Yeast

About: Yeast is a research topic. Over the lifetime, 31777 publications have been published within this topic receiving 868967 citations. The topic is also known as: yeasts.

Production of ethanol from cellulosic biomass hydrolysates using genetically engineered Saccharomyces yeast capable of cofermenting glucose and xylose.

Abstract: Recent studies have proven ethanol to be the idael liquid fuel for transportation, and renewable ligno cellulosic materials to be the attractive feed stocks for ethanol fuel production by fermentation. The major fermentable sugars from hydrolysis of most cellulosic biomass are D-glucose and D-xylose. The naturally occurring Saccharomyces yeasts that are used by industry to produce ethanol from starches and cane sugar cannot metabolize xylose. Our group at Purdue University succeded in developing genetically engineered Saccharomyces yeasts capable of effectively cofermenting glucose and xylose to ethanol, which was accomplished by cloning three xylose-metabolizing genes into the yeast. In this study, we demonstrated that our stable recombinant Sacharomyces yeast, 424A (LNH-ST), which contains the cloned xylose-metabolizing genes stably integrated into the yeast chromosome in high copy numbers, can efficiently ferment glucose and xylose present in hydrolysates from different cellulosic biomass to ethanol.

Guanidine hydrochloride inhibits Hsp104 activity in vivo: a possible explanation for its effect in curing yeast prions.

Abstract: The presence of millimolar concentrations of guanidine hydrochloride (Gdn-HCl) in growth media causes efficient loss of the normally stable [PSI + ] element from yeast cells. Although it has become common practice to include 5 mm Gdn-HCl in growth media to cure [PSI + ] and other prions of yeast, the biochemical mechanism by which it cures is unknown. We find that 5 mm Gdn-HCl significantly reduces Hsp104-mediated basal and acquired thermotolerance. Gdn-HCl also reduced the ability of Hsp104 to restore activity of thermally denatured luciferase in vivo. The abundance of Hsp104 was not reduced in cells grown in the presence of Gdn-HCl, ruling out negative effects on expression or stability of Hsp104. We therefore conclude that Gdn-HCl inhibits Hsp104 activity in vivo. Since replication of yeast prions is dependent on Hsp104, our results suggest that Gdn-HCl cures prions by inhibiting Hsp104 activity.

Research review paper Genetic improvement of Saccharomyces cerevisiae for xylose fermentation

Abstract: There is considerable interest in recent years in the bioconversion of forestry and agricultural residues into ethanol and valueadded chemicals. High ethanol yields from lignocellulosic residues are dependent on efficient use of all the available sugars including glucose and xylose. The well-known fermentative yeast Saccharomyces cerevisiae is the preferred microorganism for ethanol production, but unfortunately, this yeast is unable to ferment xylose. Over the last 15 years, this yeast has been the subject of various research efforts aimed at improving its ability to utilize xylose and ferment it to ethanol. This review examines the research on S. cerevisiae strains that have been genetically modified or adapted to ferment xylose to ethanol. The current state of these efforts and areas where further research is required are identified and discussed.

Function and autoregulation of yeast copperthionein.

Abstract: The CUP1 gene of yeast encodes a small, metallothionein-like protein that binds to and is inducible by copper A gene replacement experiment shows that this protein protects cells against copper poisoning but is dispensable for normal cellular growth and development throughout the yeast life cycle The transcription of CUP1 is negatively autoregulated This feedback mechanism, which is mediated through upstream control sequences, may play an important role in heavy metal homeostasis

Ethylene perception by the ERS1 protein in Arabidopsis.

Abstract: Ethylene perception in Arabidopsis is controlled by a family of five genes, including ETR1 , ERS1 (ethylene response sensor 1), ERS2 , ETR2 , and EIN4 . ERS1 , the most highly conserved gene with ETR1 , encodes a protein with 67% identity to ETR1. To clarify the role of ERS1 in ethylene sensing, we biochemically characterized the ERS1 protein by heterologous expression in yeast. ERS1, like ETR1, forms a membrane-associated, disulfide-linked dimer. In addition, yeast expressing the ERS1 protein contains ethylene-binding sites, indicating ERS1 is also an ethylene-binding protein. This finding supports previous genetic evidence that isoforms of ETR1 also function in plants as ethylene receptors. Further, we used the ethylene antagonist 1-methylcyclopropene (1-MCP) to characterize the ethylene-binding sites of ERS1 and ETR1. We found 1-MCP to be both a potent inhibitor of the ethylene-induced seedling triple response, as well as ethylene binding by yeast expressing ETR1 and ERS1. Yeast expressing ETR1 and ERS1 showed nearly identical sensitivity to 1-MCP, suggesting that the ethylene-binding sites of ETR1 and ERS1 have similar affinities for ethylene.