Figure 1

Heat inactivated yeast and casein reduce the longevity of chronically hypoxic flies. Flies were exposed to a 10% sucrose diet supplemented with different concentrations of yeast (A, B) or of casein (C, D) and survivorship curves were determined under chronic hypoxia. A, C: Survivorship curves. Note that yeast and casein decreased both the median and maximum longevities. B, D. Dose response curves for the inhibitory action of yeast (B) and casein (D). Mean longevities ± sem are indicated. The half maximum action of yeast was observed at a relative concentration of 0.16% (95% confidence interval: 0.07–0.38%). The half maximum action of casein was observed at 0.01% casein (95% confidence interval: 0.003–0.03%). The total numbers of flies under experimentation were 1722 and 1526 in experiments using yeast and casein respectively. Sample sizes used to define mean longevities were 40–323.