Fig. 5.

Disruption of cellular (p)ppGpp levels does not impact on gelatinase production but is associated with diminished invasion of human coronary artery endothelial cells (HCAECs). (a) Supernatants of OG1RF, ∆rel, or ∆rel∆relQ cultures grown overnight in medium supplemented with 40% horse serum were tested for gelatinase activity in a zone-of-clearance assay. The area of the zone of clearance for OG1RF was set to 100% in each biological replicate, and this was used to calculate the relative gelatinase activity based on the zone areas for the other strains tested. The symbols represent biological replicates measured on separate days; the bars show the means. The means were not significantly different by one-way ANOVA. (b) HCAECs were infected with OG1RF, ∆rel or ∆rel∆relQ at an m.o.i. of 100 : 1 for 2 hours. The ability of each E. faecalis strain to invade is reported as the percentage of intracellular bacteria recovered after 2 hours relative to the total c.f.u. of the initial inoculum. Each symbol represents one biological replicate. The horizontal bars show the mean. Ordinary one-way ANOVA was used to determine whether the difference between the means of ∆rel or ∆rel∆relQ and OG1RF was statistically significant (P<0.0001). ****, P=0.0001 by Dunnett’s multiple comparison post hoc test.