Fig 3. PGE₂ facilitates the attachment of S. aureus to human fibronectin.

The fibronectin, was coated at 1μg per well in 96-well plates and 5μg per well in 24-well plates set with cover slips at 37°C for 1h, with uncoated wells and slips as the blank control. Then, plates and cover slips were blocked overnight at 4°C. Exponential S. aureus pretreated with PGE₂ (500 pg/mL) or PBS was incubated in the conditional 96- or 24-well plates at 37°C. The adherent biomass of S. aureus was estimated by CV staining at 1 hour after incubation or by CLSM at 1 hour and 3 hour after incubation. A. The biomass of attached S. aureus quantified with crystal violent staining and expressed as the optical density at 570 nm. The adherent biomass of S. aureus cocultured with PGE₂ was approximately 6.3-fold increased than that by S. aureus without PGE₂ treated. Data are expressed as means ± standard errors from three replicates per experiment. Asterisks indicate significant (P< 0.05) differences compared to HOK without PGE₂. B. The confocal laser scanning microscopy for attached S. aureus biomass after incubation for 1 hour. C. The confocal laser scanning microscopy for attached S. aureus biomass after incubation for 3 hours. At both 1 h and 3 h time points, slides coated with fibronectin displayed higher fluorescent dense intensity than the uncoated ones and, no matter fibronectin treatment or not, the slides were attached with PGE₂-treated S. aureus more than the untreated ones. Samples were observed by an oil lens and images were at the same magnification of 630× and analyzed by the LAS AF Lite software without zoom in. The experiments were performed in triple and three images were randomly captured from each sample.