Low auxotrophy-complementing amino acid concentrations reduce yeast chronological life span

Area of Science:

• Gerontology
• Cell Biology
• Nutritional Science

Background:

• Caloric restriction in yeast (Saccharomyces cerevisiae) extends lifespan and delays aging.
• The role of essential amino acids in yeast aging and stress resistance is not fully understood.

Purpose of the Study:

• To investigate the impact of essential amino acid supplementation on yeast chronological lifespan and stress resistance.
• To determine if increased amino acid concentrations can mitigate aging phenotypes caused by essential amino acid starvation.

Main Methods:

• Culturing Saccharomyces cerevisiae strains under varying amino acid concentrations.
• Assessing chronological lifespan, biomass yield, oxidative stress indicators, cell cycle progression, and cell death.
• Evaluating the effects of amino acid supplementation in TOR1 and RAS2 deletion mutant strains.

Main Results:

• Standard amino acid concentrations led to reduced biomass, premature aging, shorter lifespan, oxidative stress, cell cycle arrest, and programmed cell death.
• Supplementing with five times higher amino acid concentrations increased biomass yield and abrogated aging phenotypes.
• Amino acid supplementation did not extend lifespan in TOR1 deleted strains but positively affected lifespan in RAS2 deleted cells.

Conclusions:

• Essential amino acid availability significantly impacts yeast cell physiology, lifespan, and stress resistance.
• The life-extending effects of caloric restriction may be specific to non-essential nutrients.
• Imbalances in essential amino acids can cause severe detrimental effects, cautioning against standard concentrations in auxotrophic yeast studies.