Team:XJTU-China/Human Practices
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XJTU-China
Table of Contents
Overview
Throughout the project, our human practices have always insisted on promoting the project and getting feedback.
In the inspiration stage of the project, the data collection on people’s perceptions of desertification status and visits of relevant authoritative institutions for desertification control showed that there is a large demand of desertification control now. But the control methods are limited, and microbial control method has not been promoted in application. This inspired us to build a more efficient microbial sand control system to help combat desertification as much as possible. After discussing with many professors of desertification control, we started the project of symbiosis of cyanobacteria and Bacillus subtilis.
In the implementation stage of the project, in order to test the content of moisture, inorganic salt, organic matter and so on of desert soil samples to provide data for model construction, we contacted students in different desertified areas to mail soil samples for us, which solved our problem of lack of real soil data. During the wet experiment, we encountered problems such as how to make cyanobacteria and Bacillus subtilis symbiosis in a proper way, and how to simulate the desert environment by the desert climate simulation incubator. At that time, our own knowledge could not effectively solve these problems. Therefore, we consulted many relevant experts and other iGEM teams across our country, and applied their suggestions to our experiment implementation, the construction of simulation box and the construction of models. At the end, a lot of progress was made.
Regarding to the future of the project, we have received help from the experts in desertification control engineering who try to apply our project in the desert experimental base in the future and further promote our project.
Mind Mapping
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Establishment Stage of Project
Questionnaire related to soil desertification control
A questionnaire was launched in order to learn people’s awareness of the status quo, hazards and control methods of desertification control and their attitudes towards desertification control. The respondents of our survery are mainly young people and the total number is 366.
The survey results shows two problems:
- Little cognition of desertification and desertification control situation：The average level of people’s awareness of desertification (desertification areas and desertification trends) is only a little aware. Regarding the severe situation of desertification control, more than 80% of people think that the form of desertification control is not optimistic, and more than 20% of them think that the current urgent Need to effectively control desertification.
- Weak control effect of desertification area：Approximately half of the people from desertification region believe that the control of their desertification areas are effective but insufficient. 30% of them believe that the desertification control of their areas have only a little effect, and it is necessary to increase the control of desertification.
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Visits of institutions related to desertification control and interviews of experts related to desertification control
Visit of Shaanxi Institute of Desert Control, interview with Professor Zhao Xiaobin and Professor Gao Chao
Group photo with Prof. Zhao Xiaobin and Prof. Gao Chao
Shaanxi Desert Control Research Institute has been committed to the application of comprehensive treatment of plant measures in the field of desertification prevention and control, and has made great progress. Therefore, we visited the institute on August 12 and discussed our project with Professor Zhao Xiaobin and Professor Gao Chao. We have learned a lot about desertification control and how to improve the project.
At first, Professor Zhao Xiaobin and Professor Gao Chao guided us to visit the institute. The two professors told us that the main purpose of sand control is to prevent wind and sandstorms that affect people’s lives and occupy land for human living. They mainly study the methods of planting plants to fix sand, mainly using shrubs, grasses, trees, like Artemisia sphaerocephalia. Small plants can survive stably for about a year or so, while large plants live longer. In addition, the commonly used sand-fixing technology is “grass grid”, in which the dead straw is made into a grid structure to help keep out the wind, with the required sand fixing plants planted in the middle. At present, the laboratory has also used large machines such as automatic tree planting to replace manpower and improve efficiency.
The two professors also provided valuable suggestions for our project. First, we can simulate the conditions of desert in a small range at the laboratory. Placing the bacteria in the grass grid may be more effective. Secondly, for the later stage of crust formation, in order to achieve stable and sustainable development, it is necessary to provide better conditions to cultivate plant communities, prevent simple crusts from being damaged by animals and other factors, and play a role in wind protection. In conclusion, if we want to apply the crust more widely, we must consider the environment where the bacteria are placed and the cultivation of the later plant community.
Thanks to Professor Zhao and Professor Gao for their guidance and suggestions, our project set out to build a desert climate simulation incubator for small-scale simulation experiments, and we also had ideas on what human practice should do next.
Visit of Shaanxi Yulin Rare Sandy-plants Conservation Field
Photo of the Shaanxi Yulin Rare Sandy-plants Conservation Field
It only took a few decades for the Shaanxi Yulin Rare Sandy-plants Conservation Field to transform the flowing sand land with vegetation coverage less than 3% into the fixed sand land with more than 80% vegetation coverage. We came here to figure out how they cultivate sand control plants here.
Through this visit, we learned about the difficulty of growing vital plants on such a barren land in the desert, and cofirmed the feasibility of our microbial method,and keep improving our project.
Visit of Xiaojihan Forest Farm in Yuyang District, interview with Secretary Wang
Group photo with Secretary Wang
The Xiaoji Han Forest Farm in Yuyang District pays more attention to the implementation of desertification in the actual environment. They have a lot of desertification control experience about field plants. On August 14th, we came to Xiaoji Han Forest Farm in Yuyang District. Secretary Wang explained the existing techniques used in sand control to us one by one. First of all, the main function of Pinus sylvestris is to prevent wind, and it has the best effect of changing quicksand. The survival rate of this plant in sand is as high as 90%, which is very rare. Secondly, the sandy cypress plants are low in the desert and tend to spread in a large area in all directions. Finally, the Secretary Wang mentioned that Artemisia sphaerocea and Salix sphaerocephala are very common in the application of desert management. Artemisia sphaerocephala is a small herb, which is widely distributed in clumps. Their growth first needs to be artificially planted, and then the plants reproduce themselves. To prevent themselves from dying, they must be manually cut and re-grown after they have flourished to achieve the best sand fixation effect. When we asked about the key to planting trees, Secretary Wang mentioned that the main restriction is water, and that nutrition and planting density also have a certain impact on plant growth.
Regarding to our project, secretary Wang said, the bacteria obtained from the symbiosis system we designed will play a certain role in desertification control, and the crusts can be produced in only one month, which is very brlliant. However, we need to consider the cost and scope of use of this project, and large-scale use needs to be further optimized.
After discussing with Secretary Wang from the perspective of actual production, we made improvements to the cost and scope of desertification control of our project, so that the desertification control effect can be maximized. At the same time, we also have ideas about what kinds of plant communities we should cultivate in the later stages of crusting to achieve stable development.
Implementation Stage of the Project
Contact with students who help collect desert soil samples
Badain Jaran Desert, Inner Mongolia
Kalamaili Mountain Ungulate Nature Reserve, Xinjiang
In order to test the content of moisture, inorganic salts, organic matter, etc. of desert soil samples to provide data for model construction, we contacted with the members of Zhiyue Walker team and Zhang Yuyan (graduate students of Xi’an Jiaotong University) who were in different desert areas. They respectively conducted environmental research in the Badain Jaran Desert in Inner Mongolia and collected insect specimens in different regions of Xinjiang. We told them about our project design in detail and asked them for collecting desert soil samples. Gratefully, they mailed us soil samples, which solved our problem of lack of real soil data.
Meetup
During the igem competition, in order to improve our project and find out the novel ideas of other iGEM teams, we participated in a series of Meetups.
Southern China Regional Online Meeting
On June 14th，Southern China Regional Online Meeting held by SZU-China. In this meetup We presented one of the three alternatives to brainstorm – glowing plants. We carefully listened to the views and suggestions of other teams on the significance, highlights and feasibility of our project. Although we had high expectations for the luminescent plant project at the beginning, our commitment to the project wavered in our communication with other teams. Other teams spoke highly of this idea, but their worries on the project cycle and other aspects prompted us to think more deeply about the feasibility of the project.
Photos of Southern China Regional Online Meeting
Shaanxi Meetup
On July 25th, all of our team members participated in the discussion with NWU-China-A and NWU-China-B. This was the first time we had meetup since we confirmed the soil reconstruction project. In the communication, three of our teams put forward suggestions on each other’s project. We were surprised to find that the NWU-China-B project required linalool synthase, and we had its gene by chance, so after the meeting, we provided B with our sequence information and plasmid. We also asked NWU-China- A lots of questions about project modeling, and listened to students from Northwestern University.
Xinan Meetup
On July 30, We participated in the Southwest Exchange meeting hosted by BUCT. Teams attending these meetups gave us a lot of plausible suggestions to improve our project. The most important one is to change the focus of our modeling work to the efficiency of the suicide switch. After this meetup, we deeply analyse the mechanism of the suicide system and established accurate model with amazing results.
Photo of Xinan Meetup
Anti-escape system
On August 2nd, we held a meetup on anti-escape systems and had an in-depth discussion with SCU-China and XMU-China on the necessity, ideas and methods of suicide switch design. In the discussion, we finally decided to design our suicide switch based on the arabinose operon.
The 7th Conference of China iGEMer Meetup
August 28th to August 31th, We participated in the 7th CCiC. During the project presentation, the judges raised many challenging questions for our project, which prompted us to think deeply about the project’s ideas and prove the feasibility of the project. After the meeting, we made great efforts to improve the relevant foundation of co-cultivation, which makes our project more reasonable.
Photo of the 7th Conference of China iGEMer Meetup schedule
Interviews
Symbiosis system, polysaccharide extraction identification and modeling
Group photo with Prof. Zhang Yali
How to co-culture cyanobacteria and Bacillus subtilis during the experiment? How to efficiently and quickly determine the production of extracellular polysaccharides? We consulted Professor Zhang Yali, an expert on microorganism cultivation, to solve this question.
She provided us with some feasible suggestions on how to co-culture cyanobacteria and Bacillus subtilis. First, the composition of LB medium and Candida medium BG11 need to be compared, including the supply of carbon source unit, pH, oxidation-reduction potential. Secondly, based on a culture medium, design orthogonal experiments of medium ratio and inoculum ratio to explore the best culture conditions for the growth of the two bacteria.
How to extract and determine polysaccharides efficiently and quickly? Professor Zhang gave empirical steps guidance: Water extraction and alcohol precipitation, namely, adding alcohol to dissolve floc protein → activated carbon adsorption, hydrogen peroxide oxidation → deproteinization with Sevage method → column chromatography, namely, the separation of polysaccharides with different molecular weight sizes. Professor Zhang also adjusted our protocol for determination of polysaccharides, and finally our experimental protocol was greatly simplified.
Finally, we also consulted her about several problems encountered in the process of model building, which was of great help to our experiments and modeling.Thanks to Professor Zhang’s suggestions, we successfully carried out the pre-experiment of co-cultivation of Bacillus subtilis and cyanobacteria, extracted and identified exopolysaccharides efficiently, and it provided constructive guidance on how the spores participate in the material circulation and the motility of cyanobacteria for modeling.
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Due to the Covid-19 epidemic, we have minimized the chance of going out and put many interviews on the Internet using email or phone.
Screening of drought-resistant bacteria and construction of desert simulation box
What is the key to microbial sand fixation? How should the incubator simulate the real desert environment? We conducted a telephone consultation with Director Wang Lide of the Gansu Desert Control Research Institute. Director Wang, based on their research on microbial crusts, put forward his suggestions. He emphasized that rainfall has a significant impact on the survival of soil microorganisms. In desertified areas, soil microorganisms (mainly algae) will produce a kind of crust when the rainy season comes, especially in July, August and September. However, under extreme rainfall conditions, the effect of microbial crust formation will not be obvious. We may need to screen and cultivate a strain with strong drought resistance, which can quickly multiply and form a crust under a small amount of rain, which can achieve the effect of sand control. As for our hardware experimental group, he proposed the following suggestions to us: If we want to build an incubator simulating the desert environment, we need to do some controls. Do another wind erosion experiment, basically 10 meters a piece, about 50 meters, and see if the biological diffusion results can get the desired effect.
After communicating with Director Wang, we conducted related literature search, and finally we obtained the result that the two bacteria have strong drought resisitance. And the function of the desert climate simulation incubator designed by the hardware group needs to be perfect.
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Desert soil ecology and microbial ecology
Photo of associate researcher Li Chenhua
In order to understand the problems of desert soil ecology and microbial ecology, we communicated with Li Chenhua, associate researcher of Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences via email. Professor Li affirmed the work of our project and praised it as interesting and meaningful. Regarding to soil microorganisms, Professor Li is pretty sure about that without human intervention, desert soil crusts will appear with cyanobacteria dominating, and Firmicutes (including Bacillus) will be also abundant.
After talking with Professor Li, we learned from the perspective of the actual desert environment that cyanobacteria and Bacillus can form desert soil crusts together, which verified that the cyanobacteria and Bacillus subtilis symbiosis in our project can form a symbiotic system.
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Plan for the Future
Photo of researcher Qu Jianjun
In order to understand the rule of sand movement, we contacted with the researcher Qu Jianjun from the Key Laboratory of Desert and Desertification of the Chinese Academy of Sciences. Mr. Qu mainly research for the sand movement rule and sand control projects. He has deep research on wind sand systems in different regions and in new materials for sand control for the prevention and control system, exploring the “six belts in one” wind-sand hazard prevention and control system that focuses on resistance and combines solid transportation. After we talked with him about the content of our project, he praised the creativity of our project, and proposed some ideas of cultivating bacteria in the desert test base for our idea of simulating the environment such as the temperature, humidity, wind and sand in the desert. This consultation will be of great help to our follow-up process and future development.