FIG 2.

Conditions and possible outcomes of TB and single WCSs. (a) Transcriptional fusion of a toxin (top) or a fluorescent protein (bottom) to a promoter that is upregulated by a QS regulator. (b) Translational fusion of a fluorescent protein with the caseinolytic-protease-specific peptide SsrA. (c) Transcriptional fusion of the lux operon to promoters that are upregulated by inhibition of T3SS or Sec/T2SS. (d) Low calcium conditions induce T3SS and inhibit growth, which is detected as luminescence by having a chromosomal copy of the lux operon. (e) Translational fusion of the T3SS-secreted effector SipA to a phospholipase reporter. (f) Translational fusion of mCherry to a TorA signal peptide and SsrA peptide to secrete mCherry by the Tat pathway. (g) Monitoring native secretion of phospholipase with a chromogenic substrate. The cell shape is depicted as shown for simplicity, but shapes vary for the bacterial taxons discussed. Chromosomal DNA is depicted as blue DNA material in the center of the bacterial cell. Plasmid DNA is depicted as a circle. Pale mustard indicates no growth, dark mustard indicates growth, green and red indicate fluorescence, pale yellow indicates luminescence, dark yellow indicates positive phospholipase activity, and white indicates no fluorescence, no luminescence, or inactive phospholipase.