Infinite 200 pro microplate plate reader

S. Enteritidis was inoculated in TSB (Tryptic Soy Broth) medium at an optical density (OD_600nm) of 0.05 measured at a wavelength of 600 nm. Bacteria were then grown in 96-well flat-bottom polystyrene plates (Greiner) at 37 °C under static conditions with or without treatment. After 24 h, S. Enteritidis biofilms were washed with distilled water (dH₂O) and stained for 1 h at room temperature (RT) with a 0.5% aqueous crystal violet solution. Next, the stained wells were washed 3 times with dH₂O and the crystal violet-stained biofilms were then solubilized in 95% ethanol solution. Finally, relative biofilm biomasses were quantified at OD_595nm using the Infinite 200 PRO microplate plate reader (Tecan). The biofilm biomasses of S. marscescens, P. aerugunosa, H. alvei, C. freundii, S. aureus, B. subtilis, S. epidermidis and E. feacalis were measured following the same staining procedure.

Cells were co-transfected with pGL3-ARE and Renilla luciferase control plasmid pRL-SV40 using Lipofectamine 3000 (Invitrogen, Carlsbad, CA, USA). For promoter analysis, cells were collected 24 h post-transfection, washed twice in PBS, and harvested for Firefly/Renilla luciferase assays using the Dual-Luciferase reporter assay system (Promega, Madision, WI, USA) according to manufacturer’s instruction. Luminescence was then read using Infinite 200 Pro microplate plate reader (TECAN, Mannedorf, Switzerland).