Figure 6

LHM4 grown under LSMMG are more sensitive to H₂O₂ but not gamma radiation or acid in comparison with NG cultures. Bacteria were grown in HARVs under LSMMG or NG for ~40 h (short exposure time) or 4 days ~35 h (long exposure time). Cultures were removed and treated with gamma radiation using a ¹³⁷Cesium source (a), H₂O₂ (b), or growth medium at pH 3.5 (c). Bacteria were grown on solid medium and colonies counted. The percent survival was calculated by dividing the colony number/ml by that obtained for a culture treated with no dose at the same time. At least three experiments were performed for each culture and treatment type, except for the short exposure time LSMMG and NG cultures treated with H₂O₂ where two experiments were performed. The average and s.d. are shown. Survival was compared between the LSMMG and NG samples using the area under the curve and the only statistically significant difference was between the long exposure LSMMG culture and the long exposure NG culture treated with H₂O₂ (*P=0.004).