Streptomycin Resistance ( rpsL ) Produces an Absolute Requirement for Polyamines for Growth of an Escherichia coli Strain Unable to Synthesize Putrescine and Spermidine [Δ( speA-speB ) Δ specC ]

Abstract
The presence of certain rpsL (strA) mutations in a strain of Escherichia coli that cannot synthesize putrescine or spermidine because of deletions in ornithine decarboxylase, arginine decarboxylase, and agmatine ureohydrolase, converts a partial requirement for polyamines for growth into an absolute requirement.