Figure 1. Characterization of the ΔPorZ secretory phenotype.

(a) Pigmentation on blood agar of P. gingivalis wild type (W83), ΔPorZ, and in trans porZ-complemented ΔPorZ (PorZ⁺) strains. Enzymatic activity of (b) Rgps, (c) Kgp, and (d) dipeptidyl peptidase IV (DPPIV) and prolyl tripeptidyl peptidase (PtpA) in whole cultures, fractionated washed cells or growth medium as determined with specific synthetic substrates. Cultures were adjusted to OD₆₀₀ = 1.0 prior to testing and processing, and results shown correspond to triplicate experiments. Significant differences between the wild type and mutants are indicated by *P < 0.05 and ****P < 0.0001.