Maze Solving Bacteria

1
Maze Solving Bacteria
2
Aim
End
Checkpoint 1
Start site
3
Implementation Outline

• Goal 1 embedded with a signalling molecule
• Bacteria start off with receptors for this
• Once first bacteria reach goal, they secrete
  chemoattractant and an Autoinducer (AI)
• Once enough bacteria are attracted to the goal,
  the AI triggers a switch to chemorepellant
  release.
• Also, receptors replaced with those for compound
  at goal 2.
• Bacteria move off to goal 2

START
Goal 1
Goal 2
4
Toggle Switch
R0051 Promotor, lambda cI repressed
B0012
B0012
B0034
B0034
C0012 LacI
C0051 ?cI
B0010
B0010
Initial state LacI is produced, ?cI is repressed.
R0011 Promotor, repressed by LacI.
5
Checkpoint 1

• Checkpoint embedded with AIP
• Arrival triggers AgrA - P production
• This activates attractant production (?cI is
  low) and production of the LuxI autoinducer
• When enough bacteria arrive, LuxI triggers
  switching of the toggle (next slide)
• lacI falls and repellant is produced

Attractant
LuxI
Repellant
R0051 ?cI repressed
R0011 lacI repressed
C0061
6
Switching
AgrA
?cI
ComA
R0051 ?cI Repressed
R0011 LacI Repressed
R0062 Activated by LuxR and HSL

• Activation of ?cI expression should cause
  switching of toggle.
• LacI goes low, therefore ComA (part of signalling
  pathway for molecule at next checkpoint) can be
  expressed
• ?cI stops production of AgrA.

7
Checkpoint 2
On arrival LacI Low, ?cI high
Q00400 Tet inverter
LacR
Promotor activated by LuxO - P (present when
LuxM is low)
Attractant
LuxM
Repellant
R0011 LacI Repressed
R0051 ?cI repressed