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Outreach: Synthetic Biol. & Space

Examples of Lesson Plans and Activities: Please contact Margaret Saha (mssaha@wm.edu) for more information and for scheduling to use these activites in your classroom.

 

 

Day 1 – Intro to Mars

Overview:

There is more to Mars than red dirt. The environment and minerals found on the Red Planet mean astronauts will face unique challenges both on their journey and once on the planet. However, with careful preparation, scientists can pack for some of these challenges and take full advantage of the resources already on Mars. The first step before a long trip is learning about where you are going, so to begin this series we will investigate what to expect from long term space travel and the ultimate destination…Mars

 

Learning Objectives:

·     Students will consider the use of Earthly diagnostic and measurement tools and their potential uses in space. 

·     Students will review the fundamentals for life found on Earth; water, shelter, nutrients, and atmosphere. 

·     Students will compare and contrast the environments and resources on Mars to those found on Earth and evaluate what components on Mars can become tools for survival. 

·     Students will investigate sampling and testing techniques used to; measure water quality, detect for toxins, take barometric pressure, test for radiation etc. 

 

Activities and Discussions:

The first step is learning how to investigate an environment. Introduce students to a few tools we use on Earth. 

·     Barometers for pressure

·     pH sensors

·     Water testing kits

·     CO2sensors

·     Soil testing kits test for nitrogen, phosphorus and potassium 

·     Biosensors – analytical device

·     Genetically engineered biosensors

 

There are free protocols available if students want to get hands on practice using these tools, many kits come with instructions. 

Ag for life provides a protocol to test for nutrients and pH - http://agricultureforlife.ca/wp-content/uploads/2016/09/Soil-Testing-Experiment-and-Lesson-Plan.pdf

 

University of Wisconsin-Stevens Point provides a protocol for testing physical characteristics of soil. - https://www.uwsp.edu/cnr-ap/leaf/SiteAssets/Pages/School-Forest-Chemistry/Soil%20Lab.pdf

 

One exciting new way for scientists detect toxins or proteins is to use genetically engineered organisms. Bioengineers can edit the genome of an organism causing it to produce florescent protein when a target molecule is present. Some research on how these sensors work can be found here: https://www.ncbi.nlm.nih.gov/books/NBK84465/. Genetic engineering allows researchers to specify which compounds or proteins they want to detect and code a measurable response, we will get more into how this science works in Day 2 – SynBio Tool Kit

After students are comfortable with the diagnostic tools we use to get environmental, students can investigate the environment on Mars. Although Martian soil can be hard to come by, students can conduct research online. A class discussion, lecture or by creating a visual aid with key Martian characteristics can all help students understand what we might expect when we land on Mars. Key traits to include are

·     The average temperature is -80 Fahrenheit

·     There are clouds, dust and wind. Sometimes these cause dust storms

·     Mars has 1/3 the gravity of earth

·     The atmosphere is 100 times thinner than that of Earth. 

o  Mars is; 95.32% CO2, 2.7% N2, 1.6% Ar, .13% O2, .08% CO

o  Earth is; .04% CO2. 78% N2, .93% Ar, 21% O2

·     Earth has a protective magnetosphere which absorbs most of the harmful radiation from the sun. Mars does not have this protective layer. Radiation can result in mutations, cell damage, and cancer. 

·     Mars, as far as we know, has no biodiversity. Humans rely on a diverse diet and microbiome for survival. These will not be available naturally on Mars. 

·     Mars has ice caps, and underground lakes. 

 

Once students have done some digging, younger students can work on recreating a Martian environment. 3-D crafts or even simple drawings may help students see the distinctions between the planets more clearly. When students have a firm grasp on the Mars environment, they can compare Mars and Earth and predict some of the challenges NASA may face when traveling to Mars. Encourage students to think about the fundamental requirements for life on Earth. Things as simple as water, shelter, nutrients and breathable air maybe taken for granted at home, but pose a real challenge on Mars. As students identify challenges they can apply testing methods and what they have learned about the Martian environment to come up with creative solutions. Push students to be creative with their solutions and remember that every additional ounce of weight students want to add to the space ship comes with a fuel cost. The activity sheet below guides students through these questions. 

 

Sources

https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-mars-k4.html

https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html

https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html

https://www.nasa.gov/feature/goddard/real-martians-how-to-protect-astronauts-from-space-radiation-on-mars

https://www.nasa.gov/feature/can-plants-grow-with-mars-soil

 

Day 2 – SynBio Tool Kit

Overview:

The problems we face on earth; food, clean water, clean air, shelter, fuel, medicine, diagnostic tools etc. will all be present on Mars. However, conventional approaches to meeting those needs may not be possible on Mars. Synthetic biology provides a new set of tools for scientists to use when addressing these needs. 

Synthetic biology or bioengineering is an interdisciplinary field that applies engineering principles to living systems. Scientists use DNA as the blueprints for biological machines, making edits to the sequence to code for new proteins and functions. A prime example of synthetic biology at work is the production of modern insulin, by inserting the human insulin gene into a bacterial cell we are able to collect human insulin from bacteria cultures. A brief history of synthetic biology (Ewen & Collins, 2014) published in Nature in provides a background in the science and provides figures illustrating the components of a synthetic circuit. 

 

Learning Objectives:

·     Students will be able to design a simple genetic circuit including all its key components; promoter, ribosome binding site, coding sequence and terminator 

·     Students will investigate and understand CRISPR Cas9 as a method for gene editing

·     Students will investigate and understand the use of transformations as a means to insert genetic material into a host bacterium

 

Activities and Discussions:

Genetic circuits require 4 major components, promoters, ribosome binding sites, target coding sequences and a terminator. Small electrical circuits consisting of an LED light and battery can be a teaching tool to get students comfortable with the needed parts of a circuit. Once students understand that circuits require each part to function properly they can design and draw out their own circuits. 

Once students have designed their own circuits it is time to consider how to get them into a host organism. One method for integrating a new circuit into a host is using CRISPR Cas9. During gene editing, a guide RNA strand shuttles Cas9 to a target sequence where scientists want to cut DNA. The RNA strand can be made highly specific and binds complementary to the DNA target. Cas9 cuts the target DNA breaking both strands. The cells repair machinery will reconnect the DNA strands however, it may repair with mutations, disabling the gene, or if researchers have introduced donor DNA it may be incorporated into the break. The key with CRISPR Cas9 is repeated breaks and repairs, although unlikely that foreign DNA will be integrated into the DNA on the first cycle, guide RNA will continue to bind to the target strand to induce another cut as long as the sequence remains unchanged. Eventually, the break will result in an imperfect repair and the guide RNA will no longer bind. CRISPR Cas9 is used to both knock out target genes as well as introduce new DNA into a host sequence. Once introduced, the cells machinery will read the new DNA and create the desired protein through the traditional transcription and translation process. The benefit of this method is its versatility. Because guide RNA’s can be designed to fit any DNA sequence Cas9 can be modified to cut any part of the DNA strand.

Restriction endonucleases also cut DNA at a specific nucleotide sequence, however, restriction enzymes which come from bacteria are highly specific and cannot be modified like CRISPR Cas9. There are a finite number of sequences that can be cut by restriction enzymes, some of which result in sticky ends while others leave blunt ends. Researches uses these gaps to insert desired DNA into plasmids. When sticky ends are left researchers must be careful that their target DNA sequence has complementary base pairing to those sticky ends. Students can practice being a restriction enzyme in the activities sheet. First students students for the target cut sites, then cut the target site leaving a sticky end. The final step includes incorporating the target DNA into the plasmid by matching up the complementary sticky ends. Once this plasmid is created it can be put into the host cell through a bacterial transformation.  

In a transformation, a competent bacteria cell is exposed to modified plasmids. When a bacterium is competent it is capable of taking up extra cellular DNA. A cell can be made competent with chemicals temperature treatments. Once the cell has taken up the plasmid it can be integrated into the host genome or remain a circularized piece of additional DNA. With every cell replication the plasmid DNA and most importantly the DNA researchers designed will be replicated. The process of transformations is covered at the bottom of the activities sheet. 

 

Day 3 – Closed Systems

Overview:

One major consideration for long term space travel is the inability to restock supplies. Unlike on Earth astronauts cannot order additional deliverers when supplies run out. They also can’t afford to pact an infinite amount of supplies, space and weight allowances are limited and so learning how reduce waste and recycle resources is incredibly important. Already NASA has done an excellent job creating systems for water reclamation and nutrient dense food sources for space travelers, as trips grow longer more recycling strategies will become vital. The ultimate recycling machine is a closed system, in which resources move through a cycle rather than being collected, used, and discarded. 

 

Learning Objectives:

·      Students will be introduced to an existing closed life support system  

·      Students will begin contemplating areas for synthetic biology to improve closed life support systems

·      Students will begin asking critical questions about the sustainability of life on Mars

 

Activities and Discussions:

Ecosystems on Earth are full of closed cycles which reuse the same water, nutrients and matter, often times these ecosystems appear to be very large, and their size helps insure organisms have ample resources to survive. However, more important than the size of the ecosystem, is its ability to remain balanced. Very small ecosystems like those in ponds or even puddles are able to carry on because systems find a stable equilibrium. To help students understand how small ecosystems can be effective they can create their own in a bottle. There are ample resources with suggestions on what to include in these small terrariums, but students should focus on the contributions each organism makes to the system, and what waste they produce. Before students build their ecosystems they should think through a design, considering each addition and evaluating if it would 1. Have all it needs to survive, 2. Contribute to the system, 3. Out compete other components of the system, use too many resources or create unusable waste.

Once students have considered their own small ecosystem, MELISSA can act as an example of a human closed ecosystem. MELISSA (Micro-Ecology Life-Support System Alternative) is a European Space Agency project set up as a model for regenerative life-support systems. Additional information can be found in Melissa: The European project of a closed life support systemby Christopher Lasseur, found at https://www.researchgate.net/publication/253263459.

            As a conceptual project, students can work on building a closed system to meet just one human need during space travel. 

 

Sources

https://www.researchgate.net/publication/253263459.