Accumulation of label from C14-streptomycin by Escherichia coli.

Hurwitz, Charles (Veterans Administration Hospital, Albany, N.Y.) and Carmen L. Rosano. Accumulation of label from C(14)-streptomycin by Escherichia coli. J. Bacteriol. 83:1193-1201. 1962.-Accumulation of label from C(14)-streptomycin by sensitive Escherichia coli occurs in the presence of chloramphenicol, provided the cells receive a prior exposure to streptomycin. The rate of accumulation increases with the concentration and length of exposure to streptomycin during the initiation phase. Accumulation of label from streptomycin in the presence of chloramphenicol is also a function of the streptomycin concentration during the killing phase. Evidence is presented for the presence of a barrier to the entry and exit of streptomycin. It is further shown that total accumulation of streptomycin can be divided into three portions: surface-adsorbed streptomycin, streptomycin present at the time of onset of loss of viability, and streptomycin accumulated by killed cells. Only about 10% of the total accumulated streptomycin is present at the onset of loss of viability and can therefore be presumed to play a role in the lethal action of the antibiotic.