| Comments |
P.9: "An earlier study in the lab noted that the ability of cultures to recover replication after H2O2 challenge depended on the medium in which they were grown (Brandy Schalow, unpublished data). Whereas cultures grown in LB rapidly restored replication after a 5 minute incubation with 10mm H2O2, cultures grown in a supplemented Davis medium failed to recover replication after this same challenge. [Investigators] noted that one significant difference between these two media is that LB medium contains significant amounts manganese and iron, whereas the supplemented Davis media had relatively low amounts of either metal (Table 1). To examine whether these metals affected the ability to recover from H2O2-induced DNA damage, [they] measured DNA synthesis and accumulation over time via radioactive DNA label following 5-minute incubation with and subsequent removal from H2O2 in Davis medium that was supplemented with either iron or manganese." DGCthy=Davis medium (Davis, 1949) supplemented with 0.4% glucose, 0.2% casamino acids, and 10 μg/mL thymine, LB=Luria Bertani |