FIG 2.

EHEC 86-24 responds to DHMA in a dose-dependent manner. The dose-response of EHEC was measured using a microflow-based MMC assay. EHEC 86-24 cells expressing GFP were suspended in CB and introduced into the center of a microflow channel containing buffer or a fixed concentration of DHMA. One hundred images were collected over a period of 6 min and were overlaid to prepare representative snapshots. (A) Representative snapshot of cells in buffer. (B) Representative snapshot of cells in 50 μM DHMA. (C) The dose-dependent chemotaxis response of EHEC 86-24 to DHMA. The migration of cells from the center of the channel was determined by image analysis and used to calculate the MMC. The data represent the means and standard errors of the means from three independent experiments. *, **, and #, statistical significance for each response compared to that for the buffer control using Student's t test at significance levels of P < 0.01, 0.005, and 0.0005, respectively.