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

 
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<p><b>Characterisation</b></p>
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<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>
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<p><b>Qualitative assay</b></p>
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<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>
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<p> Table 1: Ranges of attractant concentration tested.</p>
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<I>iGEM14_BNU-China</I>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;
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  text-align:center;line-height:normal" align="center"><span style="mso-ansi-language:SK">Attractant
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  concentration</span></p>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">Test 1</span></p>
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  </td>
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<td style="width:66.35pt;border-top:none;border-left:
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">0 M</span></p>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10<sup>-5</sup> M</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10<sup>-4</sup> M</span></p>
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  </td>
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<td style="width:66.35pt;border-top:none;border-left:
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10<sup>-3</sup> M</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10<sup>-2</sup> M</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10<sup>-1</sup> M</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">Test 2</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">0 mM</span></p>
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  </td>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">5 mM</span></p>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">10 mM</span></p>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">15 mM</span></p>
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">20 mM</span></p>
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<td style="width:66.35pt;border-top:none;border-left:
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<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;line-height:
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  normal"><span style="mso-ansi-language:SK">25 mM</span></p>
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  </td>
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</table>
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<p><b>Method</b></p>
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<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>
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<p><b>Test 1</b></p>
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[[File:ICL_semisolid_nc_0to0.1M.jpg]]
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<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>
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<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>
</html>
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<br/>
[[File:ICL_semisolid_pc_0to0.1M.jpg]]
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<h3 id="results">Results</h3>
<html>
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<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>
<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>
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<br/>
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<br />
[[File:ICL_semisolid_PA2652_0to0.1M.jpg]]
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<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>
<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>
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<br/><br/>
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<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/>  
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<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/>      
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<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.
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<p><b>Test 2</b></p>
 
===User Reviews===
 
 
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<partinfo>BBa_K515102 AddReview number</partinfo>
<I>Username</I>
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<I>iGEM14_BNU-China</I>
 
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Enter the review inofrmation here.
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<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>
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<br/>
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<h3 id="results">Results</h3>
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<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>
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<div style="width:100%; float: left;"><br /><br/></div>
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<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>
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<br/><br/>
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<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/>
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<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/>     
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<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.
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Latest revision as of 14:21, 1 November 2017

UNIQfe474eb02e857175-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.



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UNIQfe474eb02e857175-partinfo-00000003-QINU





UNIQfe474eb02e857175-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.



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UNIQfe474eb02e857175-partinfo-00000007-QINU