| Method |
p.1099 left column bottom paragraph: "To follow a large number of cells inheriting the same pole and their progeny for many generations, [investigators] employed a high-throughput, continuous, microfluidic liquid-culture device that [they] built by using a standard soft-lithographic technique that others had developed for cell biology studies [refs 14, 15, 16 and 17]. [Their] device consists of a series of growth channels, oriented at right angles to a trench through which growth medium is passed at a constant rate (Figure 1A). This constant flow results in diffusion of fresh medium into the growth channels as well as removal of cells as they emerge from the channels into the main trench (Figure 1A). [They] measured the timescale of nutrient uptake by E. coli by using the fluorescent glucose analog (2-NBDG) and found that diffusion into the channels is much faster (∼1 s) than the timescale of nutrient uptake (∼2–3 min Supplemental Experimental Procedures, available online), ensuring steady-state conditions for all cells." |