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From 2014hs.igem.org

Who are we?

We are high school students at Tecnológico de Monterrey, Mexico City Campus, a team with juniors and seniors working together. What made us a team was our passion for science, we all wanted to innovate, to create, to surprise and engine something useful. Our goal is to prove that if you plan on doing something, no matter what, you can achieve it with the right focus.

The team has been together for six months, though people have been coming aboard from time to time along the way. At first the group was put together so we could have more chemistry lessons at school, then some of our team members went to the chemistry olympics and when they came back, successful, we decided to join the iGEM project. Since August 2013, we have officially acquired the status of student group in the ITESM. Our president, Diego Molas, is really talented, prepared and dedicated. He has been working with high level chemistry since february 2013 and acquired a lot of advanced knowledge by participating in the Mexico City’s Chemistry Olympics. He was priced in the Mexico City preselection for the Mexico´s National Chemistry Olympics. In this stage of the contest he achieved the first place. All together we are 13 high school students from different years, Yael Suárez López, Daniel Aragón, Carlos MartÍnez Fornos from 3th year; Diego Hernández Molas, Gonzalo Escalante Sanjurjo, Bernardo Castillo Montes, Luis Isaías Cabrera, Luis Alfonso Soriano Pérez, Sergio Gonzales García and Maria Fernanda Rosellón from 2nd year; and Kai Kawasaki Ueda and Ingrid Guadalupe Geminiano López from 1st year. As a team of teens we need someone to guide us, that’s why we have two coaches. Jessica Flood is our main coach, and has given some of us general chemistry and biological chemistry lessons at school. She is always supportive, though she never tells us the direct answers allowing us to learn by trial and error making us think, ergo we acquire knowledge and retain it. Jessica Flood studied Chemical Sciences at UDLA-P, México (Universidad de las Américas Puebla) and later she achieved a Master degree in Science with a specialization in Biological Chemistry at the University of Toronto, Canada. Her main focus is bioinorganic chemistry, her research being done in copper chemotherapeutic agents and interaction of metal ions with proteins and enzymes. Our secondary coach is Cinthya Fernandez, who’s taught us the basics of synthetic biology. There are three more important sub-coaches, Mariana Fichtner Usela, Gerry Santiago Toledo and Said Muñoz Montero. They have already graduated from college studying their Bachelor at Tecnológico de Monterrey, Mexico City Campus as Biotechnology Engineers, they help us mainly by making us aware of what we are capable of doing and giving us alternatives, in order to avoid derailing from achievable goals and proposing incoherent theories.

Project Description

The main idea of our project is to achieve the detection of anoxia and heavy metal pollution in water systems. What we propose is to construct an easy way of monitoring the levels of O2, Pb and Fe in the lake by using biosensors. By using modified bacteria E. coli for this, we will try to find a cheaper, easier, and faster way to detect the problem of anoxia and heavy metals in some aquifers of Mexico City. We will have to analyze samples of water at different depths to know where the problem is worse and what probable native species could be more affected.

The benefits of using biosensors instead of other sensing methods are:

• A fast response in time

• A fast and continuous measurement • High specificity because of its shape-specific recognition • Simplicity in its use • Capability of measuring concentrations ranging from 10-18 to 10-19 M, so we need low sample requirements. • Capability of real time measurements

To achieve the objective using E. Coli we will construct different types of modified plasmids for our bacteria to express the biosensors. The idea is to use sensitive promoters: one for oxygen, another one for lead and another one for iron; those promoters will lead to an expression of GFP or luciferase. This will provide a visual signal to indicate the presence or absence of these elements.

Our promoters will start working when a certain concentration of oxygen is present in the samples. The oxygen promoter will be used to prove if the water sample that you’re plugging in is anoxic (lack of oxygen in water) or not. By detecting this aspect we will open the possibility for finding a solution to the problem at the right time, whether if it is caused by eutrophication (this is caused by the excess of phosphates, nitrates and hydrogen sulfurs in the environment), which can be caused mostly by human industrial activity and deposition of wastes in the water, or other elements present in the ecosystem. The iron and lead promoters will be used to detect certain concentrations of heavy metals in the water, which are harmful to the ecosystem and the living organisms living there. Anoxia and heavy metal pollution (lead, arsenic, among others) are especially serious, since it makes water useless or very dangerous for any agricultural/industrial process and also turns it undrinkable for human beings and animals, leading to widespread infections and illnesses, without taking into account the environmental contamination and alteration it causes in some lakes in Mexico. Any water ecosystem is considered hypoxic when it has levels of less than 2.8 mg of dissolved O2 in 100 mL of water (Saldías et al, 2008). Anoxia is defined as the lack of oxygen, a condition that could potentially threaten this endemic specie that rely on the presence of molecular oxygen in the water. On the other hand, lead toxicity in water is of 0.01 mL /L, by knowing the presence of this pollutant in specific aquifers, we could be able to find a solution like purification. This will make the water liveable for the inhabiting organisms and, with the proper purification techniques, it could even be a drinkable or used for other human uses.

Dissolved oxygen (DO) is one of the most important indicators of water quality. The normal values of dissolved oxygen in water are between 7.0 and 8.0 mg/L (Roldan, G. 2003). Air is the principal source of oxygen and it dissolves in water quickly because of the rivers´ turbulence and the wind on lakes. All aquatic life depends on dissolved oxygen in water. Terrestrial organisms can live in an atmosphere with 20% of oxygen, but aquatic organisms can survive with a lower concentration. However, the minimal requirement for aquatic fauna to survive when it comes to oxygen dissolved in the water is 6.0 mg/L; a result obtained in 2011 shows that Xochimilco, an important lake in the southern part of the city only has around 3.0 mg/L, which is merely half of the minimum requirement (Q. Ashton Acton, 2011). The main reason for the decrease in dissolved oxygen concentration in water is eutrophication. Eutrophication is the condition in which there is an excess of water plant population. These plants deplete the available dissolved oxygen, this is why the oxygen levels are reduced to critical points in which the live of some animal species is threatened. There are different causes of eutrophication such as the introduction of a great amount of nutrients, nitrogen or phosphorus by sewage or by agriculture fertilizers. Also the deforestation can introduce a great amount of nutrients because the rains take with the current the nutrients from the undercover soil. (Muir, 2012) The great amounts of nutrients leads to the massive reproduction of plants that consume the oxygen dissolved in water.

According to the Ecological Institute of the Mexican Autonomous National University (UNAM), in August 25, 2013 there was a massive death of Tilapia in one of the affluents of Xochimilco in part caused by the decrease of oxygen levels to almost zero (Hiriat and Gonzalez, 2014), when it needs 4.5 grams of O2 for every 45 kg of fish/hour when resting, but it needs at least three times more oxygen when feeding or in action (Rakocy, 1989). Other endemic and endangered especie in the zone is Ambystoma mexicanum, also called axolotl which also needs a minimum amount of oxygen in water. This problem of anoxia was linked to the discharge of sewage water from the city. Sewage waters contribute to eutrophication because they contain a lot of nitrates and other nutrients which favor the growth of some aquatic plants which deplete the oxygen.

We want to focus in the water of Xochimilco, because, as we have said, it is one of the most important lakes in Mexico near us and this makes it better to work with. Also this lake provides water to a lot of parts in Mexico’s city, such as the delegations of Xochimilco and part of Tláhuac, where the water from the lake Xochimilco is used for agriculture, such as irrigation of chinampas, which are a prehispanic way of cultivating. The zone of Xochimilco has certain influence over the weather in the zone, a touristic place, and something very important: it is an archeological zone and a World Heritage Site. Any problem in Xochimilco can affect the zone economically, environmentally, and the tradition of planting in chinampas that can be lost if there is a problem with the water of the lake.

References

Ajit Sadana. “Biosensors: Kintectics of Binding and dissociation using fractals.” Elsevier, 2003. “Biosensor Technology: Advantages and applications.” 2014. Azosensors. March 3, 2014 <<a href="http://www.azosensors.com/article.aspx?ArticleID=402" class="external free" rel="nofollow">http://www.azosensors.com/article.aspx?ArticleID=402</a>>.

Chaparro, Diego de Jesús and Nandini, Sarma. “Effects of water quality on the feeding ecology of axolotl Ambystoma mexicanum.” November 21, 2013. Journal of Limnology. February 27, 2014 <<a href="http://www.jlimnol.it/index.php/jlimnol/article/view/jlimnol.2013.e46" class="external free" rel="nofollow">http://www.jlimnol.it/index.php/jlimnol/article/view/jlimnol.2013.e46</a>>.

Cisneros, Roberto and Zambrano, Luis. “Aplicaciones prácticas para la conservación y restauración de humedales y otros ecosistemas acuáticos.” n.d. Instituto Nacional de Ecología y Cambio Climático. February 27, 2014 <<a href="http://www2.inecc.gob.mx/publicaciones/libros/533/aplicaciones.pdf" class="external free" rel="nofollow">http://www2.inecc.gob.mx/publicaciones/libros/533/aplicaciones.pdf</a>>.

Cisterna, José, Saldías, Gonzalo, and Cáceres, Cristian. “Efecto de la hipoxia en la conducta de forrajero de Cancer setosus alimentado con Mytilus chilensis.” August 2008. Scientific Electronic Library Online Chile. February 27, 2014 <<a href="http://www.scielo.cl/scielo.php?pid=S0718-19572008000200018&script=sci_arttext" class="external free" rel="nofollow">http://www.scielo.cl/scielo.php?pid=S0718-19572008000200018&script=sci_arttext</a>>.

Diaz, Robert and Solow, Andrew. “Ecological and Economic Consequences of Hypoxia.” May 1999. NOAA Coastal Ocean Program. February 27, 2014 <<a href="http://www.cop.noaa.gov/pubs/das/das16.pdf" class="external free" rel="nofollow">http://www.cop.noaa.gov/pubs/das/das16.pdf</a>>. Díaz, Robert, Rabalais, Nancy and Breitburg, Denise. “Agriculture´s Impact on Aquaculture: Hypoxia and Eutrophication in Marine Waters.” 2012. Organisation for Economic Co-operation and Development. February 27, 2014 <<a href="http://www.oecd.org/tad/sustainable-agriculture/49841630.pdf" class="external free" rel="nofollow">http://www.oecd.org/tad/sustainable-agriculture/49841630.pdf</a>>.

Franco Moreno, Daniela Paola et al. “Métodos para identificar, diagnosticar y evaluar el grado de eutrofia.” November 9, 2010. Universidad Autónoma Metropolitana. March 3, 2014 <<a href="http://www.izt.uam.mx/newpage/contactos/anterior/n78ne/eutrofia2.pdf" class="external free" rel="nofollow">http://www.izt.uam.mx/newpage/contactos/anterior/n78ne/eutrofia2.pdf</a>>.

Juárez, Luis Alfredo et al. “Microbiological indicators of water quality in the Xochimilco canals, Mexico City.” July 18, 2013. Salud Pública de México. February 27, 2014 <<a href="http://bvs.insp.mx/rsp/articulos/articulo.php?id=000421" class="external free" rel="nofollow">http://bvs.insp.mx/rsp/articulos/articulo.php?id=000421</a>>. Mazari Hiriart, M and Zambrano González, L. “La Fauna de Xochimilco en problemas.” January 21, 2014. Instituto de Ecología de la UNAM. February 27, 2014 <<a href="http://web.ecologia.unam.mx/proyectos/index.php?proyecto=La_Fauna_de_Xochimilco_en_problemas" class="external free" rel="nofollow">http://web.ecologia.unam.mx/proyectos/index.php?proyecto=La_Fauna_de_Xochimilco_en_problemas</a>>.

“Mercurio Hg.” 2014. Lenntech. February 27, 2014 <<a href="http://www.lenntech.es/periodica/elementos/hg.htm" class="external free" rel="nofollow">http://www.lenntech.es/periodica/elementos/hg.htm</a>>. Q. Ashton Acton. “Issues in global environment: freshwater and marine environments.” 2011 Edition. Scholarly Editions <<a href="http://books.google.com.mx/books?id=QZX8ZlVEW98C&pg=PT295&lpg=PT295&dq=Dissolved+o2+in+Xochimilco+3+mg/l&source=bl&ots=K7cv76s-p-&sig=LP3KrxUUeUrpKQP9ENIFHI4IOdo&hl=en&sa=X&ei=PBEVU4LKFcjg2gXSwIHwBA&ved=0CCYQ6AEwAA#v=onepage&q=Dissolved%20o2%20in%20Xochimilco%203%20mg%2Fl&f=false" class="external free" rel="nofollow">http://books.google.com.mx/books?id=QZX8ZlVEW98C&pg=PT295&lpg=PT295&dq=Dissolved+o2+in+Xochimilco+3+mg/l&source=bl&ots=K7cv76s-p-&sig=LP3KrxUUeUrpKQP9ENIFHI4IOdo&hl=en&sa=X&ei=PBEVU4LKFcjg2gXSwIHwBA&ved=0CCYQ6AEwAA#v=onepage&q=Dissolved%20o2%20in%20Xochimilco%203%20mg%2Fl&f=false</a>>.

Rakocy, James. “Tank Culture of Tilapia.” September, 1989. California Aquaculture. March 4, 2014 <<a href="http://aqua.ucdavis.edu/DatabaseRoot/pdf/282FS.PDF" class="external free" rel="nofollow">http://aqua.ucdavis.edu/DatabaseRoot/pdf/282FS.PDF</a>>. Roldán, G. (2003). Bioindicación de la calidad del agua en Colombia. Colombia: Universidad de Antioquia. Romero, Efrén. “Xochimilco, un enfermo que muere.” December 18, 2013. Despertar Xochimilco. February 27, 2014 <<a href="http://despertarxochimilco.org/xochimilco-un-enfermo-que-muere/" class="external free" rel="nofollow">http://despertarxochimilco.org/xochimilco-un-enfermo-que-muere/</a>>.

Yovita John Mallya. “The effects of dissolved oxygen on fish growth in aquaculture.” 2007. The United Nations University <<a href="http://www.unuftp.is/static/fellows/document/yovita07prf.pdf" class="external free" rel="nofollow">http://www.unuftp.is/static/fellows/document/yovita07prf.pdf</a>>. Muir Patricia. "1. EUTROPHICATION." 1. EUTROPHICATION. Oregon State University, 29 Oct. 2012. Web. 05 Mar. 2014. <<a href="http://people.oregonstate.edu/~muirp/eutrophi.htm" class="external free" rel="nofollow">http://people.oregonstate.edu/~muirp/eutrophi.htm</a>>.