FIG. 6.

Permeability of outer membranes in P. gingivalis wild type and the mutants. Permeability of the outer membranes was estimated by hydrolysis of p-nitrophenylphosphate with alkaline phosphatase. The released p-nitrophenol was determined by measuring the OD₄₀₀. Values are means of duplicate determinations. Similar results were obtained in three independent assays. Open bar, intact cell suspension; dotted bar, sonicated broken cells; closed bar, supernatant obtained from intact cell suspension.