Jeol2100f microscope

Transmission electron microscopy (TEM) images were obtained on a JEOL-2100 microscope or a JEOL2100F microscope, with both instruments operated at an accelerating voltage of 200 kV. Field emission scanning electron microscopy (FESEM) images were obtained on a Hitachi S-4800 instrument. Fourier-transform infrared (FTIR) spectra were collected on Excalibur 3100 (Varian, USA) spectrophotometer using an attenuated total reflection mode over the range 4000–600 cm⁻¹ at a resolution of 4 cm⁻¹. X-ray photoelectron spectroscopic (XPS) data were obtained on a Quantum 2000 Scanning ESCA Microprobe (Physical Electronics) using monochromatic Al-Kα radiation (hν = 1486.6 eV) as the excitation source. X-ray absorption fine structure (XAFS) data were collected at the Beijing Synchrotron Radiation Facility (BSRF), with the raw fluorescence mode data processed via background-subtraction, normalization and Fourier transformations using the standard procedures within the ATHENA program. Fluorescence spectra were recorded on F-4600 (Hitachi, Japan) luminescence spectrometer.

After incubation, the cells were harvested by centrifugation for 10 min at 5,000 × g and 4°C, and rinsed three times with 0.1 M PBS at pH 7.4. The pellet was collected, and the cells were fixed with 2.5% glutaraldehyde in 0.1 M PBS at 4°C for 12 h. Then, the cells were harvested by centrifugation at 5,000 × g and 4°C for 5 min, and subjected to gradual dehydration with ethanol (30, 50, 70, 80, 90, and 100%) for 10 min, respectively. Finally, the specimens were sputter-coated with gold under vacuum and subjected to microscopic examinations using Tescon Mira3 SEM, as described previously (Lv et al., 2011 (link)). For TEM observations, the MRSA252 cells treated with BER were harvested by centrifugation at 5,000 × g and 4°C for 10 min and processed as reported previously (Shi et al., 2017 (link)). The ultrathin sections were examined under a JEOL 2100F microscope (Hitachi, Tokyo, Japan).