FIG. 7.

Growth (A) and β-galactosidase activity (B) of P. gingivalis W83/lacZ. Cells were first grown in BHI to mid-log phase and resuspended in BHI (□); TYE (◊); 0.5TYE (○); or 0.5TYE supplemented with 1% BSA (▵), 1% gelatin (⊞), or 1% Casamino Acids (◊+) and incubated for the time intervals indicated. One unit of β-galactosidase activity is equivalent to hydrolysis of 1 nmol of ONPG min⁻¹ mg of total cellular protein⁻¹. OD₆₀₀, optical density at 600 nm.