Fig. 4.

Induction of PSM expression leads to biofilm detachment in dynamic S. aureus biofilms. Dynamic biofilms of the LAC psm triple mutant (Δα/Δβ/Δhld) harboring the indicated plasmids were grown in flow cells for 24 h (t = 0) in tryptic soy broth without glucose. Then, expression of the respective psm genes, which were cloned in the pTX series of plasmids under a xylose-inducible promoter (see Table S1 for all oligonucleotides used), was induced by switching the media to tryptic soy broth without glucose/0.5% xylose. In control samples, the media were not switched. (A) Total and (B) average biovolumes were measured at 24 and 48 h after in five randomly chosen biofilm CLSM images of the same extension. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; t tests vs. corresponding control (pTX16) samples.