title: Cobaltous ion effect on diauxie.
abstract: Cobaltous ions extended the duration of the diauxic lag in Escherichia coli K-12. Growth in glucose in the presence of Co(++) was necessary for the effect. Medium in which cells had been grown in the presence of Co(++) produced an extended lag when inoculated with fresh cells and lactose. Valine was found in this medium. Reversal of the extended lag was brought about by addition of l-isoleucine and related l-amino acids, but not by several metal ions. Cobaltous ion does not inhibit beta-galactosidase or the galactoside permease. These results, together with the known growth sensitivity of K-12 to valine, indicate that Co(++) disturbs the normal valine-isoleucine balance.
mesh_terms: D003035:Cobalt / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006639:Histidine / Q000494:pharmacology; D007532:Isoleucine / Q000378:metabolism / Q000494:pharmacology; D007785:Lactose / Q000378:metabolism; D013912:Threonine / Q000494:pharmacology; D014633:Valine / Q000378:metabolism
chemical_list: D007532:Isoleucine; D013912:Threonine; D003035:Cobalt; D006639:Histidine; D014633:Valine; D005947:Glucose; D007785:Lactose