Adaptive Chain in the Conversion of Antimetabolites into Metabolites

Abstract

THE adaptation of micro-organisms¹ and insects² to antimetabolites used in the control of the latter is an important contemporary problem. It has been conjectured that a possible mechanism for such adaptation might be : formation of new metabolic pathways, creation of inhibitors or enzymes neutralizing antimetabolites, or modification of the permeability of structures sensitive towards antimetabolites^3,4. These mechanisms, in so far as they concern penicillin, would involve an induced biosynthesis of penicillinase which suppresses the antimetabolic activity of penicillin, an autotrophic biosynthesis of amino-acids the assimilation of which by the milieu is inhibited by penicillin⁵, or a modification of bacterial surface structure⁶. All or any of these mechanisms might make the antimetabolite innocuous to the living cell.