iGEM Bielefeld 2015

Welcome!

This wiki is currently under construction.

Our Project

The Problem

Drinking water is the most basic of all resources, but its global exposure to toxic substances is a big problem. In particular, heavy metals endanger the health of millions of people. These metals occur naturally in small amounts in the earth’s crust. However, by erosion or human activities, such as mining or agricultures, they are released and can accumulate in soils and waters. That is why the groundwater in many regions of the world is contaminated for example with arsenic. Among others India and Bangladesh are particularly affected by this issue. In Germany, drinking water is often referred to as the cleanest in the world. However, heavy metal contaminations may occur here as well, for example caused by old lead pipes. Since these last meters of water transport normally are not controlled, such contaminations often remain undetected for a quite long time.

While some heavy metals are essential as trace elements, others lead already in low concentrations to health consequences. But in any case, the intake of larger amounts of heavy metals entail a variety of serious diseases such as nerve damage, cancer and even can lead to death. Therefore it is essential to control the heavy metal content of water and food. To enable this, a simple favorable and at the same time secure analytics is required. As laboratory tests and conventional test kits do not meet these requirements, we decided to establish a biosensor for various heavy metals.

The second topic we want to deal with is motivated by the fact that recently crimes in which so-called knock-out-drugs (date-rape-drugs?) were used become more frequent in our region. These drugs are usually a mixture of different substances which produce narcotic effects and thus make the victim unable to act and defenseless. By now the evidence of knock-out-drugs is only possible in retrospect in the laboratory and this just in a limited time frame. However there is no opportunity for checking suspicious drinks quickly and easily. We want to change this by developing a biosensor for the detection of knock-out-drugs.

The Detection System

Many organisms have genes that make them resistant to toxic substances or enabling the use of particular nutrients. However, these genes are only required if the relevant substance is actually available. A permanent expression would be an unnecessary waste of energy for the organism. Therefore, control mechanisms have evolved ensuring the identification of specific substances to allow expression of certain genes only in presence of this substance.

The lac-operon which is required for the metabolism of lactose in Escherichia coli and many other bacteria is a classic example for such a mechanism. In absence of lactose, a repressor protein binds to the operator site of the lac-operon thereby obstructing the binding of the RNA polymerase to the promoter. Consequently there is no mRNA transcript of the following lac-genes. As the repressor is an allosteric protein it may assume two different shapes. In presence of lactose the inducer allolactose binds to the repressor triggering a conformational change. As a result the repressor releases the operator DNA and thus allows the RNA polymerase to bind to the promotor and express the genes.

In some bacteria similar systems enable the resistance to certain heavy metals. For instance there are bacteria which are able to grow in presence of arsenic, because they have a mechanism for carrying the heavy metal out of the cell. The required pump for this process is only formed when a specific repressor was previously inactivated by the binding of arsenic.

These natural mechanisms can be used to construct biosensors. Therefore, the genes that are naturally activated in the presence of a particular substance are replaced by a reporter gene. If this reporter gene is expressed, it provides a measurable signal. This signal may be, for example, a color change or a fluorescence signal.

Such biosensors allow a highly specific detection of minute amounts of a substance. Moreover, biosensors can be produced inexpensively whereby they are in particular of interest to developing countries.

Our Biosensor

Although, researchers are already working for many years on biosensors, they have not yet arrived in everyday life. This can be explained with the fact that sensors based on living microorganisms create a number of problems. This involves on the one hand legal and security issues - since working with genetically modified organisms, their release into the environment must be prevented. On the other hand, these sensors are often not very user-friendly, as the application outside the laboratory is complicated and the living cells have a limited suitability for storage. In order to solve these problems and thus make biosensors applicable in everyday life, we are working on two cell free systems for our biosensor.

Our first concept is based on the in vitro transcription and translation including protein biosynthesis outside of a living organism. It is already known that there is the possibility to run this central process in a cell extract. For this purpose the cells are disrupted and an energy-source as well as other supplements is added. This concept is beneficial for example when a protein has to be produced which is toxic for the living cell.

Recently, it has been shown that it is possible to make the cell extract storable for a long time by freeze-drying it on paper. With this freeze-dried cell extract protein synthesis was even possible after one year of storage at room temperature only by adding water. In our opinion, this system is very promising for the development of easy-to-handle biosensors. Currently, we are working on the production of a cell extract and we intend to develop a test strip for heavy metals and knock-out drugs.

In parallel, we are working on a second concept that works with isolated proteins and DNA. This system is based on the interaction between a repressor protein and DNA. Thereby the repressor is immobilized on a surface and binds a small DNA molecule that carries its recognition sequence. Now, adding a water sample that contains the corresponding inducer causes a loss of the repressor-DNA-interaction and the DNA becomes detached. By labeling the DNA, for example with a fluorescent dye, it is possible to detect whether the sample contains a certain substance or not. In this concept a loss of the signal implies the presence of the sought substance.
The advantages of this system are its simplicity and thus its potential robustness. Furthermore, it works completely cell free and is therefore very interesting regarding biosafety.

Welcome to iGEM 2015!

Your team has been approved and you are ready to start the iGEM season!

Before you start:

Please read the following pages:

Styling your wiki

You may style this page as you like or you can simply leave the style as it is. You can easily keep the styling and edit the content of these default wiki pages with your project information and completely fulfill the requirement to document your project.

While you may not win Best Wiki with this styling, your team is still eligible for all other awards. This default wiki meets the requirements, it improves navigability and ease of use for visitors, and you should not feel it is necessary to style beyond what has been provided.

Editing your wiki

On this page you can document your project, introduce your team members, document your progress and share your iGEM experience with the rest of the world!

Click here to edit this page!

See tips on how to edit your wiki on the Template Documentation page.

Templates

This year we have created templates for teams to use freely. More information on how to use and edit the templates can be found on the Template Documentation page.

Tips

This wiki will be your team’s first interaction with the rest of the world, so here are a few tips to help you get started:

State your accomplishments! Tell people what you have achieved from the start.
Be clear about what you are doing and how you plan to do this.
You have a global audience! Consider the different backgrounds that your users come from.
Make sure information is easy to find; nothing should be more than 3 clicks away.
Avoid using very small fonts and low contrast colors; information should be easy to read.
Start documenting your project as early as possible; don’t leave anything to the last minute before the Wiki Freeze. For a complete list of deadlines visit the iGEM 2015 calendar
Have lots of fun!

Inspiration

You can also view other team wikis for inspiration! Here are some examples:

Uploading pictures and files

You can upload your pictures and files to the iGEM 2015 server. Remember to keep all your pictures and files within your team's namespace or at least include your team's name in the file name.
When you upload, set the "Destination Filename" to Team:YourOfficialTeamName/NameOfFile.jpg. (If you don't do this, someone else might upload a different file with the same "Destination Filename", and your file would be erased!)

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Team:Bielefeld-CeBiTec