FIG. 2.

Expression of β-lactamase during germination of spores. Spores of DZ2 were obtained and allowed to germinate in CYE nutrient broth at 32°C. Aliquots of cells were harvested at intervals, examined by microscopy, extracted, and assayed for protein and β-lactamase, as described in Materials and Methods. Triangles, turbidity as measured with a 660-nm filter in a Klett-Summerson colorimeter; solid circles, β-lactamase-specific activity (mmol/g/min) from the sonication-resistant portion of the sample; open circles, β-lactamase-specific activity from the sonication-sensitive portion of the sample. The arrows point to the times at which spores were observed to lose refractility. The experiment was performed several times, and the results of a typical experiment are reported.