FIG 1.

Low rate of release of [¹⁴C]GlcNAc from sacculi into spent medium by S. pneumoniae strain IU1945 (D39 Δcps) during exponential growth and early stationary phase. Bacteria growing exponentially in BHI broth were labeled with [¹⁴C]GlcNAc for about 7 generations, washed, and resuspended in BHI containing a chase of unlabeled GlcNAc (time zero) as described in Materials and Methods. At the times indicated, medium and cells were collected. Cells were converted to sacculi by boiling in SDS, and samples of medium and sacculi were scintillation counted. The experiment was performed twice with similar results, and a representative curve from one experiment is shown. Quenching of ¹⁴C counting was approximately 1.4-fold greater for spent medium than for sacculus samples. See the text for additional details.