Difference between revisions of "Part:BBa K1189007"
Line 112: Line 112:
 
</figcaption>
 
</figcaption>
 
</figure>
 
</figure>
 +
</html>
 +
 +
 +
 +
__NOTOC__
 +
<partinfo>BBa_K1189007 short</partinfo>
 +
 +
This part was built to allow for the extraction of Beta-lactamase with the his-tags added onto the BioBrick. The part was built with the lacI IPTG inducible promoter J04500, with RBS.
 +
<html>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/parts/e/e4/YYC2013_PlacI_Blac_His_White_Background.jpg">
 +
</figure>
 +
</html>
 +
 +
 +
===Applications of BBa_K1189007===
 +
<html>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/2013/thumb/0/03/YYC2013_Blac_Amp_Survival_Assay_with_colonies.jpg/800px-YYC2013_Blac_Amp_Survival_Assay_with_colonies.jpg">
 +
<figcaption>
 +
<p><b>Figure 1. </b>Absorbance values at 600nm for each tube at four different time points: 0, 30, 60 and 120min. The cultures that expressed beta-lactamase (<a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189007">
 +
<span class="Green"><b>
 +
BBa_K1189007
 +
</b></span>
 +
</a>) showed higher absorbance levels, showing that the cells were able to grow in the presence of ampicillin.</a>
 +
</figcaption>
 +
</figure>
 +
<p>In addition to that, we have purified our beta-lactamase (<a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189007">
 +
<span class="Green"><b>
 +
BBa_K1189007
 +
</b></span>
 +
</a>) and our mobile TALE A linked to beta-lactamase construct (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >) (Figure 2) and we have demonstrated that beta-lactamase retained its enzymatic activity for both proteins. We repeated a variation of ampicillin survival assay where we pretreated LB containing ampicillin and chloramphenicol with our purified TALE A linked to beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >). We then cultured bacteria in the treated LB that only carry resistance to chloramphenicol. Therefore, the bacteria are only able to survive if the our isolated protein retained its enzymatic abilities. We can show that the bacteria susceptible to ampicillin was able to grow in the presence of our purified construct protein (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >), which means that we are expressing and purifying functional protein which is degrading the ampicillin (Figures 1 and 3). Figure 3 shows the OD at 24 hour time point from culturing where Figure 1 shows OD change over time. Both graphs show an increase in OD for cultures pre-treated with our protein demonstrating our protein is functional.</p>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/parts/5/55/YYC2013_TALE_Blac_Western_Blot_White_Background.jpg">
 +
<figcaption>
 +
<p><b>Figure 2. </b>On the left crude lysate of beta-lactamase + His (<a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189007">
 +
<span class="Green"><b>
 +
BBa_K1189007
 +
</b></span>
 +
</a>) from different lysis protocols:  a <a href="http://2013.igem.org/Team:Calgary/Notebook/Protocols/GlassBeadsCellLysisProtocolforProteinSamples">
 +
<span class="Green"><b>
 +
mechanical
 +
</b></span>
 +
</a> and with <a href="http://2013.igem.org/Team:Calgary/Notebook/Protocols/OsmoticShock">
 +
<span class="Green"><b>
 +
sucrose
 +
</b></span>
 +
</a>, respectively. On the right, western blot of <a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K782004">
 +
<span class="Green"><b>
 +
TALE A
 +
</b></span>
 +
</a>-linker-beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a>) showing that we were able to express and purify our construct.
 +
</figcaption>
 +
</figure>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/2013/thumb/3/38/YYC2013_Blac_Amp_Survival_Assay_with_protein_24h.jpg/800px-YYC2013_Blac_Amp_Survival_Assay_with_protein_24h.jpg">
 +
<figcaption>
 +
<p><b>Figure 3. </b>Absorbance values at 600nm after 24h. Amounts from 0.1µg to 20µg of TALE A-link-Beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.</a>
 +
</figcaption>
 +
</figure>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/2013/thumb/d/de/YYC2013_Blac_Amp_Survival_Assay_with_protein_3_time_points.jpg/800px-YYC2013_Blac_Amp_Survival_Assay_with_protein_3_time_points.jpg">
 +
<figcaption>
 +
<p><b>Figure 4. </b>Absorbance values at 600nm in different time points. Amounts from 1.0µg to 10µg of TALE A-link-Beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.</a>
 +
</figcaption>
 +
</figure>
 +
        <p>After verifying that <a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K782004">
 +
<span class="Green"><b>
 +
TALE A
 +
</b></span>
 +
</a>-linker-beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >) retained enzymatic activity and was able to degrade ampicillin, we performed a <a href="http://2013.igem.org/Team:Calgary/Notebook/Protocols/BenzylpenicillianAssay">
 +
<span class="Green"><b>
 +
colourimetric assay
 +
</b></span>
 +
</a> using benzylpenicillin as our substrate. We were able to see a colour change from red to yellow. This is because there is phenol red, a pH indicator, added to the substrate solution. Beta-lactamase hydrolyzes benzylpenicillin to penicillinoic acid, which changes the pH of the solution from alkaline to acidic. This pH change causes the phenol red to change from red to yellow. Our negative controls, to which benzylpenicillin was not added, remained red. We can also see the colour change correlate to the amount of purified TALE A linked to beta-lactamase present in each sample (Figure 5).</p>
 +
<figure>
 +
<img src="https://static.igem.org/mediawiki/parts/5/5b/YYC2013_Blac_PenG_Assay.jpg">
 +
<figcaption>
 +
<p><b>Figure 5. </b>Benzylpenicillin assay. On the top, the wells only had <a href="https://parts.igem.org/wiki/index.php?title=Part:BBa_K782004">
 +
<span class="Green"><b>
 +
TALE A
 +
</b></span>
 +
</a>-linker-beta-lactamase (<a href=" https://parts.igem.org/wiki/index.php?title=Part:BBa_K1189031">
 +
<span class="Green"><b>
 +
BBa_K1189031
 +
</b></span>
 +
</a >). Benzylpenicillin was added and after a 10-minute incubation at room temperature, we were able to observe a colour output from red to yellow (bottom row) while the control wells remained red.</a>
 +
</figcaption>
 +
</figure>
 +
We examined expression of β-lactamase gene under control of the inducible <em>lacI</em> promoter (BBa_K1189007). We
 +
performed
 +
antibiotic assay and IPTG assay to look how gene expression is affected by different conditions. In our experiments
 +
we used two <em>E.coli</em> strains: DH5α and BL21.
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/3/3b/T--Moscow--BBa_K1189007-image1.png" alt="Figure 6">
 +
  <figcaption>
 +
    <b>Figure 6.</b> Growth curve of DH5α strain before and after transformation with a plasmid with β-lactamase gene
 +
    under
 +
    control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/8/8a/T--Moscow--BBa_K1189007-image2.png" alt="Figure 7">
 +
  <figcaption>
 +
    <b>Figure 7.</b> Growth curve of BL21 strain before and after transformation with a plasmid with β-lactamase gene
 +
    under
 +
    control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
Fig.6 and Fig.7 show difference in growth of <em>E.coli</em> culture with and without the plasmid carrying β-lactamase
 +
expression cassette. We expected that <em>E.coli</em> culture with the plasmid will have a lower growth rate compared to
 +
the
 +
growth rate of <em>E.coli</em> culture without the plasmid (due to stress caused to cells by hosting a plasmid). In
 +
opposite
 +
to case with DH5a strain, results for BL21 correlate with our theoretical assumption
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/c/c1/T--Moscow--BBa_K1189007_image3.png" alt="Figure 8">
 +
  <figcaption>
 +
    <b>Figure 8.</b> Growth curve of DH5α strain in LB containing Amp [100 mkg/ml] and Cm
 +
    [34 mkg/ml] before and after transformation with a plasmid with β-lactamase gene under control of the inducible
 +
    <em>lacI</em>
 +
    promoter (<a href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>.
 +
  </figcaption>
 +
</figure>
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/d/da/T--Moscow--BBa_K1189007-image4.png" alt="Figure 9">
 +
  <figcaption>
 +
    <b>Figure 9.</b> Growth curve of BL21 strain in LB containing Amp [100 mkg/ml] and Cm
 +
    [34 mkg/ml] before and after transformation with a plasmid with β-lactamase gene under control of the inducible
 +
    <em>lacI</em>
 +
    promoter (<a href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
Fig.8 and Fig.9 show that presence of Amp and Cm inhibits the growth of <em>E.coli</em> strains without plasmid carrying
 +
β-lactamase expression cassette . Strains with plasmid can grow in the presence of both Amp and Cm. Resistance to
 +
Amp is provided by β-lactamase and resistance to Cm is provided by Cm resistance gene in pSB1C3.
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/b/bb/T--Moscow--BBa_K1189007_image5.png" alt="Figure 10">
 +
  <figcaption>
 +
    <b>Figure 10.</b> Growth curve of DH5α strain in LB containing different antibiotics (Amp
 +
    [100 mkg/ml], Cm [34 mkg/ml], Kan [50 mkg/ml]) after transformation with a plasmid with β-lactamase gene under
 +
    control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/6/69/T--Moscow--BBa_K1189007_image6.png" alt="Figure 11">
 +
  <figcaption>
 +
    <b>Figure 111.</b> Growth curve of BL21 strain in LB containing different antibiotics (Amp
 +
    [100 mkg/ml], Cm [34 mkg/ml], Kan [50 mkg/ml]) after transformation with a plasmid with β-lactamase gene under
 +
    control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
Fig.10 and Fig.11 show different growth rate for <em>E.coli</em> strains in LB containing different antibiotics. For
 +
both BL21
 +
and DH5α strains maximum growth rate was reached in LB without any antibiotics. Minimum growth rate was demonstrated
 +
in the presence of Kan (because of absence of any resistance to Kan antibiotic). Growth rate of both strains was
 +
slightly lower in the presence of both Cm and Amp than in the presence of only Cm or Amp. Gene expression is
 +
observed without induction with IPTG due to promoter leakage.
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/3/36/T--Moscow--BBa_K1189007_image7.png" alt="Figure 12">
 +
  <figcaption>
 +
    <b>Figure 12.</b> Growth curve of DH5α strain in LB with Amp [100 mkg/ml] and Cm [34 mkg/ml] containing different
 +
    IPTG
 +
    concentrations (0 mM, 0.05 mM, 0,1 mM, 3 mM, 5 mM IPTG in LB) after transformation with a plasmid with β-lactamase
 +
    gene under control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
<figure>
 +
  <img src="https://2019.igem.org/wiki/images/6/63/T--Moscow--BBa_K1189007_image8.png" alt="Figure 13">
 +
  <figcaption>
 +
    <b>Figure 13.</b> Growth curve of BL21 strain in LB with Amp [100 mkg/ml] and Cm [34 mkg/ml] containing different
 +
    IPTG
 +
    concentrations (0 mM, 0.05 mM, 0,1 mM, 3 mM, 5 mM IPTG in LB) after transformation with a plasmid with β-lactamase
 +
    gene under control of the inducible <em>lacI</em> promoter (<a
 +
      href="https://parts.igem.org/Part:BBa_K1189007">BBa_K1189007</a>).
 +
  </figcaption>
 +
</figure>
 +
 +
Fig.12 and Fig.13 show different growth curve rate for <em>E.coli</em> cultures in LB containing different IPTG
 +
concentrations.
 +
As seen from these pictures, growth rate with and without IPTG induction did not differ. From this data, we can
 +
conclude that the <em>lacI</em> promoter can be used without induction and expression can be observed due to promoter
 +
leakage.
 +
 +
 
</html>
 
</html>
 +
 +
 +
<!-- Add more about the biology of this part here
 +
===Usage and Biology===
 +
 +
<!-- -->
 +
<span class='h3bb'>Sequence and Features</span>
 +
<partinfo>BBa_K1189007 SequenceAndFeatures</partinfo>
 +
 +
 +
<!-- Uncomment this to enable Functional Parameter display
 +
===Functional Parameters===
 +
<partinfo>BBa_K1189007 parameters</partinfo>
 +
<!-- -->
  
  

Revision as of 08:29, 17 October 2019

Beta-lactamase with His Tag under the control of the inducible lacI promoter

This part was built to allow for the extraction of Beta-lactamase with the his-tags added onto the BioBrick. The part was built with the lacI IPTG inducible promoter J04500, with RBS.


Applications of BBa_K1189007

Figure 1. Absorbance values at 600nm for each tube at four different time points: 0, 30, 60 and 120min. The cultures that expressed beta-lactamase ( BBa_K1189007 ) showed higher absorbance levels, showing that the cells were able to grow in the presence of ampicillin.

In addition to that, we have purified our beta-lactamase ( BBa_K1189007 ) and our mobile TALE A linked to beta-lactamase construct ( BBa_K1189031 ) (Figure 2) and we have demonstrated that beta-lactamase retained its enzymatic activity for both proteins. We repeated a variation of ampicillin survival assay where we pretreated LB containing ampicillin and chloramphenicol with our purified TALE A linked to beta-lactamase ( BBa_K1189031 ). We then cultured bacteria in the treated LB that only carry resistance to chloramphenicol. Therefore, the bacteria are only able to survive if the our isolated protein retained its enzymatic abilities. We can show that the bacteria susceptible to ampicillin was able to grow in the presence of our purified construct protein ( BBa_K1189031 ), which means that we are expressing and purifying functional protein which is degrading the ampicillin (Figures 1 and 3). Figure 3 shows the OD at 24 hour time point from culturing where Figure 1 shows OD change over time. Both graphs show an increase in OD for cultures pre-treated with our protein demonstrating our protein is functional.

Figure 2. On the left crude lysate of beta-lactamase + His ( BBa_K1189007 ) from different lysis protocols: a mechanical and with sucrose , respectively. On the right, western blot of TALE A -linker-beta-lactamase ( BBa_K1189031 ) showing that we were able to express and purify our construct.

Figure 3. Absorbance values at 600nm after 24h. Amounts from 0.1µg to 20µg of TALE A-link-Beta-lactamase ( BBa_K1189031 ) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.

Figure 4. Absorbance values at 600nm in different time points. Amounts from 1.0µg to 10µg of TALE A-link-Beta-lactamase ( BBa_K1189031 ) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.

After verifying that TALE A -linker-beta-lactamase ( BBa_K1189031 ) retained enzymatic activity and was able to degrade ampicillin, we performed a colourimetric assay using benzylpenicillin as our substrate. We were able to see a colour change from red to yellow. This is because there is phenol red, a pH indicator, added to the substrate solution. Beta-lactamase hydrolyzes benzylpenicillin to penicillinoic acid, which changes the pH of the solution from alkaline to acidic. This pH change causes the phenol red to change from red to yellow. Our negative controls, to which benzylpenicillin was not added, remained red. We can also see the colour change correlate to the amount of purified TALE A linked to beta-lactamase present in each sample (Figure 5).

Figure 5. Benzylpenicillin assay. On the top, the wells only had TALE A -linker-beta-lactamase ( BBa_K1189031 ). Benzylpenicillin was added and after a 10-minute incubation at room temperature, we were able to observe a colour output from red to yellow (bottom row) while the control wells remained red.



Beta-lactamase with His Tag under the control of the inducible lacI promoter

This part was built to allow for the extraction of Beta-lactamase with the his-tags added onto the BioBrick. The part was built with the lacI IPTG inducible promoter J04500, with RBS.


Applications of BBa_K1189007

Figure 1. Absorbance values at 600nm for each tube at four different time points: 0, 30, 60 and 120min. The cultures that expressed beta-lactamase ( BBa_K1189007 ) showed higher absorbance levels, showing that the cells were able to grow in the presence of ampicillin.

In addition to that, we have purified our beta-lactamase ( BBa_K1189007 ) and our mobile TALE A linked to beta-lactamase construct ( BBa_K1189031 ) (Figure 2) and we have demonstrated that beta-lactamase retained its enzymatic activity for both proteins. We repeated a variation of ampicillin survival assay where we pretreated LB containing ampicillin and chloramphenicol with our purified TALE A linked to beta-lactamase ( BBa_K1189031 ). We then cultured bacteria in the treated LB that only carry resistance to chloramphenicol. Therefore, the bacteria are only able to survive if the our isolated protein retained its enzymatic abilities. We can show that the bacteria susceptible to ampicillin was able to grow in the presence of our purified construct protein ( BBa_K1189031 ), which means that we are expressing and purifying functional protein which is degrading the ampicillin (Figures 1 and 3). Figure 3 shows the OD at 24 hour time point from culturing where Figure 1 shows OD change over time. Both graphs show an increase in OD for cultures pre-treated with our protein demonstrating our protein is functional.

Figure 2. On the left crude lysate of beta-lactamase + His ( BBa_K1189007 ) from different lysis protocols: a mechanical and with sucrose , respectively. On the right, western blot of TALE A -linker-beta-lactamase ( BBa_K1189031 ) showing that we were able to express and purify our construct.

Figure 3. Absorbance values at 600nm after 24h. Amounts from 0.1µg to 20µg of TALE A-link-Beta-lactamase ( BBa_K1189031 ) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.

Figure 4. Absorbance values at 600nm in different time points. Amounts from 1.0µg to 10µg of TALE A-link-Beta-lactamase ( BBa_K1189031 ) were sufficient to degrade the ampicillin in the media allowing bacteria susceptible to ampicillin to grow.

After verifying that TALE A -linker-beta-lactamase ( BBa_K1189031 ) retained enzymatic activity and was able to degrade ampicillin, we performed a colourimetric assay using benzylpenicillin as our substrate. We were able to see a colour change from red to yellow. This is because there is phenol red, a pH indicator, added to the substrate solution. Beta-lactamase hydrolyzes benzylpenicillin to penicillinoic acid, which changes the pH of the solution from alkaline to acidic. This pH change causes the phenol red to change from red to yellow. Our negative controls, to which benzylpenicillin was not added, remained red. We can also see the colour change correlate to the amount of purified TALE A linked to beta-lactamase present in each sample (Figure 5).

Figure 5. Benzylpenicillin assay. On the top, the wells only had TALE A -linker-beta-lactamase ( BBa_K1189031 ). Benzylpenicillin was added and after a 10-minute incubation at room temperature, we were able to observe a colour output from red to yellow (bottom row) while the control wells remained red.

We examined expression of β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007). We performed antibiotic assay and IPTG assay to look how gene expression is affected by different conditions. In our experiments we used two E.coli strains: DH5α and BL21.
Figure 6
Figure 6. Growth curve of DH5α strain before and after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Figure 7
Figure 7. Growth curve of BL21 strain before and after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Fig.6 and Fig.7 show difference in growth of E.coli culture with and without the plasmid carrying β-lactamase expression cassette. We expected that E.coli culture with the plasmid will have a lower growth rate compared to the growth rate of E.coli culture without the plasmid (due to stress caused to cells by hosting a plasmid). In opposite to case with DH5a strain, results for BL21 correlate with our theoretical assumption
Figure 8
Figure 8. Growth curve of DH5α strain in LB containing Amp [100 mkg/ml] and Cm [34 mkg/ml] before and after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007.
Figure 9
Figure 9. Growth curve of BL21 strain in LB containing Amp [100 mkg/ml] and Cm [34 mkg/ml] before and after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Fig.8 and Fig.9 show that presence of Amp and Cm inhibits the growth of E.coli strains without plasmid carrying β-lactamase expression cassette . Strains with plasmid can grow in the presence of both Amp and Cm. Resistance to Amp is provided by β-lactamase and resistance to Cm is provided by Cm resistance gene in pSB1C3.
Figure 10
Figure 10. Growth curve of DH5α strain in LB containing different antibiotics (Amp [100 mkg/ml], Cm [34 mkg/ml], Kan [50 mkg/ml]) after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Figure 11
Figure 111. Growth curve of BL21 strain in LB containing different antibiotics (Amp [100 mkg/ml], Cm [34 mkg/ml], Kan [50 mkg/ml]) after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Fig.10 and Fig.11 show different growth rate for E.coli strains in LB containing different antibiotics. For both BL21 and DH5α strains maximum growth rate was reached in LB without any antibiotics. Minimum growth rate was demonstrated in the presence of Kan (because of absence of any resistance to Kan antibiotic). Growth rate of both strains was slightly lower in the presence of both Cm and Amp than in the presence of only Cm or Amp. Gene expression is observed without induction with IPTG due to promoter leakage.
Figure 12
Figure 12. Growth curve of DH5α strain in LB with Amp [100 mkg/ml] and Cm [34 mkg/ml] containing different IPTG concentrations (0 mM, 0.05 mM, 0,1 mM, 3 mM, 5 mM IPTG in LB) after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Figure 13
Figure 13. Growth curve of BL21 strain in LB with Amp [100 mkg/ml] and Cm [34 mkg/ml] containing different IPTG concentrations (0 mM, 0.05 mM, 0,1 mM, 3 mM, 5 mM IPTG in LB) after transformation with a plasmid with β-lactamase gene under control of the inducible lacI promoter (BBa_K1189007).
Fig.12 and Fig.13 show different growth curve rate for E.coli cultures in LB containing different IPTG concentrations. As seen from these pictures, growth rate with and without IPTG induction did not differ. From this data, we can conclude that the lacI promoter can be used without induction and expression can be observed due to promoter leakage.


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]



Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]