The quantitative relation between the adaptations of Bact. Lactis aerogenes to two antibacterial agents (methylene blue and proflavine)

Abstract

Proflavine and methylene blue both inhibit the growth of Bact. lactis aerogenes (Aerobader aerogenes) and training to resist one of these substances confers on the cells a degree of immunity to the other substance. The theory previously developed for training to proflavine (according to which a change of enzyme balance is provoked which restores the conc. in the cells of a certain intermediate to a standard level) is applied to results obtained on the adaptation of the test organism to methylene blue. From the lag-concentration curve of untrained cells in methylene blue and from the earlier results for proflavine, it was predicted that: (1) there is a limit to the degree of adaptation to methylene blue which will occur; (2) the conc. of proflavine to which training in methylene blue gives cross immunity is also limited; and (3) the lag-cone curves for trained strains in methylene blue rise much less steeply than the corresponding curves for proflavine. The above predictions are in qualitative agreement with the exptl. observations and there is some roughly quantitative agreement showing that the assumption of a common adaptive process is probably a major portion of the truth. The discrepancies are such as to suggest that, superposed upon the common action of the 2 agents, there are specific actions.