The Intracellular Accumulation of 14C-streptomycin by Escherichia Coli strain B in Relation to its Growth-Inhibitory Effect

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Abstract
SUMMARY: The intracellular concentrations of 14C-streptomycin accumulated by Escherichia coli strain B during growth in the presence of different extracellular concentrations of the compound have been measured. They increased logarithmically with time at rates proportional to the logarithm of the extracellular concentration; the growth rates declined linearly with time at rates which were also proportional to the extracellular concentrations. Thus the same decrease in growth rate resulted from different intracellular concentrations of streptomycin, according to the conditions of uptake. After removal of extracellular streptomycin, the growth rates remained constant for several hours, during which time 40-60% of the total cell-bound radioactivity was lost. Of the radioactivity lost from the organisms during growth after removal of extracellular streptomycin, 50-80% was recovered from culture filtrates but did not behave as streptomycin with respect to adsorption to charcoal.