Gene Expression Regulation, Fungal

We describe a new chronological lifespan (CLS) assay for the yeast Schizosaccharomyces pombe. Yeast CLS assays monitor the loss of cell viability in a culture over time, and this new assay shows a continuous decline in viability without detectable regrowth until all cells in the culture are dead. Thus, the survival curve is not altered by the generation of mutants that can grow during the experiments, and one can monitor the entire lifespan of a strain until the number of viable cells has decreased over 10(6)-fold.

The heat shock factor (HSF), a protein evolutionarily conserved from yeasts to human, regulates the expression of a set of proteins called heat shock proteins (HSPs), many of which function as molecular chaperones. In Saccharomyces cerevisiae, the HSF binds to the 5' upstream region of YGR146C and activates its transcription. YGR146C encodes a functional homolog of ecl1 (+), ecl2 (+), and ecl3 (+) of Schizosaccharomyces pombe. At present, these Ecl1 family genes, which are extenders of chronological lifespan, have been identified only in fungi groups.

The anti-aging effects of phloridzin on the yeast Saccharomyces cerevisiae were investigated by employing a replicative lifespan assay of the K6001 yeast strain. After administrating phloridzin at doses of 3, 10, and 30 µM, the lifespan of the yeast was significantly prolonged in comparison with the untreated group (p<0.01, p<0.001). To determine the mechanism of action, anti-oxidative experiments and ROS assay were performed.

Aging is characterized by the accumulation of damaged cellular macromolecules caused by declining repair and elimination pathways. An integral component employed by cells to counter toxic protein aggregates is the conserved ubiquitin/proteasome system (UPS). Previous studies have described an age-dependent decline of proteasomal function and increased longevity correlates with sustained proteasome capacity in centenarians and in naked mole rats, a long-lived rodent. Proof for a direct impact of enhanced proteasome function on longevity, however, is still lacking.

Barring genetic manipulation, the diet known as calorie restriction (CR) is currently the only way to slow down ageing in mammals. The fact that CR works on most species, even microorganisms, implies a conserved underlying mechanism. Recent findings in the yeast Saccharomyces cerevisiae indicate that CR extends lifespan because it is a mild biological stressor that activates Sir2, a key component of yeast longevity and the founding member of the sirtuin family of deacetylases.

Studies of the yeast Saccharomyces cerevisiae reveal four processes determining life span: metabolism, stress resistance, chromatin-dependent gene regulation, and genome stability. The retrograde response, which signals mitochondrial dysfunction resulting in changes in nuclear gene expression, extends yeast life span and is induced during normal aging. This response involves extensive metabolic adaptations. The retrograde response links metabolism and genome stability during yeast aging. A reduction in the availability of nutrients also extends yeast life span.

We describe a new chronological lifespan (CLS) assay for the yeast Schizosaccharomyces pombe. Yeast CLS assays monitor the loss of cell viability in a culture over time, and this new assay shows a continuous decline in viability without detectable regrowth until all cells in the culture are dead. Thus, the survival curve is not altered by the generation of mutants that can grow during the experiments, and one can monitor the entire lifespan of a strain until the number of viable cells has decreased over 10(6)-fold.

Aging is a highly complex, multifactorial process. We use the yeast Saccharomyces cerevisiae as a model to study the mechanisms of cellular aging in multicellular eukaryotes. To address the inherent complexity of aging from a systems perspective and to build an integrative model of aging process, we investigated the effect of calorie restriction (CR), a low-calorie dietary regimen, on the metabolic history of chronologically aging yeast.

Aging and longevity are complex traits influenced by genetic and environmental factors. To identify quantitative trait loci (QTLs) that control replicative lifespan, we employed an outbred Saccharomyces cerevisiae model, generated by crossing a vineyard and a laboratory strain. The predominant QTL mapped to the rDNA, with the vineyard rDNA conferring a lifespan increase of 41%. The lifespan extension was independent of Sir2 and Fob1, but depended on a polymorphism in the rDNA origin of replication from the vineyard strain that reduced origin activation relative to the laboratory origin.