(1) Department of Biology, Kenyon College, Gambier, OH, 43022
Abstract:
Background
Polyamines such as spermine and spermidine are required for growth ofEscherichia coli; they interact with nucleic acids, and they bind to ribosomes. Polyamines block porins and decrease membrane permeability,
activities that may protect cells in acid. At high concentrations, however, polyamines impair growth. They impair growth more
severely at high pH, probably due to their increased uptake as membrane-permeant weak bases. The role of pH is critical in
understanding polyamine stress.