Team:CityU HK/project/overview

From 2014.igem.org

(Difference between revisions)
Line 43: Line 43:
<h1 id="title"> Overview </h1>
<h1 id="title"> Overview </h1>
-
<img class="displayed" src="https://static.igem.org/mediawiki/2014/2/29/CityU_HK_overview.jpg" width="80%">
+
<img class="displayed" src="https://static.igem.org/mediawiki/2014/2/29/CityU_HK_overview.jpg" width="75%">
-
<p class="content">Obesity is a worldwide problem that contributes to various human diseases and decreases the self-esteem of many people. Traditional remedies such as dieting or over-exercising often depress oneself, as it is no news that they take a lot of unpleasant effort. We aim to alleviate the problem with the least effect to one’s quality of life, therefore we genetically engineered an Escherichia coli strain that takes up fat from our diet and converts it into useful ALA (linolenic acid), and we name the bacteria “Fit Coli”. <br><br>
+
<p class="content">Obesity is a worldwide problem that contributes to a variety of human diseases such as diabetes and cancer, as well as psychological problems such as eating disorder and anxiety. Traditional remedies such as dieting or over-exercising can be ineffective and often lead to depression, given that both means could lead to obvious physical and mental unpleasantness. Obesity, in many cases, is linked to the accumulation of excessive free fatty acids from food. Therefore removing these fatty acids from the system could be the key to combating obesity. In an attempt to alleviating the obesity problem without causing adverse impact on one’s quality of life, we genetically engineered an <i>Escherichia coli</i> strain to confer upon it the capacity to both remove excess fat from our diet and convert it into a useful metabolic intermediate, linolenic acid (ALA). We named this genetically modified bacterium, “Fit Coli”.<br><br>
-
Fit Coli does its job in four steps. The first step is to take up free fatty acids from the guts into the periplasm present between the two membranes of the cell wall. It is achieved by the overexpressed fatty acid transporter protein, FadL. <br><br>
+
We designed the Fit Coli to do the job in several steps. The first step involves increasing its ability to take up excess free fatty acids from the external environment (e.g. human gut) which, theoretically, can be achieved by overexpressing the FadL and FadD genes in <i>E. coli</i>. FadL codes for a fatty acid transporter protein that moves free fatty acids across the outer cell membrane into the periplasmic space. FadD, on the other hand, codes for a fatty acyl-CoA synthetase which adds a coenzyme A (CoA) moiety to fatty acids and then transports the resulting fatty acyl-CoA across the inner membrane into the cytosol.  Next, <i>E. coli</i> is engineered to overexpress the TesA gene that codes for an acyl-CoA thioesterase which removes the CoA moiety from fatty acyl-CoA molecules, thereby restoring the molecule back to the form of free fatty acid. This strategy is aimed at diverting fatty acids from the beta-oxidation pathway which produces ATP. Lastly, the free fatty acids are converted into Lunder the catalysis of the three engineered enzymes, ∆9 desaturase, ∆12 desaturase and ∆15 desaturase. <br><br>
-
Second, the fatty acids need to be transported across the inner membrane into the cytosol. This is done by fatty acyl-CoA synthetase, FadD. This enzyme adds a coenzyme A (CoA) moiety to the fatty acids and then transfers the resulting acyl-CoA into the cytosol across the inner membrane.<br><br>
+
In short, Fit Coli is able to take up various excess C18 fatty acids such as stearic acid, oleic acid and linoleic acid present in our foods and converting them into ALA which can then be used by the human body to make docosohexaenoic acid/eicosanoids that are beneficial to humans.<br><br> </p>
-
 
+
-
In the third step, TesA, an acyl-CoA thioesterase, removes the CoA moiety from acyl-CoA. Therefore the uptaken molecule restores back to its free fatty acid form. This diverts the molecule from undergoing beta-oxidation.<br><br>
+
-
 
+
-
Lastly, the free fatty acids are then converted into Lunder the catalysis of the three engineered enzymes, ∆9 desaturase, ∆12 desaturase and ∆15 desaturase.<br><br>
+
-
 
+
-
In conclusion, Fit Coli can initially uptake stearic acid, oleic acid and linoleic acid present in our food, and convert them into ALA, which can then be used by our body.<br><br> </p>
+
</div>
</div>

Revision as of 15:52, 8 October 2014

Bootstrap 101 Template

Overview

Obesity is a worldwide problem that contributes to a variety of human diseases such as diabetes and cancer, as well as psychological problems such as eating disorder and anxiety. Traditional remedies such as dieting or over-exercising can be ineffective and often lead to depression, given that both means could lead to obvious physical and mental unpleasantness. Obesity, in many cases, is linked to the accumulation of excessive free fatty acids from food. Therefore removing these fatty acids from the system could be the key to combating obesity. In an attempt to alleviating the obesity problem without causing adverse impact on one’s quality of life, we genetically engineered an Escherichia coli strain to confer upon it the capacity to both remove excess fat from our diet and convert it into a useful metabolic intermediate, linolenic acid (ALA). We named this genetically modified bacterium, “Fit Coli”.

We designed the Fit Coli to do the job in several steps. The first step involves increasing its ability to take up excess free fatty acids from the external environment (e.g. human gut) which, theoretically, can be achieved by overexpressing the FadL and FadD genes in E. coli. FadL codes for a fatty acid transporter protein that moves free fatty acids across the outer cell membrane into the periplasmic space. FadD, on the other hand, codes for a fatty acyl-CoA synthetase which adds a coenzyme A (CoA) moiety to fatty acids and then transports the resulting fatty acyl-CoA across the inner membrane into the cytosol. Next, E. coli is engineered to overexpress the TesA gene that codes for an acyl-CoA thioesterase which removes the CoA moiety from fatty acyl-CoA molecules, thereby restoring the molecule back to the form of free fatty acid. This strategy is aimed at diverting fatty acids from the beta-oxidation pathway which produces ATP. Lastly, the free fatty acids are converted into Lunder the catalysis of the three engineered enzymes, ∆9 desaturase, ∆12 desaturase and ∆15 desaturase.

In short, Fit Coli is able to take up various excess C18 fatty acids such as stearic acid, oleic acid and linoleic acid present in our foods and converting them into ALA which can then be used by the human body to make docosohexaenoic acid/eicosanoids that are beneficial to humans.