Part:BBa_K957003

Salicylate inducible mtrB

The purpose of this part is to upregulate mtrB expression in response to salicylate. When expressed in a Shewanella strain lacking mtrB on the chromosome, this composite part will function as a component of a biosensor. Specifically, when such a complemented strain is inoculated in a microbial electrochemical system, current output will increase in response to salicylate. If coupled to the expression of a BioBrick part that degrades naphthalene to salicylate, this part will function as part of a naphthalene biosensor.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BglII site found at 576
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 408
  
• 1000
  COMPATIBLE WITH RFC[1000]

Usage and Biology

Fluorescence assays of BBa_K957003 with mRFP cloned downstream confirm that the salicylate reporter part without a BamHI cutsite responds to salicylate in a range of 10-100 μM. As with tests characterizing response to arsenites and arsenates, we measured fluorescence while varying concentration of salicylate in LB medium. Our controls for this assay were: blank LB, S. oneidensis with mtrB knocked out, S. oneidensis conjugated with an Anderson series promoter (0.1, 0.4, and 1.0) and mRFP, and a salicylate reporter strain without mRFP appended after mtrB. Relative fluorescence is reported using the same background subtraction and OD normalization described for the arsenic response assays.

Preliminary data of relative fluorescence at 1, 10, 100, and 500 μM of salicylate. Three strains of S. oneidensis are plotted: with mtrB knocked out, with an Anderson series promoter with strength 0.1 constitutively producing mRFP, and with our salicylate reporter with mRFP appended. Relative fluorescence is reported after normalization to optical density. For the testing strains (salicylate reporter w/o BamHI cutsite), fluorescence is averaged over 3 replicates, in addition to being averaged for each replicate individually over a time course of 7.5 hours.