Team:XHD-Wuhan-China/Human Practices
Human Practices
What's the meaning of our project? From the beginning of the iGEM preparation, we struggled to find the answer. In order to let society, know about our project, we used many different ways to show our progress and our achievements. Thus, we conducted our human practices, including the survey and expert interviews, field research, to seek the social impact we could create and explore how society affects our projects.
The beginning of our story
Our project was inspired by the movie：The Martian 2015. The film tells the story of American astronaut mark watney being left on Mars by mistake because of a huge storm. Watney was alone, and the food was only enough for a month. Fortunately, he was a botanist and decided to survive on Mars on his own, waiting for rescue. Watney used homemade fertilizer to grow potatoes on Mars, making the best use of all the materials at hand, and eventually survived on his own, waiting for rescue. This movie has triggered our thinking? Can the soil on Mars be used to plant the plants on earth, especially the various crops that human beings depend on? This problem is not only a scientific thinking about film, but also has some practical.
Background research
We analyse some data with such doubts and found that scientists have always regarded Mars as the first stop for humans to migrate to space, and many countries are also actively exploring the Martian environment. In 2015, NASA publicly released the "Analysis on NASA’s Journey to Mars-Pioneering Next Steps in Space Exploration" report, which is expected to achieve the ultimate goal of manned landing on Mars in 2030. Then we found a document , Inevitable future: space colonization beyond Earth with microbes first. In this article, the author believes that it is almost impossible to explore new planets without carrying or transporting any microbe travelers. In addition, for landing on Mars, many scientists believe that the landing of microorganisms on Mars to improve the quality of Martian soil is the first step in landing on Mars. Based on this background analysis, we set the goal to use microorganisms to transform the Martian soil, which is of scientific significance.
Interview Professor. Ma to determine the direction of our project
When we are learning synthetic biology knowledge and technical basics, we are thinking about how to use synthetic biology technology to implement our projects. We interviewed a synthetic biology expert,Professor Ma, whose professional direction is synthetic biology and systems biology to help us solve the problem. When we mentioned to him that our project was to use microbes to transform the Martian soil, he was very interested in our project and found it meaningful. And he told us that in the 2017 NASA "Innovative Advanced Concepts Program" project analysis, one of the sections was to build a Martian soil improvement synthetic biology framework for agricultural planting. The research mainly used synthetic biology methods to degrade and reduced the perchlorate present in the Martian soil. At the same time, it could also synthesize ammonium salts to make the soil more fertile. The agency intended to select two strains of Pseudomonas aeruginosa that could survive in harsh environments as a breakthrough point to achieve the process of degradation and detoxification and synthesis of ammonium salts respectively, and then merged through biotechnology to achieve the goal.So we did our project as Dr.Ma said to us.
Interview Professor. Chen for project design
After the general direction of the project is determined, the question we further ponder is, which aspect of the soil do we want to transform? And how to transform? We searched for the iGEM team’s Martian soil transformation project.For example, in 2018, an iGEM team: Exeter used synthetic biology to transform E. coli to reduce the content of perchlorate in the Martian soil and release oxygen, so as to achieve the purpose of transforming the planting capacity of Mars soil. Biological selection of E. coli is feasible.
In addition, we contacted a microbiology expert, Professor Chen Wenli, and we learned that the Martian soil contains a lot of phosphorus. However, this part of phosphorus is mostly in the form of insoluble mineral salt ions in the soil, and cannot be directly absorbed and utilized by plants. Therefore, if you want plants to grow healthily on Mars, you must apply phosphate fertilizer to them. Some of the gram-negative bacteria that exist in nature are born with the ability to convert insoluble phosphorus elements into soluble phosphorus elements. Such bacteria are called phosphate solubilizing microorganisms. Its principle of dissolving phosphorus is to catalyze the conversion of glucose into gluconic acid by expressing glucose dehydrogenase (gcd), reduce the pH value of the surrounding soil, promote the dissolution of insoluble phosphate, and finally be absorbed into the body by plant roots and participate in plants Metabolic response. E. coli contains the gcd gene. This method of dissolving phosphorus allows plants to use the insoluble phosphorus in the soil without the need for additional phosphate fertilizer. This method has also been verified in the literature and proved to be feasible. Our idea is to use synthetic biology methods to transfer the gcd gene into a suitable chassis microorganism, transform the microorganism with the ability to dissolve insoluble phosphate, and then put it on Martian soil to help plants grow.
Questionnaire survey
Professional experts and institutions agree that the initial design of our project is meaningful and feasible. In order to gain wider recognition and support from the society and revise our project, we designed a questionnaire to learn about the view of the public and attitudes towards the transformation of Martian soil. The results of the questionnaire show that half of the public are full of expectations for our desire to transform Mars planting plants, and are very supportive of our desire to use phosphorus-melting microorganisms to transform the Martian soil and make basic contributions to human landing on Mars (53.85% of respondents support it, 46.15) % Of people are very supportive.).This method confirms that the theme of our project is positive. On the other hand, the public does not know much about synthetic biology and the iGEM competition (32.37% of people have not heard of it at all), so we need to carry out public science education activities to let more general public know the practical significance of synthetic biology . The results of some of the questions are as follows:
Question 4: Do you know anything about human's project on Mars?
Question 5: What is your attitude toward growing plants on Mars?
Question 7: What do you know about the negative effects of phosphorus deficiency on plants？
Question 10: What is the technology of increasing soil soluble phosphorus by using phosphorus-soluble microorganisms?
Question 15: Do you know anything about the iGEM?
Then, under the guidance of our instructor, we used mathematical modeling to screen gcd genes from different microorganisms. We found that the glucose dehydrogenase (GDH) with the highest enzymatic activity was from E. coli MG1655, so we chose to clone the gcd gene from this bacterium. This work went successfully.
Interview Professor Tian
Selection of Deinococcus radiodurans on Chassis Design of Phosphate Dissolving System
The selection process of Deinococcus radiodurans on the bottom plate is more rugged. At the beginning we planned to use E. coli, because the background information of E. coli is relatively clear, and many iGEM teams have also used E. coli. Including the aforementioned projects to modify the perchlorate content of Martian soil, E. coli is also used. But one of our classmates suddenly thought, wouldn’t it be better if there are radiation-resistant bacteria that can better survive on Mars?
With the help of the Huazhong Agricultural University team, we found Professor Tian from the College of Life Sciences, Zhejiang University. His research field is extreme environmental microbiology.,So we contacted Professor Tian by email. He recommended us a radiation-resistant microorganism: Deinococcus radiodurans. He told us that compared to E. coli, Deinococcus radiodurans has superior radiation resistance and resistance to various extreme environments. It is the most likely known bacteria to survive on Mars. Under the guidance of our instructor, we checked the relevant literature and unexpectedly found that Deinococcus radiodurans constitutively expresses PQQ, which can form holoenzymes with GDH from E. coli and catalyze the production of gluconic acid. This unexpectedly gave us the executable Sex brings hope.
Interview Dr. Dai
Project implementation reflection and seeking help
According to our plan, using E. coli commonly used plasmids (pSB1C3 or pUC19) to construct gene circuit and transform it into Deinococcus radiodurans, but the result failed. With such difficulties, we contacted Professor.Tian again. His student Dr. Dai told us that the plasmid in E. coli cannot be replicated in Deinococcus radiodurans, but the shuttle plasmid has two origins of replication, corresponding to the replication of the two hosts. It can be replicated and expressed in E. coli and Deinococcus radiodurans, then they sent us pRADK, pRADG shuttle plasmids and plasmid profiles. This successfully promoted our project implementation.
Integrated Human Practices
Our project was inspired by a movie. From the initial brainstorming to the final project development and the results, Human Practice activities have given us a lot of help, and adjusted and influenced our project direction.
1. Many scientists believe that the landing of microorganisms on Mars to improve the quality of Martian soil is the first step in landing on Mars. Moreover, the development of synthetic biology has played a very important role in transforming the quality of Martian soil. The results of the background investigation allowed our initial ideas to be supported and recognized.
2. In the analysis of the results of the questionnaire survey of the general public, it is found that the general public still supports our project very much and is full of hope for the results of our project.
3. During the interview with Professor Chen Wenli, a microbiological expert, she told us that the insoluble phosphorus in Martian soil is very high and cannot be absorbed by plants, and phosphorus is a very important nutrient for plant growth. And gave us a concept, phosphate-solubilizing microbes. This interview prompted us to clarify our project design and theme.
4. After studying iGEM’s Martian soil improvement projects, we also planned to use E. coli as the chassis organism at the beginning, and then during the brainstorming, we wondered whether there are better radiation resistant microorganisms? Then, after interviewing Professor Tian Bing, he recommended Deinococcus radiodurans to us.
5. At the beginning of the experiment we used plasmids in E. coli (pSB1C3 or pUC19) to construct our gene circuit and transform it into Deinococcus radiodurans, but the result failed. We consulted Professor Tian’s team again. His student, Dr. Dai, provided a solution. He gave us pRADK, pRADG shuttle plasmids and plasmid profiles for free. This successfully promoted our project implementation.
