◽  
Vol 70 (6) ◽  
pp. 3377-3382 ◽  
Author(s):  
An Tanghe ◽  
Patrick Van Dijck ◽  
Didier Colavizza ◽  
Johan M. Thevelein
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Freeze Tolerance ◽  
Baker’S Yeast ◽  
Yeast Cells ◽  
Freezing Injury ◽  
Crystal Formation ◽  
Rapid Freezing ◽  
Baker's Yeast ◽  
Cooling Rates ◽  
The Difference

ABSTRACT Previous observations that aquaporin overexpression increases the freeze tolerance of baker's yeast (Saccharomyces cerevisiae) without negatively affecting the growth or fermentation characteristics held promise for the development of commercial baker's yeast strains used in frozen dough applications. In this study we found that overexpression of the aquaporin-encoding genes AQY1-1 and AQY2-1 improves the freeze tolerance of industrial strain AT25, but only in small doughs under laboratory conditions and not in large doughs under industrial conditions. We found that the difference in the freezing rate is apparently responsible for the difference in the results. We tested six different cooling rates and found that at high cooling rates aquaporin overexpression significantly improved the survival of yeast cells, while at low cooling rates there was no significant effect. Differences in the cultivation conditions and in the thawing rate did not influence the freeze tolerance under the conditions tested. Survival after freezing is determined mainly by two factors, cellular dehydration and intracellular ice crystal formation, which depend in an inverse manner on the cooling velocity. In accordance with this so-called two-factor hypothesis of freezing injury, we suggest that water permeability is limiting, and therefore that aquaporin function is advantageous, only under rapid freezing conditions. If this hypothesis is correct, then aquaporin overexpression is not expected to affect the leavening capacity of yeast cells in large, industrial frozen doughs, which do not freeze rapidly. Our results imply that aquaporin-overexpressing strains have less potential for use in frozen doughs than originally thought.

scholarly journals Overexpression of the Calcineurin Target CRZ1 Provides Freeze Tolerance and Enhances the Fermentative Capacity of Baker's Yeast

2007 ◽  
Vol 73 (15) ◽  
pp. 4824-4831 ◽  
Author(s):  
Joaquín Panadero ◽  
Maria José Hernández-López ◽  
José Antonio Prieto ◽  
Francisca Randez-Gil
Keyword(s):  
Target Genes ◽  
Freeze Tolerance ◽  
Baker’S Yeast ◽  
Freezing Process ◽  
Baker's Yeast ◽  
Freeze Resistance ◽  
Fermentative Capacity ◽  
Genes Encoding ◽  
Industrial Strains ◽  
Leavening Ability

ABSTRACT Recent years have shown a huge growth in the market of industrial baker's yeasts (Saccharomyces cerevisiae), with the need for strains affording better performance in prefrozen dough. Evidence suggests that during the freezing process, cells can suffer biochemical damage caused by osmotic stress. Nevertheless, the involvement of ion-responsive transcriptional factors and pathways in conferring freeze resistance has not yet been examined. Here, we have investigated the role of the salt-responsive calcineurin-Crz1p pathway in mediating tolerance to freezing by industrial baker's yeast. Overexpression of CRZ1 in the industrial HS13 strain increased both salt and freeze tolerance and improved the leavening ability of baker's yeast in high-sugar dough. Moreover, engineered cells were able to produce more gas during fermentation of prefrozen dough than the parental strain. Similar effects were observed for overexpression of TdCRZ1, the homologue to CRZ1 in Torulaspora delbrueckii, suggesting that expression of calcineurin-Crz1p target genes can alleviate the harmful effects of ionic stress during freezing. However, overexpression of STZ and FTZ, two unrelated Arabidopsis thaliana genes encoding Cys2/His2-type zinc finger proteins, also conferred freeze resistance in yeast. Furthermore, experiments with Δcnb1 and Δcrz1 mutants failed to show a freeze-sensitive phenotype, even in cells pretreated with NaCl. Overall, our results demonstrate that overexpression of CRZ1 has the potential to be a useful tool for increasing freeze tolerance and fermentative capacity in industrial strains. However, these effects do not appear to be mediated through activation of known salt-responding pathways.

scholarly journals Importance of Proteasome Gene Expression during Model Dough Fermentation after Preservation of Baker's Yeast Cells by Freezing

2018 ◽  
Vol 84 (12) ◽  
Author(s):  
Daisuke Watanabe ◽  
Hiroshi Sekiguchi ◽  
Yukiko Sugimoto ◽  
Atsushi Nagasawa ◽  
Naotaka Kida ◽  
...  
Keyword(s):  
Cell Viability ◽  
Transcriptional Activator ◽  
Proteasomal Degradation ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Fermentation Performance ◽  
Content Type ◽  
Freeze Thaw ◽  
Ubiquitinated Proteins ◽  
Yeast Strains

ABSTRACT Freeze-thaw stress causes various types of cellular damage, survival and/or proliferation defects, and metabolic alterations. However, the mechanisms underlying how cells cope with freeze-thaw stress are poorly understood. Here, model dough fermentations using two baker's yeast strains, 45 and YF, of Saccharomyces cerevisiae were compared after 2 weeks of cell preservation in a refrigerator or freezer. YF exhibited slow fermentation after exposure to freeze-thaw stress due to low cell viability. A DNA microarray analysis of the YF cells during fermentation revealed that the genes involved in oxidative phosphorylation were relatively strongly expressed, suggesting a decrease in the glycolytic capacity. Furthermore, we found that mRNA levels of the genes that encode the components of the proteasome complex were commonly low, and ubiquitinated proteins were accumulated by freeze-thaw stress in the YF strain. In the cells with a laboratory strain background, treatment with the proteasome inhibitor MG132 or the deletion of each transcriptional activator gene for the proteasome genes ( RPN4 , PDR1 , or PDR3 ) led to marked impairment of model dough fermentation using the frozen cells. Based on these data, proteasomal degradation of freeze-thaw-damaged proteins may guarantee high cell viability and fermentation performance. We also found that the freeze-thaw stress-sensitive YF strain was heterozygous at the PDR3 locus, and one of the alleles (A148T/A229V/H336R/L541P) was shown to possess a dominant negative phenotype of slow fermentation. Removal of such responsible mutations could improve the freeze-thaw stress tolerance and the fermentation performance of baker's yeast strains, as well as other industrial S. cerevisiae strains. IMPORTANCE The development of freezing technology has enabled the long-term preservation and long-distance transport of foods and other agricultural products. Fresh yeast, however, is usually not frozen because the fermentation performance and/or the viability of individual cells is severely affected after thawing. Here, we demonstrate that proteasomal degradation of ubiquitinated proteins is an essential process in the freeze-thaw stress responses of S. cerevisiae . Upstream transcriptional activator genes for the proteasome components are responsible for the fermentation performance after freezing preservation. Thus, this study provides a potential linkage between freeze-thaw stress inputs and the transcriptional regulatory network that might be functionally conserved in higher eukaryotes. Elucidation of the molecular targets of freeze-thaw stress will contribute to advances in cryobiology, such as freezing preservation of human cells, tissues, and embryos for medical purposes and breeding of industrial microorganisms and agricultural crops that adapt well to low temperatures.

scholarly journals Self-Cloning Baker's Yeasts That Accumulate Proline Enhance Freeze Tolerance in Doughs

2008 ◽  
Vol 74 (18) ◽  
pp. 5845-5849 ◽  
Author(s):  
Tomohiro Kaino ◽  
Tetsuya Tateiwa ◽  
Satomi Mizukami-Murata ◽  
Jun Shima ◽  
Hiroshi Takagi
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Freeze Tolerance ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Wild Type ◽  
Proline Oxidase ◽  
Frozen Dough ◽  
Yeast Strains ◽  
Constructed Self

ABSTRACT We constructed self-cloning diploid baker's yeast strains by disrupting PUT1, encoding proline oxidase, and replacing the wild-type PRO1, encoding γ-glutamyl kinase, with a pro1(D154N) or pro1(I150T) allele. The resultant strains accumulated intracellular proline and retained higher-level fermentation abilities in the frozen doughs than the wild-type strain. These results suggest that proline-accumulating baker's yeast is suitable for frozen-dough baking.

scholarly journals Stress Tolerance in Doughs of Saccharomyces cerevisiae Trehalase Mutants Derived from Commercial Baker’s Yeast

1999 ◽  
Vol 65 (7) ◽  
pp. 2841-2846 ◽  
Author(s):  
Jun Shima ◽  
Akihiro Hino ◽  
Chie Yamada-Iyo ◽  
Yasuo Suzuki ◽  
Ryouichi Nakajima ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Tolerance ◽  
Freeze Tolerance ◽  
Fermentation Medium ◽  
Baker’S Yeast ◽  
Yeast Cells ◽  
Baker's Yeast ◽  
Critical Determinant ◽  
Acid Trehalase ◽  
Dry Conditions

ABSTRACT Accumulation of trehalose is widely believed to be a critical determinant in improving the stress tolerance of the yeastSaccharomyces cerevisiae, which is commonly used in commercial bread dough. To retain the accumulation of trehalose in yeast cells, we constructed, for the first time, diploid homozygous neutral trehalase mutants (Δnth1), acid trehalase mutants (Δath1), and double mutants (Δnth1 ath1) by using commercial baker’s yeast strains as the parent strains and the gene disruption method. During fermentation in a liquid fermentation medium, degradation of intracellular trehalose was inhibited with all of the trehalase mutants. The gassing power of frozen doughs made with these mutants was greater than the gassing power of doughs made with the parent strains. The Δnth1 and Δath1strains also exhibited higher levels of tolerance of dry conditions than the parent strains exhibited; however, the Δnth1 ath1 strain exhibited lower tolerance of dry conditions than the parent strain exhibited. The improved freeze tolerance exhibited by all of the trehalase mutants may make these strains useful in frozen dough.

Development of a Novel Microbial Sensor with Baker's Yeast Cells for Monitoring Temperature Control during Cold Food Chain

2005 ◽  
Vol 68 (1) ◽  
pp. 182-186 ◽  
Author(s):  
H. KOGURE ◽  
S. KAWASAKI ◽  
K. NAKAJIMA ◽  
N. SAKAI ◽  
K. FUTASE ◽  
...  
Keyword(s):  
Temperature Control ◽  
Frozen Storage ◽  
Freeze Tolerance ◽  
Gas Production ◽  
Baker’S Yeast ◽  
Yeast Cells ◽  
Baker's Yeast ◽  
Microbial Sensor ◽  
Cold Food ◽  
Fine Adjustment

A novel microbial sensor containing a commercial baker's yeast with a high freeze tolerance was developed for visibly detecting inappropriate temperature control of food. When the yeast cells fermented glucose, the resulting gas production triggered the microbial sensor. The biosensor was a simple, small bag containing a solution of yeast cells, yeast extract, glucose, and glycerol sealed up with multilayer transparent film with barriers against oxygen and humidity. Fine adjustment of gas productivity in the biosensor at low temperatures was achieved by changing either or both concentrations of glucose and yeast cells. Moreover, the amount of time that food was exposed to inappropriate temperatures could be deduced by the amount of gas produced in the biosensor. The biosensor was stable without any functional loss for up to 1 week in frozen storage. The biosensor could offer a useful tool for securing food safety by maintaining low-temperature control in every stage from farm to fork, including during transportation, in the store, and at home.

Purification and Properties of a Thermo-labile Antigen from Baker’s Yeast Cells

1981 ◽  
Vol 45 (12) ◽  
pp. 2713-2721
Author(s):  
Youichi Tamai ◽  
Hiroshi Shinmoto ◽  
Masayoshi Takakuwa
Keyword(s):  
Baker’S Yeast ◽  
Yeast Cells ◽  
Baker's Yeast ◽  
Purification And Properties
Sign in / Sign up

Export Citation Format

Share Document