Genetic manipulation of longevity-related genes as a tool to regulate yeast life span and metabolite production during winemaking

Abstract

BackgroundYeast viability and vitality are essential for different industrial processes where the yeast Saccharomyces cerevisiae is used as a biotechnological tool. Therefore, the decline of yeast biological functions during aging may compromise their successful biotechnological use. Life span is controlled by a variety of molecular mechanisms, many of which are connected to stress tolerance and genomic stability, although the metabolic status of a cell has proven a main factor affecting its longevity. Acetic acid and ethanol accumulation shorten chronological life span (CLS), while glycerol extends it.ResultsDifferent age-related gene classes have been modified by deletion or overexpression to test their role in longevity and metabolism. Overexpression of histone deacetylase SIR2 extends CLS and reduces acetate production, while overexpression of SIR2 homolog HST3 shortens CLS, increases the ethanol level, and reduces acetic acid production. HST3 overexpression also enhances ethanol tolerance. Increasing tolerance to oxidative stress by superoxide dismutase SOD2 overexpression has only a moderate positive effect on CLS. CLS during grape juice fermentation has also been studied for mutants on several mRNA binding proteins that are regulators of gene expression at the posttranscriptional level; we found that NGR1 and UTH4 deletions decrease CLS, while PUF3 and PUB1 deletions increase it. Besides, the pub1Δ mutation increases glycerol production and blocks stress granule formation during grape juice fermentation. Surprisingly, factors relating to apoptosis, such as caspase Yca1 or apoptosis-inducing factor Aif1, play a positive role in yeast longevity during winemaking as their deletions shorten CLS.ConclusionsManipulation of regulators of gene expression at both transcriptional (i.e., sirtuins) and posttranscriptional (i.e., mRNA binding protein Pub1) levels allows to modulate yeast life span during its biotechnological use. Due to links between aging and metabolism, it also influences the production profile of metabolites of industrial relevance.

Reduction of Ethanol Yield and Improvement of Glycerol Formation by Adaptive Evolution of the Wine Yeast Saccharomyces cerevisiae under Hyperosmotic Conditions

“…Also, high osmolarity extends the life span by activating Hog1, leading to an increase in the biosynthesis of glycerol from glycolytic intermediates (40). Links between aging and redox metabolism during wine fermentation have also been highlighted (41).…”

Silk-elastin-like protein biomaterials for the controlled delivery of therapeutics

“…Once the DNA sequences and sizes are confirmed, the plasmid is re-transformed into a bacterial host for expression. Modified pET 19b [25, 35] and pET 25(+) [41, 43] vectors that contain an inducible T7 promoter and a purification tag are the most commonly used plasmids for SELP expression. The inducible T7 promoter allows the host bacteria to grow without expressing the cloned gene until the cells reach an appropriate cell density.…”

“…Currently, SELPs are mainly produced by the pET - E. coli BL 21 system. To achieve an optimal yield, the induction time is critical for this system [41]. In contrast to E. coli induction with isopropyl β-D-1-thiogalactopyranoside (IPTG) in mid log phase, optimal production of SELPs from E. coli BL21 was obtained by induction at the beginning of the stationary phase [41].…”

“…To achieve an optimal yield, the induction time is critical for this system [41]. In contrast to E. coli induction with isopropyl β-D-1-thiogalactopyranoside (IPTG) in mid log phase, optimal production of SELPs from E. coli BL21 was obtained by induction at the beginning of the stationary phase [41]. Yields of 25–500 mg/L by shake flask culture [25, 41, 42, 72] and 4.3g/L [43] by bioreactor cultivation were reported for purified SELPs produced in E. coli .…”

“…Recombinant DNA technology is usually used to generate SELPs [23, 35, 41–43] and other types of recombinant proteins [44–46]. This bioengineering approach has enabled systematic studies to correlate sequence with molecular architecture and functionality [47–52].…”