Lambda 12 uv vis spectrometer

pABA and HEA used for the synthesis of HEA-pABA were of analytical grade and purchased from Fluka AG (Buchs SG). HEA was freshly distilled before any use. FT-IR spectra in the range 4000−400 cm⁻¹ were recorded with a JASCO − FT/IR-4200 spectrometer, using the KBr pellet technique with a resolution of 4.0 cm⁻¹ and a scanning speed of 16 mm s⁻¹. The optical properties of HEA-pABA were examined by using a UV−Vis spectrophotometer at room temperature. UV−visible spectra were recorded in the 190−800 nm range with PERKIN-ELMER LAMBDA 12 UV−Vis spectrometer. Melting point was found for finely purifying compound (by repeated recrystallization) using a Boetius instrument.

Bacterial stocks were maintained in TSB broth with 15% glycerol at −80 °C. Bacterial cultures were routinely prepared on LB or TSB agar and incubated overnight at 32 °C. Bacterial suspensions were prepared in DPBS (Lonza™ BE17-512F, Walkersville, MD, USA) and diluted to an optical density (OD600, PerkinElmer Lambda 12 UV/VIS spectrometer, PerkinElmer, Macquarie Park, Australia) corresponding to the desired colony forming units cfu/mL (colony forming unit). For high-throughput screening, bacterial strains were cultured in 96-microtiter plates with LB or TSB, and OD was measured using a Spectra Thermo microplate reader (Tecan A-5082, Tecan, Grödig, Austria).