Extension of chronological lifespan in Schizosaccharomyces pombe

Abstract

There are several examples in the nature wherein the mechanism of longevity control of unicellular organisms is evolutionarily conserved with that of higher multicellular organisms. The present microreview focuses on aging and longevity studies, particularly on chronological lifespan (CLS) concerning the unicellular eukaryotic fission yeast Schizosaccharomyces pombe. In S. pombe, >30 compounds, 8 types of nutrient restriction, and >80 genes that extend CLS have been reported. Several CLS control mechanisms are known to be involved in nutritional response, energy utilization, stress responses, translation, autophagy, and sexual differentiation. In unicellular organisms, the control of CLS is directly linked to the mechanism by which cells are maintained in limited-resource environments, and their genetic information is left to posterity. We believe that this important mechanism may have been preserved as a lifespan control mechanism for higher organisms.

Keywords: Schizosaccharomyces pombe; aging; chronological lifespan; fission yeast; longevity; stationary phase.

FIGURE 1

Hypothetical model summarizing the representative signaling pathways and factors involved in chronological lifespan (CLS) regulation in Schizosaccharomyces pombe. Genetic interactions with clear hierarchies are connected by black lines, and genetic interactions with unknown hierarchies are connected by blue lines. Physical interactions are connected by red lines

FIGURE 2

(a) The DNA fragment that was inserted into the plasmid was carried by the cells whose CLS was measured. (b) The results of the CLS measurements. The strain of Schizosaccharomyces pombe used was JY333, and the plasmid vector was pLB‐Dblet. To determine cell viability, the cells were grown in SD liquid medium, sampled at each growth phase, and then plated onto yeast extract agar plates using suitable dilutions (Ohtsuka et al., 2008). After incubation for several days at 30°C, the number of colonies derived from 1 ml of the culture suspension was counted. This number was divided by the cell turbidity at the sampling time