Quorum sensing, Two component signaling and

Bacterial Photography

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.

PigmentLight

SensorDevice

Actuator Device

S-gal pigmentCph8

OmpR regulated

LacZ

This two component signaling system consists of the following parts:

The Sensor (labeled PCB)The Regulator (ompR)/transcription factorThe Promoter (ompC)The RBS (not indicated)The Open Reading frame (lacZ)The Terminator sequence (not indicated)

P

OmpRLight

SensorCph8

Lac Z On

No light

In the dark:The Cph8 sensor is stimulatedOmpR (a transcription factor) is phosphorylatedWhich activates the promoterLac Z gene is expressedBeta gal enzyme is madeBeta gal converts S-gal into pigment

And the media becomes dark.

B-gal is produced

Dark pigment

What happens in the bacterial photography system?

Light SensorCph8

OmpR No B-gal

light Lac Z Off

In the light:The Cph8 sensor is not stimulatedOmpR (a transcription factor) is dephosphorylatedPromoter is not activeLac Z gene is not expressedNo Beta gal to convert S-gal into pigmentSo no pigment is produced by the bacteria and the

pigment stays light

No Pigment