Roles of trace metals in transcriptional control of microbial secondary metabolism.

Secondary metabolism in bacteria and fungi requires a much narrower range of environmental concentrations of key trace metals than that permitted for primary metabolism. The cells acquire appropriate quantities of the key metals at the initiation of the shift from primary to secondary metabolism. Evidence suggests that these essential micronutrients participate in regulating the expression of genes responsible for synthesis of secondary metabolites and/or morphological alterations associated with cellular differentiation.