Difference between revisions of "Part:BBa K1758320"
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<h2><i>in vitro characterisation</i></h2>
 
  
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<p>For the characterization of the chromium sensor with CFPS we used parts differing from that we used in vivo characterization. For the in vitro characterization we used a cell extract produced from cells which contain the plasmid (<a href="https://parts.igem.org/Part:BBa_K1758310" target="_blank">BBa_K1758310</a>). The plasmid contains the gene <i>chrB</i> under the control of a constitutive promoter, so that the cell extract is enriched with repressor molecules. In addition to that we added plasmid-DNA of the chromium specific promoter <i>chrP</i> with 5’UTR-sfGFP under the control of T7-promoter (<a href="https://parts.igem.org/Part:BBa_K1758314" target="_blank">BBa_K1758314</a> (figure 5))to the cell extract. The T7-promoter is needed to get a better fluorescence expression. </p>  
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<h2><i>in vitro</i></h2>
  
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<p>For the characterization of the copper sensor with CFPS we used parts differing from that we used in vivo characterization. For the <i>in vitro</i> characterization we used a cell extract out of cells which contain the plasmid  (<a href="https://parts.igem.org/Part:BBa_K1758320" target="_blank">BBa_K1758320</a>) (figure 4), so that the resulting extract is enriched with the activator CueR. To this extract we added plasmid-DNA of the copper specific promoter <i>copAP</i> with 5’-UTR-<i>sfGFP</i> under the control of T7-promoter (<a href="https://parts.igem.org/Part:BBa_K1758325" target="_blank">BBa_K1758325</a>) to the cell extract. The T7-promoter is needed to get a better fluorescence expression. </p>   
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<img src=" https://static.igem.org/mediawiki/2015/e/e4/Bielefeld-CeBiTec_in_vitro_ChrB-part.jpeg" width="70%"><figcaption> Figure 4: To produce the cell extract for <i>in vitro</i> characterization a construct (<a href="https://parts.igem.org/Part:BBa_K1758310" target="_blank">BBa_K1758310</a> ) with chromium repressor under the control of a constitutive promoter and strong RBS (BBa_K608002) is needed.</figcaption>
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  <img src="https://static.igem.org/mediawiki/2015/0/05/Bielefeld-CeBiTec_in_vitro_CueR-part.jpeg"width="60%"><figcaption> Figure 4: To produce the cell extract for <i>in vitro</i> characterization a construct (<a href="https://parts.igem.org/Part:BBa_K1758320" target="_blank">BBa_K1758320</a>) with copper activator under the control of a constitutive promoter and strong RBS (BBa_K608002) is needed.  
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</figcaption>
 
</figure>
 
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   <img src="https://static.igem.org/mediawiki/2015/1/1f/Bielefeld-CebiTec_in_vitro_T7-chrP-UTR-sfGFP.jpeg" width="70%"> <figcaption>Figure 5: T7-chrP-UTR-sfGFP <a href="https://parts.igem.org/Part:BBa_K1758314" target="_blank">BBa_K1758314</a> used for<i>in vitro</i> characterization.</figcaption>
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   <img src="https://static.igem.org/mediawiki/2015/1/15/Bielefeld-CebiTec_in_vitro_T7-copAP-UTR-sfGFP.jpeg"width="60%"><figcaption>Figure 5: T7-copAP-UTR-sfGFP <a href="https://parts.igem.org/Part:BBa_K1758325" target="_blank">BBa_K1758325</a> used for <i>in vitro</i> characterization. </figcaption>
 
</figure>   
 
</figure>   
  
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<p>The results presented in figure 6 illustrate the influences of different copper concentrations on the cell extract. </p>
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<!-- Einfluss von Kupfer auf den Zellextrakt, keinen negative Einfluss auf das CFPS so mit kann gezeigt werden dass dieses System relativ stabil gegenüber verschiedenen Kupferkonzentratione ist -->
 
<figure>
 
<figure>
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<img src="https://static.igem.org/mediawiki/2015/9/99/Bielefeld-CeBiTec_Influence_of_chromium_on_the_cell_extract.jpeg" width="100%">
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<img src="https://static.igem.org/mediawiki/2015/3/37/Bielefeld-CeBiTec_Influence_of_copper_on_the_cell_extract.jpeg" width="100%"></a>
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<figcaption>Figure 6: Influence of different chromium concentrations on our crude cell extract. Error bars represent the standard deviation of three biological replicates. </figcaption>
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<figcaption>Figure 6: Influence of different copper concentrations on our crude cell extract. Error bars represent the standard deviation of three biological replicates. </figcaption>
 
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</figure>
  
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<p>Chromium’s influence on the cell extract as shown in figure 6 is minimal for low concentrations. Higher chromium concentrations have a measurable impact on the viability of the cell extract, which is visible at concentrations of 120 µg/L and obvious at concentrations of 240 µg/L chromium.</p>
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<p>As shown in figure 6 copper has no negative influence on the functionality of our cell extract. Therefore, a relatively stable system for copper sensing is provided.
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First tests with specific cell extract and different copper concentrations lead to further tests and normalizations, illustrated in figure 7.</p>
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<!-- Induktion mit Kupfer im Kupfer spezifischen Extrakt -->
  
 
<figure>
 
<figure>
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<img src="https://static.igem.org/mediawiki/2015/f/fb/Bielefeld-CeBiTec_induction_chromium_in_chrB_cell_extract.jpg" width="100%">
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<img src="https://static.igem.org/mediawiki/2015/4/45/Bielefeld-CeBiTec_induction_copper_in_CueR_cell-extract.jpeg" width="100%"></a>
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<figcaption>Figure 7: Chromium specific cell extract made from <i>E. coli</i> cells which already expressed the repressor before cell extract production. Induction with different chromium concentrations. Error bars represent the standard deviation of three biological replicates. </figcaption>
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<figcaption>Figure 7: Copper specific cell extract made from <i>E. coli</i> cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter without T7 upstream of the operator site with different copper concentrations. Error bars represent the standard deviation of three biological replicates.</figcaption>
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</figure>
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<figure>
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<img src="https://static.igem.org/mediawiki/2015/4/4c/Bielefeld-CeBiTec_correction_induction_copper_in_cueR_cell-extract.jpeg" width="100%"></a>
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<figcaption>Figure 8: Copper specific cell extract made from <i>E. coli</i> cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter without T7 in front of the operator site with different copper concentrations. Error bars represent the standard deviation of three biological replicates. Data are normalized on coppers influence to the cell extract.</figcaption>
 
</figure>
 
</figure>
  
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<p>The decrease of fluorescence for higher chromium concentrations in chromium specific cell extract is shown in figure 8. An increase of fluorescence at higher chromium concentrations would have been expected resulting out of the induction of the chromium sensor.  
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<p>In addition,we measured the operator device under the control of T7 promoter as described before.</p>
  
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A factor which should be considered is the influence of high chromium concentrations to the cell extract. The test for influence of chromium on the specific cell extract, illustrated in figure 6 showed that the influence of chromium at low concentrations is not significant. But the graphic shows that high concentrations of chromium induce fatal damages to the cell extract. </p>
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<p>Fluorescence was normalized to influence of copper on the the cell extract (figure 9 and figure 10).</p>
  
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<!--obrige Abbildung durch den errechneten Korrekturfaktor angepasst, da verschiedene Faktoren auf Zellextrakt wirken und so diesen beeinflussen.-->
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<!-- Es wurde auch das Konstrukt mit einen T7 davor eingesetzt, es zeichen sich unterschhiede inder Flurescens ausbeute, so mit ist für das CFPS system ein vorgeschalteter T7 sinnvoll zur besseren sensitivität des Systems. -->
  
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<figure>
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<figure>
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<img src="https://static.igem.org/mediawiki/2015/1/1e/Bielefeld-CeBiTec_correction_induction_chromium_in_chrB-cell-extract.jpeg" width="100%">
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<img src="https://static.igem.org/mediawiki/2015/c/ce/Bielefeld-CeBiTec_induction_T7-copAP_copper_in_cueR_cell-extract.jpeg" width="100%"></a>
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<figcaption>Figure 8: Chromium specific cell extract made from <i>E. coli</i> cells which already expressed the repressor before cell extract production. Induction with different chromium concentrations. The data are normalized on chromium’s influence to the cell extract. Error bars represent the standard deviation of three biological replicates. </figcaption>
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<figcaption>Figure 9: Copper specific cell extract made from <i>E. coli</i> cells which have already expressed the activator before cell extract production. Induction with different copper concentrations. Error bars represent the standard deviation of three biological replicates. </figcaption>
 
</figure>
 
</figure>
  
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<p>Taking the influence of different chromium concentrations under consideration measured fluorescence can be normalized on chromium’s influence on the cell extract (figure 8). Normalized data suggest, that higher concentrations of chromium induce fluorescence in relevance to chromium’s influence on the cell extract. </p>
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<figure>
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<img src="https://static.igem.org/mediawiki/2015/0/01/Bielefeld-CeBiTec_correction_induction_T7-copAP_in_cueR_cell-extract.jpeg" width="100%">
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<figcaption>Figure 10: Copper specific cell extract made from <i>E. coli</i> cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter with different copper concentrations. Error bars represent the standard deviation of three biological replicates. Data are normalized on coppers influence to the cell extract. </figcaption>
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</figure>
  
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<p>Compared to the former fluorescence levels the T7 reporter device showed higher levels. Therefore, a reporter device under the control of T7 promoter is more suitable for our CFPS.</p>
  
 
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Revision as of 18:12, 20 September 2015

copper activator under control constitutive promoter and strong RBS

Activator for copper induceble promoter copAP under the control of constitutive promoter (K608002)


Usage and Biology

cueR is a merR like regulator, which stimulates the transcription of copAP, a P-type ATPase pump (Outten et al. 2000). CopAP is the central component in obtaining copper homeostasis, it exports free copper from cytoplasm to the periplasm. This is enabled by copper induced activation of the operon transcription via CueR. The CueR-Cu+ is the DNA-binding transcriptional dual regulator which activates transcription (Yamamoto, Ishihama 2005). This part was used for our in vivo and in vitro characterisation. The CueR serve in our systems as activator and regulate the discription of sfGFP.

Functional Parameters

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 7
    Illegal NheI site found at 30
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


Results

in vivo characterisation

Our sensor for copper detection consists of CueR a MerR like activator and the copper specific promoter copAP. The promoter is regulated by CueR, which binds Cu 2+ ions. We also used a sfGFP downstream the promoter for detection through a fluorescence signal.

For our copper sensor we used the native operator of cooper homeostasis from E.coli K12. We constructed a part (BBa_K1758324) using the basic genetic structur shown in our biosensors.The operator sequence, which includes the promoter (copAP), is regulated by the activator CueR. In BBa_K1758324 we combined a codon optimized version of cueR (BBa_K1758320) under the control of a constitutive promoter with sfGFP under the control of the corresponding promoter copAP (BBa_K1758321)(figure 1). Through the addition of a 5’ UTR upstream of the sfGFP we optimized the expression of sfGFP and increased fluorescence.

genetical approach
Figure 1: The concept of our in vivo copper sensor (BBa_K1758324), which consists of the activator under the control of a constitutive promoter (BBa_K1758320) and the operator and promoter sequence of the copper inducible promoter. An untranslated region in front of the sfGFP, which is used for detection, enhances its expression (BBa_K1758323).
Adjusting the detection limit
Figure 2: Time course of the induction of a copper biosensor with sfGFP for different copper concentrations in vivo. The data are measured with BioLector and normalized on OD600. Error bars represent the standard deviation of two biological replicates.
Adjusting the detection limit
Figure 3: Fluorescence levels at three different stages of cultivation. Shown are levels after 60 minutes, 150 minutes and 650 minutes.

In vivo we could show that the adding different concentrations of copper has effects on the transcription levels of sfGFP.

in vitro

For the characterization of the copper sensor with CFPS we used parts differing from that we used in vivo characterization. For the in vitro characterization we used a cell extract out of cells which contain the plasmid (BBa_K1758320) (figure 4), so that the resulting extract is enriched with the activator CueR. To this extract we added plasmid-DNA of the copper specific promoter copAP with 5’-UTR-sfGFP under the control of T7-promoter (BBa_K1758325) to the cell extract. The T7-promoter is needed to get a better fluorescence expression.

Figure 4: To produce the cell extract for in vitro characterization a construct (BBa_K1758320) with copper activator under the control of a constitutive promoter and strong RBS (BBa_K608002) is needed.
Figure 5: T7-copAP-UTR-sfGFP BBa_K1758325 used for in vitro characterization.

The results presented in figure 6 illustrate the influences of different copper concentrations on the cell extract.

Figure 6: Influence of different copper concentrations on our crude cell extract. Error bars represent the standard deviation of three biological replicates.

As shown in figure 6 copper has no negative influence on the functionality of our cell extract. Therefore, a relatively stable system for copper sensing is provided. First tests with specific cell extract and different copper concentrations lead to further tests and normalizations, illustrated in figure 7.

Figure 7: Copper specific cell extract made from E. coli cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter without T7 upstream of the operator site with different copper concentrations. Error bars represent the standard deviation of three biological replicates.
Figure 8: Copper specific cell extract made from E. coli cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter without T7 in front of the operator site with different copper concentrations. Error bars represent the standard deviation of three biological replicates. Data are normalized on coppers influence to the cell extract.

In addition,we measured the operator device under the control of T7 promoter as described before.

Fluorescence was normalized to influence of copper on the the cell extract (figure 9 and figure 10).

Figure 9: Copper specific cell extract made from E. coli cells which have already expressed the activator before cell extract production. Induction with different copper concentrations. Error bars represent the standard deviation of three biological replicates.
Figure 10: Copper specific cell extract made from E. coli cells which have already expressed the activator before cell extract production. Induction of copper inducible promoter with different copper concentrations. Error bars represent the standard deviation of three biological replicates. Data are normalized on coppers influence to the cell extract.

Compared to the former fluorescence levels the T7 reporter device showed higher levels. Therefore, a reporter device under the control of T7 promoter is more suitable for our CFPS.