EFFECTS OF AMMONIA, METHYLAMINE, AND HYDROXYLAMINE ON THE ADAPTIVE ASSIMILATION OF NITRITE AND NITRATE BY A MYCOBACTERIUM

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Abstract
Nitrite is adaptively assimilated by Mycobacterium tuberculosis strain BCG after a latent period which corresponds to the induction of a reductase. Preceding assimilation, a small amount of nitrite is taken up probably by diffusion. The latent period for nitrate assimilation is much longer. Nitrite induces nitrate assimilation and vice versa. Ammonium ion, methylamine, and dimethylamine are assimilated without a latent period. Nitrite assimilation is suppressed as long as these compounds are being assimilated whether they are added at the beginning or after nitrite induction has occurred. Ammonium ion, nitrite and nitrate, but not methylamine and dimethylamine can be used for protein synthesis as evidenced by a shortened latent period and an increased rate of oxidation of benzoate, which is adaptively oxidized. Hydroxylamine is also assimilated without a latent period. Very small amounts inhibit induction, but have no effect on nitrite assimilation after the enzyme is formed. Its effect is primarily on enzyme formation rather than on nitrite transport. The active transfer of positive ions (ammonium, methylamine, dimethylamine) appears to interfere with the transfer of negative ions (nitrite, nitrate) perhaps by pre-emptying a common pathway or receptor.