Regulation of polyamine and streptomycin transport during stringent and relaxed control in Escherichia coli.

Inhibition of polyamine uptake was observed during amino acid depletion in a stringent strain of Escherichia coli CP78 but not in a relaxed strain (CP79). Chloramphenicol was shown partially to relieve the inhibition of uptake. Stringent cells which were induced for a transport system common to both polyamines and streptomycin were found to restrict the uptake of spermidine as well as streptomycin.