Aging is a complex biological process that occurs in all living organisms. Aging is initiated by the gradual accumulation of biomolecular damage in cells leading to the loss of cellular function and ultimately death. Cellular senescence is one such pathway that leads to aging. The accumulation of nucleic acid damage and genetic alterations that activate permanent cell-cycle arrest triggers the process of senescence. Cellular senescence can result from telomere erosion and ribosomal DNA instability. In this review, we summarize the molecular mechanisms of telomere length homeostasis and ribosomal DNA stability, and describe how these mechanisms are linked to cellular senescence and longevity through lessons learned from budding yeast.

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Certain plant extracts (PEs) contain bioactive compounds that have antioxidant and lifespan-extending activities on organisms. These PEs play different roles in cellular processes, such as enhancing stress resistance and modulating longevity-defined signaling pathways that contribute to longevity. Here, we report the discovery of PEs that extended chronological life span (CLS) in budding yeast from a screen of 222 PEs. We identified two PEs, the leaf extracts of Manihot esculenta and Wodyetia bifurcata that extended CLS in a dose-dependent manner. The CLS-extending PEs also conferred oxidative stress tolerance, suggesting that these PEs might extend yeast CLS through the upregulation of stress response pathways.

Ageing-related proteins play various roles such as regulating cellular ageing, countering oxidative stress, and modulating signal transduction pathways amongst many others. Hundreds of ageing-related proteins have been identified, however the functions of most of these ageing-related proteins are not known. Here, we report the identification of proteins that extended yeast chronological life span (CLS) from a screen of ageing-related proteins. Three of the CLS-extending proteins, Ptc4, Zwf1, and Sme1, contributed to an overall higher survival percentage and shorter doubling time of yeast growth compared to the control. The CLS-extending proteins contributed to thermal and oxidative stress responses differently, suggesting different mechanisms of actions. The overexpression of Ptc4 or Zwf1 also promoted rapid cell proliferation during yeast growth, suggesting their involvement in cell division or growth pathways.