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Team:Paris Bettencourt/Experiments/T7 diffusion experiments
From 2011.igem.org
Testing nanotubes with T7 RNA polymerase diffusion
Summary
Emitter construct in E.coli - Receiver construct in B.subtilis (plasmid)
Emitter & receiver constructs in B.subtilis (receiver in plasmid)
Emitter & receiver constructs in B.subtilis (receiver in genome)
Using the microfluidic chip (B.subtilis/B.subtilis)
Concentrating the cells more for microscopy (B.subtilis/B.subtilis)
Conclusions
Diffusion experiments
Results negative at first
This design was successfully implemented both in E.coli and B.subtilis. We were therefore able to test the diffusion of the T7 RNA polymerase through nanotubes. We ran several experiments:
- Diffusion from E.coli to B.subtilis with our receptor construct on a plasmid. Find more about it here
- Diffusion from B.subtilis to B.subtilis with our receptor construct on a plasmid. Find more about it here.
- Diffusion from B.subtilis to B.subtilis with our receptor construct integrated in the genome. Find more about it here.
The first three experiments gave us negative results. We saw no obvious increase of the GFP expression in receiver cells when our construct was on a plasmid and absolutely no GFP fluorescence when it was integrated in the genome.
Unexepected breakthrough
However, our microfluidic experiment gave unexepected and encouraging results. We used for this experiment two B.subtilis strains (one emitter, one receiver, both integrated in the genome). Our chromosomic T7 autoloop was brightly activated during this experiment, but only in densely packed mix of emitter and receiver cells. Find more about this experiment here.
Seeing that cell concentration seemed to be the key factor and taking advantage of our perfectly not leaky chromosomic autoloop we conducted a final set of experiments where we concentrated our cells even more. We invite you to see our final results here.
