ETH2006 iptg


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Chemical sensing device

The chemical sensing device's PoPS output activity should be a monotonic function of the concentration of a certain substance in the cell's environment.

Implementation alternatives

  1. Lactate lacI represses, IPTG induces (BBa_R0011 or BBa_R0010 )
  2. Tetracycline, TetR inhibitor, Tet inducer by inhibiting TetR (or aTc, it's analog) (BBa_R0040)
  3. combination thereof (BBa_I13614 / BBa_13617 / BBa_I13623 / BBa_I13624 / BBa_I13627 / BBa_I13637 / BBa_I13653)
  4. simple sugar Arabinose (BBa_R0080)

I see the main difficulty in the spatial separation as the cells are growing in the petri dishes. Since the inducers are water-soluble we would have to fix the chemicals onto the petri dish.

Current implementation

Since most parts were already existing in the registry, we decided to use the LacI system with IPTG as chemical to be sensed.

complete system based on alternative 1


simulation results

Assembly procedure

Where we got it and link to their documentation


Made LB-Agar plates with antibiotics
Transformed cells, plated them
Found plates empty after 18h on the table, put into incubator at 37°C
found lot of colonies, picked single ones and restreaked onto fresh plates

Test procedure

streaked transformed bacteria on 4 different plates:
  • plus IPTG, plus X-Gal
  • plus IPTG, no X-Gal
  • no IPTG, plus X-Gal
  • no IPTG, no X-Gal

all plates contained the appropriate antibiotic (Chloramphenicol)

Test results

  • plus IPTG, plus X-Gal: blue
  • plus IPTG, no X-Gal: white
  • no IPTG, plus X-Gal: light blue (system is leaky)
  • no IPTG, no X-Gal: white
Chem test.jpg
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