Difference between revisions of "Part:BBa K515102:Experience"

 
(19 intermediate revisions by 4 users not shown)
Line 1: Line 1:
__NOTOC__
+
<!-- DON'T DELETE --><partinfo>BBa_K515102 StartReviews</partinfo>
<p><b>Characterisation</b></p>
+
{|width='80%' style='border:1px solid gray'
<p>This part (BBa K515102) has been characterised qualitatively and quantitatively for chemotactic response towards L (-) malic acid. The tests were performed across a range of different attractant concentrations to observe optimal functioning of the part. Qualitative tests were performed using semi solid agar assays, quantitative analysis was performed using high - throughput capillary assay with cell count for each capillary evaluated using FACS. Behavioral analysis of E. coli expressing this part was done using Wide - field microscopy, and manual tracking was used to evaluate tactic response. Negative control used was <i>E. coli 5α strain</i> with a selectable marker for ampicillin and kanamycin. As positive control chemotactic response of <i>E. coli 5α strain</i> to attractant L (-) serine was tested, as serine is compatible with endogenous chemotaxis system of <i>E. coli 5α strain</i>. </p>
+
|-
<p><b>Qualitative assay</b></p>
+
|width='10%'|
<p> Two tests were performed to observe chemotactic response over a large range of chemoattractant concentration and to observe differences in much finer milimolar ranges of attractant concentration.Images of semi - solid agar plates were obtained using LAS 3000 Imager.</p>
+
<partinfo>BBa_K515102 AddReview number</partinfo>
<p> Table 1: Ranges of attractant concentration tested.</p>
+
<I>iGEM14_BNU-China</I>
<table class="MsoTableGrid" style="width:464.4pt;margin-left:-1.9pt;border-collapse:collapse;border:none;
+
|width='60%' valign='top'|
mso-border-alt:solid windowtext .5pt;mso-padding-alt:0cm 3.5pt 0cm 3.5pt" border="1" cellpadding="0" cellspacing="0" width="619">
+
+
<tr style="mso-yfti-irow:0;mso-yfti-firstrow:yes;height:17.65pt">
+
 
+
<td colspan="7" style="width:464.4pt;border:solid windowtext 1.0pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 3.5pt 0cm 3.5pt;height:17.65pt" valign="top" width="619">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;
+
  text-align:center;line-height:normal" align="center"><span style="mso-ansi-language:SK">Attractant
+
  concentration</span></p>
+
  </td>
+
</tr>
+
+
<tr style="mso-yfti-irow:1">
+
 
+
<td style="width:66.3pt;border:solid windowtext 1.0pt;
+
  border-top:none;mso-border-top-alt:solid windowtext .5pt;mso-border-alt:solid windowtext .5pt;
+
  padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">Test 1</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">0 M</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10<sup>-5</sup> M</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10<sup>-4</sup> M</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10<sup>-3</sup> M</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10<sup>-2</sup> M</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10<sup>-1</sup> M</span></p>
+
  </td>
+
</tr>
+
+
<tr style="mso-yfti-irow:2;mso-yfti-lastrow:yes">
+
 
+
<td style="width:66.3pt;border:solid windowtext 1.0pt;
+
  border-top:none;mso-border-top-alt:solid windowtext .5pt;mso-border-alt:solid windowtext .5pt;
+
  padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">Test 2</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">0 mM</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">5 mM</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">10 mM</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">15 mM</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">20 mM</span></p>
+
  </td>
+
 
+
<td style="width:66.35pt;border-top:none;border-left:
+
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
+
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
+
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt" valign="top" width="88">
+
 
+
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
+
  normal"><span style="mso-ansi-language:SK">25 mM</span></p>
+
  </td>
+
</tr>
+
</table>
+
<p><b>Method</b></p>
+
<p> Bacteria were induced for chemotaxis, and filter paper circle was soaked in the bacterial culture. 20µl of attractant diluteed in the motility buffer was placed on another filter paper and positioned exactly 2 cm away from the filter paper with bacterial culture. For control only motility buffer was added to the filter paper. The plates were left overnight for bacteria to grow and move.</p>
+
<p><b>Test 1</b></p>
+
[[Image:ICL_semisolid_nc_0to0.1M.jpg]]
+
<html>
+
<p><i>Figure 1: Negative control pictured for the attraction E. coli cells, with added attractant malate. Rising consentrations of malate were tested, 0 M, 10<sup>-5</sup> M, 10 <sup>-4</sup> M, 10 <sup>-3</sup> M, 10 <sup>-2</sup> M, 10 <sup>-1</sup> M. Circular colonies are observed with rising concentrations.</i></p>
+
</html>
+
[[Image:ICL_semisolid_pc_0to0.1M.jpg]]
+
<html>
+
<p><i>Figure 3: Positive control pictured for the attraction E. coli cells, with added attractant serine, which is compatible with native E. coli chemoreceptors. Rising consentrations of serine were tested, 0 M, 10<sup>-5</sup> M, 10 <sup>-4</sup> M, 10 <sup>-3</sup> M, 10 <sup>-2</sup> M, 10 <sup>-1</sup> M. Circular colonies are observed with 0 M & 10<sup>-5</sup> M concentrations, result for 10 <sup>-4</sup> M has been rendered void due to mishandling with semi - solid agar. Possible elipse shape of the 10 <sup>-3</sup> M sample can be observed. Directed colony shape towards the attractant source is observed at 10 <sup>-2</sup> M, and circular colony shape is observed in the 10 <sup>-1</sup> M sample.</i></p>
+
</html>
+
[[Image:ICL_semisolid_PA2652_0to0.1M.jpg]]
+
<html>
+
<p><i>Figure 7: Modified 5α E. coli cells with PA2652 receptor on pSB1C3 plasmid pictured with added attractant malate. Rising consentrations of malate were tested, 0 M, 10<sup>-5</sup> M, 10 <sup>-4</sup> M, 10 <sup>-3</sup> M, 10 <sup>-2</sup> M, 10 <sup>-1</sup> M. Circular colony can be observed for control, elipse shape of colonies can be observed at 10<sup>-5</sup> & 10 <sup>-3</sup>M concentrations. Elipse shaped colony can also be observed at 10 <sup>-4</sup> M however a large spread of bacteria can also be observed to the right side of the plate. Bacteria exposed to 10 <sup>-2</sup> M, 10 <sup>-1</sup> M concentrations, appear as circular colonies, however the colony spread is smaller it is possible due to saturation by malate at high concentrations.</i></p></i></p>
+
</html>
+
  
<p><b>Test 2</b></p>
 
[[Image:ICL_semisolid_nc_0to25mM.jpg]]
 
 
<html>
 
<html>
<p><i>Figure 2: Negative control pictured for the attraction E. coli cells, with added attractant malate. Rising consentrations of malate in milimolar range were tested, 0 mM, 5 mM, 10 mM, 15 mM, 20 mM, 25 mM. Circular colonies are observed with rising concentrations.</i></p>
+
<p>The plants root exudates contain TCA intermediates that can attract bacteria having the ability of chemotaxis.  <i>E.coli</i> has five kinds of chemoreceptors, which interact with factors of the flagella that leads to chemotaxis. But <i>E.coli</i> doesn’t have specific chemotaxis towards some TCA intermediates while <i>Pseudomonas putida</i> has some McpS, like McfQ and McfR. We made a part <a href="#top">BBa_K1405004</a> containing the sequence of McfR, which detects succinate, malate and fumarate. Then we detected its chemotaxis towards malate and succinate, and did the same assay to BBa_K515102. What's more, we changed the chassis to BL21, which expresses better than DH5α they had used.</p>
 +
<br/>
 +
<h3 id="results">Results</h3>
 +
<p>We did capillary assay to detect the response of <i>E.coli</i> to different attractants and different concentrations of each attractant. We show the results of capillary assay (Fig.1) below. We made a negative control using washing buffer and five concentration gradients (100mM/10mM/1mM/0.01mM/0.0001mM) of attractants. These <i>E.coli</i>s were divided into three groups based on the plasmid they have been transformed into. The plasmids are biobricks, BBa_K608003 and <a href="https://parts.igem.org/Part:BBa_K515102" target="_blank">BBa_K515102</a> (they are from 5A and 8F wells in plate1), and the McfR plasmid was designed by us. <a href="https://parts.igem.org/Part:BBa_K608003" target="_blank">BBa_K608003</a> (5A) only has a strong promoter and medium RBS, so it doesn’t have specific chemotaxis towards TCA intermediates. BBa_K515102 (8F) is a biobrick from 2011_Imperial_College_London, which responds to L(-)malic acid (HO2CCH2CH(OH)CO2H).</p>
 +
<br/>
 +
<br />
 +
<div style="width:100%; float: left;"><br /><br/></div>
 +
<a href="https://static.igem.org/mediawiki/2014/2/23/Bnu_delivery.png" rel="prettyPhoto"> <span class="overlay zoom" style="display: none;"></span><img style="opacity: 1; width:80%; margin-left: 100px;" src="https://static.igem.org/mediawiki/2014/2/23/Bnu_delivery.png"> </a>
 +
<br/><br/>
 +
<p style=" background-color: rgba(226,210,197,0.5);font-size:12px;padding: 8px 20px 8px 20px; border-radius: 0.5em 0.5em 0.5em 0.5em;  ">Fig.2  <i>E. coli</i>’s ability of chemotaxis towards different concentrations of succinate or malate.<br/>The cells were diluted 20000 times. 5A is a control which doesn’t have chemotaxis towards malate or succinate.<br/>
 +
<strong>Malate</strong>: McfR showed the strongest respond. The tendency of curve of 8F was biphasic with maximums at attractant concentration of about 10<sup>-2</sup> M and 10<sup>-5</sup> M, while the tendency of curve of McfR was biphasic with maximums at attractant concentration of about10<sup>-2</sup> M and 10 <sup>-7</sup> M. Both of them reached minimum at attractant concentration of about 10 <sup>-1</sup> M, the number of cells decreased slowly with attractant concentration decreasing for 8F and McfR. There was a significant difference among test and control (p < 0.05), and quantity of cells of 8F and McfR was much more than that of 5A. So both of 8F and McfR have chemotaxis towards malate. And McfR shows stronger response. <br/>     
 +
<strong>Succinate</strong>: The tendencies of curves of 8F and McfR towards succinate are same. As the attractant concentration increased, the number of cells arose and reached the maximum at attractant concentration of about 10<sup>-2</sup> M and fell sharply with the minimum at attractant concentration of 10<sup>-1</sup> M. The quantities of cells of 8F and McfR were almost equivalent and did not have significant difference. But there were significant differences among 8F & 5A, and McfR & 5A: the number of cells of 5A are far less than 8F or McfR (p < 0.05), which demonstrated that 8F and McfR have chemotaxis towards succinate and the capacity of chemotaxis of 8F and McfR towards succinate are almost equal. When compared with malate, 8F shows stronger response, while McfR shows weaker response.
 +
</p>
 +
</p>
 +
<br/><br/>
 +
 
 +
 
 
</html>
 
</html>
[[Image:ICL_semisolid_pc_0to25mM.jpg]]
+
|};
<html>
+
<!-- End of the user review template -->
<p><i>Figure 4: Positive control pictured for the attraction E. coli cells, with added attractant serine, which is compatible with native E. coli chemoreceptors. Rising consentrations of serine in milimolar range were tested, 0 mM, 5 mM, 10 mM, 15 mM, 20 mM, 25 mM. Circular colony can be observed at 0 mM concentration as control, at all other milimolar concentrations directed colony shape towards attractant source can be observed.</i></p>
+
<!-- DON'T DELETE --><partinfo>BBa_K515102 EndReviews</partinfo>
</html>
+
 
[[Image:ICL_semisolid_PA2652_0to25mM.jpg]]
+
 
<html>
+
 
<p><i>Figure 8:Modified 5α E. coli cells with PA2652 receptor on pSB1C3 plasmid pictured with added attractant malate. Rising concentrations of malate in milimolar range were tested, 0 mM, 5 mM, 10 mM, 15 mM, 20 mM, 25 mM. Circular colonies can be observed for 0 mM, 10 mM, 15 mM, 25 mM concentrations. Colonies exposed to 5 mM and 20 mM concentration of attractant were rendered void due to mishandling with semi - solid agar.</i></p>
+
 
<p><b>Comments</b></p>
+
 
<p> Semi - solid agar assay is only a qualitative measure of evaluating chemotactic movement. The only conclusion that could be drawn from the results is if bacteria do or do not perform chemotaxis towards the source. As a method for characterisation of part BBa_K515102 and its functioning within cells is very inaccurate and therefore this assay was done only to give initial clues about the behaviour of the BBa_K515102 in cells, however to analyse the parameters of the part quantitative assays were performed. Another factor of this assay is semi - solid agar which can not be replicated to exactly same measure for each sample and therefore it can to lesser or greater extent affect the assay. Some semi - solid agar plates due to fluid nature can be rendered void while manipulating with them, and the results from these have to be ignored.</p>
+
 
<p><b>Quantitative assay</b></p>
+
 
<p>Chemotaxis of <i>E. coli 5α strain</i> towards malate was quantified using capillary assay. The data were collected using FACS machine and analyzed with CyflogicTM software, CyFlo Ltd, Finland.<p>
+
 
===User Reviews===
+
 
<!-- DON'T DELETE --><partinfo>BBa_K515102 StartReviews</partinfo>
 
<!-- DON'T DELETE --><partinfo>BBa_K515102 StartReviews</partinfo>
<!-- Template for a user review
 
 
{|width='80%' style='border:1px solid gray'
 
{|width='80%' style='border:1px solid gray'
 
|-
 
|-
 
|width='10%'|
 
|width='10%'|
 
<partinfo>BBa_K515102 AddReview number</partinfo>
 
<partinfo>BBa_K515102 AddReview number</partinfo>
<I>Username</I>
+
<I>iGEM14_BNU-China</I>
 
|width='60%' valign='top'|
 
|width='60%' valign='top'|
Enter the review inofrmation here.
+
 
 +
<html>
 +
<p>The plants root exudates contain TCA intermediates that can attract bacteria having the ability of chemotaxis. <i>E.coli</i> has five kinds of chemoreceptors, which interact with factors of the flagella that leads to chemotaxis. But <i>E.coli</i> doesn’t have specific chemotaxis towards some TCA intermediates while <i>Pseudomonas putida</i> has some McpS, like McfQ and McfR. We made a part <a href="#top">BBa_K1405004</a> containing the sequence of McfR, which detects succinate, malate and fumarate. Then we detected its chemotaxis towards malate and succinate, and did the same assay to BBa_K515102. What's more, we changed the chassis to BL21, which expresses better than DH5α they had used.</p>
 +
<br/>
 +
<h3 id="results">Results</h3>
 +
<p>We did capillary assay to detect the response of <i>E.coli</i> to different attractants and different concentrations of each attractant. We show the results of capillary assay (Fig.1) below. We made a negative control using washing buffer and five concentration gradients (100mM/10mM/1mM/0.01mM/0.0001mM) of attractants. These <i>E.coli</i>s were divided into three groups based on the plasmid they have been transformed into. The plasmids are biobricks, BBa_K608003 and <a href="https://parts.igem.org/Part:BBa_K515102" target="_blank">BBa_K515102</a> (they are from 5A and 8F wells in plate1), and the McfR plasmid was designed by us. <a href="https://parts.igem.org/Part:BBa_K608003" target="_blank">BBa_K608003</a> (5A) only has a strong promoter and medium RBS, so it doesn’t have specific chemotaxis towards TCA intermediates. BBa_K515102 (8F) is a biobrick from 2011_Imperial_College_London, which responds to L(-)malic acid (HO2CCH2CH(OH)CO2H).</p>
 +
<br/>
 +
<br />
 +
<div style="width:100%; float: left;"><br /><br/></div>
 +
<a href="https://static.igem.org/mediawiki/2014/2/23/Bnu_delivery.png" rel="prettyPhoto"> <span class="overlay zoom" style="display: none;"></span><img style="opacity: 1; width:80%; margin-left: 100px;" src="https://static.igem.org/mediawiki/2014/2/23/Bnu_delivery.png"> </a>
 +
<br/><br/>
 +
<p style=" background-color: rgba(226,210,197,0.5);font-size:12px;padding: 8px 20px 8px 20px; border-radius: 0.5em 0.5em 0.5em 0.5em;  ">Fig.2  <i>E. coli</i>’s ability of chemotaxis towards different concentrations of succinate or malate.<br/>The cells were diluted 20000 times. 5A is a control which doesn’t have chemotaxis towards malate or succinate.<br/>
 +
<strong>Malate</strong>: McfR showed the strongest respond. The tendency of curve of 8F was biphasic with maximums at attractant concentration of about 10<sup>-2</sup> M and 10<sup>-5</sup> M, while the tendency of curve of McfR was biphasic with maximums at attractant concentration of about10<sup>-2</sup> M and 10 <sup>-7</sup> M. Both of them reached minimum at attractant concentration of about 10 <sup>-1</sup> M, the number of cells decreased slowly with attractant concentration decreasing for 8F and McfR. There was a significant difference among test and control (p < 0.05), and quantity of cells of 8F and McfR was much more than that of 5A. So both of 8F and McfR have chemotaxis towards malate. And McfR shows stronger response. <br/>     
 +
<strong>Succinate</strong>: The tendencies of curves of 8F and McfR towards succinate are same. As the attractant concentration increased, the number of cells arose and reached the maximum at attractant concentration of about 10<sup>-2</sup> M and fell sharply with the minimum at attractant concentration of 10<sup>-1</sup> M. The quantities of cells of 8F and McfR were almost equivalent and did not have significant difference. But there were significant differences among 8F & 5A, and McfR & 5A: the number of cells of 5A are far less than 8F or McfR (p < 0.05), which demonstrated that 8F and McfR have chemotaxis towards succinate and the capacity of chemotaxis of 8F and McfR towards succinate are almost equal. When compared with malate, 8F shows stronger response, while McfR shows weaker response.
 +
</p>
 +
</p>
 +
<br/><br/>
 +
 
 +
 
 +
</html>
 
|};
 
|};
 
<!-- End of the user review template -->
 
<!-- End of the user review template -->
 
<!-- DON'T DELETE --><partinfo>BBa_K515102 EndReviews</partinfo>
 
<!-- DON'T DELETE --><partinfo>BBa_K515102 EndReviews</partinfo>

Latest revision as of 14:21, 1 November 2017

UNIQ504bd689b92e5988-partinfo-00000000-QINU

No review score entered. iGEM14_BNU-China

The plants root exudates contain TCA intermediates that can attract bacteria having the ability of chemotaxis. E.coli has five kinds of chemoreceptors, which interact with factors of the flagella that leads to chemotaxis. But E.coli doesn’t have specific chemotaxis towards some TCA intermediates while Pseudomonas putida has some McpS, like McfQ and McfR. We made a part BBa_K1405004 containing the sequence of McfR, which detects succinate, malate and fumarate. Then we detected its chemotaxis towards malate and succinate, and did the same assay to BBa_K515102. What's more, we changed the chassis to BL21, which expresses better than DH5α they had used.


Results

We did capillary assay to detect the response of E.coli to different attractants and different concentrations of each attractant. We show the results of capillary assay (Fig.1) below. We made a negative control using washing buffer and five concentration gradients (100mM/10mM/1mM/0.01mM/0.0001mM) of attractants. These E.colis were divided into three groups based on the plasmid they have been transformed into. The plasmids are biobricks, BBa_K608003 and BBa_K515102 (they are from 5A and 8F wells in plate1), and the McfR plasmid was designed by us. BBa_K608003 (5A) only has a strong promoter and medium RBS, so it doesn’t have specific chemotaxis towards TCA intermediates. BBa_K515102 (8F) is a biobrick from 2011_Imperial_College_London, which responds to L(-)malic acid (HO2CCH2CH(OH)CO2H).







Fig.2 E. coli’s ability of chemotaxis towards different concentrations of succinate or malate.
The cells were diluted 20000 times. 5A is a control which doesn’t have chemotaxis towards malate or succinate.
Malate: McfR showed the strongest respond. The tendency of curve of 8F was biphasic with maximums at attractant concentration of about 10-2 M and 10-5 M, while the tendency of curve of McfR was biphasic with maximums at attractant concentration of about10-2 M and 10 -7 M. Both of them reached minimum at attractant concentration of about 10 -1 M, the number of cells decreased slowly with attractant concentration decreasing for 8F and McfR. There was a significant difference among test and control (p < 0.05), and quantity of cells of 8F and McfR was much more than that of 5A. So both of 8F and McfR have chemotaxis towards malate. And McfR shows stronger response.
Succinate: The tendencies of curves of 8F and McfR towards succinate are same. As the attractant concentration increased, the number of cells arose and reached the maximum at attractant concentration of about 10-2 M and fell sharply with the minimum at attractant concentration of 10-1 M. The quantities of cells of 8F and McfR were almost equivalent and did not have significant difference. But there were significant differences among 8F & 5A, and McfR & 5A: the number of cells of 5A are far less than 8F or McfR (p < 0.05), which demonstrated that 8F and McfR have chemotaxis towards succinate and the capacity of chemotaxis of 8F and McfR towards succinate are almost equal. When compared with malate, 8F shows stronger response, while McfR shows weaker response.



;

UNIQ504bd689b92e5988-partinfo-00000003-QINU





UNIQ504bd689b92e5988-partinfo-00000004-QINU

No review score entered. iGEM14_BNU-China

The plants root exudates contain TCA intermediates that can attract bacteria having the ability of chemotaxis. E.coli has five kinds of chemoreceptors, which interact with factors of the flagella that leads to chemotaxis. But E.coli doesn’t have specific chemotaxis towards some TCA intermediates while Pseudomonas putida has some McpS, like McfQ and McfR. We made a part BBa_K1405004 containing the sequence of McfR, which detects succinate, malate and fumarate. Then we detected its chemotaxis towards malate and succinate, and did the same assay to BBa_K515102. What's more, we changed the chassis to BL21, which expresses better than DH5α they had used.


Results

We did capillary assay to detect the response of E.coli to different attractants and different concentrations of each attractant. We show the results of capillary assay (Fig.1) below. We made a negative control using washing buffer and five concentration gradients (100mM/10mM/1mM/0.01mM/0.0001mM) of attractants. These E.colis were divided into three groups based on the plasmid they have been transformed into. The plasmids are biobricks, BBa_K608003 and BBa_K515102 (they are from 5A and 8F wells in plate1), and the McfR plasmid was designed by us. BBa_K608003 (5A) only has a strong promoter and medium RBS, so it doesn’t have specific chemotaxis towards TCA intermediates. BBa_K515102 (8F) is a biobrick from 2011_Imperial_College_London, which responds to L(-)malic acid (HO2CCH2CH(OH)CO2H).







Fig.2 E. coli’s ability of chemotaxis towards different concentrations of succinate or malate.
The cells were diluted 20000 times. 5A is a control which doesn’t have chemotaxis towards malate or succinate.
Malate: McfR showed the strongest respond. The tendency of curve of 8F was biphasic with maximums at attractant concentration of about 10-2 M and 10-5 M, while the tendency of curve of McfR was biphasic with maximums at attractant concentration of about10-2 M and 10 -7 M. Both of them reached minimum at attractant concentration of about 10 -1 M, the number of cells decreased slowly with attractant concentration decreasing for 8F and McfR. There was a significant difference among test and control (p < 0.05), and quantity of cells of 8F and McfR was much more than that of 5A. So both of 8F and McfR have chemotaxis towards malate. And McfR shows stronger response.
Succinate: The tendencies of curves of 8F and McfR towards succinate are same. As the attractant concentration increased, the number of cells arose and reached the maximum at attractant concentration of about 10-2 M and fell sharply with the minimum at attractant concentration of 10-1 M. The quantities of cells of 8F and McfR were almost equivalent and did not have significant difference. But there were significant differences among 8F & 5A, and McfR & 5A: the number of cells of 5A are far less than 8F or McfR (p < 0.05), which demonstrated that 8F and McfR have chemotaxis towards succinate and the capacity of chemotaxis of 8F and McfR towards succinate are almost equal. When compared with malate, 8F shows stronger response, while McfR shows weaker response.



;

UNIQ504bd689b92e5988-partinfo-00000007-QINU