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Team:Evry/Biology/Sensors
From 2014.igem.org
Biology - Classic & RNAseq-based sensors
Phenol biosensor :
Phenol and its derivative are of major concern since their accumulation in the environment, as a result of
intensive human activity, cause toxicity for both flora and fauna [1] [2].
In the context of bioremediation and preservation of water we designed a biosensor of phenol that allows us to measure the concentration of phenol in a given marine environnement.
This phenol biosensor rely on both signal transducing component, DmpR and inducible fluorescence emitting component based on the Green Fluorescent Protein (GFP). Both elements are assembled in a single plasmid and allow bacteria carrying it to respond to the presence of phenol by emmiting fluorescence.
In the context of bioremediation and preservation of water we designed a biosensor of phenol that allows us to measure the concentration of phenol in a given marine environnement.
This phenol biosensor rely on both signal transducing component, DmpR and inducible fluorescence emitting component based on the Green Fluorescent Protein (GFP). Both elements are assembled in a single plasmid and allow bacteria carrying it to respond to the presence of phenol by emmiting fluorescence.
PCBs biosensor :
- Biosensor parts
Pseudomonas pseudoalcaligenes KF707 is one of the strain which are able to degrade polychlorinated biphenyls (PCBs). The bacteria contains a biphenyl-catabolic (bph) gene cluster (bphR1A1A2-(orf3)-bphA3A4BCX0X1X2X3D). bphR1 is a positive regulator for itself and bphX0X1X2X3D and is responsible of the degradation of PCBs. Watanabe et al showed that an other regulatory protein, bphr2, is involved in the regulation of theses genes. bphR2 can detect PCBs when it diffuses into the cell and activate degradation genes by activating the transcription of bphR1.
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In 2013, Saclays' team wanted to construct a biosensor for PCBs, a project that failed. So our first aim was to finish their construct and to optimize it. The construction is composed by a constitutive promoter (BBa_J23114), a RBS (BBa_B0034), bphR2 gene (BBa_K1413021), which has been mutated because of a pstI site in its sequence, bphR1 promoter region (BBa_K1155001), received from Saclay’s team, RFP (BBa_E1010) and a terminator (BBa_B0015)
- How function our biosensor ?
In absence of PCBs :
bphR2 (BBa_K1413021) is bound to bphR1 promoter (BBa_K1155001). Transcription of RFP isn't possible.
In presence of PCBs :
When compound diffuses into the cell, it binds to bphr2 protein. This protein undergoes a conformational change and releases from the promoter that its allows the transcription of RFP.
- Improvement
Their first problem was a pstI site in their bphR2 sequence (BBa_K1155009) so this gene has been mutated by keeping the same codon bla bla bla
