FIG. 4.

Quantitative murein hydrolase assays of the cidA mutant. One-hundred-microgram aliquots of the extracellular proteins used in the experiment the results of which are shown in Fig. 3 were added to a 1-mg · ml⁻¹ suspension of M. luteus cells, and the turbidity was monitored for 6 h. Strains used in this analysis were RN6390(pRN5548) (closed circles), RN6390(pRN-cidA) (open circles), KB350(pRN5548) (closed squares), and KB350(pRN-cidA) (open squares). These data are from a single representative experiment and were reproduced several times. OD, optical density.