Figure 2

Natural amino acids reduce the longevity of chronically hypoxic flies. A. Flies were fed on a 10% sucrose diet supplemented with each individual amino acid (10 mM) and survivorship curves were determined under chronic hypoxic conditions. Mean longevities ± sem are shown. Amino acids are ranked according to their life-shortening effect. The top and bottom black bars show the two control situations which correspond to a pure sucrose diet and starvation conditions. All differences with the pure sucrose condition were statistically significant (p < 0.0001, log rank test). Colour codes were used to label basic amino acids (blue), acidic amino acids (magenta) and amidinated amino acids (red). The total number of flies used was 2341. Sample sizes were 70–237. B-D. Dose dependent actions of L-proline, L-arginine and L-glutamine. Hypoxic flies were fed on a 10% sucrose medium supplemented with the indicated concentrations of amino acids and survivorship curves were determined. The dotted lines show the survivorship curves obtained for hypoxic flies fed on a pure sucrose diet (blue) or under starvation conditions (red). Sample sizes are indicated in parentheses. Note that low mM concentrations of amino acids produced near half maximum reductions in the median and maximum longevities of the flies.