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</figure> | </figure> | ||
<p> | <p> | ||
− | The well-studied regulatory system for competence development in <i>B. subtilis</i> provided a genetic set-up based on quorum sensing that we used as a proof of principle <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/12576575">[4]</a> ( | + | The well-studied regulatory system for competence development in <i>B. subtilis</i> provided a genetic set-up based on quorum sensing that we used as a proof of principle <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/12576575">[4]</a> (Figure 1). |
<i>B. subtilis</i> constantly secretes the ComX pheromone, a 9- to 10-amino acid oligopeptide, as a signalling molecule <b>(a)</b>. By rising cell-density, the ComX-concentration in the surrounding medium increases until it reaches a threshold and activates ComP, a membrane-spanning protein kinase <b>(b)</b>. | <i>B. subtilis</i> constantly secretes the ComX pheromone, a 9- to 10-amino acid oligopeptide, as a signalling molecule <b>(a)</b>. By rising cell-density, the ComX-concentration in the surrounding medium increases until it reaches a threshold and activates ComP, a membrane-spanning protein kinase <b>(b)</b>. | ||
The kinase reacts to the accumulation of ComX by phosphorylating the response regulator ComA <b>(c)</b> which then works as a transcription factor by binding to several promoters and enhancing their activity <b>(d)</b> | The kinase reacts to the accumulation of ComX by phosphorylating the response regulator ComA <b>(c)</b> which then works as a transcription factor by binding to several promoters and enhancing their activity <b>(d)</b> | ||
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<h3>Communication between encapsulated bacteria and bacteria in the surroundings </h3> | <h3>Communication between encapsulated bacteria and bacteria in the surroundings </h3> | ||
<p> | <p> | ||
− | Based on this genetic background, we wanted to set-up a simple experiment that shows communication between two <i>B. subtilis</i> strains. The basic idea is comparable to a radio broadcast: you need a transmitter that sends out the radio waves and a receiver that receives the waves and convert them into an acoustical signal. Transferred to our project this means that we need a sender strain (SeSt) that secretes the ComX pheromone, and a receiver strain (ReSt) that reacts to the ComX-stimulation by producing an easy-detectable output ( | + | Based on this genetic background, we wanted to set-up a simple experiment that shows communication between two <i>B. subtilis</i> strains. The basic idea is comparable to a radio broadcast: you need a transmitter that sends out the radio waves and a receiver that receives the waves and convert them into an acoustical signal. Transferred to our project this means that we need a sender strain (SeSt) that secretes the ComX pheromone, and a receiver strain (ReSt) that reacts to the ComX-stimulation by producing an easy-detectable output (Figure 2).</p> |
<p> | <p> | ||
In our case, we fused target promoters of the competence machinery of <i>B. subtilis</i> to the <i>lux</i> operon and measured luminescence output. Additionally, the ReSt needed to be <i>comX</i>-deficient to prevent autoinduction. We encapsulated the ReSt within Peptidosomes and incubated it together with the SeSt in the surrounding medium. Thus, we expected ComX that is produced outside the Peptidosme to diffuse through the membrane and stimulate the ReSt. As a result, the luminescence signal should be restricted to the Peptidosome.</p> | In our case, we fused target promoters of the competence machinery of <i>B. subtilis</i> to the <i>lux</i> operon and measured luminescence output. Additionally, the ReSt needed to be <i>comX</i>-deficient to prevent autoinduction. We encapsulated the ReSt within Peptidosomes and incubated it together with the SeSt in the surrounding medium. Thus, we expected ComX that is produced outside the Peptidosme to diffuse through the membrane and stimulate the ReSt. As a result, the luminescence signal should be restricted to the Peptidosome.</p> |
Revision as of 20:06, 25 October 2017