Genesys 150 uv visible spectrophotometer

Fer (100 μg of Fe/ml) and Fer (100 μg of Fe/ml) + SnF₂ (100 μg/ml) prepared in DI water were used for determining hydrodynamic diameter and zeta potential. The measurements were carried out using a Nano-ZS 90 (Malvern Instrument, Malvern, UK) at indicated time points. TEM was performed using a Tecnai T12 (FEI Tecnai) electron microscope at 100 kV. In brief, solutions of Fer and Fer + SnF₂ were prepared in 0.1 M sodium acetate buffer (pH 4.5) and incubated for 1 h. After that, 5 μl of the solution of Fer or Fer + SnF₂ was dropped onto a TEM grid, and the liquid was dried before microscopy was conducted. ¹H NMR spectroscopic data of CMD with or without SnF₂ were recorded using a Bruker DMX 500, equipped with a z-gradient amplifier and 5 mm DUAL (1H/13C) z-gradient probe head, in D₂O. UV-visible absorption spectra were recorded using a Genesys 150 UV − visible spectrophotometer (Thermo Scientific, Waltham, MA).

Cell growth was analyzed with the optical density (OD₆₀₀) using a UV spectrophotometer (GENESYS 150 UV-visible spectrophotometer; Thermo Scientific, Waltham, MA, USA). All stress survival studies were performed using cells in the exponential phase after adjustment to approximately 10⁷ CFU/mL (OD₆₀₀ ≈ 0.1). For the γ-radiation tolerance assay, Deinococcus strains were irradiated to different doses (3~15 kGy) of γ-radiation using a ⁶⁰Co-gamma irradiator (Advanced Radiation Technology Institute, Jeongeup, Republic of Korea), then serially diluted in TGY media (0.5% Tryptone, 0.3% Yeast extract and 0.1% glucose), and spotted on TGY agar. To investigate the UV-C tolerance of D. radiodurans and D. proteolyticus, they were irradiated with 800 J/m² UV-C using a UV-C crosslinker (CX-2000 UV Crosslinker, UVP, Milwaukee, CA, USA) after successive dilution and dropping on a TGY plate. For oxidative stress survival, the Deinococcus strains were serially diluted in TGY broth and spotted onto TGY containing 0.4 mM of hydrogen peroxide (H₂O₂), then incubated at 30 °C for 36 h. The recombinant E. coli strains introducing pRadgro and pRad-0871 were also tested with the same process at 37 °C for 18 h as described above using LB and a 0.2 mM H₂O₂ LB plate. The surviving fraction was calculated by dividing the number of colonies in each sample by the number of cells in the control group.