Figure 4.

Enhancement of Bacterial Resistance to UV-B by Glycerol Fermentation. The photographic images of (a) 10⁷ CFU S. epidermidis (B) in the absence (a) or presence (b) of 2% glycerol (G) was irradiated by different UV-B dosages of 0, 0.5, 1, 5, and 10 mJ/cm². 5-MF-pretreated S. epidermidis (10⁷ CFU) in the presence of 2% glycerol (5-MF/B/G/UV-B) was irradiated by 5 mJ/cm². CFUs of bacteria with/without UV-B irradiation were counted after dropping the serially diluted (1:10⁰–1:10⁵) bacteria onto TSB agar plates and illustrated by the mean ± SD, in triplicate. ns = non-significant. * p < 0.05; ** p < 0.01 *** p < 0.001 (two-tailed t-tests).