Induction and Inhibition of Adaptive Enzyme Formation in a Phytoflagellate.

Abstract

The oxidation of butyric acid by a strain of Polytoma uvella was found to be adaptive. The rate of butyric acid oxidation (measured by standard Warburg techniques) by non-proliferating cells not previously exposed to butyric acid was initially very low, but increased exponentially at a rate proportional to the concentration of exogenous N (NH4Cl). No increase occurred in the absence of an exogenous N source. In the presence of 50 mg% NH4Cl the rate of butyric acid oxidation increased to 600% of the initial rate in 6 hours without cellular proliferation or significant increase in cell mass. Low intensities of UV markedly reduced viability without inhibiting adaptation significantly. At higher intensities, however, UV progressively inhibited the oxidative adaptation, but without inhibiting the oxidative activity of constitutive enzymes. These data show this adaptive mechanism in a group of microorganisms in which it had not previously been demonstrated.