FIG. 3.
G. obscuriglobus tolerates high levels of UVC irradiation. Actively growing cultures of G. obscuriglobus and E. coli were irradiated with increasing doses of UV radiation using a germicidal UVC lamp. The corresponding D10 values were calculated as described previously (21) and were found to be 675.8 J/m2 and 24.33 J/m2 for G. obscuriglobus and E. coli, respectively. Statistical analysis of a covariance test revealed a significant “species by exposure time” interaction (F1,49 = 24.19; P < 0.001), indicating that the UVC radiation sensitivity of E. coli was significantly higher than that of G. obscuriglobus. Bars indicate standard errors.