1. Quorum sensing, Two component signaling and Bacterial Photography

2. With the two component bacterial photography system bacteria can grow light or dark and take “photos” like these… The genetic system that produces these is complicated. It is based on the two component signaling system found in bacteria. It is related to quorum sensing.

7. Pigment Light Sensor Device Actuator Device S-gal pigment Cph8 OmpR regulated LacZ

9. This two component signaling system consists of the following parts: The Sensor (labeled PCB) The Regulator (ompR)/transcription factor The Promoter (ompC) The RBS (not indicated) The Open Reading frame (lacZ) The Terminator sequence (not indicated)

11. P OmpR Light Sensor Cph8 Lac Z On No light In the dark: The Cph8 sensor is stimulated OmpR (a transcription factor) is phosphorylated Which activates the promoter Lac Z gene is expressed Beta gal enzyme is made Beta gal converts S-gal into pigment And the media becomes dark. B-gal is produced Dark pigment What happens in the bacterial photography system?

12. Light Sensor Cph8 OmpR No B-gal light Lac Z Off In the light: The Cph8 sensor is not stimulated OmpR (a transcription factor) is dephosphorylated Promoter is not active Lac Z gene is not expressed No Beta gal to convert S-gal into pigment So no pigment is produced by the bacteria and the pigment stays light No Pigment