Difference between revisions of "Team:Wageningen UR/ecoli survival"

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  <h4><a href="#header">MetabolicModeling</a></h4>
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  <h4><a href="#header"><i>E. coli</i> survival</a></h4>
 
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  <a href="#MMlb_intro">Introduction</a>
 
 
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  <a href="#MMlb_results">Key Results</a>
 
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  <a href="#MMlb_mm">Methods</a>
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<area alt="Home" href="https://2016.igem.org/Team:Wageningen_UR" shape="rect" coords="12,10,331,205" />
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<comic>
<section id="MMlb_intro">
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<img src="https://static.igem.org/mediawiki/2016/0/03/T--Wageningen_UR--metaboliccomic.jpg" usemap="#metamap" alt="comic">
<h1>Introduction</h1>    <!-- Written as abstract-->
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</comic><section id="MMlb_intro">
<p>The final BeeT product will be applied using sugar water which is transported into the hive by worker bees. This means that our chassis needs to be able to survive in a high sucrose, low (non-carbonic) nutrient environment. In order to test this we looked into whether or not any bacteria would survive such an environment over various time steps. The result of this was that our chassis bacteria, <i>Escherichia coli </i>, was able to grow to at least an entire day in the sugar water. This result shows us that the bees will have at least 24 hours to pick up some of our BeeT. Assuming of course the addition of the various sub systems we have in mind doesn't affect the survival time.</p>
+
<h1 text-align='center'>Testing chassis survival in sugar water</h1>    <!-- Written as abstract-->
<h2>Background</h2>    <!-- "Why did we start this experiment"-->
+
<p>The final BeeT product will be applied using sugar water, which is transported into the hive by worker bees. This means that our chassis needs to be able to survive in a nutrient limited environment, which does have a high sucrose content. In order to test this, we simulated a sugar water environment and tested whether bacteria can survive it. The result of this was that our chassis bacteria, <i>Escherichia coli </i>, was able to survive up to at least an entire day in the sugar water. This means that the bees will have at least 24 hours to pick up some of our BeeT.</p>
<p>The modeling results from the <a href=https://2016.igem.org/Team:Wageningen_UR/Model#metabolic > metabolic modeling </a> project only showed what would happen in the time period of 90 seconds to 90 minutes after being put in the sugar water. Because of this, more evidence was needed to see what would happen to the <i>E. coli </i> in the sugar water, for the time scales we were interested in. We know the presence of the high amount of sugar water leads to osmotic pressure. This is because the sucrose molecules from the medium are not able to travel across the cell-membrane, but they still pull the water molecules present inside the cell towards them. The effects of the osmotic pressure on the bacterium were not clear outside of the 90 minute range determined by the metabolic model. However, as determined by the <a href=https://2016.igem.org/Team:Wageningen_UR/Model#beehave>BeeHave model</a>, we require that the BeeT survives for days in the sugar water. In this project we aimed to experimentally determine how long BeeT can survive in osmotically unfavourable conditions. </p>
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    <!-- "Why did we start this experiment"-->
 +
<p>The modeling results from the <a href=https://2016.igem.org/Team:Wageningen_UR/Model#metabolic > metabolic modeling </a> project only showed what would happen in the time period of 90 seconds to 90 minutes after being put in the sugar water. Because of this, more evidence was needed to see what would happen to the <i>E. coli </i> in the sugar water for the time scales we are interested in. We know the presence of the high amount of sugar water leads to osmotic stress.<sup><a href="#mm1" id="refmm1">1</a></sup>
 +
This is because the sucrose molecules from the medium are not able to travel across the cell-membrane, but still pull the water molecules present inside the cell towards them. The effects of the osmotic stress on the bacterium were not clear outside of the 90 minute range determined by the metabolic model. However, as determined by the <a href=https://2016.igem.org/Team:Wageningen_UR/Model#beehave>BEEHAVE model</a>, we require that the BeeT survives for days in the sugar water. In this project we aimed to experimentally determine how long BeeT can survive in osmotically unfavourable conditions. </p>
 
</section>
 
</section>
<section id="MMlb_mm">
 
<h2>Materials and Methods </h2> <!-- might go to "Experiments" in full. -->
 
<p> The method used to test the survival of <i>E. coli</i> in sugar water experiment is a simple growth experiment. First the bacteria grow overnight to saturate an LB solution. Then a small amount of this is pipetted into various concentrations of sterile sugar water made of high amounts of sucrose and sterilized tap water. After this they are left there for various time steps and then put into sterile LB medium and left to grow overnight. </p>
 
 
<p>Materials used: <ul>
 
<li>Pure sucrose</li>
 
<li>Tap water</li>
 
<li>(Multi-)Pipettes</li>
 
<li><i>E. coli K12 MG1655 </i> strain, upon which the harvard strain and the iJO1366 model are based.</li>
 
<li>96 wells plate (well volume ~200 μL)</li>
 
<li>Plate-reader</li>
 
</ul>
 
protocols applied: <ul>
 
<li>Day before, inoculate LB with <i>E. coli</i> then let that solution grow overnight at optimal conditions (12 hours). This is our saturated LB solution.</li>
 
<li>Under sterile conditions: <ul>
 
<li>Put concentrations of 0, 100, 200 and 400 grams sucrose, per Liter of sterilized tap water, plate 1, row 1 and 3. With three replicates each.</li>
 
<li>Put LB in all wells of plate 2, close and keep sterile.</li>
 
<li>Put bacteria in plate 1 row 1 (sugar water)</li>
 
<li>After time steps of 30, 50, 90, 120 minutes inoculate LB wells of plate 2 with 5 μL from row 1 of plate 1. At room temperature with a closed lid./ul></li>
 
<li>For exp 1 a plate reader was used to compare overnight growth curves in the LB. For the other experiments a visual confirmation was enough.</li>
 
</ul>
 
</p>
 
Plate set ups (tables):                           
 
</section>
 
 
<section id="MMlb_results">         
 
<section id="MMlb_results">         
<h2>Results </h2>
+
<h2>Testing Survival </h2>
<p> [pictures of plates + picture of plate reader results??, showing growth curves overnight]
+
<p> The results from the experiments were a great success, as you can see in Figure 1 and 2. The result of experiment 3 is that the <i>E. coli</i> was still able in the LB was still possible after the 24 hours in the sugar water solution.
Exp1: failure, did not work sterile (put 96 wells plate on shaker, bad idea)
+
All three experiments clearly show that sugar water is not as lethal as first hypothesized. Not only that, but the results fit with the model hypothesis in that long-term survival is indeed possible. Thus we have shown that <i>​ E. coli</i> can indeed be used as a chassis for our BeeT. This result was taken into account in the <a href=https://2016.igem.org/Team:Wageningen_UR/Model#beehave>BEEHAVE model</a>.
Repeat Exp1: success, growth visible after up to 2 hours in sugar water. See table 1 and figure 1.
+
<figure>
Exp2: success, growth shown after 6 hours in sugar water. See table 2 and figure 2.
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<img height="301" width="500" src="https://static.igem.org/mediawiki/2016/2/2f/T--Wageningen_UR--ecoli_exp1_success.jpg">
Exp3: success, bacteria from exp2 survived overnight. See figure 3.
+
<figcaption>Figure 1. Photo of plate 2 of the repeat of the first experiment. The top row shows growth after having spent 30 minutes in the sugar water and then overnight growth. The time step increases for row 3 to 50 minutes, row 5 to 90 minutes, and row 7 to 120 minutes. Row 8 and all intermediate rows are negative controls. The first three columns are replicates of 0g/L sucrose, then 3 columns of 100g/L sucrose, then 3 columns of 200g/L sucrose, and finally 3 columns of 400g/L sucrose. (The image appears to be flipped upside down for some reason, in case it shows as such, the pencil marks are in the upper right corner of the plate)</figcaption>
</p>
+
<figure><figcaption>Table 1. Results of experiment number one, all combinations were done with 3 replicates, which all showed the same result. All rows were interspersed with rows of sterile LB and the final row was inoculated with sterilized sugar water as negative controls. </figcaption>
+
 
</figure>
 
</figure>
<ul class='table'>
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<figure>
<table>
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<img height="300" width="500" src="https://static.igem.org/mediawiki/2016/5/58/T--Wageningen_UR--ecoli_exp2_success.jpg">
    <tbody>
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<figcaption>Figure 2. Photo of plate 2 of the second experiment. The top row shows growth after having spent 1 hour in the sugar water and then overnight growth. The time step increases for row 3 to 2 hours, etc (as shown in the right side of the photo). Row 8 and all intermediate rows are negative controls.The first 4 columns are replicates of 625g/L sucrose concentration, whilst the last 4 columns are replicates of the 312.5g/L sucrose concentration conditions. </figcaption>
        <tr>
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            <td dir="ltr">
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                    Sucrose Concentration (g/L)
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<figure><figcaption>Table 2. Results of experiment two, all combinations were done with 4 replicates, which all showed the same result. All rows were interspersed with rows of sterile LB and the final row was inoculated with sterilized sugar water as negative controls. </figcaption>
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<section id="MMlb_mm">
</figure>
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<h2>Method of testing</h2>  
<ul class='table'>
+
<p> The method used to test the survival of <i>E. coli</i> in sugar water is a <a href=2016.igem.org/Team:Wageningen_UR/Experiments#ecoli>simple growth experiment</a>. First, the bacteria grow overnight in LB medium. Then, 5 µL per sample of this is pipetted into various concentrations of sterile sugar water made of varying amounts of sucrose, ranging from 0 g/L up to 625 g/L, and sterilized tap water. We then took 5 µL samples of the sugar water and inoculated them into fresh 200µL LB medium wells and left to grow overnight. </p>
 
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                625
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<section id="MMlb_disc">
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<h2>Discussion </h2>
+
<p>
+
Clearly shows sugar water is not as lethal as first hypothesized, results fit with the model in that survival is indeed possible. (Model just shows the effects that water efflux can have on the bacteria, for the range between 90 seconds and 90 minutes).
+
Recommendation:
+
In order to measure a more quantitative effect of the sugar water, the bacteria could have been put on LB plates instead of wells, and measuring the Colony Forming Units after an overnight growth step.
+
</p></section>
+
 
<section id="MMlb_refs">
 
<section id="MMlb_refs">
 
<h2>References</h2>
 
<h2>References</h2>
 
<ul>
 
<ul>
<a id="ts@" href= >@.</a>  
+
<a id="mm1" href= https://www.microbiology.ubc.ca/sites/default/files/roles/drupal_ungrad/JEMI/15/JEMI15_15-21.pdf >1.</a>
<a href="#ts@ " title="Jump back to footnote @  in the text.">↩</a>
+
Cheng, Y. L., Hwang, J., & Liu, L. (2011). The Effect of Sucrose-induced Osmotic Stress on the Intracellular Level of cAMP in Escherichia coli using Lac Operon as an Indicator. Journal of Experimental Microbiology and Immunology (JEMI) Vol, 15, 15-21.
<br><br><a id="ts@" href=  >@.</a> 
+
<a href="#refmm1" title="Jump back to footnote 1 in the text.">↩</a>
<a href="#ts@ " title="Jump back to footnote @  in the text.">↩</a>
+
<br><br><a id="ts@" href=  >@.</a> 
+
<a href="#ts@ " title="Jump back to footnote in the text.">↩</a>
+
 
<br><br>
 
<br><br>
 
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</ul>
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Latest revision as of 16:07, 18 October 2016

Wageningen UR iGEM 2016

 

Home Model Lab comic

Testing chassis survival in sugar water

The final BeeT product will be applied using sugar water, which is transported into the hive by worker bees. This means that our chassis needs to be able to survive in a nutrient limited environment, which does have a high sucrose content. In order to test this, we simulated a sugar water environment and tested whether bacteria can survive it. The result of this was that our chassis bacteria, Escherichia coli , was able to survive up to at least an entire day in the sugar water. This means that the bees will have at least 24 hours to pick up some of our BeeT.

The modeling results from the metabolic modeling project only showed what would happen in the time period of 90 seconds to 90 minutes after being put in the sugar water. Because of this, more evidence was needed to see what would happen to the E. coli in the sugar water for the time scales we are interested in. We know the presence of the high amount of sugar water leads to osmotic stress.1 This is because the sucrose molecules from the medium are not able to travel across the cell-membrane, but still pull the water molecules present inside the cell towards them. The effects of the osmotic stress on the bacterium were not clear outside of the 90 minute range determined by the metabolic model. However, as determined by the BEEHAVE model, we require that the BeeT survives for days in the sugar water. In this project we aimed to experimentally determine how long BeeT can survive in osmotically unfavourable conditions.

Testing Survival

The results from the experiments were a great success, as you can see in Figure 1 and 2. The result of experiment 3 is that the E. coli was still able in the LB was still possible after the 24 hours in the sugar water solution. All three experiments clearly show that sugar water is not as lethal as first hypothesized. Not only that, but the results fit with the model hypothesis in that long-term survival is indeed possible. Thus we have shown that ​ E. coli can indeed be used as a chassis for our BeeT. This result was taken into account in the BEEHAVE model.

Figure 1. Photo of plate 2 of the repeat of the first experiment. The top row shows growth after having spent 30 minutes in the sugar water and then overnight growth. The time step increases for row 3 to 50 minutes, row 5 to 90 minutes, and row 7 to 120 minutes. Row 8 and all intermediate rows are negative controls. The first three columns are replicates of 0g/L sucrose, then 3 columns of 100g/L sucrose, then 3 columns of 200g/L sucrose, and finally 3 columns of 400g/L sucrose. (The image appears to be flipped upside down for some reason, in case it shows as such, the pencil marks are in the upper right corner of the plate)
Figure 2. Photo of plate 2 of the second experiment. The top row shows growth after having spent 1 hour in the sugar water and then overnight growth. The time step increases for row 3 to 2 hours, etc (as shown in the right side of the photo). Row 8 and all intermediate rows are negative controls.The first 4 columns are replicates of 625g/L sucrose concentration, whilst the last 4 columns are replicates of the 312.5g/L sucrose concentration conditions.

Method of testing

The method used to test the survival of E. coli in sugar water is a simple growth experiment. First, the bacteria grow overnight in LB medium. Then, 5 µL per sample of this is pipetted into various concentrations of sterile sugar water made of varying amounts of sucrose, ranging from 0 g/L up to 625 g/L, and sterilized tap water. We then took 5 µL samples of the sugar water and inoculated them into fresh 200µL LB medium wells and left to grow overnight.

References

    1. Cheng, Y. L., Hwang, J., & Liu, L. (2011). The Effect of Sucrose-induced Osmotic Stress on the Intracellular Level of cAMP in Escherichia coli using Lac Operon as an Indicator. Journal of Experimental Microbiology and Immunology (JEMI) Vol, 15, 15-21.