Effects of Auxotrophic Mutations on the Adaptation to Inositol Degradation in Aerobacter Aerogenes. ∗

Summary

The ability of amino acid and of purine and pyrimidine auxotrophs of Aerobacter aerogenes to form adaptive enzymes for the degradation of myo-inositol has been investigated. It was found that adaptive enzyme synthesis by the amino acid auxotrophs could be stimulated in the absence of growth by addition of the required nutrilite, but not by addition of (NH₄)₂SO₄. In contrast, adaptation in the guanine and pyramidine auxotrophs was enhanced by addition of (NH₄)₂SO₄ alone. In all cases, dividing cells attained higher levels of adaptive enzyme than resting cells. The bearing of these results on the mechanism of adaptation is discussed. The poor utilization of histidine by strain 50 for growth on inositol does not seem to be due to the effect of histidine on adaptation,; but rather seems to suggest a metabolic relationship between inositol and histidine.