Figure 1.

Longevity factors are present in conditioned media from calorie-restricted yeast cultures.A, schematic of conditioned media CLS experiments. BY4741 was grown to stationary phase in SC media containing 2% (NR) or 0.5% (CR) glucose. Cells were pelleted by centrifugation and the conditioned media (CRCM or NRCM), then concentrated tenfold with a Büchi Rotavap apparatus, and supplemented into small 15 ml NR cultures of BY4741 or FY4. B, quantitative chronological life span (CLS) assay. Concentrated CRCM and NRCM were supplemented at 1% or 2% (vol/vol) into NR cultures at time of inoculation. To measure the fraction of viable cells over time, microcolony forming units were counted after 18 h of regrowth after spotting onto YPD plates. Error bars indicate standard deviations (n = 3). C, mean life span in days was calculated using Online Application for Survival Analysis Software (OASIS 2), which reports standard error of the mean (SEM) and 95% confidence intervals. D, quantitative CLS assay showing effect of CRCM at 1% (vol/vol) on prototrophic strain FY4. E, statistical analysis of results from panel D. All CLS assays had three biological replicates.