Figure 2

ROS accumulation in BD3749 exposed to oxygen.
(A) Relative ROS accumulation in BD3749 cells grown aerobically in medium containing glucose or sucrose as a sole carbon source, as described in Materials and Methods. The amount of ROS was calculated by the intensity of the DCF fluorescence per mg total protein of the cell lysate. The relative ROS level of the BD3749 culture in glucose (Circle) and sucrose (Triangle) are shown. Experiments were performed in triplicate, and the average intensity and standard deviations are shown. (B) Relative ROS level in aggregated and planktonic cells of BD3749. A logarithmic culture was set on the table for 2 min for natural sedimentation of the aggregates. Aggregated and planktonic cells were collected independently, and the ROS level was monitored as described in Materials and Methods. (C) The percent aggregation was monitored for 24 hours of aerobic growth. Aggregated cells were collected as described above, and planktonic cells were harvested by centrifugation at 8000 rpm for 5 minutes. The collected cells were then resuspended in PBS to a volume equivalent to that of the culture after 3 washes with 0.5 M NaOH before sonication. The protein content of sonicated cell lysate was then quantified using the Bradford method. The percent of aggregation was calculated by protein content of aggregated cells divided by that of aggregated cells plus planktonic cells. All the experiments were performed in triplicate, and the standard deviations are shown in the graphs.