Figure 2
Kinetics of Lac+ colony formation. Cultures of TP1004, an MG1655 derivative bearing the (lacIZ33Y)2-cat duplication, were plated on lactose minimal agar. Data points represent mean daily colony counts from 19 independent cultures. Error bars represent 1 standard deviation. A least-squares linear regression curve is shown; its slope is 4.71 colonies per million viable chloramphenicol-resistant cells plated per day.