Difference between revisions of "Team:BNDS China/Description"

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                <h3 style="padding-top: 6%;">Project Description</h3>
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                <p>The goal of our 2017 iGEM project is to genetically modify <i>E. coli</i> Nissle 1917, a probiotic, in such a way as to allow this organism to produce γ-Aminobutyric Acid (GABA). The three key words of our project are: GABA, GAD, and <i>E. coli</i> Nissle 1917. </p>
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                <br>
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                <h5>I.  GABA</h5>
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                <p>GABA is a four carbon non-protein amino acid that functions as an inhibitory neurotransmitter in the brain, affecting one’s personality and stress management ability. AM et. al tested sixty-three adults with capsules containing 100 mg of GABA or dextrin as a placebo, and found that after 30 min, the experimental group had a decrease in the alpha and beta band waves compared to the control group, indicating that GABA might have alleviated the stress induced by mental tasks during the experiment. Moreover, GABA may be able to treat diabetes, according to Watanabe M, 2017. Clinically, GABA is used for treating sleeplessness, depression, autonomic disorders, chronic alcohol-related symptoms, and stimulation of immune cells ,<cite>(Siragusa S et al., 2007)</cite>. Besides these uses, GABA is also sold on the market as an over the counter dietary supplement.</p>
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                <img src="https://static.igem.org/mediawiki/2017/thumb/1/1b/20171101214736.png/800px-20171101214736.png" />
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                <p>Fig. 1. Two mechanisms of GABA in CNS</p>
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                <p>Though GABA is beneficial to human beings in many ways, it is not allowed to be produced through chemical process if the chemical is sold as an edible product since there may be harmful impurities during the production. Therefore, it becomes meaningful for us to use synthetic biology methods to produce food grade GABA.</p>
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                <br>
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                <h5>II.     Glutamate Decarboxylase (GAD)</h5>
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                <br>
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                <img src="https://static.igem.org/mediawiki/2017/thumb/9/9c/20171101230427.png/800px-20171101230427.png" />
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                <img src="https://static.igem.org/mediawiki/2017/thumb/a/a8/20171101230440.png/800px-20171101230440.png" />
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                <p>Many microorganisms, including some <i>Escherichia coli</i> and <i>Lactobacillus</i> strains, can produce GABA <cite>(Dhakal et al.)</cite>. Among these microorganisms, <em>Lactobacillus brevis</em> NCL912 has shown the highest production of GABA: 3.57 g/l. According to Dhakal et al., the difference in productivity of GABA in different strains is caused by the difference in their GAD enzymes’ properties, suggesting that the strain <i>Lactobacillus brevis</i> NCL912 may possess a unique GAD system, incorporating a unique GAD gene.</p>
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                <p>Li et al. characterized the components of GAD operon in <i>Lactobacillus</i> NCL912 in 2013: <em>gadC, gadA</em>, and <em>gadR</em>. <em>GadA</em> is the glutamate decarboxylase that catalyzes the chemical reaction from glutamate to GABA, while <i>gadC</i> functions as a glutamate/GABA antiporter, an exchanger of GABA and glutamate. Typically, <i>gadC</i> is only present in the genomes of limited strains indicating their strain-specific characteristic of GABA production <cite>(Wu et al., 2017)</cite>. <i>GadCA</i> forms an operon and is regulated by <i>gadR</i>, which had much higher expression levels <cite>(Li, Li, Liu & Cao, 2013)</cite>.</p>
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                <p>For the outstanding GABA producing ability of the GAD system in <i>Lactobacillus brevis</i> NCL912, we picked proteins from this system as components of our device.</p>
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                <br>
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                <br>
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                <h5>III. <i>E. coli</i> Nissle 1917</h5><br>
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                <img src="https://static.igem.org/mediawiki/2017/thumb/f/f5/BNDS%E2%80%94%E2%80%94mutaflor.jpg/800px-BNDS%E2%80%94%E2%80%94mutaflor.jpg" />
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                <br>
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                <p><i>E. coli</i> Nissle 1917, a harmless strain of <i>E. coli</i> isolated by Alfred Nissle, is a commonly used probiotic in treating Ulcerative colitis, chronic constipation, and Crohn's disease. We chose this strain as our genetic engineering project due to its safety and its controllability. Since many researches have shown that <i>E. coli</i> Nissle 1917 is edible, we are able to derive our product, GABA containing milk, directly from the genetically modified species. Moreover, <i>E. coli</i> Nissle can be transformed and cultured using the same techniques as that of other <i>E. coli</i> strains.</p>
 +
                <p>Thus, by inserting the sequence of unique GAD system found in <i>Lactobacillus brevis</i> NCL912 into <i>E. coli</i> Nissle, we designed multiple parts and tested their individual abilities.</p>
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                <br>
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                <hr>
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                <br>
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                <h5>References</h5>
 +
                <cite>
 +
                <p>Abdou AM, Higashiguchi S, Horie K, Kim M, Hatta H, Yokogoshi H. (2006).Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans [abstract]. BoiFactor. 26(3):201-8. doi: 10.1002/biof.5520260305</p>
 +
                <p>Dhakal, Radhika., Bajpai, Vivek K., Baek, Kwang-Hyun. (2012, Jun 7). Production of
 +
                gaba (γ - Aminobutyric acid) by microorganisms: a review. Brazilian Journal of Microbiology, 1230-1241. doi: http://dx.doi.org/10.1590/S1517-83822012000400001</p>
 +
                <p>Li H, Cao Y, Gao D, Xu H. (2008, Dec.). A high γ-aminobutyric acid-producing ability Lactobacillus brevis isolated from Chinese traditional paocai. Ann Microbiol, 58, 649–653. doi: 10.1007/BF03175570</p>
 +
                <p>Li H, Li W, Liu X & Cao Y. (2013 Nov. 6). gadA gene locus in Lactobacillus brevis NCL912 and its expression during fed-batch fermentation. FEMS Microbiol Lett, 349 (2013) 108–116 doi: 10.1111/1574-6968.12301</p>
 +
                <p>Siragusa S., De Angelis M., Di Cagno R., Rizzello CG., Coda R., Gobbetti M. (2007 Nov.). Synthesis of γ-aminobutyric acid by lactic acid bacteria isolated from a variety of Italian cheeses. Appl Environ Microbiol, 73(22), 7283–7290. doi: 10.1128/AEM.01064-07.</p>
 +
                <p>Wu Q, Tun HM, Law YS, Khafipour E, Shah NP. (2017 Feb.). Common Distribution of gad Operon in Lactobacillus brevis and its GadA Contributes to Efficient GABA Synthesis toward Cytosolic Near-Neutral pH. Front Microbiol. 2017; 8: 206. doi: 10.3389/fmicb.2017.00206</p>
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            <p style="margin-left: 20px; padding-top:15px; font-size: 20px;">© 2017 BNDS_China All Rights Reserved.<p>
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<h1>Description</h1>
 
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<p>Tell us about your project, describe what moves you and why this is something important for your team.</p>
 
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<h5>What should this page contain?</h5>
 
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<li> A clear and concise description of your project.</li>
 
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<li>A detailed explanation of why your team chose to work on this particular project.</li>
 
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<h5>Advice on writing your Project Description</h5>
 
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We encourage you to put up a lot of information and content on your wiki, but we also encourage you to include summaries as much as possible. If you think of the sections in your project description as the sections in a publication, you should try to be consist, accurate and unambiguous in your achievements.
 
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Judges like to read your wiki and know exactly what you have achieved. This is how you should think about these sections; from the point of view of the judge evaluating you at the end of the year.
 
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<h5>References</h5>
 
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<p>iGEM teams are encouraged to record references you use during the course of your research. They should be posted somewhere on your wiki so that judges and other visitors can see how you thought about your project and what works inspired you.</p>
 
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<h5>Inspiration</h5>
 
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<p>See how other teams have described and presented their projects: </p>
 
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<li><a href="https://2016.igem.org/Team:Imperial_College/Description">2016 Imperial College</a></li>
 
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<li><a href="https://2016.igem.org/Team:Wageningen_UR/Description">2016 Wageningen UR</a></li>
 
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<li><a href="https://2014.igem.org/Team:UC_Davis/Project_Overview"> 2014 UC Davis</a></li>
 
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<li><a href="https://2014.igem.org/Team:SYSU-Software/Overview">2014 SYSU Software</a></li>
 
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Latest revision as of 03:13, 2 November 2017

Project Description


The goal of our 2017 iGEM project is to genetically modify E. coli Nissle 1917, a probiotic, in such a way as to allow this organism to produce γ-Aminobutyric Acid (GABA). The three key words of our project are: GABA, GAD, and E. coli Nissle 1917.


I. GABA

GABA is a four carbon non-protein amino acid that functions as an inhibitory neurotransmitter in the brain, affecting one’s personality and stress management ability. AM et. al tested sixty-three adults with capsules containing 100 mg of GABA or dextrin as a placebo, and found that after 30 min, the experimental group had a decrease in the alpha and beta band waves compared to the control group, indicating that GABA might have alleviated the stress induced by mental tasks during the experiment. Moreover, GABA may be able to treat diabetes, according to Watanabe M, 2017. Clinically, GABA is used for treating sleeplessness, depression, autonomic disorders, chronic alcohol-related symptoms, and stimulation of immune cells ,(Siragusa S et al., 2007). Besides these uses, GABA is also sold on the market as an over the counter dietary supplement.

Fig. 1. Two mechanisms of GABA in CNS

Though GABA is beneficial to human beings in many ways, it is not allowed to be produced through chemical process if the chemical is sold as an edible product since there may be harmful impurities during the production. Therefore, it becomes meaningful for us to use synthetic biology methods to produce food grade GABA.


II. Glutamate Decarboxylase (GAD)

Many microorganisms, including some Escherichia coli and Lactobacillus strains, can produce GABA (Dhakal et al.). Among these microorganisms, Lactobacillus brevis NCL912 has shown the highest production of GABA: 3.57 g/l. According to Dhakal et al., the difference in productivity of GABA in different strains is caused by the difference in their GAD enzymes’ properties, suggesting that the strain Lactobacillus brevis NCL912 may possess a unique GAD system, incorporating a unique GAD gene.

Li et al. characterized the components of GAD operon in Lactobacillus NCL912 in 2013: gadC, gadA, and gadR. GadA is the glutamate decarboxylase that catalyzes the chemical reaction from glutamate to GABA, while gadC functions as a glutamate/GABA antiporter, an exchanger of GABA and glutamate. Typically, gadC is only present in the genomes of limited strains indicating their strain-specific characteristic of GABA production (Wu et al., 2017). GadCA forms an operon and is regulated by gadR, which had much higher expression levels (Li, Li, Liu & Cao, 2013).

For the outstanding GABA producing ability of the GAD system in Lactobacillus brevis NCL912, we picked proteins from this system as components of our device.



III. E. coli Nissle 1917


E. coli Nissle 1917, a harmless strain of E. coli isolated by Alfred Nissle, is a commonly used probiotic in treating Ulcerative colitis, chronic constipation, and Crohn's disease. We chose this strain as our genetic engineering project due to its safety and its controllability. Since many researches have shown that E. coli Nissle 1917 is edible, we are able to derive our product, GABA containing milk, directly from the genetically modified species. Moreover, E. coli Nissle can be transformed and cultured using the same techniques as that of other E. coli strains.

Thus, by inserting the sequence of unique GAD system found in Lactobacillus brevis NCL912 into E. coli Nissle, we designed multiple parts and tested their individual abilities.



References

Abdou AM, Higashiguchi S, Horie K, Kim M, Hatta H, Yokogoshi H. (2006).Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans [abstract]. BoiFactor. 26(3):201-8. doi: 10.1002/biof.5520260305

Dhakal, Radhika., Bajpai, Vivek K., Baek, Kwang-Hyun. (2012, Jun 7). Production of gaba (γ - Aminobutyric acid) by microorganisms: a review. Brazilian Journal of Microbiology, 1230-1241. doi: http://dx.doi.org/10.1590/S1517-83822012000400001

Li H, Cao Y, Gao D, Xu H. (2008, Dec.). A high γ-aminobutyric acid-producing ability Lactobacillus brevis isolated from Chinese traditional paocai. Ann Microbiol, 58, 649–653. doi: 10.1007/BF03175570

Li H, Li W, Liu X & Cao Y. (2013 Nov. 6). gadA gene locus in Lactobacillus brevis NCL912 and its expression during fed-batch fermentation. FEMS Microbiol Lett, 349 (2013) 108–116 doi: 10.1111/1574-6968.12301

Siragusa S., De Angelis M., Di Cagno R., Rizzello CG., Coda R., Gobbetti M. (2007 Nov.). Synthesis of γ-aminobutyric acid by lactic acid bacteria isolated from a variety of Italian cheeses. Appl Environ Microbiol, 73(22), 7283–7290. doi: 10.1128/AEM.01064-07.

Wu Q, Tun HM, Law YS, Khafipour E, Shah NP. (2017 Feb.). Common Distribution of gad Operon in Lactobacillus brevis and its GadA Contributes to Efficient GABA Synthesis toward Cytosolic Near-Neutral pH. Front Microbiol. 2017; 8: 206. doi: 10.3389/fmicb.2017.00206

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