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Calorie restriction hysteretically primes aging Saccharomyces cerevisiae toward more effective oxidative metabolism.

Tahara EB, Cunha FM, Basso TO, Della Bianca BE, Gombert AK, Kowaltowski AJ - PLoS ONE (2013)

Bottom Line: Here, we measured wild-type and respiratory incompetent (ρ(0)) S. cerevisiae biomass formation, pH, oxygen and glucose consumption, and the evolution of ethanol, glycerol, acetate, pyruvate and succinate levels during the course of 28 days of chronological aging, aiming to identify metabolic changes responsible for the effects of CR.Instead, we found that CR primed the cells for earlier, faster and more efficient metabolism of respiratory substrates, especially ethanol.Since lifespan-enhancing effects of CR are absent in respiratory incompetent ρ(0) cells, we propose that the hysteretic effect of glucose limitation on oxidative metabolism is central toward chronological lifespan extension by CR in this yeast.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil.

ABSTRACT
Calorie restriction (CR) is an intervention known to extend the lifespan of a wide variety of organisms. In S. cerevisiae, chronological lifespan is prolonged by decreasing glucose availability in the culture media, a model for CR. The mechanism has been proposed to involve an increase in the oxidative (versus fermentative) metabolism of glucose. Here, we measured wild-type and respiratory incompetent (ρ(0)) S. cerevisiae biomass formation, pH, oxygen and glucose consumption, and the evolution of ethanol, glycerol, acetate, pyruvate and succinate levels during the course of 28 days of chronological aging, aiming to identify metabolic changes responsible for the effects of CR. The concomitant and quantitative measurements allowed for calculations of conversion factors between different pairs of substrates and products, maximum specific substrate consumption and product formation rates and maximum specific growth rates. Interestingly, we found that the limitation of glucose availability in CR S. cerevisiae cultures hysteretically increases oxygen consumption rates many hours after the complete exhaustion of glucose from the media. Surprisingly, glucose-to-ethanol conversion and cellular growth supported by glucose were not quantitatively altered by CR. Instead, we found that CR primed the cells for earlier, faster and more efficient metabolism of respiratory substrates, especially ethanol. Since lifespan-enhancing effects of CR are absent in respiratory incompetent ρ(0) cells, we propose that the hysteretic effect of glucose limitation on oxidative metabolism is central toward chronological lifespan extension by CR in this yeast.

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Specific growth rates in ethanol or glycerol.Specific growth rates in ethanol (EtOH) or glycerol (Gly) were determined as described in Materials and Method, with cells removed from their original media and added to media containing each of these substrates (8.98 g/L ethanol and 0.68 g/L glycerol). *p < 0.05 vs. 2.0% (unpaired Student t-test).
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pone-0056388-g009: Specific growth rates in ethanol or glycerol.Specific growth rates in ethanol (EtOH) or glycerol (Gly) were determined as described in Materials and Method, with cells removed from their original media and added to media containing each of these substrates (8.98 g/L ethanol and 0.68 g/L glycerol). *p < 0.05 vs. 2.0% (unpaired Student t-test).

Mentions: Since it was not possible to separate the contributions of ethanol and glycerol in the growth of WT cells under control and CR conditions, we cultured cells in standard YPD until the maximal concentrations of ethanol and glycerol were achieved (see Fig. 2B and C). The cells were then transferred to media in which ethanol or glycerol were the only substrate, present at the maximal concentration they reach in culture (8.98 g/L for ethanol and 0.68 g/L for glycerol), and the specific growth rates for ethanol and glycerol were determined (Fig. 9). Growth rates under these conditions were higher than those in native growth media (compare Figs. 8B and 9), possibly due to the refreshed yeast extract and peptone. Despite this, we were able to verify that, under control and CR conditions, growth in ethanol is much higher than in glycerol. In addition, we verified that CR cells presented substantially larger growth rates when compared to control cells with both respiratory substrates. This confirms that CR culture conditions hysteretically prime cells toward better growth in respiratory media, long after glucose is exhausted.


Calorie restriction hysteretically primes aging Saccharomyces cerevisiae toward more effective oxidative metabolism.

Tahara EB, Cunha FM, Basso TO, Della Bianca BE, Gombert AK, Kowaltowski AJ - PLoS ONE (2013)

Specific growth rates in ethanol or glycerol.Specific growth rates in ethanol (EtOH) or glycerol (Gly) were determined as described in Materials and Method, with cells removed from their original media and added to media containing each of these substrates (8.98 g/L ethanol and 0.68 g/L glycerol). *p < 0.05 vs. 2.0% (unpaired Student t-test).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569431&req=5

pone-0056388-g009: Specific growth rates in ethanol or glycerol.Specific growth rates in ethanol (EtOH) or glycerol (Gly) were determined as described in Materials and Method, with cells removed from their original media and added to media containing each of these substrates (8.98 g/L ethanol and 0.68 g/L glycerol). *p < 0.05 vs. 2.0% (unpaired Student t-test).
Mentions: Since it was not possible to separate the contributions of ethanol and glycerol in the growth of WT cells under control and CR conditions, we cultured cells in standard YPD until the maximal concentrations of ethanol and glycerol were achieved (see Fig. 2B and C). The cells were then transferred to media in which ethanol or glycerol were the only substrate, present at the maximal concentration they reach in culture (8.98 g/L for ethanol and 0.68 g/L for glycerol), and the specific growth rates for ethanol and glycerol were determined (Fig. 9). Growth rates under these conditions were higher than those in native growth media (compare Figs. 8B and 9), possibly due to the refreshed yeast extract and peptone. Despite this, we were able to verify that, under control and CR conditions, growth in ethanol is much higher than in glycerol. In addition, we verified that CR cells presented substantially larger growth rates when compared to control cells with both respiratory substrates. This confirms that CR culture conditions hysteretically prime cells toward better growth in respiratory media, long after glucose is exhausted.

Bottom Line: Here, we measured wild-type and respiratory incompetent (ρ(0)) S. cerevisiae biomass formation, pH, oxygen and glucose consumption, and the evolution of ethanol, glycerol, acetate, pyruvate and succinate levels during the course of 28 days of chronological aging, aiming to identify metabolic changes responsible for the effects of CR.Instead, we found that CR primed the cells for earlier, faster and more efficient metabolism of respiratory substrates, especially ethanol.Since lifespan-enhancing effects of CR are absent in respiratory incompetent ρ(0) cells, we propose that the hysteretic effect of glucose limitation on oxidative metabolism is central toward chronological lifespan extension by CR in this yeast.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil.

ABSTRACT
Calorie restriction (CR) is an intervention known to extend the lifespan of a wide variety of organisms. In S. cerevisiae, chronological lifespan is prolonged by decreasing glucose availability in the culture media, a model for CR. The mechanism has been proposed to involve an increase in the oxidative (versus fermentative) metabolism of glucose. Here, we measured wild-type and respiratory incompetent (ρ(0)) S. cerevisiae biomass formation, pH, oxygen and glucose consumption, and the evolution of ethanol, glycerol, acetate, pyruvate and succinate levels during the course of 28 days of chronological aging, aiming to identify metabolic changes responsible for the effects of CR. The concomitant and quantitative measurements allowed for calculations of conversion factors between different pairs of substrates and products, maximum specific substrate consumption and product formation rates and maximum specific growth rates. Interestingly, we found that the limitation of glucose availability in CR S. cerevisiae cultures hysteretically increases oxygen consumption rates many hours after the complete exhaustion of glucose from the media. Surprisingly, glucose-to-ethanol conversion and cellular growth supported by glucose were not quantitatively altered by CR. Instead, we found that CR primed the cells for earlier, faster and more efficient metabolism of respiratory substrates, especially ethanol. Since lifespan-enhancing effects of CR are absent in respiratory incompetent ρ(0) cells, we propose that the hysteretic effect of glucose limitation on oxidative metabolism is central toward chronological lifespan extension by CR in this yeast.

Show MeSH
Related in: MedlinePlus