Spectrum spotlight 400 ft ir

Fourier transform infrared (FT-IR) spectroscopy were performed using 5 × 10⁶ LX-2 cells from each independent culture. After treatments, cells were collected, extensively washed with PBS and dried at 37 °C overnight. The spectra were obtained using universal attenuated total reflectance FTIR (UART-FTIR), as described in Sakane et al. (2014) [35 (link)], and the analyses focused between the region 4000 cm^− 1 and 450 cm^− 1 at 20 °C. The samples were added directly to the surface of a Zn-Se-Diamond crystal and the spectra were collected using the Spectrum Spotlight 400 FT-IR (PerkinElmer, USA). Thirty-two scans were taken with resolution of 4 cm^− 1 and digital data were processed with Spectrum 5.2 software (PerkinElmer, USA). The spectra were normalized to amide I band and the baseline-corrected spectrum was considered to determine the variations. The Savitzky-Golay algorithm with 9 points was used to reduce the noise level in a spectrum. The protocol was adapted from Stuart (2004) [36 ] .