FIG 1.
Cell flow sorting of S. aureus labeled with a fluorescent reporter under growth conditions in milk. CIM433 served as a negative gating control. CIM433 carrying plasmid pIF1, pCM11, or pIF2 was used for the FCM test. Each strain was grown for 24 h in reconstituted milk, the cell density was adjusted to 106 CFU/ml after filtering, and populations of 20,000 cells were separated by FCM after 4 (a) and 24 (b) h of growth (insets show zoom on cytographs). The percentage of fluorescent cells collected with a 527-nm bandpass filter (FL1 channel) and the fluorescence intensity of each signal are indicated.