Difference between revisions of "Team:HK SSC/Description"

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<h3>Abstract/ Overview</h3>
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<p>Microcystis aeruginosa is one of the most common cyanobacteria responsible for harmful algal blooms. This cyanobacterium produces microcystin, a hepatotoxin that damages the liver. However, direct lysis of Microcystis aeruginosa may not best for the environment as it holds ecological values of heavy metal sorption and oxygen synthesis. In this project, we hope to silence the microcystin biosynthesis cluster(mcy) using a catalytically dead Cas9 (dCas9) enzyme lacking endonuclease activity. When the dCas9 enzyme is co-expressed with a guide RNA(sgRNA), the dCas9-sgRNA complex specifically binds to the McyB gene and blocks transcript elongation, leading to the repression of the McyB gene without altering the chromosome of the Microcystis. Here we provide the design of a dCas9-sgRNA expression gene in a shuttle vector that can replicate in both E.coli and cyanobacteria. We will also be conducting downstream analysis to see how our dCas9-sgRNA expression plasmid affects the microcystin-production rate and oxygen synthesis rate of Microcystis.</p>
  
<div class="WordSection1">
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<h3>Project Inspiration</h3>
 +
<p>Our project is inspired from various aspects, including school lessons, books, news articles hiking trips, and even previous iGEM teams. </p>
 +
<h4>i. School lessons: </h4>
 +
<h5>Chemistry: </h5>
 +
<p>We’ve learnt that certain species of cyanobacteria is capable of nitrogen fixation. We understand the ecological importance of nitrogen fixation. Microcystis aeruginosa can carry out metal sorption. However, they also produce neurotoxins and hepatotoxins, microcystin. These cyclic heptapeptides can cause lethal consequences. </p>
 +
Chemical structure of Microcystin-LR
  
<p class="MsoNormal" style="line-height:150%"><span class="SpellE"><b><span lang="EN-US" style="mso-ansi-language:EN-US">iGEM</span></b></span><b><span lang="EN-US" style="mso-ansi-language:EN-US"> 2019 description<o:p></o:p></span></b></p>
 
  
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
<h5>Biology:</h5>
EN-US"><o:p>&nbsp;</o:p></span></p>
+
<p>We have learnt the cellular structure of cyanobacteria. From teachers and text books, we have had a brief understanding in how photosynthesis is carried out in cyanobacteria. More than half of the world’s oxygen is produced via phytoplankton (including cyanobacteria). On the contrary, we are aware that the bloom of cyanobacteria will blocked sunlight and slow down the photosynthesis rate of other water plants. Certain cyanobacteria (including Microcystis) may even produce toxins that inhibit certain enzymes in animals. </p>
 +
https://www.usgs.gov/media/images/microcystis-aeruginosa-microscopic-view
 +
Accessed on 18/8
  
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
<h5>Geography: </h5>
EN-US">Microcystis aeruginosa is one of the highly deleterious freshwater
+
<p>Through studies in soil and water sources, we learnt how excessive use of fertilizers create eutrophic waters, which gives rise to cyanobacterial blooms. Teachers also taught us how global warming raises the temperature, which favours the rapid growth of cyanobacteria (especially Microcystis Aeruginosa). </p>
cyanobacteria; it is well-known for causing harmful algae blooms in rivers and
+
lakes. These algae blooms produce a large number of <span class="SpellE">microcystins</span>
+
and neurotoxins, which potentially leads to death of fish and human as well as
+
contamination of fresh water. However, M. aeruginosa also poses ecological
+
value in oxygen synthesis and absorption in heavy metal.<o:p></o:p></span></p>
+
  
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
<h4>ii. News Articles</h4>
EN-US"><o:p>&nbsp;</o:p></span></p>
+
<p>Cyanobacterial bloom has always been a global concern. Countries from all around the world, especially countries with agricultural industries. New articles from around the world have shown economic losses and environmental damages caused by algal blooms. Severe cases of blue-green algal blooms resulted in the contamination of fresh water sources. Recreational activities in nearby areas have to be banned. Inspired by these articles, we hope to solve the problem of the accumulation of toxic substances produced by harmful algal blooms.</p>
 +
UK: https://www.bbc.com/news/uk-49344232
 +
China: https://chinadialogueocean.net/2959-algal-blooms-are-starving-chinas-seas-of-oxygen/
 +
US Texas: https://www.kwtx.com/content/news/Blue-green-algae-lethal-to-dogs-also-can-affect-humans-547547641.html
 +
US Iowa: https://www.iowapublicradio.org/post/toxic-bacteria-blooms-impacting-water-systems-across-iowa-dnr-survey-shows#stream/0
 +
Lake Erie: https://www.accuweather.com/en/weather-news/vibrant-green-algae-overwhelming-lake-erie-visible-from-outer-space/70008969
 +
Canada: https://globalnews.ca/news/5660170/saint-john-river-blue-green-algae/
  
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
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<h4>iii. Trips</h4>
EN-US">We can see how these cyanobacteria have such a significant impact on the
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<h5>T-PARK</h5>
aquatic system which could subject to adverse impacts on the aquatic ecosystem
+
<p>We visited T-PARK, at Tuen Mun Hong Kong, near Deep Bay. This picture is taken facing Shen Zhen. Oyster fisheries are common there. As seen from the photo, certain areas were found to be green. We were unsure whether the green patches are algae or not, and decided to conduct further investigation. </p>
as a whole. Take Lake <span class="SpellE">Taihu</span> as an example; the algae
+
blooms are a serious threat to drinking water supplies and agriculture
+
supplies. Chinese ecologists and marine biologists describe the lake as the
+
smell of decaying fish. In the United States, such harmful cyanobacterial algae
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blooms have inflicted around 2 billion USD a year in losses as the water is
+
unfit for drinking, recreation and agriculture.<o:p></o:p></span></p>
+
 
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<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
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EN-US"><o:p>&nbsp;</o:p></span></p>
+
 
+
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
EN-US">Through investigation on the cause of algae blooms, we found out that
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farmland and factories are usually built next to rivers and lakes, as water is
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vital for both agriculture and industrial uses. Since chemical fertilizers and
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sewage all contain nitrates and phosphates, this catalyzes the reproduction of
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cyanobacteria such as Microcystis Aeruginosa. However, we realized that
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limiting the use of fertilizers and the amount of sewage released from
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factories are impractical because this would affect the efficiency of
+
production.<o:p></o:p></span></p>
+
 
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<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
EN-US"><o:p>&nbsp;</o:p></span></p>
+
 
+
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
EN-US">Therefore, instead of limiting the use of such fertilizers, our project
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not only aims to mutate M. aeruginosa through modifying its toxin-producing
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gene but also aims to characterize the cyanobacteria’s ability to absorb heavy
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metal. Dcas9 is transformed into and co-expressed in the toxin-producing gene
+
in Microcystis aeruginosa. As dcas9 serves the purpose to block transcription,
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the transcription of the toxin-producing gene cannot be carried out. Hence the
+
toxin-producing ability of M. aeruginosa is eliminated.<o:p></o:p></span></p>
+
 
+
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
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EN-US"><o:p>&nbsp;</o:p></span></p>
+
 
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<p class="MsoNormal" style="line-height:150%"><o:p>&nbsp;</o:p></p>
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<p class="MsoNormal" style="line-height:150%"><o:p>&nbsp;</o:p></p>
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<p class="MsoNormal" style="line-height:150%"><o:p>&nbsp;</o:p></p>
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<p class="MsoNormal" style="line-height:150%"><o:p>&nbsp;</o:p></p>
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<p class="MsoNormal" style="line-height:150%">Bibliography:</p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm"><span class="SpellE">Forastier</span>,
+
Marina Elizabet, et al. “Occurrence and Toxicity of Microcystis Aeruginosa
+
(Cyanobacteria) in the Paraná River, Downstream of the <span class="SpellE">Yacyretá</span>
+
Dam (Argentina).” <span class="SpellE"><i>Revista</i></span><i> De <span class="SpellE">Biologia</span> Tropical</i>, U.S. National Library of Medicine,
+
Mar. 2016, <a href="http://www.ncbi.nlm.nih.gov/pubmed/28862419">www.ncbi.nlm.nih.gov/pubmed/28862419</a>.
+
Accessed 21 May 2019.</p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm"><span class="SpellE">Giannuzzi</span>,
+
Leda, et al. “An Acute Case of Intoxication with Cyanobacteria and Cyanotoxins
+
in Recreational Water in Salto Grande Dam, Argentina.” <i>Marine Drugs</i>,
+
Molecular Diversity Preservation International, 31 Oct. 2011, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229228">www.ncbi.nlm.nih.gov/pmc/articles/PMC3229228</a>.
+
Accessed on 6 Jun 2019.<o:p></o:p></p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm"><o:p>&nbsp;</o:p></p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm">“On Lake <span class="SpellE">Taihu</span>,
+
China Moves To Battle Massive Algae Blooms.” <i>Yale E360</i>, <a href="https://e360.yale.edu/features/on_lake_taihu_china_moves_to_battle_massive_algae_blooms">https://e360.yale.edu/features/on_lake_taihu_china_moves_to_battle_massive_algae_blooms</a>.
+
Accessed on 11 Jun 2019.</p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm">Yan, Hai, et al. “Effects of
+
Nitrogen Forms on the Production of Cyanobacterial Toxin Microcystin-IR by an
+
Isolated Microcystis Aeruginosa.” <i>Journal of Environmental Science and
+
Health. Part A, Toxic/Hazardous Substances &amp; Environmental Engineering</i>,
+
U.S. National Library of Medicine, 2004, <a href="http://www.ncbi.nlm.nih.gov/pubmed/15533019">www.ncbi.nlm.nih.gov/pubmed/15533019</a>.
+
Accessed on 23 Jun 2019.</p>
+
 
+
<p style="margin-left:1.0cm;text-indent:-1.0cm">Zhang, <span class="SpellE">Limin</span>,
+
et al. “Eutrophication Status and Control Strategy of <span class="SpellE">Taihu</span>
+
Lake.” <i>SpringerLink</i>, SP Higher Education Press, 6 Aug. 2008, <a href="http://link.springer.com/article/10.1007/s11783-008-0062-4">link.springer.com/article/10.1007/s11783-008-0062-4</a>.
+
Accessed on 9 Jun 2019.</p>
+
 
+
<p class="MsoNormal"><span style="font-family:&quot;Times New Roman&quot;,serif;mso-fareast-font-family:
+
&quot;Times New Roman&quot;"><o:p>&nbsp;</o:p></span></p>
+
 
+
<p class="MsoNormal" style="line-height:150%"><o:p>&nbsp;</o:p></p>
+
 
+
<p class="MsoNormal" style="line-height:150%"><span lang="EN-US" style="mso-ansi-language:
+
EN-US"><o:p>&nbsp;</o:p></span></p>
+
 
+
</div>
+
  
 +
<h5>Hiking</h5>
 +
<p>Some team members discovered unusual green patches, which were thought to be algae. We were interested in knowing how these organisms impact our daily lives. As we dwell into this topic, we realized that cyanobacteria can bring both benefits and disadvantages to the ecological system. Therefore, we decided to design a project that minimizes the harms that cyanobacteria may bring. </p>
 +
Photo taken at Yuk Kwai Shan, Hong Kong
  
 +
<h3>Goals of project</h3>
 +
<p>The goal of our project is to remove Microcystin production from cyanobacteria Microcystis, without lysing or changing other characteristics in the cell. This is because Microcystis has its benefits in heavy metal sorption, supplying us with oxygen and many other more. We aim to maintain these abilities in Microcystis, while silencing its toxin producing gene. </p>
  
 +
<h3>Usage of synthetic biology</h3>
 +
<p>We used synthetic biology as the in vivo expression system in our design will not affect other species in the aquatic environment. This will pose minimal effects on the environment, while successfully silencing the toxin producing gene. </p>
  
 
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Revision as of 06:57, 20 October 2019

Abstract/ Overview

Microcystis aeruginosa is one of the most common cyanobacteria responsible for harmful algal blooms. This cyanobacterium produces microcystin, a hepatotoxin that damages the liver. However, direct lysis of Microcystis aeruginosa may not best for the environment as it holds ecological values of heavy metal sorption and oxygen synthesis. In this project, we hope to silence the microcystin biosynthesis cluster(mcy) using a catalytically dead Cas9 (dCas9) enzyme lacking endonuclease activity. When the dCas9 enzyme is co-expressed with a guide RNA(sgRNA), the dCas9-sgRNA complex specifically binds to the McyB gene and blocks transcript elongation, leading to the repression of the McyB gene without altering the chromosome of the Microcystis. Here we provide the design of a dCas9-sgRNA expression gene in a shuttle vector that can replicate in both E.coli and cyanobacteria. We will also be conducting downstream analysis to see how our dCas9-sgRNA expression plasmid affects the microcystin-production rate and oxygen synthesis rate of Microcystis.

Project Inspiration

Our project is inspired from various aspects, including school lessons, books, news articles hiking trips, and even previous iGEM teams.

i. School lessons:

Chemistry:

We’ve learnt that certain species of cyanobacteria is capable of nitrogen fixation. We understand the ecological importance of nitrogen fixation. Microcystis aeruginosa can carry out metal sorption. However, they also produce neurotoxins and hepatotoxins, microcystin. These cyclic heptapeptides can cause lethal consequences.

Chemical structure of Microcystin-LR
Biology:

We have learnt the cellular structure of cyanobacteria. From teachers and text books, we have had a brief understanding in how photosynthesis is carried out in cyanobacteria. More than half of the world’s oxygen is produced via phytoplankton (including cyanobacteria). On the contrary, we are aware that the bloom of cyanobacteria will blocked sunlight and slow down the photosynthesis rate of other water plants. Certain cyanobacteria (including Microcystis) may even produce toxins that inhibit certain enzymes in animals.

https://www.usgs.gov/media/images/microcystis-aeruginosa-microscopic-view Accessed on 18/8
Geography:

Through studies in soil and water sources, we learnt how excessive use of fertilizers create eutrophic waters, which gives rise to cyanobacterial blooms. Teachers also taught us how global warming raises the temperature, which favours the rapid growth of cyanobacteria (especially Microcystis Aeruginosa).

ii. News Articles

Cyanobacterial bloom has always been a global concern. Countries from all around the world, especially countries with agricultural industries. New articles from around the world have shown economic losses and environmental damages caused by algal blooms. Severe cases of blue-green algal blooms resulted in the contamination of fresh water sources. Recreational activities in nearby areas have to be banned. Inspired by these articles, we hope to solve the problem of the accumulation of toxic substances produced by harmful algal blooms.

UK: https://www.bbc.com/news/uk-49344232 China: https://chinadialogueocean.net/2959-algal-blooms-are-starving-chinas-seas-of-oxygen/ US Texas: https://www.kwtx.com/content/news/Blue-green-algae-lethal-to-dogs-also-can-affect-humans-547547641.html US Iowa: https://www.iowapublicradio.org/post/toxic-bacteria-blooms-impacting-water-systems-across-iowa-dnr-survey-shows#stream/0 Lake Erie: https://www.accuweather.com/en/weather-news/vibrant-green-algae-overwhelming-lake-erie-visible-from-outer-space/70008969 Canada: https://globalnews.ca/news/5660170/saint-john-river-blue-green-algae/

iii. Trips

T-PARK

We visited T-PARK, at Tuen Mun Hong Kong, near Deep Bay. This picture is taken facing Shen Zhen. Oyster fisheries are common there. As seen from the photo, certain areas were found to be green. We were unsure whether the green patches are algae or not, and decided to conduct further investigation.

Hiking

Some team members discovered unusual green patches, which were thought to be algae. We were interested in knowing how these organisms impact our daily lives. As we dwell into this topic, we realized that cyanobacteria can bring both benefits and disadvantages to the ecological system. Therefore, we decided to design a project that minimizes the harms that cyanobacteria may bring.

Photo taken at Yuk Kwai Shan, Hong Kong

Goals of project

The goal of our project is to remove Microcystin production from cyanobacteria Microcystis, without lysing or changing other characteristics in the cell. This is because Microcystis has its benefits in heavy metal sorption, supplying us with oxygen and many other more. We aim to maintain these abilities in Microcystis, while silencing its toxin producing gene.

Usage of synthetic biology

We used synthetic biology as the in vivo expression system in our design will not affect other species in the aquatic environment. This will pose minimal effects on the environment, while successfully silencing the toxin producing gene.