FIG. 3.

Accumulation of [¹⁴C]erythromycin in cells carrying pUCmacAB and pUC119. Cells were incubated with 25 mM glucose and 1.53 μg of [¹⁴C]erythromycin per ml as described in Materials and Methods. Aliquots were then filtered through Millipore filters. After washing of the filters, radioactivity was measured with a liquid scintillation counter. Radioactivity is indicated as disintegrations per minute. Open symbols, cells carrying pUCmacAB; closed symbols, cells carrying pUC119.