Role of AaPAL in cell physiology and membrane integrity. Panel A: Colony density and morphology (a, b) and the cell morphology of A. actinomycetemcomitans strains D7SS and D7SS-p grown on TSA as examined by phase contrast microscopy (c, d) and scanning electron microscopy (e, f). Panel B: Growth rates of D7SS and D7SS-p in TSB measured by turbidimetry (OD600). The results are shown from two separate experiments. Panel C: Antibiotic susceptibility comparison between the strains D7SS and D7SS-p. The results are means (SD) from three independent experiments (*P < 0.05). P, penicillin; E, erythromycin; C, cefotaxime.